Terrestrial avoidance behaviour tests as screening tool to assess soil contamination.

The {Sigma}PAH model estimates the probability of toxicity of PAH-contaminated sediments using a combination of equilibrium partitioning, WSAR, toxic unit, additivity, and concentration-response models. The sediment concentration of organic carbon and 13 PAH (polynuclear aromatic hydrocarbon) compounds were measured. Interstitial water concentrations (PAH{sub iw}) of the 13 compounds were predicted by equilibrium partitioning. The 10-d LC50 of each compound in interstitial water (10-d LC50{sub iw}) was predicted by a QSAR regression of 10-d LC50{sub iw} (From spiked sediment tests) to K{sub ow}. Toxic unit concentrations of individual compounds (TU{sub i}) were predicted as PAH{sub iw}/10-d LC50{sub iw}. The total number of toxic units of the 13 compounds ({Sigma}TU{sub i}) was calculated assuming the additivity of toxic effects of PAHs. {Sigma}TU{sub i} was used to predict the probability of toxicity to marine and estuarine amphipods using a concentration-response model derived from spiked sediment toxicity tests. The {Sigma}PAH model was verified by comparing predicted and observed toxicity in field-collected sediment samples. There was 86.6% correspondence and no significant difference between predicted and observed toxicity at PAH-contaminated sites. Ecological-effect levels predicted by the {Sigma}PAH model correspond with several sediment-quality guidelines.

ΣPAH: A Model to predict the toxicity of polynuclear aromatic hydrocarbon mixtures in field‐collected sediments

Sediment quality guidelines (SQGs) for polycyclic aromatic hydrocarbons (PAHs) have been derived from a variety of laboratory, field, and theoretical foundations. They include the screening level concentration, effects ranges—low and—median, equilibrium partitioning concentrations, apparent effects threshold, ΣPAH model, and threshold and probable effects levels. The resolution of controversial differences among the PAH SQGs lies in an understanding of the effects of mixtures. Polycyclic aromatic hydrocarbons virtually always occur in field-collected sediment as a complex mixture of covarying compounds. When expressed as a mixture concentration, that is, total PAH (TPAH), the guidelines form three clusters that were intended in their original derivations to represent threshold (TEC = 290 μg/g organic carbon [OC]), median (MEC = 1,800 μg/g OC), and extreme (EEC = 10,000 μg/g OC) effects concentrations. The TEC/MEC/EEC consensus guidelines provide a unifying synthesis of other SQGs, reflect causal rather than correlative effects, account for mixtures, and predict sediment toxicity and benthic community perturbations at sites of PAH contamination. The TEC offers the most useful SQG because PAH mixtures are unlikely to cause adverse effects on benthic ecosystems below the TEC.

Consensus sediment quality guidelines for polycyclic aromatic hydrocarbon mixtures

Sediment toxicity testing: a bioassay approach using the amphipod Corophium volutator and the polychaete Arenicola marina

Toxicity and heavy metal contamination of surficial sediments from the Bay of Thessaloniki (Northwestern Aegean Sea) Greece.

Halifax Harbour sediments contain heavy metals and organic contaminants To assess the biological effects of these compounds in the sediment, seven sites spanning a range of known sediment types, water depths, metal levels, and organic contaminant levels were chosen for assessment by a series of tests Sediment toxicity was measured by the reduction of microbial luminescence (Photobacterium phosphoreum) in three Microtoxr tests (pore water, solvent extract, and solid phase), by the percentages of survival and reburial in two amphipod species (Rhepoxynius abronius and Corophium volutator), and by the survival and change in biomass of juvenile polychaete (Neanthes sp) Uptake of contaminants from sediment was assessed by a bioaccumulation test, using a bivalve mollusc (Macoma balthica) The chronic effects of the sediment on bottom-dwelling fish were assessed by histopathological studies on winter flounder (Pseudopleuronectes americanus) collected from the harbor The results of this study showed detectable biological effects of the Halifax sediments on two (Photobacterium phosphoreum and Rhepoxynius abronius) of the four species of tested organisms These effects were associated with high concentrations of polynuclear aromatic hydrocarbons (PAHs) in the harbor sediments The order of sensitivity for the various sediment toxicity tests was Microtox solvent extract = Microtox solid phase > Rhepoxynius abronius > Microtox pore water > Corophium volutator = Neanthes sp Mortality in Macoma was increased, although no significant uptake of contaminants was detected in the bioaccumulation test Hepatic lesions were observed in winter flounder collected from the harbor, suggesting a chronic effect of the contaminated harbor sediment

