THE ROYAL SOCIETY OF CHEMISTRY ENVIRONMENTAL CHEMISTRY ... · Halley Station in Antarctica (75.35˚S, 26.19˚W, 30 m above mean sea level): Measurement of tropospheric hydrogen peroxide

BulletinTHE ROYAL SOCIETY OF CHEMISTRY

ENVIRONMENTAL CHEMISTRY GROUP

1

July 2004

Chairman’s report .......................................... 2

Review:The global arsenic crisis ......................... 2

News of the EHSC ....................................... 7

An abandoned arsenic mine ................ 8

Book review: Arsenic Exposureand Health Effects ......................................... 9

Meeting report: Genomicsand risk assessment ...................................... 9

Tropospheric hydrogenperoxide and hydroperoxides ......... 12

Problems with plastics? ........................ 15

Environmental informationfrom the RSC .................................................. 16

Faraday Discussion 130 ....................... 17

Meeting report: DGL 2004 ............... 18

Recent acquisitions by theRSC library ....................................................... 19

This issue of the ECG Bulletin maybe seen on the Internet athttp://www.rsc.org/lap/rsccom/dab/scaf003.htm

BULLETIN EDITORDr Rupert Purchase,38 Sergison Close,Haywards Heath,West Sussex RH16 1HUTel: 01444 [email protected]

ChairmanDr Brendan Keely,Department of Chemistry,University of York,Heslington,York YO10 5DDTel: 01904 [email protected]

Vice-Chairman &Honorary TreasurerDr Andrea Jackson,School of the Environment,University of Leeds,Leeds LS2 9JTTel: 0113 233 [email protected]

Honorary SecretaryDr Leo Salter,Centre for Science,Cornwall College,Trevenson Road,Pool,Redruth,Cornwall TR15 3RDTel: 01209 [email protected]

CONTENTS

ECG Bulletin – July 2004

RSC ENVIRONMENTAL CHEMISTRY GROUP OFFICERS(from March 2004)

Halley Station in Antarctica (75.35˚S, 26.19˚W, 30 m above mean sealevel): Measurement of tropospheric hydrogen peroxide andhydroperoxides: page 12

Weddell Sea

Brunt Ice Shelf

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Coats Land

groundingarea

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100 km

Environmental Chemistry Group Bulletin July 2004

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Chairman’s reportwork on monitoring for arseniccontamination in the UK (ECGBulletin, July 2003). Now we reporta survey by the BGS of a disusedarsenic and copper mine in Devon.

• The latest in a series of proceedingsfrom the SEGH* InternationalConferences on Arsenic Exposureand Health Effects was published in2003, and Leo Salter takes theopportunity to review this book forthe Bulletin.

• The 22nd European Meeting ofSEGH was held this year at theUniversity of Sussex. Arseniccontamination and remediation werethe topics for many of the papers andposters at this meeting, and we aregrateful to Professor Mike Ramseyfrom the Centre for EnvironmentalResearch at Sussex University forpermission to reproduce some of the

The repercussions of arseniccontamination of drinking water inBangladesh have been described inseveral past issues of the ECG Bulletin.This human tragedy has drawn togetherscientists from many disciplines in aneffort to understand the geologicalcircumstances of this disaster, how thedrinking water might be purified, themechanisms of arsenic toxicity, and thelikelihood that other countries couldbecome similarly affected. In this issueof the Bulletin, these themes are furtherexplored:

• First we are grateful to the editorialstaff of the Journal ofEnvironmental Monitoring forallowing us to reproduce a reviewarticle by Mike Sharpe on the globalaspects of arsenic contamination.

• We have featured previously theBritish Geological Survey’s (BGS)

posters. (The selected postersaccompany the version of thisBulletin, which appears on the RSCWebsite).

• For next year’s Distinguished GuestLecture, we will expand further onthe relationship between health andexposure to metals and metalloidsin the environment with apresentation by Professor Jane Plantfrom the BGS.

BRENDAN KEELY,University of York,June 2004

* Society for EnvironmentalGeochemistry and Health

Deadly waters run deep: the global arsenic crisisThis article was written byMike Sharpe (MS Consulting),Contributing News Editor forthe Journal of EnvironmentalMonitoring (JEM) and wasfirst published in JEM Volume5, issue 5, 2003, pages 81-85N.

As any reader of detectivestories knows, arsenic is themurder’s poison of choice.While deliberate poisoningsmay be rare, we neverthelesshave a killer in our midst. Overrecent years, the growing globalpopulation and lack of safedrinking water have led to theexploitation of groundwaterresources in many parts of theworld. In so doing, we haveinadvertently tapped–literally–into another problem: arsenic-rich waters from deep-water

aquifers. The implications willbe with us for many years tocome.

Arsenic is a relatively common elementfound throughout the earth’s crust. It isintroduced into water through thedissolution of minerals and ores, and insome areas concentrations in ground-water are elevated as a result of erosionfrom local rocks.1 Commercial uses, suchas in alloying agents and woodpreservatives, may result in environ-mental releases and industrial effluentsalso contribute arsenic to water.Combustion of fossil fuels is a source ofarsenic in the environment throughatmospheric deposition.

The greatest threat to public health fromarsenic is through drinking water.2

Exposure at work and mining andindustrial emissions may also besignificant locally. Inorganic arsenic canoccur in the environment in several formsbut in natural waters, and thus indrinking-water, it is mostly found astrivalent arsenite (As(III)) or pentavalentarsenate (As(V)). The arsenite form is

more mobile and toxic for livingorganisms. Organic arsenic species,abundant in seafood, are very much lessharmful to health, and are readilyeliminated by the body.

Health effects and healthstandards

Chronic arsenic poisoning, as occursafter long-term exposure throughdrinking water, is very different to acutepoisoning.2 Immediate symptoms of anacute poisoning typically includevomiting, oesophageal and abdominalpain, and diarrhoea. Long-term exposurecauses cancer of the skin, lungs, bladder,and kidney, as well as other skin changessuch as pigmentation changes andthickening (hyperkeratosis). Increasedrisks of lung and bladder cancer and ofarsenic-associated skin lesions have beenobserved at drinking water arsenicconcentrations of less than 0.05 mg l-1.Absorption of arsenic through the skinis minimal and thus hand-washing,bathing, laundry, etc. with watercontaining arsenic do not pose a humanhealth risk.

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However, the symptoms and signs ofchronic exposure appear to differbetween individuals, population groupsand geographic areas. Thus, there is nouniversal definition of the disease causedby arsenic, which complicates assess-ment of the health burden. Similarly,there is no method to differentiateinternal cancers caused by arsenic fromcancers induced by other factors.Following long-term exposure, the firstchanges are usually observed in the skin:pigmentation changes, and thenhyperkeratosis. Cancer is a latephenomenon, and usually takes morethan 10 years to develop.

The relationship between arsenicexposure and other health effects is stillunclear. For example, some studies havereported cardiovascular and pulmonarydisease, diabetes, and neurological andreproductive effects.1 According to onerecent study, long-term exposure toarsenic in drinking water is directlyrelated to the development of athero-sclerosis in the arteries leading to thebrain.3

Research published in 2001 claims tohave found an underlying mechanism toat least partly explain cancer effects.4 Itdemonstrated that a human cell’s ownmetabolic responses to arsenic exposureproduce compounds capable of causinggenetic damage. A joint US–Canadianteam, led by researchers from EPA’sNational Health and EnvironmentalEffects Research Laboratory, studied theeffects of methylated trivalent arsenic onhuman lymphocytes in culture and onisolated DNA. They found thatmethylated trivalent arsenic derivatives,which can be produced by the body inan attempt to detoxify arsenic, result inreactive compounds that cause DNA tobreak. The findings could be used toquantify genetic damage in humanpopulations exposed to arsenic.

More recent research has claimed afurther, indirect health mechanism.5

Earlier this year, scientists at DartmouthMedical School, US, reported thatexposure to small amounts of arsenic indrinking water may inhibit expression ofgenes involved in a critical housekeepingfunction that enables cells to repairdamaged DNA. The process, known asDNA repair, is considered a majorbiological defence in the body’s ability

to fight cancer. According to lead authorDr. Angeline Andrew: “This studysupports the hypothesis that arsenic mayact as a co-carcinogen–not directlycausing cancer, but allowing othersubstances, such as cigarette smoke orultraviolet light, to cause mutations inDNA more effectively.” A similar DNAinhibiting mechanism has also beenreported for another toxic metal,cadmium.6

The World Health Organisation (WHO)has set norms for arsenic in drinkingwater since 1958.2 Since 1963, WHO’s“Guideline Value” has been 0.05milligrams per litre (mg l-1) (or 50 ppb,parts per billion), and many countrieshave adopted this as the national standardor as an interim target. WHO’s latest(1993) guidance set a “provisionalguideline value” for arsenic in drinkingwater of 0.01 mg l-1. Based on healthcriteria, the guideline value would be lessthan 0.01 mg l-1, but this level representsthe realistic limit of measurement.

The US experience

As a continental landmass where manycommunities rely on groundwater, theUnited States is affected by high levelsof arsenic in some drinking watersupplies.7 Because small water systemstypically rely on wells for drinking water,while the larger systems typically rely onsurface-water sources, arsenic tends tooccur in higher levels more often in waterused by small communities. The averagelevel measured in US groundwatersamples is around 1 ppb, but higher levelsare not uncommon. Compared to the restof the US, Western states have morewater systems with levels exceeding 10ppb, and levels exceed 50 ppb in somelocations. Levels exceeding 10 ppb arealso found in parts of the Midwest andNew England. According to EPA, 5.5%of water systems, serving 11 millionpeople, exceed the 10 ppb level.

In 1986, arsenic was included on a listof 83 contaminants for which EPA wasrequired to issue new standards under theSafe Drinking Water Act (SDWA).8 Theexisting standard of 50 ppb had been setin 1975, but dates back much earlier.Having missed a previous deadline, in1996 Congress directed EPA to proposea new standard for arsenic in drinkingwater by January 2000, and to issue a

final standard by January 2001. Congressalso directed EPA, with the NationalAcademy of Sciences (NAS), to studyarsenic’s health effects to reduce theuncertainty in assessing health risksassociated with low level arsenicexposure. In 1999, the National ResearchCouncil (NRC)–the research arm of theNAS–concluded that the existingstandard was inadequate for EPA’spublic health goals and recommended aprompt reduction.7 In June 2000, EPAproposed a revised standard of 5 ppb andprojected that compliance could be costlyfor small communities.

Following the 2000 Presidential election,the Bush Administration reopened thetopic to consider levels of 3 ppb, 5 ppb,10 ppb, and 20 ppb and re-examine therisk and cost issues.9 The final rule,setting the standard at 10 ppb, came intoeffect on February 22, 2002 and requirespublic water systems to meet the newstandard by January 2006.

