Phototoxic evaluation of marine sediments collected from a PAH-contaminated site.

The phototoxicity potential of PAH-contaminated field sediment was evaluated and compared to standard sediment toxicity test results. Marine sediments were collected from 30 sites along a presumed PAH sediment pollution gradient in Elliot Bay, WA. Standard 10-day acute and 28-day chronic sediment toxicity tests were conducted with the infaunal amphipods Rhepoxynius abronius and Leptocheirus plumulosus using mortality and the ability to rebury as endpoints. The survivors of these tests were then subjected to 1-h exposures to UV radiation with mortality and reburial again determined. The most highly toxic sediments identified in these experiments were evaluated further for toxicity and phototoxicity by serially diluting them with uncontaminated sediment and repeating the toxicity tests. Standard 10-day toxicity test results indicated that over 70% of the sites sampled in Elliot Bay exhibited measurable toxicity with nine sites being highly toxic to both species of amphipods. Results of standard 28-day chronic sediment toxicity tests were similar. In contrast, almost all of the sites were found to be highly phototoxic. Results indicated that exposure to UV increased toxicity five- to eightfold. This suggests that standard toxicity tests underestimate the potential ecological risk of PAH-contaminated sediments in animals exposed to sunlight. However, only when PAH contamination was between 0.05 and 1.0 toxic units would conducting a phototoxicity evaluation add information to that gained from conducting a standard sediment toxicity test alone.

Photoinduced toxicity of fluoranthene to seven marine benthic crustaceans.

Seven marine benthic crustaceans were exposed in 4 d water-only toxicity tests to five concentrations of fluoranthene. After exposures, mortality (LC50) and the ability to bury in clean sediment (EC50) were determined. Survivors were then exposed to UV radiation for 1 h. The differences between LC50s and EC50s before and after UV exposure were used to assess photoinduced toxicity. UV exposure enhanced fluoranthene toxicity by as much as tenfold in five of the seven species tested (Rhepoxynius abronius, Eohaustorius estuarius, Leptocheirus plumulosus, Grandidierella japonica, and Corophium insidiosum). Species having the greatest potential for natural exposure to sunlight (Excirolana vancouverensis and Emerita analoga) were the least sensitive to photoinduced fluoranthene toxicity. Although photoinduced toxicity needs to be considered in environmental risk assessments, testing should be done, using ecologically relevant species and exposures.

Depuration kinetics of hexachlorobenzene in the clam, Macoma nasuta.

1. The depuration rate constant for [14C]hexachlorobenzene (HCB) in the clam, Macoma nasuta, was determined following a short-term exposure to HCB contaminated seawater. 2. Depuration was not correlated with ventilation volume, nor did the amount of sediment ingested during depuration have a significant effect. 3. The half-life for HCB in M. nasuta was estimated to be 16 days with a bioconcentration factor of 3490 (wet weight basis).

Petroleum refinery wastewater induction of the hepatic mixed-function oxidase system in Pacific staghorn sculpin.

Induction of hepatic microsomal cytochrome P450 and aldrin epoxidase was observed in the estuarine sculpin (Leptocottus armatus), following in vivo exposure to Class B petroleum refinery effluent from two West Coast refineries. The data demonstrate the presence and inducibility of the mixed-function oxidase system in Leptocottus armatus. Differences in the extent of mixed-function oxidase induction between the two effluents may be related to differences in wastewater chemistry.

Effects of petroleum refinery wastewater exposure on gill ATPase and selected blood parameters in the Pacific staghorn sculpin (leptocottus armatus).

1. The effects of in vivo exposure to various concentrations of petroleum refinery wastewater on gill ATPase, plasma protein, plasma osmolarity, and hematocrit were measured in the euryhaline fish, Leptocottus armatus. 2. The extent of the reduction in Na,K-ATPase activity resulting from the exposure to the two refineries wastewaters may be related to wastewater chemical composition. 3. Changes in the blood chemistry parameters did not follow a consistent or easily explainable pattern.