International programme on chemical safety

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Toxicological profile for nickel

Toxicological profile for benzene

Xenobiotic chemicals that are present in aquatic environments are typically concentrated on suspended particles and sedimentary materials where they represent a source of chronic contamination to benthic and pelagic organisms. Laboratory and field studies of bioaccumulation, toxicity, and food-chain transfer of chemicals bound to sediment have shown the potential ecological impacts that may result from the contamination of sediments. In this review, the chemical and physical processes that determine the environmental fate of sediment-sorbed organic chemicals are outlined, and their relationship to bioavailability is discussed. Methods currently used to predict the fate of pollutants in the aquatic environment are of limited use for the assessment of sediment-sorbed chemical bioavailability because they are based on the compound's behavior in the water column. Furthermore, an organism's morphology and ecological niche can profoundly affect its ability to accumulate xenobiotic chemicals from sediments and these must be considered before the populations at greatest risk can be identified.

The bioavailability of sediment-sorbed organic chemicals: A review

Experiments were designed to expose blue mussels (Mytilus edulis) to contaminated sediment collected from Narragansett Bay, Rhode Island, USA in 1982. Measurements were taken to allow comparisons of the uptake and depuration of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). In addition, concentration factors in the mussels were calculated separately against the dissolved and particulate phase concentrations and the results from the exposure and control systems were compared. Both PAHs and PCBs were rapidly accumulated by the mussels exposed to the contaminated sediment. After the mussels were transferred to control seawater, individual PAHs were depurated with half-lives ranging from 12 to 30 d. Individual PCBs showed depuration half-lives which ranged from 16 to 46 d. Concentration factors in the mussels calculated against the particulate phase concentrations were very different in the exposure and control systems. Concentration factors calculated using only the dissolved phase concentrations (bioconcentration factors) showed excellent agreement in the two systems, possibly an indication that the dissolved phase was the direct source of the contaminants accumulated by the mussels. The bioconcentration factors for PCBs were higher than those of PAHs when compounds with similar n-octanol/water partition coefficients were compared.

Uptake and depuration of organic contaminants by blue mussels ( Mytilus edulis ) exposed to environmentally contaminated sediment

Volatile organic pollutants in biota and sediments of Lake Pontchartrain.

Mallard drakes were dosed with 5 mL a day of South Louisiana crude oil for 14 days. Tissues from control and experimental ducks were then examined for petroleum hydrocarbons by combined high-resolution gas chromatography and mass spectrometry. Three characteristics of the saturated hydrocarbon fraction were used to assess the presence of crude oil: the n-alkane distribution pattern, the presence of homologous series of petroleum-derived hydrocarbons, and the n-C/sub 17//pristane ratio. Oil was found in every experimental tissue examined but the brain. The skin (and underlying adipose tissue) contained the highest level of saturated petroleum hydrocarbons. The other tissues were ranked relative to the skin as follows: skin > uropygial gland > breast muscle, heart muscle > liver > brain. The blood contained low levels of petroleum-derived hydrocarbons 3--4 h after the final dose of crude oil. That saturated petroleum hydrocarbons did not accumulate in the duck tissues in the same relative amounts observed in South Louisiana crude oil suggested selective uptake and/or metabolism.

Accumulation of aromatic hydrocarbons in tissues of petroleum-exposed mallard ducks (Anas platyrhynchos)

The U.S. National Mussel Watch Program initially used split-sample analyses for interlaboratory quality control purposes. These indicated the possibility of interlaboratory analytical discrepancies as well as problems in the split-sample technique itself. For the third year of the program, two mussel homogenates were produced to serve as intercomparison samples — one for metals and organics, the other for radionuclides. The results obtained using these homogenates are encouraging in that generally good agreement is seen among analyses done by several labs in diverse pollutant classes. We conclude from this experience that a quality-control program relying on the analysis of large homogeneous samples of the matrix being dealt with is an essential part of any extensive, multilaboratory analytical program.

George C. Lawler

Papers

Volatile organic pollutants in biota and sediments of Lake Pontchartrain.

Accumulation of aromatic hydrocarbons in tissues of petroleum-exposed mallard ducks (Anas platyrhynchos)

The mussel watch: Intercomparison of trace level constituent determinations

An Automated Glass Capillary Gas Chromatographic System for Routine Quantitative Analysis