Global Contamination Issues Emerging in Coastal Regions

33Global Contamination Issues...J. KAU: Mar. Sci., vol. 12, Special Issue, pp. 33-46 (1421 A.H. / 2001 A.D.)

Introduction

Coastal waters, the transition area between theopen sea and the land, absorb much of the impactsof human activities. They are subjected to multipleand often conflicting uses, ranging from recrea-tional beaches and resorts, to fishing, to consump-

Global Contamination Issues Emerging in Coastal Regions: Implications for the Red Sea Ecosystem

J.P. COAKLEY and N.M. RASUL

National Water Research Institute, Canada Centre for Inland Waters, 867 Lakeshore Road, Burlington, Ontario, L8S 3E9 Canada; and

Faculty of Marine Science, King Abdulaziz UniversityP.O. Box 80207, Jeddah 21589, Saudi Arabia

ABSTRACT. Coastal waters in tropical and sub-tropical regions of the world are amongthe most productive and intensely commercialized marine ecosystems, and are alsothe most threatened by contamination from industrial and urban land-use activities. In-sights into issues of potential importance for the Red Sea area may be obtained fromexperiences in analogous waters elsewhere in the world, including the western hemi-sphere. Globally, the major challenges to a healthy coastal environment are posed byurbanization/industrial activity, intense coastal shipping, offshore petroleum exploita-tion, and tourism development. Although the Red Sea is characterized by low popula-tion densities along its coasts, the need still exists for proper coastal zone manage-ment. Urbanization and industrial activity are the major factor in pollution by metalsin the vicinity of the city of Jeddah as well as by effluents from desalination plantsand refineries. Such urban-generated contamination almost always goes together withcontamination by sewage and nutrients from waste water treatment. All can have anegative effect on valued coastal amenities such as coral reefs, bathing beaches, coast-al fisheries/mariculture, and coastal mangroves. Research in Lake Ontario, Canadacan be used to provide means to study the dispersal of such pollutants via sediments.Ships using the Suez Canal carry cargoes (some of which are toxic or harmful toaquatic life) that pose a threat to coastal resources by accidental and deliberate spills/discharges. Research carried out elsewhere (the Bahamas) into the fouling of touristbeaches by petroleum tar-balls has shown that this effect is serious and cumulativeand, in addition to sensitive coastal amenities (beaches, coral reefs, and fishinggrounds), might also cause damage to valued benthic communities. Ships traversingthe Red Sea also have the potential for introducing exotic species from remote areasthat may be harmful to the diverse Red Sea aquatic fauna, especially Acanthasterplanci, the crown-of-thorns starfish. This possibility is dramatically illustrated by thecase of the inadvertent introduction of the European zebra mussel (Dreissena) to theGreat Lakes in 1986.

tive uses, to use as receiving waters for municipaland industrial wastes. As a result, they are the mostthreatened by contamination from industrial andurban land-use activities and from a variety of oth-er environmental problems. This is true whetherthese waters are located in tropical and sub-tropical

33

J.P. Coakley and N.M. Rasul34

regions such as the Red Sea, or in the temperatenorthern regions of the world. The Red Sea is, inmany ways, still a pristine ecosystem, as yet littlestressed by human activities. However, it is hopedthat by being aware and watchful for some of theavoidable problems encountered elsewhere, thatthis environmental situation could be preserved.This report will discuss some of these coastal con-tamination problems, from the perspective of re-search done on the Great Lakes of North Americaand in the Caribbean, and suggest parallels be-tween these ecosystem and that of the Red Sea.The research all focus on the use of the bottomsediment record as a means of determining the im-pact and dynamics of contaminants in the coastalzone.

The Laurentian Great Lakes

The Great Lakes of North America (Fig. 1) wereformed in the Pleistocene epoch by glacial occupa-tion and deepening of existing drainage systems.These lakes represent the largest fresh-water body

in the world, a property that contributed to theirpresent status as centres for North American agri-culture, industry, and transportation. During theshipping season, scores of ships use the St. Law-rence Seaway, an aquatic sea-corridor bringing ma-rine ships more than 3000 km into the heart of theNorth American continent. The coastal zone ofthese lakes now is home to an estimated 20 millionpeople, most of whom live in fewer than 8 cities inthe United States and Canada. The conflicting usesof this large reserve of fresh water by an increasingpopulation has created a number of environmentalproblems, which are now the subject of intense re-search and remediation by the governments ofCanada and the United States.