In developing standards, EPA is requiredto set a Maximum Contaminant Level(MCL), defined as the maximumallowable concentration using the best-available technology, treatment or othermeans, and taking costs into consider-ation.8, 10 EPA’s cost determinations aretypically based on costs to systemsservicing more than 50 000 people. Lessthan 2% of community water systems arethis large, but they serve roughly 56%of the population served by communitysystems. The smallest systems, thoseserving fewer than 3300 people, will beexempt from the new standard for up to9 years and EPA has announced financialassistance to help them comply with thisand other SDWA rules.

EPA’s revision of the arsenic rule hasbeen hugely controversial. Critics saythere is little evidence as to whethersignificant adverse health effects occurfrom ingesting arsenic at very low levels,and consequently the costs of the newrule for the American public utilities isnot justified.10 Indeed, the NRC reportstated: “No human studies of sufficientstatistical power or scope have examinedwhether consumption of arsenic indrinking water at the current MCL [50ppb] results in an increased incidence ofcancer or noncancer effects.” Subsequentstudies, reviewed at the time of the 2001reappraisal, failed to fill this gap.

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The most contentious point in thescientific debate has been the assumptionthat the toxicity of arsenic increaseslinearly (i.e. uniformly) in proportion toincreases in its concentration.10,11

Virtually all known toxicologicalprocesses follow a sublinear model–i.e.increases in cancer risk are negligible atlow doses. Critics say the NRC acceptedthat only sublinear models were plausiblebut was forced to opt for the linear modelinstead because it could not agree onwhich sublinear model was correct. This,they claim, led to a conclusion in favourof a lower arsenic standard that was notsupported by the science.

Bangladesh: a country incrisis

One area where the health effects ofarsenic exposure are beyond doubt isBangladesh12, 13 (see Analyst, 1994, 119,168N for one of the earliest reports onthis).14 In the mid-1990s it emerged thatarsenic had contaminated well water inparts of the Bengal Delta. This is thecoastal floodplain of numerous rivers,including the Ganges and is shared byBangladesh and the Indian state of WestBengal. The latest surveys estimate thataround 36 million people in the BengalDelta are drinking contaminated water,and 150 million are at risk.15

Ironically, the crisis has its origins indevelopment efforts to give the peopleof the region access to safe drinkingwater. Until the 1970s, most villages inBangladesh and West Bengal had eitherdug shallow wells, or collected waterfrom ponds or rivers–and regularlysuffered cholera, dysentery and otherwaterborne diseases. Instead, develop-ment agencies advised local people tobore deep “tube wells” into the wateraquifers to reach clean, pathogen-freewater. Up to 20 million of these tubewells were dug. Unfortunately thedrilling hit precisely the depth of arsenic-rich rock.

Hydrogeologists have determined thatthe source of the problem is rocksnaturally rich in arsenic which wereeroded from the Himalayas thousands ofyears ago and deposited by the region’srivers. The arsenic-bearing sedimentsbecame buried and lie about 50 to 75 mbeneath the surface. Until relatively

recently, however, arsenic was notrecognised as a problem in water suppliesand the standard water testing proceduresdid not include tests for it. The role ofalluvial aquifers as a potential source ofarsenic in groundwater is now muchbetter understood [Box 1].16, 17

WHO experts predict the situation willget much worse and should be consideredas a public health emergency. “It isreasonable to expect marked increases inmortality from internal cancers oncesufficient latency has been reached,”says Professor Allan H. Smith of theUniversity of California, a WHOadviser.18 Studies in other countrieswhere the population has had long-termexposure to arsenic in groundwaterindicate that one in ten people who drinkarsenic-contaminated water mayultimately die from cancer. Dramaticincreases in such deaths and cases have

been reported in Taiwan, Chile andArgentina.

In Britain the issue has ended up in court,with 750 Bangladeshis suing the BritishGeological Survey (BGS), whichassessed more than 50 wells in 1992.15

BGS was paid by the UK OverseasDevelopment Agency from developmentaid funds to conduct a hydrochemicalbaseline survey of the tube-well waterquality in Bangladesh and assess itstoxicity to humans. The claimants sayBGS should have tested for arsenic, butBGS argues there was no indication inthe scientific literature at the time thatarsenic might be associated with riverand delta plains.

In a statement outlining its case, BGSsaid: “Arsenic only occurs in a water-soluble form in certain hydrogeologicalconditions. It is one of a large number of

BOX 1: Mobilisation of arsenic in alluvial aquifers

In areas such as the Bengal Delta Plains, the source of arsenic in alluvialsediments is dependent on the geology of the source terrain, while themobility of arsenic in groundwater is influenced by the sediments’geochemical and hydrogeological characteristics. Specifically, the retentionand/or mobility of As within the subsurface environment under differentredox conditions is controlled predominantly by the interaction of theaqueous phase with the different mineral phases of the aquifer sediments.

Redox conditions within sedimentary aquifers are known to be controlledby chemical processes such as adsorption–desorption, precipitation–dissolution of unstable As minerals, organic content, and biological activity.However, mechanisms governing the mobilisation of arsenic from thesedimentary aquifers are less well understood.

Recent investigations reveal that secondary Fe and Al phases play a keyrole. These Fe- and/or Al-phases are characterized by variable surfacecharge, negative at higher pH and positive at lower pH. At lower pH, thesesurface reactive phases attain net positive charge leading to significantadsorption of As(V) (arsenate) species. The occurrence of As ingroundwater is a process driven by the changing redox conditions wherethe arsenic phases are selectively desorbed as a response to the reductionof Fe3+ phases to soluble Fe2+ species. High-As occurrences concomitantwith the increased Fe contents in groundwater supports this hypothesis.Part of the As in the groundwater appears to be quantitatively related tothe release of As phases, mainly as As(V) form adsorbed on the surfacereactive Fe-oxides and hydroxides.

The researchers conclude that although the geological sources of As couldbe proved unequivocally in this case, more detailed research is needed tocharacterize the chemistry of the aquifer materials in order to understandthe water–solid-phase reactions. Another important aspect of researchwas to highlight the need to develop low-cost geochemical techniques forthe removal of As suitable for application in developing countries.Adapted from: ref. 16.

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trace elements which are therefore notroutinely tested for in groundwatersunless there is independent evidence tosuggest its presence. In 1992 suchevidence did not exist in relation toBangladesh, since alluvial plains of thesort which underlie much of Bangladeshwere not generally recognised as posingan arsenic risk. We now know that anumber of such areas of the world dohave enhanced levels of arsenic ingroundwaters.”

The British High Court did not agreeand in May 2003 dismissed BGS’sapplication to strike out the claim. Aidagencies have a “duty of care” to thosethey aim to help, the judge said. The caseis due to return to court early next year,when the BGS will have to answer whyit failed to carry out the arsenic tests.

Meanwhile, new research across India’sGanges Basin suggests that the crisis inthe sub-continent could extend muchfarther than previously thought.According to epidemiologist Dr.Dipankar Chakraborti of JadavpurUniversity, the Bengal Delta “may beonly the tip of the iceberg”.19 Untoldnumbers of the region’s 450 millionresidents could be exposed to dangerouslevels of the element in their drinkingwater. He is calling for urgent regionwidewater-well analysis. “The arsenicproblem intensified during a period oflong neglect. Our earlier mistakes mustnot be repeated,” he says.

Tipped-off to a spate of cancer deathsand skin lesions in the village of SemriaOjha Patti in the Indian state of Bihar,Chakraborti’s team sampled wells in thevillage. Half contained five times theaccepted safe limit of arsenic; one in fivewells had 30 times the safe level. Biharis 500 kilometres west of the BengalDelta and is geologically akin to muchof the Ganges Basin. The research inBihar has sparked fears that similararsenic contamination in Vietnam,Thailand and Taiwan could also be morewidespread.

Research for a global problem

The issue of arsenic in drinking water isnow recognised as a global problem.Relevant research is being undertaken onmany fronts.

Treatment technologies

A number of established technologies areeffective in reducing arsenic in drinkingwater. These include:activated aluminafilters, anion exchange, distillation,reverse osmosis, and nanofiltration.1, 2

Also, as a safeguard against organicarsenic, granular activated carbonfiltration may be used.

While many large water systems areequipped with these treatmenttechnologies, they may be less amenablefor use by small community watersystems or individual households. Aspart of its Arsenic Rule ImplementationPlan, EPA has committed to sponsorfurther research and development ofmore cost-effective technologies as wellas technical assistance and training tooperators of small systems to reduce theircompliance costs.20 Around US$20million has been pledged for the period2002/2003.

As well as research, a strong emphasisis being placed on demonstrations oflow-cost treatment technology. Twelvesites have already been selected forpractical demonstrations of technologiesand treatment techniques, and aninvitation for a further round waslaunched earlier this year.

Appropriate technologies

Even technologies designed for small-scale community treatment systems maynot be suitable for developing countries,as they are moderately costly and requiretechnical expertise. Hence, internationaldonors and aid agencies are fundingresearch into appropriate treatmenttechnologies and techniques that couldbe deployed quickly and effectively insouthern Asia and other affected regions.

WHO, for instance, has sponsored atechnique called STAR (StevensTechnology for Arsenic Removal) as aneffective and inexpensive method forfiltering out arsenic from householddrinking water supplies.18 The systemuses a mixture of iron sulfate, calciumhypochlorite and sand as a filtering agent.Another filtration agent is laterite, a localraw material found throughout the Indiansub-continent.16

Genetic engineering

Another field of interest is the use ofgenetic engineering to create plants thatcould clean arsenic from contaminatedsoil and groundwater. Phytoremediation–the use of plants to absorb chemicalpollution from soils–is a well establishedtechnique, but few naturally occurringplants thrive on toxic sites.

By inserting two bacterial genes intothale cress, Arabidopsis thaliana, USresearchers have created a plant that notonly grows well in the presence ofarsenic but is able to store the toxin in itsleaves.21 The genes, from the bacteriumEscherichia coli, make enzymes thatdigest arsenic compounds so they can beabsorbed. The arsenic-rich leaves canthen be harvested relatively easily andsafely incinerated, making it ideal forphytoremediation. Eventually plantscould be developed that might clean acontaminated site in just two or threeyears. The technique may also beapplicable to a wide variety of plantspecies able to grow in differentenvironments.

Australian scientists are investigating adifferent genetic approach–harnessingbacteria to help purify arsenic–contaminated water. A team at La TrobeUniversity, led by microbiologist Dr.Joanne Santini, is studying 13 rarebacteria isolated from gold mines in theNorthern Territory and Bendigo,Victoria.22 They have found onebacterium, NT-26, that is an arsenite-munching champion. It eats arsenite–themost problematic form of environmentalarsenic–and excretes arsenate, which iseasier to get rid of. Dr Santini’s grouphas found the enzyme directlyresponsible for converting arsenite toarsenate and is working to identify thesame enzyme in other microbes. Theteam is also hunting for other proteinsand genes involved in eating arsenite.They hope to use their findings to set upa bioremediation system for cleaning upmining wastewater and also provide saferdrinking water for areas such asBangladesh and West Bengal.

Health studies

Finally, researchers continue to probe thehealth effects of prolonged low-levelarsenic exposure. As noted above, recent

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work has made important breakthroughshere, suggesting mechanisms both fordirect DNA interactions and co-carcinogenic effects. Other research intobiomarkers of exposure seems to confirmthat, for the same level of exposure, somepeople run a higher risk of developingcancer than others [Box 2].