Sediment bioassessment in Halifax Harbour

Sediments in Sydney Harbour, Nova Scotia, are highly contaminated by polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and heavy metals. Histopathologic and histochemical evaluations were made on the Baltic clam, Macoma balthica, exposed to 11 Sydney Harbour sediment samples. Histologic lesions in digestive gland (tubular dilation or atrophy, macrophage aggregates, tubular cell necrosis, and tissue inflammation) and gonads (macrophage aggregates, supporting cell, germ cell, and ovarian cell necroses) were frequently detected in clams exposed to the most contaminated sediments from the harbor. Clams exposed to these contaminated sediments also had the highest acid phosphatase activity. The average scores of tubular dilation or atrophy, ovarian cell necrosis, and the sums of mean digestive gland lesions correlated significantly with sediment PCBs, and the activities of acid phosphatase correlated significantly with sediment heavy metals, PAHs, and PCBs. Among the lesions, digestive gland tubular dilation or atrophy, tubular cell, germ cell, and ovarian cell necroses, and the activity of acid phosphatase are the best sublethal effect indicators in Macoma exposed to Sydney Harbour sediments. Key words: biomarkers, chronic biologic effects, clams, histology, histochemistry, Macoma balthica, marine sediment, polynuclear aromatic hydrocarbons, polychlorinated biphenyls.

Histopathologic and histochemical biomarker responses of Baltic clam, Macoma balthica, to contaminated Sydney Harbour sediment, Nova Scotia, Canada.

An evaluation of the use of soil and sediment bioassays in the assessment of three contaminated sites in atlantic canada

Biological effects of gold mine tailings on the intertidal marine environment in Nova Scotia, Canada.

The current, managed process of disposal at sea, practiced by most nations worldwide, is in sharp contrast to practices, extending even as late as 1970, involving indiscriminant dumping, based largely on ignorance and an attitude that the ocean had unlimited resources and an unending capacity to absorb impact. If done in an environmentally acceptable manner, disposal at sea can be an attractive option, since it is generally less expensive than other waste management options such as waste treatment or land disposal. The London Convention 1972 and the London 1996 Protocol have essentially banned the disposal at sea of all waste and other matter other than the wastes listed in the Annexes to the convention, namely, dredged material, sewage sludge, ships and platforms, fish wastes, organic wastes of natural origin, inert inorganic geologic material and bulky wastes. Ocean disposal should be the last option if the wastes can be recovered for beneficial use. For instance, ocean disposal of nutrient-rich biosolids has been terminated in the U.S. in favor of land application and compost, in which biosolids are used as a soil amendment, fertilizing material, or compost conditioner. This chapter discusses these important topics: international convention on marine pollution prevention and control, waste assessment guidance, waste assessment audit, waste characterization process and resource recovery, an ocean disposal permit system, disposal site selection and monitoring, and land-based discharges of wastes to the sea. A design example is provided, and the biosolids Environmental Management System (EMS) of the City of Los Angeles for ocean pollution prevention is discussed.

Kok-Leng Tay

Papers

Sediment bioassessment in Halifax Harbour

Histopathologic and histochemical biomarker responses of Baltic clam, Macoma balthica, to contaminated Sydney Harbour sediment, Nova Scotia, Canada.

An evaluation of the use of soil and sediment bioassays in the assessment of three contaminated sites in atlantic canada

Biological effects of gold mine tailings on the intertidal marine environment in Nova Scotia, Canada.

Ocean Disposal Technology and Assessment