The Red Sea

In sharp contrast to the Great Lakes, the Red Seais a marine body of water located in the sub-tropical zone within an area most properly de-scribed as desert. Almost twice the area of theGreat Lakes combined (Fig. 2), it forms a single,elongated body more than 2000 km long. It was

1. Toronto Waterfront2. Burlington S.T.P.3. Western Lake Erie

Lake Superior

Canada Centre for Inland WatersGeorgian Bay

Lake Huron

Lake Michigan

Lake Erie

The Great Lakes

Lake Ontario1

2

3

100 0 100 200 Kilometers

N

FIG. 1. The Great Lakes of North America are the largest body of fresh water in the world and are situated on the border betweenCanada and the United States of America. The numbered solid dots mark areas where the Great Lakes research mentionedhere was carried out.

Top inset : The Canada Centre for Inland Waters, in Burlington, is Canada's foremost centre for aquatic and environmental re-search.

35Global Contamination Issues...

Saudi Arabia

formed as a result of relative vertical movementsof crustal plates (it is a continuation of the East Af-rica rift system) separating the African and Asiancontinents. Because of the associated tectonicdown-faulting, its maximum depths, more than2000 m, are much greater than in the Lakes. TheRed Sea is bordered by Egypt, Saudi Arabia, Su-dan, Djibouti, Ethiopia, Yemen, and Jordan (Fig.2), but population density along its coast, with the

exception of Jeddah (1.25 million people) and PortSudan (300,000 people) is relatively low. As a re-sult, the Red Sea remains overall an extremelypristine environment with the largest diversity ofaquatic life of any body of water in the world.However, the above population centres neverthe-less contribute much to the environmental stresseson the coastal Red Sea (industrial and municipalwaste discharges, petroleum discharges and spills,

FIG. 2. The Red Sea is located in the Middle East region, occupying a rifted depression between the African and the Asian continents.It is surrounded by 8 countries. Major ports are Jeddah, Saudi Arabia and Port Sudan.

Top Inset: The Red Sea compared in area with the Great Lakes of North America.


brine disposal from desalination plants, coastalzone abuse, to name a few). Other significant in-dustries in this regard are those associated with pe-troleum exploitation (transport and refinery) andshipping through the Suez Canal that connects theRed Sea to the Mediterranean. The most valuedcoastal ecosystems are the abundant coral reefsand bathing beaches that attract large numbers ofdivers and tourists, primarily to resorts in Egypt,although mangroves also provide valuable sites forcoastal wildlife.

The Bahamas

The Bahamas archipelago is located in the west-ern Atlantic Ocean within 200 km from the coastof Florida (Fig. 3). It comprises over 700 islands

and cays, of which only 19 have sufficient watersupplies to be inhabited. The islands are composedentirely of coral sand derived from reef materialand carbonate deposition on the shallow banks.The principal industries are offshore banking andtourism, although there is an increasing diversifica-tion into light industries (petroleum refining andtrans-shipment, cement production and fish pro-cessing), most of which are located on the islandsof Grand Bahama and New Providence/Nassau.The overall pristine condition of the Bahamasaquatic environment, like that of most of the RedSea, is the main component in a steady growth inthe areas of underwater recreation and eco-tourism.Plans are also under consideration to initiate mari-culture as another industrial initiative.

FIG. 3. The Bahamas archipelago lies between Florida and the Dominican Republic. Most of the economic activity and tourist visitstake place in the capital, Nassau.


To provide for its population of 280,000 and atransient tourist population of up to 3.5 million peryear, the capital island, New Providence, must relyon desalination plants and inter-island water ship-ments to supply more than 2 million gallons perday. The waste brines from this plant are dis-charged into deep wells located close to the southshore of the island.