Such findings should help us to developa better informed public health responseto the arsenic issue in both developed anddeveloping countries.

References

1. United Nations Synthesis Report onArsenic in Drinking Water, WorldHealth Organisation, 2001.www.who.int/water_sanitation_h e a l t h / d w q / a r s e n i c 3 / e n /

2. Arsenic in Drinking Water, WHOFactsheet No. 210, World HealthOrganisation, 2001. www.who.int/inf-fs/en/fact210.html

3. Arsenic in drinking water mayaccelerate artery disease, Sci. Am.,26 March 2002, citing paperpublished in Circulation: J. Am.Heart Assoc. www.sciam.com

4. Arsenic compounds may causegenetic damage by a directmechanism, press release, EPANational Health and EnvironmentalEffects Research, citing paper in the16 April 2001 edition of Chem. Res.Toxicol. www.epa.gov/nheerl/ordpr/2001/pr_041901.pdf

5. Arsenic in drinking water may belinked to cancer Dartmouth studyfinds, press release, DartmouthMedical School, Dartmouth, NH.www.dartmouth.edu/dms/news/

6. Cadmium studies suggest newpathway to cancer, J. Environ.Monit., 2003, 5, 67N.

7. Arsenic in Drinking Water, NationalResearch Council, 1999 and 2001Update. ISBN 0-309-06333-7.www.nap.edu/catalog/6444.html

8. Mary Tiemann, Arsenic in DrinkingWater: Recent RegulatoryDevelopments and Issues, RS20672,Congressional Research Service,2001, National Library for theEnvironment: www.ncseonline.org

9. For news reports on revisions of thearsenic standard see: J. Environ.Monit., 2001, 3, 20N, 38N & 85N.

10. Arsenic, Drinking Water, andHealth, A Position Paper of theAmerican Council on Science andHealth, ACSH, 2002. www.acsh.org

11. S. Milloy, National ResearchCouncil poisons arsenic debate, FoxNews, 27 April 2001.ww.foxnews.com

12. Researchers warn of impendingdisaster from mass arsenicpoisoning, press release WHO/55,World Health Organisation,September 2000. www.who.int/inf-pr-2000/en/pr2000-55.html

13. For further information on theBangladesh crisis see: Arsenic CrisisInformation Centre, http://bicn.com/

BOX 2: Biomarkers of arsenic exposure

While the health effects of exposure to high levels of arsenic are significantand well documented, the impact of low to moderate level exposuresremains unclear. Researchers at the Harvard School of Public Health, ledby Dr. David Christiani, have studied biomarkers of exposure to arsenicand heritable susceptibility in two of the worst affected areas–Taiwanand Bangladesh. These studies are designed to fill important researchgaps in our understanding of arsenic and human health.

The researchers are utilising a population-based approach, incorporatingmarkers of exposure (drinking water arsenic, toenail arsenic, and measuresof inorganic arsenic in urine), susceptibility (genetic polymorphisms inmetabolizing genes), and outcome (squamous cell carcinoma of the skin,bladder cancer, and non-malignant skin lesions). In addition to studyingthe impact on health status including cumulative arsenic exposure, age,gender, and diet, they will examine the effect of gene polymorphisms inthe Glutathione S-transferase (GST) superfamily of enzymes, which playsan active role in arsenic metabolism processes.

Similar research to date on bladder and skin cancer in Taiwan has revealedthat:

• A person’s ability to metabolize inorganic arsenic into less toxicmetabolites (monomethylarsonic acid [MMA] and dimethylarsinic acid[DMA]) is directly related to the risk of both bladder and skin cancer.Methylation of DMA to MMA plays an important role in lowering, butnot eliminating, the risk of skin and bladder cancer. Methylation ofinorganic arsenic to DMA exhibits a weak effect in the oppositedirection.

• In cases with similar methylation abilities and cumulative arsenicexposures, men had a higher risk of skin cancer, suggesting thatadditional behavioural or genetic factors may play a role.

• There is a significant relationship between smoking status, cumulativearsenic exposure, and increased risk of bladder cancer.

• The risk of developing skin cancer after long-term exposure to arsenicin drinking water was enhanced by certain genetic characteristics,most significantly by variation at codon 72 of the tumor suppressorgene p53.

These findings have important public health significance, suggesting thatat the same level of exposure, some persons are at higher risk of cancerdevelopment than are others. Efforts to protect the more susceptibleamong us will ensure protection for all.Adapted from: ref 23.

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acic/; SOS Arsenic.Net,www.sosarsenic.net; and TheLondon Arsenic Group,www.es.ucl.ac.uk/research/lag/as/

14. D. Das, A. Chatterjee, G. Samanta,B. Mandal, T. R. Chowdhury, G.Samanta, P. P. Chowdhury, C.Chanda, G. Basu, D. Lodh, S. Nandi,T. Chakraborty, S. Mandal, S. M.Bhattacharya and D. Chakraborti,Analyst, 1994, 119, 168N–170N.

15. John Vidal, Deadly waters, report inThe Guardian, 8 May 2003.www.guardian.co.uk

16. P. Bhattacharya et al., Genesis ofarseniferous groundwater in thealluvial aquifers of Bengal DeltaPlains and strategies for low-costremediation, presented at the DhakaArsenic Conference February 1998,Arsenic Crisis Information Centre:www.bicn.com/acic/resources/i n f o b a n k / d c h 9 8 - 0 2 c o n f /confpap.htm

17. For further papers on science ofarsenic in groundwater see: sessionpapers from Natural Arsenic inGroundwater: Science, Regulationsand Health Implications, GeologicalSociety of America AnnualMeeting, November 5-8, 2001, http://gsa.confex.com/gsa/2001AM/finalprogram/session_781.htm; andworkshop papers Natural Arsenic inSedimentary Aquifers–A Global

Concern, Mar del Plata, Argentina,October 2002, http://amov.ce.kth.se/P E O P L E / P r o s u n /workshop_Argentina.htm

18. Arsenic–mass poisoning on anunprecedented scale, WHO Feature206, World Health Organisation,2002.w w w . w h o . i n t / i n f - f s / e n /feature206.html

19. D. Chakraborti et al., Arsenicgroundwater contamination inmiddle Ganges Plain, Bihar, India:A future danger? Environ. HealthPerspect., 2003.http://ehpnet1.niehs.nih.gov/docs/2003/5966/abstract.html. And newsreport: T. Clarke, Asia’s arseniccrisis deepens, 15 February 2003.www.nature.com

20. See EPA’s Arsenic RuleImplementation Research Program,www.epa.gov/ORD/NRMRL/arsenic/index.html

21. O. P. Dhankher, et al., Engineeringtolerance and hyperaccumulation ofarsenic in plants by combiningarsenate reductase and c-glutamylcysteine synthetaseexpression, Nature Biotechnol.,2002, 20, 1140–1145; And newsreport: K. Powell, Genes improvegreen cleaning, 7 October 2002,www.nature.com

22. Aussie arsenic-eating bacteria maysave lives and clean mines, pressrelease, La Trobe University,Melbourne.

www.sciencenow.org.au/fresh/santini.htm

23. Arsenic Exposure and HumanHealth, Research Brief 104,Superfund Basics ResearchProgram, National Institutes ofEnvironmental Health Sciences,wwwapps.niehs.nih.gov/sbrp/rb/rbs.cfm?Year~2003. HarvardSchool of Public Health’s work isreported in: Y. C. Chen, H. G. Su,Y. L. Guo, Y. M. Hsueh, T. Smith,L. R. Ryan, M. S. Lee and D. C.Christiani, Arsenic methylation andbladder cancer risk in Taiwan,Cancer, Causes Control, 2003, 14,303–310; Y. C. Chen, L. L. Xu, Y.L. Guo, H. J. Su, Y. M. Hsueh, T.Smith, L. R. Ryan, M. S. Lee andD. C. Christiani, Genetic poly-morphisms in p53 codon 72 and skincancer in south-western Taiwan, J.Environ. Sci.Health, 2003, A38(1),201–211; Y. C. Chen, Y. L. Guo,H. J. Su, Y. M. Hsueh, T. Smith, L.R. Ryan, M. S. Lee and D. C.Christiani, Arsenic methylation andskin cancer risks in south-westernTaiwan, J. Occup. Environ. Med.,2003, 45(3), 241–248.

MIKE SHARPE

News of the EHSCThe Environment Health and SafetyCommittee has recently responded to aDepartment for Environment, Food andRural Affairs consultation reviewing thefuture of the UK Chemicals StakeholderForum on which the Royal Society ofChemistry has a representative. TheCommittee will shortly be submitting itresponse to the DEFRA consultation onthe latest EU Chemicals Strategy knownas REACH. This consultation is aimedat informing the Government’s positionon the proposed REACH regulation.

The Working Party on Notes, in keepingwith its strategy to engage with the widerpublic has produced a ‘message’ note

Steven Lipworth,Royal Society of Chemistry,Burlington House,Piccadilly, London W1J 0BA, UK,Tel +44 (0) 20 7440 3337,Fax +44 (0) 20 7437 8883,Email [email protected]

entitled ‘Why do we worry aboutchemicals?’ This note is aimed atpromoting an understanding about risksassociated with chemicals and that theserisks can be controlled. WPN will shortlybe publishing the note ‘What is apoison?’ as well as two revised notes, oneon the ‘Harmful effects of chemicals onchildren’, the other a guidance note onthe ‘Safety of laboratory workers withdisabilities’. The above submissions andnotes will all be available on the RSCwebsite.

For further information on EHSCactivities and publications, pleasecontact:

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Arsenic bioaccessibility and speciation in soils at an abandonedarsenic mine in SW England

and for the Bere Alston background soils(PBET As median: 7 mg kg-1). Theresults suggest that bioaccessible As is abetter measurement than the total Ascontent when considering risk assess-ment, and bioaccessibility data have clearimplications for site-specific riskassessments.

Chemical sequential extraction data havebeen used to help elucidate the nature ofthe physico-chemical forms of As in thesoils and mine waste material. Chemo-metric data processing allows character-isation of the matrix by resolving thenumber and composition of the physico-chemical components present. The mostsignificant component contains mainlyiron, As, and traces of sulphur, and isextracted in the last part of the test.

Further evidence of the Fe-As associationcomes from scanning electronmicroscopy, which shows As-rich, ironoxyhydroxides coating the surface ofaltered waste fragments and clastic grains(Figure 1). The coatings show variousmicrofabrics from colloform ironoxyhydroxide to more crystallinecoatings (fine-needle-like crystals).

X-ray absorption near edge structure(XANES) analysis indicates that As(V)is the dominant oxidation state in the

mine waste materials and soils.Quantitative fits of EXAFS spectra usingtheoretical standards indicate As(V) intetrahedral coordination with O andsecond and third -neighbour Fe atoms,ruling out the presence of majorarsenopyrite. Second and third neighbourAs-Fe EXAFS distances imply eitheradsorption of the As onto an iron oxide/hydroxide substrate or incorporation ofthe As into a mixed metal oxide phase.The two different As-Fe distances mayreflect the presence of doubly oxo-bridged and singly oxo-bridged species.

