Showing papers by "Stephen J. Klaine published in 1994"
TL;DR: It is suggested that the bioavailability of contaminants such as those tested cannot be accurately pre dicted in bioassays that expose organisms to aqueous representations of whole sediment.
Abstract: Bioassays have frequently been used as tools to simulate exposure of benthos to sediment-associated contaminants in hazard assessments. Due to the problems involved with estimating bioavailability in whole-sediment bioassays, aqueous frac tions such as elutriates and pore water have been substituted for whole-sediment exposures. The objective of this research was to compare and evaluate the bioavailability of representative neutral hydrophobic contaminants in whole sediments and in aque ous extracts of whole sediment (elutriate and pore water) in simultaneous bioassays, using three representative indicator spe cies, Diporeia spp., Chironomus riparius larvae, and Lumbriculus variegatus. Aqueous extracts of whole sediment did not accurately represent the exposure observed in whole sediment. Generally, the aqueous extracts underexposed organisms com pared to whole sediment, even after adjusting accumulation to the fraction of organic carbon in the test media. Accumulation comparisons among whole-sediment, elutriate, and pore-water exposures depended on sampling time. At some sampling times for some contaminants, differences in accumulation between a particular aqueous extract and whole sediment were not signifi cant; however, these similarities were not observed for all species at the particular sampling time. Bioaccumulation and con taminant clearance data suggest that a number of factors such as the indicator species, exposure media, and chemical/physical properties of individual contaminants are responsible for the accumulation differences observed among the tested media. Nor malizing bioaccumulation to the amount of organic carbon in a source compartment adjusted for bioavailability differences of only some contaminants. We suggest that the bioavailability of contaminants such as those tested cannot be accurately pre dicted in bioassays that expose organisms to aqueous representations of whole sediment.
134 citations
TL;DR: In this article, the utility of peroxidase (POD) activity as a biochemical indicator of contaminant exposure in the aquatic plant Hydrilla verticillata, Royle was determined.
Abstract: Laboratory bioassays were conducted to determine the utility of peroxidase (POD) activity as a biochemical indicator of contaminant exposure in the aquatic plant Hydrilla verticillata, Royle. The plants were exposed to anthracene, sulfomet-uron methyl (Oust®), Cd2+, Cr6+, Cu2+, Mn2+, and Se4+ in concentration factors of 10. POD was extracted and measured by spectrophotometric assay. There was a significant increase in POD activity after a 5-d exposure to each of the chemicals at 1 mg/L. The optimum pH for POD activity after exposure to the chemicals was 5.5 to 6.0. The increase in POD was found to be dose dependent for each of the chemicals. The lowest concentration of chemical to induce a significant POD increase was 0.01 mg/L for anthracene, Oust, Cd, Cr, and Cu; 0.1 mg/L for Se; and 1.0 mg/L for Mn.
50 citations
TL;DR: It appears that contaminant bioavailability can be altered by the addition of uncontaminated food, however, this phenomenon appears to be compound-specific and not broadly predictable.
38 citations
TL;DR: Contaminant partitioning did not change during 96-h exposures in bioassays, and partitioning of contaminants in porewater and elutriates did not follow a linear trend with the amount of sediment aging or manipulation.
18 citations
TL;DR: Developmental assay results indicated that selenate had no effect on emergence or hatching of brine shrimp regardless of the sulfate concentration, but selenates was lethal to nauplier larvae, and mortality was significantly reduced with increased sulfate concentrations in the media.
12 citations