After relying on in-ground septic systems untilrecently, much of the island's sewage now under-goes partial treatment before being discharged intodeep wells located on the north shore close to theharbour (Fig. 4). Given the porous nature of thelimestone bedrock, it is noteworthy that no studiesare available on the effect of both these dischargeson sensitive environmental amenities located near-by, in particular, coral reefs, bathing beaches, andfish retention facilities.

Coastal Environmental Problems of a Global Nature

Coastal contamination in the Great Lakes

Environmental problems affecting the GreatLakes that might have relevance to the Red Sea en-vironment are:

� Contamination of coastal waters, beaches andcommercial marine species by effluents from hu-man activities (sewage treatment plant discharges)

� Invasion of aggressive alien aquatic species(Zebra mussel impacts)

There are a variety of vectors for inputs of con-taminants to the coastal zone of the Great Lakes.Non-point sources include surface run-off from ag-ricultural areas using chemical fertilizers, pesti-cides, and herbicides. A major non-point source isthe atmosphere, which is the main vector for long-range transport of pollutants; these affect mostlythe larger-area deep-water zones of the lakes.Point-sources, however, are the most important forthe nearshore zone, and will be the focus of this re-port. Such sources include inputs from municipalsewage treatment plants and industrial discharges.

Sediment Tracer Studies in Lake Ontario

In management of coastal resources, it is criticalto identify the zones of influence (mixing zones) ofknown point-source contaminant inputs. In the To-ronto area the largest point-sources for contami-nants are the Main and Humber Sewage TreatmentPlants (STP) and the Humber River (Fig. 5). TheHamilton area to the southwest represents another

FIG. 4. Oblique aerial photograph of Nassau Harbour to the north of the island. The bridge shown connects Nassau to Paradise Is-land, a major tourist destination. Note the proximity of the sewage treatment plant installation (STP) to the local fish market.


FIG. 5. Tracer studies in the vicinity of two major sources of contaminants to the Toronto waterfront, nearshore Lake Ontario (loca-tion 1 in Figure 1).

Top: Transport pattern of sediment contaminated by sewage effluent from the Humber Sewage Treatment Plant (STP) outfall,using as a tracer, the conservative faecal sterol, coprostan ol. Inferred flow is to the south and southwest around theheadlandÆ

Bottom: Use of bottom sediment concentrations of cobalt, released by metal-working industries in the Humber River wa-tershed, as a tracer of sediment transport patterns near the mouth of the river. Pattern shows two principal modes oftransport.


FIG. 6. Transport pattern using the tracer, coprostanol, around the Burlington Skyway STP outfall (location 2 in Figure 1). Radialsampling grid and sample locations of bottom samples are shown. Dotted lines shows interpreted contaminated sedimenttransport patterns. Inset shows relationship of study area to Hamilton Harbour, a major inland industrial.

important point source of sewage and industrialdischarges. Tracer studies were carried out in bothareas, i.e., the vicinity of the Humber STP and theriver mouth in the Toronto area, and at the outfallfor the Burlington Skyway STP in the Hamiltonarea (Fig. 6). The aim was to determine whetherthe effluent plumes constituted a threat to clean-water amenities, such as nearby drinking-water in-takes, bathing beaches, and fish spawning areas.

Methodology

The methodology of the studies is described inthe publications listed below, but is summarizedbriefly here. In the Toronto study, statistical analy-sis of a selected suite of trace metals Coakley andPoulton (1991) was used to identify the principalpoint sources, the Humber River and the HumberSewage Treatment Plant (STP) outfall. Dispersalof contaminated sediments from the river wasinvestigated using as tracers a cesium-containingmineral, as well as naturally-occurring trace met-als. The cesium tracer mineral is inert and non-reactive and is conservative over the study period.In the case of the STP effluent, an array of conser-vative sewage-related compounds was used totrace the outfall dispersion; these included the fe-cal steroid, coprostanol (Bachtiar et al., (1996) the

vitamin-E compound, a-tocopheryl acetate, andstable isotopes of nitrogen and carbon (Coakley etal., (1992).