Acknowledgments This article ispublished with the permission of theExecutive Director, British GeologicalSurvey. Dr Helen Taylor of the BGShelped in the acquisition of the XAFS/XANES data. Dr John Charnock,Daresbury, provided assistance with datainterpretation. Tony Milodowski, BGS,carried out the SEM work.

BEN KLINCK, BARBARAPALUMBO, MARK CAVE andJOANNA WRAGG,British Geological Survey,Keyworth,NottinghamshireMay, 2004

Possible sources of arseniccontamination have become aconcern internationally. BenKlinck and colleagues from theBritish Geological Surveydescribe in detail one source ofarsenic exposure in the UK – adisused arsenic and coppermine in South West England.

In the mid 1800’s the use of arsenic (As)as a pesticide became common and by 1869the Devon Great Consols Mine nearTavistock in Devon was supplying half theworld’s arsenic from calcined arsenopyrite.Production ceased around about 1925.

Arsenic in soils is spatially widelydistributed at Devon Great Consols. TheAs median concentration in mine soilsis 2100 mg kg-1, but ranges from 250mgkg-1 to 69000 mg kg-1. Background soilsamples taken from agricultural fieldsnear to the village of Bere Alston and notaffected by mineralisation or miningdisturbance, have a median As value of71 mg kg-1and a range from 17 mg kg-1

to 172 mg kg-1. A further set of soilsamples collected from a farm to thesouth west of Devon Great Consol, withunderlying, unworked mineralisation,show higher As concentrations than thebackground soils (As medianconcentration: 163 mg kg-1).

The As bioaccessibility has beeninvestigated using an in vitro test – aphysiologically based extraction test(PBET) developed to simulate theleaching of a solid matrix in the humanstomach and gastrointestinal tract. Theterm bioaccessibility is here used todescribe the fraction of the total Asconcentration that is soluble in thestomach and gut and as a result isavailable for systemic uptake. Theamount of As that is actually adsorbedsystemically, the bioavailable fraction, isless than or equal to the amount that isbioaccessible. The median value ofbioaccessible As for the soils on the minesite is 408 mg kg-1. Much lowerconcentrations are measured for theagricultural soils over mineralisation(PBET As median value of 14 mg kg-1)

Figure 1 BSEM image showing detail of arsenic-rich iron oxyhydroxide cementcoating the surfaces of altered waste fragments. It shows banded colloformoxyhydroxide gel material displaying shrinkage (desiccation) cracks. This is encrustedby more crystalline acicular oxyhydroxide.


Book reviewExposure, Epidemiology, Biomarkersand Animal Models, Mode of Action,Intervention and Medical Treatment, andWater Treatment and Remediation. So,in a way, something for everyone. Myown interest was drawn by the severalpapers which examined the Mode ofAction where a battery of biomoleculartechniques had been focused onelucidating the mechanisms of arsenictoxicity – particularly in relation tocarcinogenicity. The nature andconsequences of oxidative stress inducedby arsenic, the effects of antioxidants andsignalling cascades induced by arsenicwere clearly and authoritativelydiscussed. In particular, the paper byKitchin and co-workers (“SomeChemical Properties UnderlyingArsenic’s Biological Activity”) wasilluminating.

The thread that links Occurrence (Eightpapers variously from India, Nepal,Slovakia, Canada, California, Viet Nam)through modes of action and medicaleffects becomes uncertain when chroniclow dose effects need to be demonstrated

Arsenic Exposure and HealthEffects

W. R. Chappell, C. O. Abernathy, R. L.Calderon, D. J. Thomas (Eds.)Elsevier 2003, pp 533, ISBN: 0-444-51441-4, £100.00

This book records the proceedings of theFifth International Conference onArsenic Exposure and Health Effects tobe organised by SEGH (the Society ofEnvironmental Geochemistry andHealth), and which took place in July2002 at San Diego, California. Thegenesis and history of these conferencesfrom 1992 to the present day (the SixthConference is in July 2004) is admirablyset out in the book’s Preface whichdelineates the increasing US and globalinterest in arsenic exposure with a rangeof countries being represented(Bangladesh, India, Nepal, Thailand,China, Slovakia and others).

This volume includes contributions frommany of these regions and is divided intosub-sectors covering Occurrence and

epidemiologically – and without such ademonstration legislation, interventionand remediation will be deprioritised.Although exposure in some areas of theworld is apparent at a population level(for instance in Kshitish Saha’s paper“Grading of Arsenicosis: Progressionand Treatment” – photos not for thesqueamish!), methods for identifying lowlevels of exposure and for monitoring theconsequences of such exposure aredifficult, expensive and fraught withcomplexity. The papers relating to theseissues offer much of interest.

So, I am enthusiastic about this text if alittle overwhelmed by the detail. Thebook is a massive source of literaturereferences and the papers themselves areoften introduced by reviews andsummaries which would feed easily intoa lecturing programme. I don’t think it’sthe sort of book I will be lending.

Dr LEO SALTER,Cornwall College,Pool, Redruth, Cornwall

Meeting report: How useful will genomics, proteomics andmetabonomics be to assess chemical risk in humans?The RSC’s Occupational andEnvironmental ToxicologyGroup (OETG) held a one daymeeting in September 2003 atthe Society of ChemicalIndustry, London to discuss theuse of ‘omic’ technology in therisk assessment of chemicals.One objective was to comparethe present states of technologywith the promised potential.The targeted audienceconsisted of those peopleinvolved in risk assessment butnot currently versed in thetechnological advances. Thiswas reflected successfully inthe background of registrants

who mainly came fromindustry, occupational healthorientated academia andgovernment organizations.Speakers from academia andindustry provided an excellentframework and stimulations fordiscussion. Not only were thetechnologies discussed but theproblems in their potential usefor human risk assessmentprocesses. Andy Smith,Chairman of the OETG reports.

Can genomics contribute to theassessment of chemical risk in humans?(Dr T. Gant, MRC Toxicology Unit).

The current state of toxicogenomics wasintroduced by Dr T. Gant who described,

firstly, the technological bases of genearrays to detect changes in geneexpression following experimentaladministration of drugs and chemicals.The importance of replicates, good studydesign and appropriate statisticalanalyses were emphasized. The ILSI/HESI (International Life Sciences/Healthand Environmental Sciences Institute)collaboration was described which hasaimed to examine the reproducibility ofgenomics on test toxicological samplesbetween different laboratories and forvarious phenotypic endpoints. It hasbeen clear that for some samples verydifferent results have been achieved withdifferent genomic systems. The moredata the better was emphasized and theEuropean Bioinformatics Institute incollaboration with ILSI was aiming toproduce a toxicogenomics database.This would of course require a great dealof standardization of informationacquisition across the toxicogenomic

9


field. Dr Gant described how patternsof gene expression with certain drugs andchemicals in experimental animals mightbe used to extrapolate to humans.Alternatively, the global gene expressionchanges could lead to greaterunderstanding of the mechanisms oftoxicity of particular drugs andchemicals. This could speed up drugdevelopment and could be taken incomparison with other data but notnecessarily substitute for it. Wholenetworks of gene expression may berevealed not seen so far using othermethods. In addition, the mechanisticbases of genetic variation in response todrugs and chemicals could now beexplored in much more detail.

One of the challenges would be how todistinguish primary responses fromsecondary responses due to subsequenttissue damage. Temporal studies andmodel non toxic chemicals would beimportant approaches for comparisonwith human exposure responses at lowdoses. Failure to see lack of a changingprofile would not in itself be conclusiveproof that toxicity did not occur.

As far as studies on humans areconcerned, obtaining appropriate tissuecould be difficult. Rationales forextrapolating from available tissues suchas blood to non-available tissues may bea way forward.

The role of proteomics in preclinicalsolutions(Dr P. Camilleri, BiochemicalSolutions)

Of course toxicogenomic data revealpatterns of gene expression changes orstability at the RNA level. What is moreimportant, but technically at the momentmore difficult, is to resolve completepatterns of protein changes in cells orwhole tissues following exposure todrugs and chemicals. Dr Camilleridescribed the electrophoretic and massspectrometric techniques constitutingproteomics. As far as toxicity studies areconcerned samples from liver, kidney,plasma and urine have usually beenused to appreciate the responsesof experimental models to drugs.Proteomics has now become anautomated procedure in cutting anddigesting protein spots from electro-phoretic gels and their analysis and

identification by mass spectrometry. Byjudicious choice of proteins, such asthose involved in cell proliferation, it hasbeen possible to distinguish betweenmedian and high doses the effects ofwhich could be extrapolated to humandoses. As with toxicogenomics, bio-informatics increasingly has an importantrole to play. So far the resolution andsensitivity is probably not as great as withtoxicogenomics. However, importantdata can be obtained from readilyavailable human samples such as urineand plasma that are not appropriate forgenomic investigations.

Incorporation of toxicogenomics intopredictive and mechanistic toxicology(Dr T. Zacharewski, Michigan StateUniversity)

Dr T. Zacharewski was invited to themeeting especially for his experiencein the USA. He was supported bya generous contribution from theRSC Angela and Tony Fish Bequest.Dr Zacharewski outlined howcomputational models were beingdeveloped to integrate DNA, RNA andprotein interaction data which can beused to further elucidate mechanisms oftoxicity as well as support riskassessments. Recently, blocks of SNP(single nucleotide polymorphisms)have been found to be inherited and theseblocks might be used to generatedata to rationalize drug dosing.Dr Zacharewski’s present field ofresearch is particularly concerned withthe assessment of chemical endocrinedisruptors that might be pharmaceuticals,industrial chemicals, phytoestrogens orenvironmental pollutants. Tiers oftesting were described that increasinglyuse genomic molecular knowledge in theassessment process. For instance,searches for the distribution of dioxinresponses elements in genes across threespecies were compared. As with aprevious speaker, the importance oftemporal studies were emphasised.

It was of interest to learn that both theUS FDA (Food and DrugAdministration) and EPA (Environ-mental Protection Agency) wereencouraging the submission oftoxicogenomic data. The FDA weredeveloping guidelines on the use andsubmission of such data but it is notknown exactly if those data will be used

in decision making. However, datasubmitted by a sponsor might be used tomake a case for a drug.

Metabonomics: The biochemical oracle(Dr J. Shockcor, Metabometrix)

Although genomic and proteomictechnologies are currently of high profile,in recent years there has been a steadydevelopment of nuclear magneticresonance (NMR) to analyse plasma andurine, for instance, to identify changesin levels of natural metabolites in humansand experimental animals. Many of thebioinformatic and statistical techniquesemployed have much in common withthose used in proteomics andtoxicogenomics.

