Pollution of Lakes and Rivers

Chapter 10:Mercury, ‘the metal that slipped away’

Copyright © 2008 by DBS

Contents

• A metal on the move

• The sedimentary record of mercury pollution

• Assessing the fidelity of lake sediment cores to track known point sources of mercury contamination

• The contributions of mercury and other metals from domestic sewage

• Tracking mercury pollution from a point source down a river system

• Evaluating the regional dimensions of mercury deposition in arctic and boreal ecosystems using lake sediment mercury flux ratios

• Regional patterns of mercury deposition in Norwegian lakes

• Four thousand years of atmospheric mercury deposition recorded in peat profiles

MercuryA Metal on the Move

• A metal that shares features with POPs:

– Biomagnification

– Long-range transport

– Biovector transport

MercuryA Metal on the Move

• Minamata Bay, Japan (1953-1960)• Plastic manufacturer (Chisso Corp.), used mercury in the

production of acetaldehyde• Discharged methyl mercury into the bay• Main diet of locals was fish + shellfish

– 5-20 ppm (106 water)• Over 3,000 people suffered (730 deaths):

Minamata disease / Dancing Cat Disease

various deformities, damage to nervous system, retardation or death

• Developing embryos are especially vulnerableWHO limit 0.5 mg kg-1

Minamata 50 mg kg-1

MercuryA Metal on the Move

Tomiyasu et al, 2006

MercuryA Metal on the Move

Natural (1/3)• Volcanic eruptions• Sedimentary erosion• Emissions from earth’s

crust and ocean

Mineral: Cinnabar (HgS)

Anthropogenic (2/3)• Fossil Fuel Burning• Waste incineration• Mining (Au + Hg)• Smelters• Chlor-alkali Plants

x10

Biosynthetic• Biological methylation

MercuryA Metal on the Move

1. industrial chemicals – e.g. drugs, fungicides, and as a cathode in chlorine and sodium hydroxide production (chlor-alkali process)

Cl2 ←NaCl → Na

H2 + NaOH ← Amalgam

2. electronics – switches, batteries, electrodes, mercury vapor + fluorescent lamps3. scientific instruments – barometer, thermometer, blood-presure meter4. pesticides5. Dentistry – amalgams6. gold and silver extraction for mining7. Skin lightening creams

Na forms amalgam with Hg, otherwise Na would explode on contact with water

Hg

Speciation

Mercury Ion Hg2+

AKA ‘reactive gaseous’ mercury’ (RGM) e.g. HgCl2(g)

Methyl MercuryCH3Hg+

Elemental MercuryHg0

Particulate bound Hg-P

Inorganic Organic

ReactiveVolatile

Global Regional ?

Dimethyl MercuryCH3HgCH3

Atmosphere

Waterways

[O]

1-20μg m2 yr-1

USGS

Fish

pH/DOC

UV

Watershed-Lake Cycling

MercuryA Metal on the Move

• Toxicity: all forms

MeHg >> vapor >> Hg2+ >> liquid

– Liquid Hg is readily excreted– Hg2+ not readily transported across membranes – affects liver + kidneys– Vapor – diffuses from lungs to bloodstream to brain

• Methylmercury is lipophillic (soluble in fatty tissue)– More mobile – bioconcentrates, bioaccumulates and biomagnifies– Crosses blood-brain barrier– Converted to Hg2+ in brain (neurotoxin)

Usual barrier to Hg2+ is circumvented by vapor and MeHg

MercuryThe Sedimentary Record of Mercury Pollution

• Is mercury in sediments affected by diagenesis?