Sediment samples were collected in a systematicgrid pattern around the point sources and analyzedfor the above tracers. Analysis of organic com-pounds was by gas chromatography/mass spec-trometry. For trace elements, some were analyzedby standard ICP atomic emission spectrometry andothers (cesium) by neutron activation analysis, us-ing accepted standards of quality control and quali-ty assurance (QA/QC). The concentration of thevarious tracers was plotted onto maps of the areaand contoured to identify spatial distributions, pat-terns, and concentration gradients. These were theninterpreted in terms of contaminant transportplumes.

Toronto Waterfront (Humber Bay)

The dispersal patterns inferred for the dischargefrom the Humber River are shown in Fig. 5 (Bot-tom). There appear to be two distinct patterns, oneresembling a jet pattern pointing directly offshore,while the other follows the western shore of theBay in a southward direction. A net southwardtransport plume along the western shore of the Bay


FIG. 7. Tar balls, rounded desiccated masses of crude petroleum, are found commonly on many Bahamian beaches, causing concernespecially in tourist areas. They are most often associated with masses of seaweed stranded on shore at high tide.

was also visible in the coprostanol pattern aroundthe STP outfall (Fig. 5 Top). However, significantflow reversals toward the northeast were identified(Coakley et al., 1992). This reversed pattern is im-portant in that sensitive areas (beaches) are locatedin that direction; however, this pattern is relativelyminor, and in general, the plumes were in direc-tions away from sensitive areas Æ

Hamilton Harbour and Western Lake Ontario

Dispersal patterns associated specifically withsewage discharges from the outfall of the Burling-ton Skyway STP within Hamilton Harbour wereinvestigated using coprostanol as a tracer. A dis-tinctive shore-parallel plume, having a principalsouthward trend was identified, with a secondarytransport direction toward the north and west(Bachtiar et al., 1996). In connection with plans torelocate the outfall from the Harbour to the openlake, another study was carried out in the vicinityof the new outfall site using an artificial tracer sim-ilar to that used in the Humber River study. The re-sults showed that transport in this area was at alow rate under summer conditions and the tracerwas displaced only a short distance from the originover a period of three months. This is indicative ofa relatively low mixing capacity at that particularsite, and suggests further search for another moreenergetic site.

Coastal Contamination in the Bahamas

Coastal contamination has not been extensivelystudied in the Bahamas, largely because the gener-al perception is that it is not a problem. While thisis generally true, there are some environmental is-sues impacting the coastal zone that merit atten-tion, and also could have relevance to coastal is-sues in the Red Sea area, namely:

� Pollution of bathing beaches by oil residuesfrom production and shipping of petroleum.

� Placement of conflicting facilities, such assewage treatment plant outfalls and areas of mari-culture or temporary fish-retention areas.

Tar Balls on Bahamian beaches

Many of the beaches in the Bahamas, especiallyon the island of Grand Bahama (the locus of petrole-um trans-shipment and refining, as well as intensetourist development), are contaminated to a greateror lesser extent by petroleum residue. This pollu-tion, commonly referred to as "tar balls", occurs inthe form of semi-solid, flattened, rounded masses,generally less than 10 cm in maximum dimension(Fig. 7). These are recognized as global phenomenaand as alarming indicators of world-wide pollutionof the oceans and coastal waters by petroleum dis-charges of various types (accidental spills, irrespon-sible discharges of tanker washings and coastal zone


oil production). In the Bahamas, the economic andaesthetic impact on tourist amenities is considera-ble, as these tar balls attach themselves to the feetand clothing of sun-bathers and are brought insideto damage carpets and flooring. The tar balls thatsettle on the sea-bottom may also affect the healthof benthic organisms and bottom-feeding fish. Thephenomenon has been studied in only a few places,mostly in the Caribbean (Coakley, 1977 and Den-nis, 1974) but represents a potential contaminationproblem for petroleum production, refining, andshipping areas such as the Red Sea.

In a beach survey carried out in 1976, the num-ber of tar balls at 19 beach sites on the south coastof Grand Bahama were estimated. Bulk samples ofthe top 5 cm of beach sand were collected at thehigh-water mark using a square quadrat sampler0.25 m2 in area. The sand was passed through asieve with a mesh size of 6.4 mm, and the tar ballsseparated, weighed and counted. The results dem-onstrated that the tar balls were highly variable insize and degree of weathering. The beaches aver-aged 50 tar balls or 24 g.m�2 (i.e., balls larger than6.4 mm). Statistical analysis on the distribution ofthese contaminants was inconclusive as to theirorigin, but their overall weathered state suggeststhat they were not derived locally but originatedfar away, possibly as discharges of tank-washings

along the tanker shipping lanes off the west coastof Africa.