Dr Shockcor demonstrated how sensitiveNMR techniques can be applied toanalyse urine samples to detect metabolicresponses to pathophysiological stimulior genetic modification. Changes inlevels of individual metabolites frommany metabolic systems can berecognised in pattern recognition. Thiscan be used not only for classificationbut also to identify new metabolites andprobe for pathological mechanisms.Principle component analyses has proveda powerful statistical tool and can feedback information to other techniquessuch as genomics and proteomics. Mostwork has been done with clinical samplesfrom drugs. Although sensitivity perhapsrequires more development forapplication to some chemical riskassessment circumstances, it has thegreat advantage over the other techniquesin only requiring urine samples and thusin human studies need not be invasive.

Identification of metabolic biomarkersusing open and closed systems and theproblems of cross species validation(Dr C. Waterfield, GlaxoSmithKline)

In a continuation of the metabonomicstheme Dr Waterfield illustrated its usein the safety assessment of peroxisomeproliferator drugs following admin-istration to test systems. In particular,metabolism of phospholipids andperoxidation were studied to understandmechanisms of action, identify potentialbiomarkers and investigate potentialconfounding factors. Findings could befed back to proteomic studies for furtherinvestigation. It was important for safety

10


assessment to make cross speciescomparison if new biomarkers identifiedwere to be of a use in human riskassessment.

Rational risk assessment in a changingworld(Professor A. Boobis, Imperial College)

So far much of the discussion had beenof the potential of ‘omic’ technology butan important objective of the meetingwas to discuss the current limitations foruse in human risk assessment exercises.From his extensive experience ProfessorBoobis outlined his own view of presenthuman risk assessment processes forchemicals and considerations for the useof the ‘new’ technologies in the light ofevolving ideas and expectations. Forinstance, modest enlarged liver in rodentsis no longer necessarily considered atoxic response but perhaps just adaptive.There are increasingly higherexpectations of minimum risk but costsincrease and there is great pressure forlowering animal usage. The genomicsrevolution and other advances in

biomedical research may contribute toeasier and more certain assessments. Toidentify new highly relevant biomarkersfrom ‘omic’ data much more mechanisticinformation will be required. However,resources can be limiting and often studydesigns and validation are unsatisfactory.In addition, biology is complex and therecan be multiple interacting and parallelpathways leading to toxicity. Not allmolecular changes are necessarilyadverse or relevant and chemicals canhave multiple unrelated affects. Speciesdifferences can be significant.

Professor Boobis pointed out that theremust be quantitative relationshipsbetween any new potential biomarkersand adverse effects. Are therethresholds? We also have limitedknowledge on what is normal variationwithin and amongst individuals. Whatgoverns homeostasis in an individual tomaintain a constant environment, e.g.body temperature or fluid content, inresponse to chemicals? Finally, the roleof risk assessment was to take on boardadvances in sciences but not to drive the

development of science. ILSI/HES istrying to bring government and academictogether with industry to develop the riskassessment process.

The number of issues raised in this lastpresentation stimulated a vigorousdebate. It was clear that all three typesof techniques were promising andprovided complimentary information.Tremendous progress had been made inthe last few years. Considerabledevelopments and data generation wererequired, however, to reach the utopia ofselectivity and sensitivity required foruse in the field of non-drug chemical riskassessment for human studies.

Dr. A. G. SMITH,MRC Toxicology Unit,University of Leicester

This report originally appeared in theOccupational and EnvironmentalToxicology Group Newsletter, Spring2004. The ECG thanks the OETG forpermission to reproduce this article.

Environment, Sustainability and Energy Forum(i) Chemistry of the Natural

Environment. The Forum isdeveloping plans for a workshop onthe Chemical Aspects of ClimateChange later in the year which willbring together environmentalchemists and other key scientificdisciplines (e.g. biologists) tounderstand the key challenges facingchemists in understanding forcingsand feedback mechanisms in climatechange and to explore the challengesat the interface of chemistry andother disciplines. This workshopwill set the context for RSC actionin this area and form the first of aseries of workshops in the subjectarea

(ii) Sustainable Energy. ESEF isformulating new RSC energy policywhich will outline the key prioritiesfor chemistry and the chemicalsciences which must be overcometo meet our future energy demands.We are also organising workshopsand collaborating with other learnedsocieties on energy conferences.

(iii) Green Chemistry. We are buildingon an RSC report published last year

Benign and Sustainable EnergyTechnologies (http://www.rsc.org/lap/polacts/benign_report.htm)which makes several recommend-ations to further promote greenchemical technologies. Activitieshere include organising workshopswith organisations such asFIRSTFARADAY partnership onland and natural water remediation,workshops focussed on greenproducts and developing links withthe American Chemical Society.

ESEF is also active in developing RSCpolicy on topics which fall within itsremit. For example, we are currentlyresponding to the consultation on Defra’sSustainable Development Strategy. Weare also formulating RSC position paperson current topical environmental issuessuch as air quality and many more.

If you would like more information aboutany of these activities then please contactDr Eimear Cotter, Manager,Environment, Sustainability and EnergyForum on 020 7440 3333 [email protected]

The Environment, Sustainability andEnergy Forum (ESEF) recently carriedout a consultation exercise to obtainviews on a proposal to change reportingarrangements within the Royal Societyof Chemistry (RSC). RSC specialistinterest groups with an interest inenvironmental matters, namely theEnvironmental Chemistry Group (ECG),Water Science Forum (WSF) andOccupational and EnvironmentalToxicology Group (OETG) were invitedto change their reporting requirements sothat they report to ESEF in the future.We were delighted to hear that both ECGand OETG have decided with go withthese new arrangements, and we lookforward to working with them in thefuture on areas of mutual interest.

ESEF’s portfolio of activities is growingand we are beginning to develop apresence both within the RSC and in thewider community to promote the centralrole that chemistry plays in environment,sustainability and energy issues.

Our activities are organised underthree key initiatives:

11


12

Tropospheric hydrogen peroxide and hydroperoxidesorganic hydroperoxides in Antarctica.The ground-based measurements arebeing acquired at the new Clean AirSector (CAS) Laboratory at the HalleyStation, Antarctica (see p. 1). Thesemeasurements are part of the campaign:Chemistry of the Antarctic BoundaryLayer and the Interface with Snow(CHABLIS), which is due to culminatein an intensive summer campaign in2005. We aim, through involvement inthis project, to:

• Estimate a complete annual cycle forspeciated peroxides in the Antarctictroposphere, investigate seasonaland diurnal variations, and facilitatethe understanding of troposphericchemical processes.

• Assist with the development ofatmospheric chemical models, andtest these models under extremeconditions.

• Help understand the chemistry of anunpolluted region in order to givereal context to chemical processesoccurring in polluted atmospheres.

This NERC-funded investigation is partof the Atmospheric Chemistry researchprogramme within the School of theEnvironment at the University of Leeds(http://www.env.leeds.ac.uk/research/ias/chemistry/index.htm).

To prepare for CHABLIS, instrumentfield testing was undertaken inSwitzerland at the Jungfraujoch HighAltitude Research Station (46.55˚N,7.98˚E, 3580 m above mean sea level),during the Free Tropospheric Experiment(FREETEX 2003) in February/ March2003. A nebulising reflux concentratorsampled ambient air twice hourly, priorto on-site analysis by HPLC speciation,coupled with post-column peroxidasederivatisation and fluorescencedetection. Hydrogen peroxide (H2O2)ranged between 0.92 ppbv down tobelow the detection limit (19 pptv) overa 14-day period. Methyl hydroperoxide(CH3OOH) was also observed andranged between 0.12 ppbv down tobelow this detection limit. No otherorganic hydroperoxides (ROOH) weredetected. The peroxide data have beencompared to other species and

meteorological parameters that weremeasured during the campaign. (ppmv= parts per million by volume; ppbv =parts per billion by volume; pptv = partsper trillion by volume).

Background

Peroxides are produced predominantlyby the self-reaction of hydroperoxyradicals (HO2, reaction 1a) or by cross-reactions between HO2 and other peroxyradicals (RO2, reaction 1b). They are alsoproduced via the ozonolysis of alkenes4, 5

and are found within plumes as a directresult of biomass burning.6

The formation of peroxy radicals,discussed extensively by Lightfoot et al,7occurs predominantly via the photo-oxidation of carbon monoxide (CO) andvolatile organic compounds8 (VOC).Other sources of these radicals includethe thermal decomposition of peroxy-acetyl nitrate3 (PAN) and the ozonolysisof alkenes9 via stabilized Criegeebiradicals (R1R2COO). Peroxy radicalsare relatively reactive species. This isbecause the presence of an H atom (or Rgroup) weakens the O-O bond in O2, soHO2 (or RO2) reacts much more easilythan O2 itself. Peroxy radicals can alsoreact with nitrogen oxides, NOx (NO andNO2) via termination reactions formingnitric acid and organic nitrate, RONO2reactions 2a and 2b); these reactionscompete with self/cross-terminationreactions 1a and 1b, and thus suppressthe production of H2O2 and ROOH.

Additionally, HO2 (and RO2) can reactwith NO in propagation reactions,producing NO2 and hydroxyl radicals,.OH (and RO; see reactions 3a and 3b).NO2 can then be photolysed10 to replenishNO (see reactions 4a and 4b) and thusfurther decreasing peroxy radical, andtherefore hydroperoxide concentrations.

Gas phase formation of hydroperoxidesis therefore dependent on NO con-centrations. At low NO concentrations,reactions 1a and 1b dominate11 andexhibit a second-order dependence12 onHOx concentrations. At higher NOlevels, NO oxidation reactions 2a, 2b, 3a,and 3b become more important. At NOlevels exceeding 100 pptv, the

Data from the HalleyStation, Antarctica and theJungfraujoch, Switzerland

Sarah Walker from the Schoolof the Environment, Universityof Leeds and colleagues explainthe significance of measuringtropospheric H2O2 and ROOH.

Introduction

Oxidants in the troposphere principallycontrol the levels of trace gases in theatmosphere. The presence of natural andanthropogenic pollutants e.g. carbonmonoxide (CO), nitrogen oxides (NOx)and sulphur dioxide (SO2) in turn affectatmospheric oxidant composition.Peroxides are strongly oxidising species,so as well as being oxidation products,are important oxidants in their own right.1As such, they play an important role inthe gas phase free radical chemistry ofthe atmosphere. They are formed via freeradical chemistry involving the hydroxylradical (.OH) so the presence of highH2O2 concentrations is symptomatic ofatmospheric reactions involving the .OHradical.

H2O2 also plays a key role in theatmospheric oxidation of SO2 tosulphuric acid (H2SO4) and sulphate(SO4

2-) aerosol2 so its presence indicatesthe occurrence of aqueous phasechemistry leading to acid precipitation.Furthermore, there has been speculationthat H2O2 in the atmosphere can leaddirectly to vegetation damage.3 Tosummarise, peroxides are present in bothunpolluted and polluted air and are usefulin providing an indication of thechemistry occurring at a particularlocation. Measurements of peroxides ina ‘pristine’ environment such as theAntarctic, remote from the complicatingfactors of additional chemical pollutants,will improve our understanding of thechemical composition of the naturalbackground atmosphere.