• Much debate…not agreed upon (Lockhart et al, Fitzgerald et al 1998; 2000; Rasmussen, 1994)

• Agreed that mercury pollution is recorded in sediments (Rada et al, 1989)

MercuryAssessing the Fidelity of lake Sediment Cores to Track Known Point Sources

Lock

hart

et

al,

2000

MercuryAssessing the Fidelity of lake Sediment Cores to Track Known Point Sources

Lock

hart

et

al,

2000

Chlor-alkali Plant - Clay Lake, Ontario

Check 1995 core data against earlier studies…

MercuryAssessing the Fidelity of lake Sediment Cores to Track Known Point Sources

Chlor-alkali Plant - Clay Lake, Ontario

No or negligible diagenesis diffusion or diagenesis… Lock

hart

et

al,

2000

MercuryAssessing the Fidelity of lake Sediment Cores to Track Known Point Sources

Gold Mining – Giauque Lake, Canadian Sub-Arctic

Lock

hart

et

al,

2000

Gold peak may extend lower since deeper slices were below detection limit

1946 – 1962 Gold mining

1965 - 1968dumping of tailings

MercuryAssessing the Fidelity of lake Sediment Cores to Track Known Point Sources

Mercury Mine – Stuart Lake, Bt. Columbia, Canada

Lock

hart

et

al,

2000

Shows success of environmental controls,All 3 lakes show clear and unambiguous high-resolution archives

1940 – 1944

Tailings dumped into lake

1968 – 1975

No lake dumping

MercuryThe Contributions of Mercury and Other Metals from Domestic Sewage

• Sewage disposal is difficult when ground freezes

• Communities rely on piped systems or tanker trucks, sewage is dumped in lakes (sewage lagoons)

• Sewage is a good indicator of metal exposure

• Mercury inputs were x15 higher than nearby control lake

Her

man

son,

199

8

MercuryTracking Mercury Pollution from a Point Source Down a River System

• Sudbury River, (MA), Hg shows high affinity for fine grained organic sediments

Fra

zier

et

al,

2000

Highest conc. closest to dumping site

V. low natural background

MercuryEvaluating the Regional Dimensions of Mercury Deposition

• Transported long distances

• Sources and relative fluxes are required

• Absence of long-term data

Mercury flux ratios (post-1880/pre-1880) from 5 of the 8 Arctic countries

i) Removes biasesii) Allows for global comparison

Land

ers

et a

l, 19

98

MercuryEvaluating the Regional Dimensions of Mercury Deposition

Pre-industrial fluxes:Can be VERY different

(in this case explained by geology)

Land

ers

et a

l, 19

98

Hawk Lake (0.7 μg m-2 yr-1)

Feniak Lake (54 μg m-2 yr-1)

MercuryEvaluating the Regional Dimensions of Mercury Deposition

High Ratio: Sites associated w/ regional anthropogenic sources

Land

ers

et a

l, 19

98

Low Ratio: Remote sites

e.g. Noril’sk uses natural gas (low in Hg)

Large differences in pre-industrial Hg flux and flux ratios

Mercury Regional Patterns of Mercury Deposition in Norwegian Lakes

• Top/Bottom sediments from 210 Norwegian lakes

• Southern lakes close to other European sources were most polluted

Rog

neru

d an

d F

jeld

, 20

01

Russian sources

European sources

MercuryFour Thousand Years of Atmospheric Mercury Deposition from Peat Profiles

• 600 km NW from Almadén

Total mercury and the natural component of mercury accumulation (black area) recorded in a Spanish peat core. The shaded area represents estimates of the anthropogenic component of accumulated mercury, calculated as the difference between total mercury and the natural component. The major phases of mercury exploitation in Spain are marked on the figure.

Mar

tíne

z-C

ortiz

as e

t al

, 19

99

Natural inc. due to little ice age?

(colder, less volatile)

MercurySummary

• Controversy still exists around accuracy of mercury profiles

• Many profiles from lake sediments and peat cores appear to track changes very well

• Studies so far have focused on temperate and arctic regions

• Due to toxicology and long-range transport there is a need for more global studies

References

• Arctic Monitoring and Assessment Programme (1998) AMAP Assessment Report: Arctic Pollution Issues. AMAP, Oslo.

• Barrie, L., Gregor, D., Hargrave, B., Lake, R., Muir, D., Shearer, R., Tracey, B. and Bidleman, T. (1992) Arctic contaminants: sources, occurrence and pathways. The Science of the Total Environment, Vol. 122, pp. 1-74.