Contamination from Sewage?

Like most growing metropolitan areas, the Baha-mas is constantly upgrading its waste water treat-ment infrastructure. The present location of themain STP for Nassau, the capital was located onthe north shoreline, adjacent to the harbour (Fig.4). This site is within a kilometre of the newly relo-cated fish market with its extensive holding areasfor live shellfish, turtles, and grouper (Fig. 8).Within a short time, there were frequent outbreaksof gastro-intestinal complaints from customers ofthe fish market, and a bacteriological survey wasinitiated. The results pointed to the STP as a possi-ble source of harmful bacteria, which were reach-ing the market area and contaminating the live fish.This is especially serious considering that much ofthe shellfish sold (conch) is consumed raw. Thiscase illustrates clearly the need to conduct priorsurveys of hydrodynamic mixing and current pat-terns before locating STP outfalls or clean-waterfacilities within reach of each other.

Zebra Mussel Impacts in Western Lake Erie.

Zebra mussels (Dreissena polymorpha, ZM) arebivalved mollusks native to fresh and brackish wa-

FIG. 8. Fish being processed at the Nassau fish market. This market is located within several hundred metres of the major STP for thecity. Holding and aeration tanks are visible at the top left of the photo.


ter areas of eastern and northern Europe. Adultsnormally reach sizes (maximum shall length) of upto 25 mm (Fig. 9). They are encrusting by natureand form thick, strongly-attached coverings on anysubmerged hard surface available (Leach, 1993),including intake pipes of cooling water systems forcoastal installations and ships, and the surfaces ofnavigation buoys (de la Fontaine, 1996). Deleteri-ous effects include complete blockage of water cir-culation, increased hull drag and slower speeds ofvessels, sinking of buoys, as well as the fouling ofbeaches with sharp-edged mollusk shells. ZMpropagate very efficiently, and are spread overlarge distances via an initial planktonic larval (veli-ger) stage before attachment to a suitable hard sur-face. There, they tend to form dense masses (drus-es) firmly bonded to the substrate by their strongbyssal threads (Dermott and Munawar, 1993).

This reproductive mechanism, when added tothe lack of local predators or any other significantecological check on their growth, has made ZM aserious threat to commercial installations and shipson the Great Lakes. Since their inadvertent releaseinto Lake St. Clair through dumping of ballast wa-

ters of a European vessel in 1986, ZM have ex-panded rapidly throughout most of the LaurentianGreat Lakes and adjacent watersheds. These exoticmollusks now occur in dense colonies on the bot-tom of western Lake Erie where they cover virtual-ly all the exposed hard substrates (bedrock out-crops, shipwrecks) and areas on the bottomcovered by boulder- and cobble-sized material,usually found in shallow waters. More recently, ex-tensive zebra mussel colonies are being found indeeper areas of western Lake Erie (average depth:10 m) on soft, muddy substrates once believed tobe inhospitable to them. Given the fact that theyare filter-feeders, drawing in and filtering nutrientscarried as suspended particles from considerablequantities of water, their expansion to such habitatsmight have serious implications for contaminanttransfer from the water column to the bottom sedi-ments, and also for bottom sediment resistance toerosion and resuspension. The study was aimed atquantifying the density and the distribution pat-terns of mussel colonization in the basin as a firststep in investigating the effect on key sediment

FIG. 9. Since 1986, when they were inadvertently introduced to the Great Lakes, populations of the benthic zebra mussel (Dreissenapolymorpha) have risen to as high as 300,000 individuals per square metre in the western basin of Lake Erie.centre and port.


properties of such an abrupt change in benthiccommunity structure. By linking their distributionwith substrate properties, we hope to identify keyprocesses and controls on colonization. Some pre-liminary findings of this study have been publishedin Rasul et al. (1999) and in Coakley et al. (1997).