An automated instrument has beendeveloped to measure the annual cycleof gas phase hydrogen peroxide and

production of hydroperoxides can besubstantially suppressed9 where byreactions 3a and 3b dominate, implyingnet photochemical production of O3 (via4a and 4b) is favoured overhydroperoxide production. At muchhigher NO levels (~2 ppbv), terminationreactions 2a and 2b dominate givingincreased free radical scavenging.

In contrast to the effect of NO, otherpollutants can cause raised peroxidelevels. High levels of VOC and COcause H2O2 concentrations to increase(e.g. reactions 5a and 5b) due to theincreased availability of free radicalspecies. Hence, peroxide concentrationsare enhanced when there is higherVOC:NOx ratios. This is in contrast toozone, whose concentration increaseswith CO, VOC and NOx.

ROOH in the Antarctic troposphere,however, have not been investigated tosuch an extent. Jacob and Klockow18

measured H2O2 concentrations inambient air, in conjunction with snowand firn cores, at the German ResearchStation, Neumayer. Despite diurnalvariation in temperature and relativehumidity of 100%, sufficient fordepositing gaseous H2O2 onto the snowsurface, no significant diurnal cycle wasobserved. H2O2 was found to rangebetween 0.1-1.1 ppbv.

Riedel et al.19 conducted the first year-round Antarctic measurements, also atNeumayer. It was assumed that no otherorganic hydroperoxides would be presentin such a remote marine atmospherethrough previous measurementsconducted by Weller et al.20, where only

ProductionHO2 + HO2 ➝ H2O2 + O2 (1a)RO2 + HO2 ➝ ROOH + O2 (1b)

Effect of NOHO2 + NO (+ M) ➝ HNO3 (+ M) (2a)RO2 + NO (+ M) ➝ RONO2 (+ M) (2b)HO2 + NO ➝ NO2 + .OH (3a)RO2 + NO ➝ NO2 + RO (3b)NO2 + hυ ( < 420 nm) ➝ O + NO (4a)O + O2 (+ M) ➝ O3 (+ M) (4b)

Effect of CO (and VOC).OH + CO ➝ CO2 + H (5a)H + O2 (+ M) ➝ HO2 (+ M) (5b)

Effect of NO2NO2 + .OH ➝ HNO3 (6)

Sinks(a) H2O2 + OH ➝ H2O + HO2 (7)(b) H2O2 + hυ ( < 350 nm) ➝ 2.OH (8)(c) dry and wet deposition

The principal sinks for hydroperoxides13, 14

are dry and wet deposition, reaction with.OH radicals (reaction 7) and photolysis(reaction 8) at ultraviolet wavelengthsbetween 190 and 350 nm.

Hydrogen Peroxide andOrganic Hydroperoxides inAntarctica

Measurements of hydroperoxides inAntarctica have previously focussed onsnow and firn,15 (aged snow that isgranular and compact and in atransitional state between snow and ice),Antarctic waters16 and preserved H2O2concentrations in ice cores.17 Themechanisms controlling H2O2 and

CH3OOH, alongside H2O2 could bedetected. The data indicated theoccurrence of seasonal variations.During polar night, H2O2 ranged frombelow the limit of detection (LoD) of0.05 ppbv, up to 0.11 ppbv. CH3OOHwas also detected and ranged from belowthis LoD, up to 0.14 ppbv. As expected,higher mixing ratios were found duringthe sunlit period (see Table 1 on next page).

It is therefore important to implementhighly sensitive and reliable techniquesto measure the sub-ppbv concentrationspresent in ‘pristine’ Antarctic air, awayfrom the complicating influence ofanthropogenic pollutants. Only then canthe natural seasonal and diurnal variationof these trace species, be deduced.

Field Testing at theJunfraujoch

Gas phase hydroperoxides were sampledtwice hourly via an automatic nebulisingreflux concentrator. Analysis wasperformed on-site by HPLC speciation(C-18 reversed-phase column) followedby post-column peroxidasederivatisation21 and fluorescencespectrophotometric detection.Calibration was performed daily viaserial dilution of a stock solution of H2O2(previously standardised by titrationagainst a known KMnO4 solution)producing liquid standards. A schematicof the instrument is shown in Figure 1.The field tests for CHABLIS duringFREETEX 2003 emphasised anytechnical modification needed fordeployment in Antarctica.

Figure 1: Schematic diagram showing assembly of the gas phase peroxide instrument

13


Results from the Jungfraujoch

A summary of results is shown in Table2. The LoD was based on three timesthe standard deviation of the baseline.

Figure 2 shows a time series for H2O2.The three maxima (1st, 6th and 10-12th

March 2003) correspond to a regionalwind direction change from NW to SW(based on 5-day back trajectories22). Thisimplies NW air masses carry a lowerperoxide/peroxide pre-cursor concentrationthan SW air, and suggests SW air masseshad increased photochemical activitycompared to NW air, agreeing withprevious research23, 24. Average localwind direction25 was 224o, 265o (SW),312o (NW) respectively, so the thirdevent (10th-12th March) occurred duringa local north-westerly which may explainwhy it is less well-defined. Increasedatmospheric pressure and low NOx werealso observed during this period, whichcould also enhance peroxide production(reactions 1a and 1b) whilst suppressingreactions 2 - 4 and 6.

The diurnal cycle for 1st March (see inset,Figure 2) shows that peak H2O2 (0.51

ppbv) at 13:08 corresponded tomaximum solar radiation intensity (~750W m-2). The earlier peak (0.30 ppbv) at04:00 occurred during minimum solarradiation intensity, may be due tosecondary factors e.g. rising watervapour levels that were experienced atthis time.

Hydroperoxide formation is alsosensitive to the rate of .OH radicaloxidation of NO2 (reaction 6). Duringpeak NO2 levels, reaction 6 may exceed.OH-initiated oxidation of CO and VOCsto produce HO2 and RO2 (reactions 5aand b), and thus hydroperoxides.Maximum observed NO2 was 4.36 ppbv(21:20, 6th March), which correspondedto minimum H2O2 levels. Figure 2 showsH2O2 reducing to a minimum when NOconcentrations exceeded 0.1 ppbv. Thisimplies suppression of H2O2 productionand agrees with previous research.9

ConclusionA 14-day dataset was achieved at theJungfraujoch where the instrument wastested for deployment in Antarctica. Theinstrument, currently at Halley, is

equipped to measure peroxides until2005. Datasets collected duringCHABLIS are required to advance theunderstanding of how peroxides behavein the Antarctic troposphere, and henceenhance our knowledge of troposphericphotochemistry, acid deposition and theoxidative capacity of the atmosphere.

References

1. e.g. S. A. Penkett, B. M. R. Jones,K. A. Brice, and A. E. J. Eggleton,Atmospheric Environment, 1979,13, 123.

2. J. G. Calvert, A. Lazrus, G. L. Kok,B. G. Heikes, J. G. Walega, J. Lind,and C. A. Cantrell, Nature, 1985,317, 27.

3. D. W. Gunz and M. R. Hoffmann,Atmospheric Environment Part a-General Topics, 1990, 24, 1601.

4. H. Niki, P. D. Maker, C. M. Savage,L. P. Breitenbach, and M. D. Hurley,Journal of Physical Chemistry,1987, 91, 941.

5. G. K. Moortgat, D. Grossmann, A.Boddenberg, G. Dallmann, A. P.Ligon, W. V. Turner, S. Gab, F.Slemr, W. Wieprecht, K. Acker, M.Kibler, S. Schlomski, and K.Bachmann, Journal of AtmosphericChemistry, 2002, 42, 443.

6. M. Lee, B. G. Heikes, D. J. Jacob,G. Sachse, and B. Anderson,Journal of Geophysical Research-Atmospheres, 1997, 102, 1301.

7. P. D. Lightfoot, R. A. Cox, J. N.Crowley, M. Destriau, G. D.Hayman, M. E. Jenkin, G. K.Moortgat, and F. Zabel,Atmospheric Environment Part a-General Topics, 1992, 26, 1805.

8. B. J. Finlayson-Pitts and J. N. Pitts-Jr, ‘Atmospheric Chemistry:Fundamentals and ExperimentalTechniques’, John Wiley and Sons,1986.

9. M. H. Lee, B. G. Heikes, and D. W.O’Sullivan, AtmosphericEnvironment, 2000, 34, 3475.

10. P. S. Monks, L. J. Carpenter, S. A.Penkett, G. P. Ayers, R. W. Gillett,I. E. Galbally, and C. P. Meyer,Atmospheric Environment, 1998,32, 3647.

11. W. Tsai, H. Sakugawa, I. R. Kaplan,and Y. Cohen, EOS Transactions-American Geophysical Union, 1988,69, 1053.

12. A. V. Jackson and C. N. Hewitt,

Conditions H2O2 Mixing Ratios (ppbv) CH3OOH Mixing Ratios (ppbv)Mean Range Mean Range

Polar Night 0.054 ± 0.046 < 0.03 - 0.11 0.089 ± 0.052 < 0.05 - 0.14Sunlit Period 0.20 ± 0.13 < 0.03 - 0.91 0.19 ± 0.10 < 0.05 - 0.89

Table 1: Mixing Ratios for H2O2 and CH3OOH at Neumayer during 1997 – 1998

Species LoD (pptv) Range (ppbv) Average (ppbv)H2O2 19 < 0.019 – 0.92 0.17CH3OOH 19 < 0.019 – 0.12 0.03Other ROOH 19 < 0.019 not detected

Table 2: Summary of results from the Jungfraujoch

Figure 2: H2O2 time series with air mass classifications22, 26 and NOx data25 for27/02-12/03/2003; Inset: diurnal cycle for 1st March alongside solar radiationintensity25

14


Critical Reviews in EnvironmentalScience and Technology, 1999, 29,175.

13. J. A. Logan, M. J. Prather, S. C.Wofsy, and M. B. McElroy, Journalof Geophysical Research-Oceansand Atmospheres, 1981, 86, 7210.

14. W. G. DeMore, S. P. Sander, D. M.Golden, R. F. Hampson, M. J.Kurylo, C. J. Howard, A. R.Ravishankara, C. E. Kolb, and M. J.Molina, ‘Evaluation No. 11:Chemical Kinetics andPhotochemical Data for Use inStratospheric Modeling’, JPLPublication 94-26, 1994.

15. e.g. K. Kamiyama, H. Motoyama,Y. Fujii, and O. Watanabe,Atmospheric Environment, 1996,30, 967.

16. e.g. D. Abele, G. A. Ferreyra, and I.Schloss, Antarctic Science, 1999,11, 131.

17. e.g. R. W. Gillett, T. D. van Ommen,A. V. Jackson, and G. P. Ayers,Journal of Glaciology, 2000, 46, 15.

18. P. Jacob and D. Klockow, FreseniusJournal of Analytical Chemistry,1993, 346, 429.

19. K. Riedel, R. Weller, O. Schrems,

and G. Konig-Langlo, AtmosphericEnvironment, 2000, 34, 5225.

20. R. Weller, O. Schrems, A.Boddenberg, S. Gab, and M.Gautrois, Journal of GeophysicalResearch-Atmospheres, 2000, 105,14401.