• Campbell, L.M., Hecky, R.E., Muggide, R., Dixon, G.G. and Ramlal, P.S. (2003) Variation and distribution of total mercury in water, sediment and soil from northern Lake Victoria, East Africa. Biogeochemistry, Vol. 65, pp. 195-211.

• Esposito, K. (1998) The metal that slipped away. Wisconsin Natural resources Magazine, Vol. 21, No. 1, pp. 19-25.

• Fitzgerald, W.F., Engstrom, D.E., Mason, R.P. and Nater, E.A. (1998) The case for atmospheric mercury contamination in remote areas. Environmental Science & Technology, Vol. 32, pp. 1-7.

• Frazier, B., Wiener, J., Rada, R. and Engstrom, D. (2000) Stratigraphy and historic accumulation of mercury in recent depositional sediments in the Sudbury River, Massachusetts, U.S.A. Canadian Journal of Fisheries and Aquatic Sciences, Vol. 57, pp. 1062-1072.

References

• Heinke, G.W. and Deans, B. (1973) Water supply and waste disposal systems for Arctic communities. Arctic, Vol. 26, pp. 149-159.

• Hermanson , M.K. (1998) Anthropogenic mercury deposition to Arctic lake sediments. Water, Air, and Soil Pollution, Vol. 101, pp. 309-321.

• Hermanson, M.K. and Brozowski , J.R. (2005) History of Inuit community exposure to lead, cadmium, and mercury in sewage lake sediments. Environmental Health Perspectives, Vol. 113, pp. 1308-1312.

• Landers, D., Gubala, C., Verta, M., Lucotte, M., Johansson, K., Vlasova, T. and Lockhart, L. (1998) Using lake sedimentary mercury flux ratios to evaluate the regional and continental dimensions of mercury deposition in arctic and boreal ecosystems. Atmospheric Environment, Vol. 32, pp. 919-928.

• Lockhart, W.L., Macdonald, R.W., Outridge, P.M., Wilkinson, P., De laronde, J.B. and Rudd, J.W.M. (2000) Tests of the fidelity of lake sediment core records of mercury deposition to known histories of mercury contamination. The Science of the Total Environment, Vol. 260, pp. 171-180.

• Martínez-Cortizas, A., Pontevedra-Pombal, X., García-Rodeja, E., Nóvoa-Muñoz, J.C. and Shotyk, W. (1999) Mercury in a Spanish peat bog: Archive of climate change and atmospheric deposition. Science, Vol. 284, pp. 939-942.

References

• Moore, J.W. and Ramoorthay, S. (1984) Heavy Metals in Natural Waters. Springer-Verlag, New York.

• Morel, F.M.M., Kraepiel, A.M.L. and Amyot, M. (1998) The chemical cycle and bioaccumulation of mercury. Annual Review of Ecology and Systematics, Vol. 29, pp. 543-566.

• Rada, R.G., Wiener, J.G., Winfrey, M.R. and Powell, D.E. (1989) Recent increases in atmospheric deposition of mercury to north-central Wisconsin lakes inferred from sediment analyses. Archives of Environmental Contamination and Toxicology, Vol. 18, pp. 175-181.

• Rasmussen, P.E. (1994) Current methods of estimating atmospheric mercury fluxes in remote areas. Environmental Science & Technology, Vol. 28, pp. 2233-2241.

• Rognerud , S.and Fjeld, E. (2001) Trace element contamination of Norwegian lake sediments. Ambio, Vol. 30, pp. 11-19.

• Shotyk, W., Norton, S.A. and Farmer, J.G. (eds.) (1997) Peat Bog Archives of Atmospheric Metal Deposition. Kluwer Academic Publishers, Dordrecht.

• Tomiyasu, T., Matsuyama, A., Eguchi, T., et al. (2006) Spatial variations of mercury in sediment of Minamata Bay, Japan. Science of the Total Environment, Vol. 368, pp. 283-290.