Study Methodology and Results

Underwater video imagery and diver-collectedsamples taken from representative soft-sedimentareas in western Lake Erie showed colonizationlevels of up to 25,000 live mussels per m2 in softsediments (adults with shells >10 mm comprised20-50 %). This is lower than the densities exceed-ing 342,000 mussels per m2 found on hard sub-strates (Leach, 1993). More than 170 km of digitalside-scan sonar records confirmed that coloniza-tion patterns over the area were not random, butshowed distinctive spatial signatures ranging from30 m long parallel stripes, to ovate, football-shaped masses. Broad irregular mats were found inassociation with hard bottoms (bedrock, boulders,or wrecks and large debris). From the four repre-sentative areas, relationships were assumed be-tween major substrate type and mussel quantities.Colonization density of each of the major bottomtypes was combined with digitized percentage ofareal coverage for these bottom types in westernLake Erie (Rasul et al., 1999), producing a first-order approximation figure of 1014 individuals forthe total population of mussels in the western ba-sin. Such a large number of benthic organisms,constantly filtering the overlying water for organicmatter and nutrients, is bound to have a significantimpact on the lake ecology, ranging from disrup-tion of nutrient dynamics to interference with fish-spawning conditions. These effects are only nowbeing investigated and brought to light.

Discussion

Comparisons with the Red Sea Coastal Contami-nation Situation

The differences between the physical environ-ment of the Red Sea and that of the Great Lakesare considerable and any comparison must be donewith caution. Therefore, the chemical behavior anddynamics of individual aquatic contaminants is ex-pected to be somewhat different, given the con-

trasting conditions of salinity, depth and tempera-ture. Also important differences in population den-sities and industrial activities of bordering commu-nities preclude any direct transfer of researchinsights from one area to the other. The experienc-es with coastal contamination observed in the trop-ical waters of the Bahamas (tar balls on beaches,sewage contamination of fish retention areas),however, may be related more readily to the RedSea environment. In the discussion below, we usethe experiences in the Great Lakes and the Baha-mas to provide some useful lessons and cautionsfor managers of coastal ecosystems in the Red Sea.

Coastal Zone Contamination Issues for the RedSea

The level and type of coastal zone contaminationin the Red Sea is generally quite low at present,and confined mainly to around major populationcentres, such as Jeddah. In northern areas such asSinai region (Gulf of Aqaba) and the Egyptiancoast (Gulf of Suez) environmental resource con-flicts between the expanding tourist and reef-diving concerns and the petroleum exploitation andshipping sector are possible. For the Saudi Arabiancoast, the major contaminant problem appears tobe related to the disposal of industrial wastes, mu-nicipal sewage, hypersaline brines from desalina-tion plants, and fish treatment wastes associatedwith the city of Jeddah (El-Rayis et al., 1984 andSaad & Fahmy, 1996). Refineries and oil handlingfacilities south of Jeddah are also cited as sourcesof marine pollution through the release of toxic pe-troleum compounds (Al-Lihaiby & Al-Ghamdy,1997). A comprehensive discussion of the prob-lems posed by all these environmental hazards isbeyond the scope of this report; rather we will dis-cuss those that have an affinity with studies by theauthors in the western hemisphere. Because of thedifficulty in obtaining references for other Red Seaareas, this report will focus primarily on the SaudiArabian coast and on the Jeddah area in particular.

Sewage-based Contaminants

Partially treated sewage effluent treatment forthe city of Jeddah is discharged directly into coast-al lagoons, or into the harbour, where it is trans-ported to the open sea by tidal action. According toEl-Rayis (1998) Jeddah's two STP facilities dis-


charge a total of more than 100,000 m3-day �1, or37 million m3.y�1. The harbour (South Corniche)site has a discharge of 100,000 m3.day�1 of sewageand industrial waste. Depending on the level oftreatment, these effluents carry significant loadingsof nutrients (P, N, Si) and faecal colliform bacte-ria, as well as toxic trace metals and organics, tothe coastal zone. This transfer of contaminants isincreased greatly if the lagoons are dredged period-ically.