21. A. L. Lazrus, G. L. Kok, J. A. Lind,S. N. Gitlin, B. G. Heikes, and R. E.Shetter, Analytical Chemistry, 1986,58, 594.

22. National Oceanic and AtmosphericAdministration’s (NOAA) AirResources Laboratory (ARL),Hybrid Single-Particle LangrangianIntegrated Trajectory (HYSPLIT 4)model, www.arl.noaa.gov, (March2003).

23. L. J. Carpenter, T. J. Green, G. P.Mills, S. Bauguitte, S. A. Penkett,P. Zanis, E. Schuepbach, N.Schmidbauer, P. S. Monks, and C.Zellweger, Journal of GeophysicalResearch-Atmospheres, 2000, 105,14547.

24. J. Forrer, R. Ruttimann, D.Schneiter, A. Fischer, B. Buchmann,and P. Hofer, Journal of Geo-physical Research-Atmospheres,2000, 105, 12241.

25. EMPA (Swiss Federal Laboratoriesfor Materials Testing and Research),Technischer Bericht zum NationalenBeobachtungsnetz furLuftfremdstoffe (NABEL),Switzerland, 1994.

26. L. K. Whalley, A. C. Lewis, J. B.McQuaid, R. M. Purvis, J. D. Lee,K. Stemmler, C. Zellweger, and P.Ridgeon, Journal of EnvironmentalMonitoring, 2004, 6, 234.

SARAH WALKERa, ANDREAJACKSONa, JIM MCQUAIDa andRHIAN SALMONb

a Institute for Atmospheric Sciences,School of the Environment, Universityof Leeds, Leeds, LS2 9JT, UK b BritishAntarctic Survey, Physical SciencesDivision, High Cross, Madingley Road,Cambridge, CB3 0ET UK

Web links:Glacier glossary http://nsidc.org/glaciers/glossary/ (includes a definition of firn)

Halley & other Antarctic researchstations http://www.antarcticconnection.com/antarctic/stations/halley.shtml

Problems with Plastics?Media storm! That is probably the mostappropriate term to describe the receptionof our short article published recently inthe journal Science [1]. There wereported our observations of thedistribution of microscopic particles ofplastic in the marine environment. Inaddition to worldwide TV coverage,publications as diverse as the Wall StreetJournal, The Guardian and Plastics &Rubber Weekly all ran reports of ourwork – the result of a multidisciplinarystudy by ecologists and environmentaland physical chemists.

In collaboration with Andrea Russellfrom Southampton University and someof our former students, and with fundsfrom the Leverhulme Trust, we identifiedplastics and other particles – obtained byflotation from a variety of intertidal andsubtidal sediments – using microscopyinterfaced with Fourier Transform-Infrared Spectroscopy (FT-IR).Comparison of the FT-IR spectra withthose in published databases allowed usto identify fragments of polythene, nylonand many other polymers in thesediments. These probably form fromabrasion and mechanical degradation of

larger pieces of plastics. We do not knowthe environmental consequences, if any,of these minute fragments, but inlaboratory trials we were able to showthat the particles were ingested bybarnacles, lugworms and amphipods.Furthermore, when we studied archivedplanktonic samples collected by the SirAlister Hardy Foundation for OceanScience’s Continuous Plankton Recordersince the 1960s, we were able to showhow the amounts of microscopic plasticsin the oceans have increased with time.

We would like to know the fate of anychemicals associated with these plasticparticles. It is known that somehydrophobic pollutants are stronglysorbed by different polymers. Forexample, it is possible that the plasticsact in the same way as solid phaseextractants (SPEs) when SPEs are usedto isolate pollutant analytes from water.Also, many additives and processingagents are used in plastics’ manufacture,e.g. as pigments, biocides, plasticizersetc., and many of these chemicals aredesigned to leach to the surface of theplastics. We now need to establishwhether such chemicals can be transferred

from the plastic to marine organisms. Wehope that our current research programme,again funded by the Leverhulme Trust,will soon provide answers to these urgentenvironmental questions.

STEVE ROWLAND and RICHARDTHOMPSON,University of Plymouth,June 2004

[1] Richard C. Thompson, Ylva Olsen,Richard P. Mitchell, Anthony Davis,Steven J. Rowland, Anthony W. G. John,Daniel McGonigle, Andrea E. Russell.Lost at Sea: Where does all the plasticgo? Science, 2004, 304, 838.

Web links:

The Sir Alister Hardy Foundation forOcean Science (SAHFOS)www.sahfos.org

R. C. Thompson et al, ‘Lost at Sea:Where does all the plastic go?’Science, 2004, 304, 838 http://www.biology.plymouth.ac.uk/staff/Thompson/Thompson.pdf

15


The RSC’s Library and Information Centre – An environmentalchemistry knowledge centre

16

The foremost repository ofchemical knowledge in Europe,the Royal Society ofChemistry’s Library andInformation Centre (LIC) atBurlington House is also anexcellent source of informationon the environment andenvironmental chemistry. TheLIC has accumulated animpressive array of resourcesfor chemists over 160 years –from rare journals to bookscovering all aspects of thechemical sciences. These daysit also subscribes to electronicjournals and databases. NazmaMasud from the LIC explainshow the library’s collectionscan benefit environmentalscientists.

One of the latest additions to the LIC’selectronic database collection is Knovel( h t t p : / / w w w . r s c . o r g / l i c /knovel_library.htm). RSC membershave free access to this web portal, whichallows quick but thorough searches ofa collection of 700 essential databanksand electronic books – including theEnvironmental Contaminant ReferenceDatabook, the Hazardous ChemicalsHandbook and Patty’s Toxicology.

The LIC provides among its core servicesthe Chemical Enquiries Helpdesk – acomprehensive, confidential, and largelycost-free service for RSC members.Relevant information resources – notalways available in other libraries – areutilised by the Helpdesk’s chemicalinformation specialists to answermembers’ information enquiries. TheHelpdesk can often supply that crucialpiece of elusive information, providefurther leads, or add a new perspectiveto a search strategy. There are regularenquiries in the area of chemical hazards,health & safety legislation, andenvironmental chemistry. For example:

• Levels of ammonia in East Anglianpeat bogs;

• Toxicity of methyl bromide;

• Antibiotic and hormone content ofsewage sludge and possibleexposure from the spreading ofsludge onto land near residentialareas;

• Olfactory detection limits for ozone.

Resources used for this work include:

Chemical Abstracts

Handbook of Environmental Data onOrganic Chemicals, 4th Edition

Dictionary of Substances and theirEffects (DOSE), 2nd Edition

A reference book on chemicals and theirimpact on humans and the environmentacross the globe, the new edition fromthe RSC brings together data on over4,100 chemicals and providescomprehensive information onmammalian and avian toxicity,occupational exposure, ecotoxicity, andenvironmental fate.

ECH&S (Environmental Chemistry,Health and Safety)

This RSC publication containsinformation on chemicals deemed tocause actual or potential problems tohumans or the environment. It covers theenvironment not only from a scientific/technical standpoint, but also frombusiness and legal perspectives.

TOXLINE

The US National Library of Medicine’stoxicology database (http://toxnet.nlm.nih.gov) contains bibliographicinformation on the biochemical,pharmacological, physiological, andtoxicological effects of drugs and otherchemicals.

Croner’s Waste Management

Croner Publications (Wolters Kluwer)

regularly update this manual, whichcovers UK and European legislation,practical guidance to aid compliance,specific information on different typesof waste, directory of contractors,consultants, local authorities andrecyclers, and a list of statutes andofficial guidance publications.

ECETOC (European Centre forEcotoxicology and Toxicology ofChemicals) Publications

Environmental Health Criteria(EHCs): Publications of theInternational Programme of ChemicalSafety under the auspices of WHO

Provide risk assessments of the effectsof chemicals on human health and theenvironment.

Members can visit the LIC at BurlingtonHouse in Piccadilly or at www.rsc.org/lic to see what other services we offer.The LIC is an invaluable benefit ofmembership, and the services of theChemical Enquiries Helpdesk are avaluable knowledge resource. Send usan enquiry from http://www.rsc.org/lic/library3.htm or [email protected] to seewhat we can do for you or call us on+(44) 207 440 3373 for moreinformation.


17

Forthcoming symposium

Faraday Division

Faraday Discussion 130

ATMOSPHERICCHEMISTRY

University of Leeds, UK11 – 13 April 2005

Introduction

Faraday Discussion 130 will beheld exactly 10 years after the firstDiscussion on atmosphericchemistry and at a time when publicawareness of the consequences ofclimate change and the healthimplications of air pollution hasnever been higher. Chemistry playsa key role in the removal ofgreenhouse gases, the production ofsecondary pollutants and the rate ofrecovery of stratospheric ozone.

Why Should You Attend?

An interdisciplinary approach has ledto major advances in understandingatmospheric chemistry. A widerange of experimental methods, fieldinstrumentation (from surface tospace) and modelling tools havebeen developed to study all regionsof the atmosphere in order to betterunderstand links between chemistryand our changing atmosphere. ThisFaraday Discussion seeks to bringtogether chemists, physicists,meteorologists and atmosphericscientists, from diverse back-grounds in laboratory studies, fieldmeasurements, and the develop-ment of numerical models andchemical mechanisms.

The Science

New and unpublished experimentaland theoretical work will bepresented in the following areas:

• Gas phase spectroscopy,chemical kinetics and photo-chemistry

• Atmospheric processes at the air/liquid and air/solid interface

• Chemical field measurements inthe atmosphere and instrumentdevelopment

• Development of chemicalmechanisms and interpretation offield data through modelling

• Satellite measurements

• Interaction of atmosphericchemistry and climate change

Call for Papers

Offers of papers related to thethemes for discussion are nowinvited. Abstracts that fit mostclosely with the themes of themeeting will be selected for oralpresentation. Authors of theselected abstracts will then beinvited to submit their work as a fullpaper, which will form the basis oftheir short presentation at themeeting. The full paper must containnew, unpublished work and besubmitted five months in advance ofthe Discussion. The papers selectedfor presentation and discussion willbe refereed and then sent to allparticipants as preprints four weeksin advance of the meeting.

How to Submit a PosterAbstract

Abstracts of presentations should bee-mailed to Christine Hall as a Wordattachment with the subject header:05FD130 abstract.Deadline: 4th February 2005.

Sponsorship andExhibitions

Sponsorship and exhibitionopportunities are available. Pleasecontact the RSC Conference Officefor details.

Request for FurtherInformation on FaradayDiscussion 130Atmospheric Chemistry

The programme and applicationform will be circulated in Autumn2004. All enquiries about attendingthe Discussion should be addressedto Christine Hall:Telephone: +44 (0) 20 7437 8656 or+44 (0) 20 7734 1227E-mail: [email protected] post: FD130, RSC ConferenceOffice, Burlington House, Piccadilly,London W1J 0BA UKWebsite: http://www.rsc.org/FD130


The RSC EnvironmentalChemistry Group was fortunatein attracting three exceptionalspeakers for this year’sDistinguished Guest Lectureand Symposium, which tookplace on March 3rd 2004 in theMeeting Room of the LinneanSociety of London.

