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cross-shelf sampling schemes

(from rivers out to reefs) would

be needed to help pinpoint the

origin of chemicals found in reef

organisms. Therefore, caution

and prudence must be exercised

in interpreting bioaccumulation

results, which must be placed in

the appropriate context in order

to be understood and acted

upon properly.

It is important to remember that

the mere presence of these

chemicals in marine life and

sediments is only a potential

problem, with ecotoxicological

tests  needed  to  determine

the physiological or ecological

significance

of

different

concentrations.

Great care and attention must be

taken in field sampling protocols

Craig Downs

to  avoid  cross-contamination

and subsequent contamination of samples. Likewise,

Data

Data Needs

strict laboratory procedures and controls are required

Further sampling is needed to establish baseline

to ensure consistent and accurate results.

values for a variety of chemicals and locations

Status

Status

throughout the MAR. Data from ecotoxicology studies

using a variety of marine organisms are needed,

Few data on contaminant accumulation in reef

including those on sensitive larval and settlement

organisms are available, although work is currently

phases. A variety of marine organisms (e.g., corals,

underway by WWF and partners. Preliminary data

crustaceans, mollusks, echinoderms, and fishes)

indicate that the most prevalent compounds in reef

need to be evaluated because the response and

organisms are chlorothalonil, imidacloprid, malathion,

physiological pathways of chemical exposure vary

DDT, mancozeb, deltamethrin, fipronil, propanil,

among these organisms.

lindane, and aldrin. Contaminant concentrations

in marine organisms range from non-detectable to

relatively high ~ 2 ppm (mg/kg)24.

Top-level predator fish species are more likely to

have the highest concentrations of highly persistent

chemicals. Other species (like the white grunt) have

been found to contain the widest range of compounds

in rather high concentrations, probably due to their

variety of food sources.

The MBRS Synoptic Monitoring Program has collected

some data on chlordane and hexachlorocyclohexane

(HCH). Both pesticides have been banned or severely

restricted in the MAR region, but, due to their

persistence, traces still remain in the environment.

Maps of summarized data are available at the MBRS

website (www.mbrs.org.bz)25.

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