Nevertheless, studies of contaminants in thecoastal zone of the Red Sea are still at the stage ofidentification of impacts, and focus mainly on thewater column (El-Rayis et al., 1984). A number ofauthors have cited the negative effects of sewagecontamination on zooplankton, benthic foraminife-ra and on mangroves. No studies were found deal-ing with the transport or spread of contaminants toclean-water coastal amenities such as beaches, co-ral reefs, fishing grounds or nurseries. The onlysediment-based contaminant studies noted were byRifaat (1994).

The scarcity of sediment surveys or assessmentsis a major problem, especially with respect tocoastal zone management and monitoring of con-flicting resource uses. In the Great Lakes, bottomsediments provide a more accurate long-term as-sessment of contaminant dynamics in the environ-ment than that provided by the water column or in-dicator organisms (Coakley and Mudroch, 1996).Systematic survey of nearshore sediments and con-taminant distributions in the vicinity of sources ofnearshore pollution that share the coast with clean-water amenities can provide valuable informationfor the design and location of municipal and indus-trial outfalls. The environmental problems asso-ciated with the system for disposal of sewage ef-fluents now in place in Jeddah (smells, impacts onmangroves) might also be having an unknown cu-mulative impact on nearby facilities that are sensi-tive to sewage contamination (for instance, mari-culture, fishing grounds). Tracer studies usingfecal sterols or other conservative organic speciescould play a role in the assessment of this impact,as well as in providing a baseline for future moni-toring.

Industrial Contaminants

The severity of the problem of industrial dis-charges into the Red Sea has not been clearly de-fined. Contaminants from refineries and desalina-tion plants contain a number of toxic componentsthat can harm reef organisms and fish stocks. In theGreat Lakes, tracer studies in the Humber Riverarea of Lake Ontario have shown that the spatialdistribution of sediment concentrations of tracemetals and organics, if they are conservative, canbe used to indicate their transport patterns clearly.Before such techniques can be feasible in the RedSea environment, a careful evaluation of the behav-ior and stability of priority metal species in condi-tions of varying temperature, Eh, and salinitywould be necessary.

As shown by the Bahamas experience, petrole-um discharges into the aquatic environment is al-ways undesirable and causes harm to sensitive eco-systems. The impacts range from surface slicks totar balls on beaches or on the bottom in the near-shore zone. Tar balls have already been reported inthe Gulf of Suez and are identified components inthe coastal environment surveys of the Red Seaproposed by the World Bank Blue Team and theUNEP.

Invasion by Exotic Species

As noted in the Great Lakes, alien species intro-duced to a new area have the potential for a popu-lation explosion that can have devastating effectson the local ecosystem. Like the zebra mussel inCanada, there are marine species from other areasthat can negatively impact Red Sea aquatic life. Al-though no such threat appears in the current litera-ture on the Red Sea, the impacts of species such asthe "crown-of- thorns" starfish (Acanthaster plan-ci) elsewhere in the Pacific region (e.g., the GreatBarrier Reef of Australia) is cause for concern.

Conclusion

Despite the major difference in physical environ-ment between the Great Lakes, the Bahamas, andSaudi Arabia, there is much common ground inso-far as coastal zone contaminant problems are con-cerned. For this reason, similar methods of study-ing and assessing the problems can be applied toall these areas. Research on the dispersal and mix-


ing of sewage-related contaminants in Lake Onta-rio using tracers has provided a methodology foruse in the design and location of sewage treatmentplant outfalls. Experience from the Bahamas aswell shows that these discharges can travel consid-erable distances to impact sensitive areas, such asbeaches and mariculture. The use of fecal sterols tounderstand the impacts of the sewage wastes atJeddah might provide some useful answers to theseenvironmental problems. Other problems experi-enced outside the Red Sea (beach pollution by tarballs, exotic species) have not yet appeared to anygreat extent in the area. Nevertheless, the countriesbordering the Red Sea must remain vigilant andalso encourage multi-lateral protocols to ensurethat petroleum discharges from ships or fromshore-based operations are controlled. Also thetransfer of exotic organisms through ballast waterdumping of ships from the Pacific Rim, whereAcanthaster is endemic, should be a high priorityconcern of all the Red Sea nations.