Dr Paul Monks (University ofLeicester) opened the meeting with apresentation on “Probing thetroposphere from space”. Hisdescription of the Earth System as acoupled multi-phasic land-sea-air systemilluminated one of the salient reasons forsatellite studies of the atmosphere – howcan the Earth System be studiedholistically unless from space? This isespecially important in relation to long-range pollutant transport (twenty percentof any air pollution event is from a distantsource) and for monitoring geopoliticalinitiatives such as Kyoto. However, DrMonks also pointed out the difficultiesassociated with satellite measurements –the troposphere is a well-mixed layersome 10 km from the Earth’s surface andthere are problems with studying thislayer through the whole bulk of theatmosphere from a satellite 800/900 kmup in a Low Earth Orbit. He explainedthat the satellite systems are an integralpart of a network of measurementtechniques for studying troposphericchemistry. Land stations such as thoseat Mace Head in Ireland and Cape Grimin Tasmania provide single site data(spatially limited) and flights by researchaircraft such as the BAE-146 providesnapshot data (temporally limited) to adata repository and then comparisons canbe made to the continuous globalcoverage from satellites – “… satellitemeasurements provide data whichintegrate the limited spatio-temporalscales of the each of the othertechniques”.

In the second talk of the afternoon –“Remote-sensing of air-sea fluxes ofCO2: constraining the global C02budgets” – Professor Jim Aiken fromthe Plymouth Marine Laboratory (PML)described work at the Centre forObservation of Air-Sea Interactions and

Fluxes (CASIX) in supporting NERCinitiatives on the quantification andunderstanding of the Earth System. Datafrom satellites are used to studyphenomena such as the air-sea fluxes ofchemical species, surface planktadistributions, marine biogeochemistry,sea temperature and ocean circulationprocesses – but with a focus on carbondioxide fluxes, the core carbon cycle andglobal climate. Models are needed toexploit these data and to quantify carbonfluxes; three-dimensional models withcoupled biology are being used (NorthAtlantic Model, North-West EuropeanShelf Model). Satellites provide data onwinds, sea surface temperature, solarradiation, and ocean colour to modellers,and these are used as an input to modelparameterisation and also to measure thesuccess of the models’ predictivecapacities in relation to the carbon cycle.As always, the modellers seek moreaccurate data – which can only comefrom geostationary satellites.

Professor John Burrows (University ofBremen) closed the symposium with theECG 2004 Distinguished GuestLecture “Viewing the Earth’s environ-ment from space: the challenges, theprogress and the future.” He viewed theuse of remote sensing via satellite as ameans of obtaining objective data aboutthe impacts of anthropogenic activitieson the biogeophysical system, anddelineated several crucial questions thatneeded a continuous programme ofexpansion in Earth Observation Systems.The enormous economic and social costsof climate change to the worldcommunity highlight the need forobservations of emissions to theatmosphere – these are crucial forunderstanding the rate at which climatechange is occurring and for detecting anysuccesses in its amelioration. Ozonedepletion was continuing to occur. Thecoupling of climate change with ozonedepletion via phenomena such as theoccurrence of polar meso spheric cloudsmeant that expectations of a post-Montreal Protocol smooth, continued,diminishment of the ozone hole might beconfounded. Studies of NOx sources inthe stratosphere, the impact of meteoritesand solar proton events on the Earth’satmosphere, the quantification ofatmospheric aerosols, and surfacetemperature measurements are alldependent on satellite observations –

because it is only via satellites (both LowEarth Orbit and Geostationary EarthOrbit) that data with adequate temporaland spatial resolution can be obtained.

Satellite measurements of theatmosphere began in the 1960s when theUSSR attempted to measure ozone byUV spectrophotometry from space.Subsequently the NASA Nimbus seriesand other satellite systems improved andextended these early experiments. In2002 the European Space Agencylaunched SCIAMACHY (ScanningImaging Absorption Spectrometer forAtmospheric Chartography).

This satellite (together with the GOME(Global Ozone Monitoring Experiment)series) has extensively increased theunderstanding of global pollutionprocesses. Tropospheric nitrogen dioxidehas been tracked from sources such asindustrial centres in Japan and China,burning in Africa, South America andIndonesia, and the success of vehicularemission reduction technology in the USand Europe is clearly demonstrated byobservations of continent-widereductions in nitrogen dioxideconcentrations. Cloud formation andgrowth has been examined via aerosolstudies, chlorophyll-a is being trackedacross the oceans, and reactive speciessuch as OClO and BrO (which are crucialin ozone depletion) are being quantified.

Professor Burrows completed his lecturewith a clear exposition of the argumentsfor extending the range and accuracy ofsatellite data via the use of advancedtechnology detectors in geostationarysatellites. More accurate data wouldprovide continuous regional-scaleinformation for policy development andregulatory purposes, reduce the need forground stations (and avoid theirlimitations) and assist co-operativeactions by the global community for thebenefit of us all.

Dr LEO SALTER,Cornwall College,Pool, Redruth, Cornwall

This summary first appeared in ESEFNews, Issue No. 2, Spring 2004. Moredetailed accounts of these threepresentations will appear in the January2005 issue of the ECG Bulletin.

Meeting report: ECG DGL 2004 Environmental Chemistry from Space

18


19


Recent books on the environment and on toxicology at the RSClibrary

Ionic Liquids as Green Solvents:Progress and Prospects(ACS Symposium Series No. 856)Rogers, R. D.; Seddon, K. R. (Eds.),American Chemical Society,Washington DC, 2003, ISBN:0841238561

Nutritional Aspects of Bone HealthNew, S. A.; Bonjour, J. (Eds.), RoyalSociety of Chemistry, Cambridge 2003,ISBN: 0854045856

Oriental Foods and Herbs: Chemistryand Health Effects(ACS Symposium Series No. 859)Ho, C. T.; Lin, J. K.; Zheng, Q. Y. (Eds.),American Chemical Society,Washington DC, 2003, ISBN:0841238413

Pesticide Decontamination andDetoxification(ACS Symposium Series No. 863)Gan, J. J.; Zhu, P. C.; Aust, S. D.;Lemley, A. T. (Eds.), AmericanChemical Society, Washington DC,2003, ISBN: 0841238472

QSARs: Evaluation of theCommercially Available Software forHuman Health and EnvironmentalEndpoints with respect to ChemicalManagement Applications(ECETOC Technical Report No. 89)ECETOC, Brussels, 2003, ISBN:0773807289

Tetrafluoroethylene(Joint Assessment of CommodityChemicals No. 42)ECETOC, Brussels, 2003, ISBN:0773633942

Utilization of Greenhouse Gases(ACS Symposium Series No. 852)Liu, C.; Mallinson, R. G.; Aresta, M.(Eds.), American Chemical Society,Washington DC, 2003, ISBN:0841238278

The following books and monographs onenvironmental topics, toxicology, andhealth and safety have been acquired bythe Royal Society of Chemistry library,Burlington House, during the periodJanuary to June 2004.

Aldo-keto Reductases and ToxicantMetabolism(ACS Symposium Series No. 865)Penning, T. M.; Petrash, J. M. (Eds.),American Chemical Society,Washington DC, 2003, ISBN:0841238464

sec-Butanol(Joint Assessment of CommodityChemicals No. 43)ECETOC, Brussels, 2003, ISBN:0773633943

n-Butanol(Joint Assessment of CommodityChemicals No. 41)ECETOC, Brussels, 2003, ISBN:0773633941

Consumer’s Good Chemical Guide: AJargon-free Guide to Chemicals ofEveryday LifeEmsley, J., Spektrum, Oxford 1994,ISBN: 0716745054

Environmental Fate and Effects ofPesticides(ACS Symposium Series No. 853)Coats, J. R.; Yamamoto, H. (Eds.),American Chemical Society,Washington DC, 2003, ISBN:0841237220

Environmental Impact of Fertilizer onSoil and Water(ACS Symposium Series No. 872)Hall, W. L.; Robarge W. P. (Eds.),American Chemical Society,Washington DC, 2003, ISBN:0841238111

Food Factors in Health Promotion andDisease Prevention(ACS Symposium Series No. 851)Shahidi, F.; Ho, C-T.; Watanabe, S.;Osawa, T. (Eds.), American ChemicalSociety, Washington DC, 2003, ISBN:0841238073

Optimising Pesticide Use Edited by MICHAEL WILSON, Central Science Laboratory, UK

Brings together the wide range of scientific disciplines necessary toensure best practice for pesticide use through monitoring what isused and improving how it is formulated and applied.

• An in-depth exploration of pesticide optimisation from the viewpoint of industry and research scientist

• A unique combination of contributors covering the concept fromphysical application of pesticides to active ingredient andformulation chemistry

• Contains a case study on the development of a new range ofactive chemistries from bacteria

0-471-49075-X September 2003 222pp Hbk £75.00 €115.00

Pesticide Residues in Food & Drinking WaterHuman Exposure and Risks Edited by DENIS HAMILTON, Queensland Dept of Primary Industries, Australia andSTEPHEN CROSSLEY, Food Standards Australia New Zealand, Australia

This book not only combines the elements of risk assessment (dietary exposure andtoxicity, but also positions them within the broader picture, which includesenvironmental fate of pesticides, identification of the exact nature of the residues andthe international standards for acceptable levels of food pesticide residues in food andwater.

• The subjects covered reflect the increasing concerns over food safety and risks tohumans

• Takes an international approach with contributors from the EU, US and Australia

0-471-48991-3 November 2003 378pp Hbk £95.00 €149.00

Helping balance food production and environmental concerns

The Wiley Series in Agrochemicals and Plant Protection bringstogether current scientific and regulatory knowledge and perspectives on all

aspects of the use of chemicals and biotechnology in agriculture.

How to order…

EUROPE, MIDDLE EAST, AFRICA & ASIAJohn Wiley & Sons LtdTel: +44 (0)1243 843294Fax: +44 (0)1243 843296E-mail: [email protected]

NORTH, CENTRAL & SOUTH AMERICAJohn Wiley & Sons IncTel: 877 762 2974Fax: 800 597 3299E-mail: [email protected]

GERMANY, SWITZERLAND & AUSTRIAWiley-VCH Verlag GmbHTel: +49 6201 606 152Fax: +49 6201 606 184E-mail: [email protected]

All books are available fromyour bookseller. Prices subject to change. Postage and handlingadditional.

Ref: CPM

Chirality in Agrochemicals0-471-98121-4£125.00 / €195.00

PesticideRemediation in Soils & Water0-471-96805-6£105.00 / €165.00

Metabolism ofAgrochemicals inPlants0-471-80150-X£135.00 / €209.00

COMING SOON..

Occupational &ResidentialExposureAssessment forPesticides0-471-48989-1£110.00 / €169.00

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THE ROYAL SOCIETY OF CHEMISTRY ENVIRONMENTAL CHEMISTRY ... · Halley Station in Antarctica (75.35˚S, 26.19˚W, 30 m above mean sea level): Measurement of tropospheric hydrogen peroxide