References

Al-Lihaiby, S.S. and Al-Ghamdy, T.S. (1997) Petroleum hy-drocarbons in Saudi Red Sea coastal waters, Jour. KingAbdulaziz University, Marine Sciences, 8: 83-89.

Awad, H. (1984) Role of Petromin refinery in adding crudeoils to Jeddah coastal waters, Proc. Sympos. Coral ReefEnrivonment of the Red Sea, Faculty of Marine Science,King Abdulaziz University, Jeddah, Saudi Arabia, p.108.

Bachtiar, T., Coakley, J.P. and Risk, M. (1996) Tracingsewage-contaminated sediments in Hamilton Harbourusing selected geochemical indicators, Sci. Total Envi-ron., 179: 3-16Æ

Coakley, J.P. (1977) Distribution of tar-balls on Bahamianbeaches, Shore and Beach, Jour. American Shore andBeach Preservation Assoc., 45(2): 30-35.

Coakley, J.P. and Poulton, D.J. (1991) Tracing long-termfine sediment transport in HumberBay, Lake Ontario,Jour. Great Lakes Res., 17(3): 289-303.

Coakley, J.P., Carey, J.H. and Eadie, B.J. (1992) Specificorganic components as tracers of contaminated fine sed-iment dispersal in Lake Ontario near Toronto, Hydrobi-ologia 235/236: 85-96.

Coakley, J.P. and Mudroch, A. (1996) Contaminated sedi-ments in urban environments: sources, transport, andfate, In: Environmental Geology of Urban Areas, N.Eyles, Ed., Geoscience Canada, pp. 227-239.

Coakley, J.P., Brown, G.R., Ioannou, S.E. and Charlton,M.N. (1997) Colonization patterns and densities of ze-bra mussel Dreissena in muddy offshore sediments ofwestern Lake Erie, Canada. Jour. Water, Air, and SoilPollution, 99: 623-632.

De La Fontaine, Y. (1996) Recruitment variability of zebramussels in the St. Lawrence River, 6th. Internat. ZebraMussels and Other Aquatic Nuisance Species Conf.,March 1996, Dearborn, Mich., Abstracts p. 76.

Dennis, J.V. (1974) A second oil pollution survey of the southeast Florida coast, Amer. Petroleum Inst. Publ., 4231:36.

Dermott, R. and Munawar, M. (1993) Invasion of Lake Erieoffshore sediments by Dreissena, and its ecological im-plications, Canadian Jour. Fisheries and Aquat. Sci.,50: 2294-2304.

El-Rayis, O.A. (1998) Environmental conditions of two RedSea coastal lagoons in Jeddah. 2 � Nutrients, Jour.King Abdulaziz University, Marine Sciences, 9: 49-59.

El-Rayis, O.A., El-Sayed, M.M. and Turki, A.J. (1984) Apreliminary investigation for level and distribution ofsome heavy metals in coastal water of Jeddah, Red Seaduring 1981- 1982. Proc. Sympos. Coral Reef Environ.,Red Sea, Jeddah, pp. 147-169.

Leach, J.H. (1993) Impacts of the zebra mussel (Dreissenapolymorpha) on water quality and fish spawning reefs inwestern Lake Erie. In: T.F. Nalepa and D. Schloesser(Ed.), Zebra Mussels: Biology, Impacts, and Control,Lewis Publishers, Inc., Chelsea, Michigan, pp. 381-397.

Rasul, N.M, Coakley, J.P. and Pippert, R. (1999) Sedimen-tary environment of Lake Erie: geologic setting, sedi-ment distribution, and modern evolutionary trends.NWRI Contrib. 96-64, In: State of Lake Erie: Past,Present, and Future, M. Munawar (ed.), Backhuys Pub-lishers, Leiden, the Netherlands, pp. 57-74.

Rifaat, A.E. (1994) Metal composition of recent carbonatesediments off Jeddah, Kingdom of Saudi Arabia, Jour.King Abdulaziz University, Marine Sciences, 7: 133-138.

Saad, M.A.H. and Fahmy, M.A. (1996) Heavy metal pollu-tion in the coastal Red Sea waters, Jeddah, Jour. KingAbdulaziz University, Marine Sciences, 7: 67-74.


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