Recommendations for the derivation and use of biota-sediment bioaccumulation models for carcinogenic polycyclic aromatic hydrocarbons.

Carcinogenic polycyclic aromatic hydrocarbons (cPAHs) are important sediment contaminants that can pose health risks to people who eat shellfish from contaminated sites. Biota-sediment accumulation factors (BSAFs) are quotients of colocated lipid-normalized tissue concentrations and organic carbon (OC)-normalized sediment concentrations, whereas biota-sediment accumulation regressions (BSARs) are models describing the relationships between these tissue and sediment concentrations. BSAR/Fs (BSARs and/or BSAFs) are commonly used to back-calculate sediment preliminary remediation goals (PRGs) from target tissue concentrations; the PRGs are then used to set target action levels (i.e., sediment concentrations above which remedial actions will be prescribed). The cPAH BSAR/Fs reported across sites and species are highly variable due to both site- and species-specific differences and inconsistent BSAR/F calculation methods and assumptions. We reviewed past studies, identified best practices for developing BSAR/Fs, and compiled publicly available colocated tissue and sediment data for 7 cPAHs from 13 sites across the United States. Of the 249 unique cPAH data sets compiled for various species, only 17 yielded acceptable BSAR/Fs, 16 of which were for clams. The influence of BSAR/Fs on sediment remedial action decisions and costs can be disproportionate to the quality of the statistical models from which they are derived. Therefore, it is important to establish and follow best practices for deriving BSAR/Fs and for deciding whether and how BSAR/Fs should be used. Based on our review and analysis, we highlight the advantages of relying on BSARs and propose a consistent method for deriving and judging the reliability of these relationships. We also offer guidance for evaluating the ramifications of BSAR uncertainty on remedial decision making at contaminated sediment sites, and we discuss alternative ways to make risk management decisions in the absence of a reliable site-specific BSAR. Integr Environ Assess Manag 2017;13:1060-1071. © 2017 SETAC.

Sensitivity of lamprey ammocoetes to six chemicals.

As part of the ecological risk assessment for Portland Harbor Superfund site, a study was conducted to address the question of whether the use of surrogate species in the risk assessment would be protective of lamprey ammocoetes. The study evaluated the acute toxicity of six chemicals: pentachlorophenol, copper, diazinon, aniline, naphthalene, and lindane; these chemicals represent the toxic modes of action of oxidative phosphorylation uncoupler, gill dysfunction, acetylcholinesterase inhibitor, polar narcosis, narcosis, and central nervous system interference, respectively. Field-collected lamprey ammocoetes were exposed to each of the six chemicals in a definitive 96-h flow-through acute water-only toxicity test. LC(50)s were calculated for pentachlorophenol at 31 µg/l, copper at 46 µg/l, diazinon at 8.9 mg/l, and aniline at 430 mg/l. Species sensitivity distributions based on LC(50)s for aquatic organisms indicated that lamprey ammocoetes were relatively sensitive to pentachlorophenol (15th percentile). The sensitivity of lamprey ammocoetes to copper approximated the average of aquatic species tested (46th percentile). Lamprey ammocoetes were relatively insensitive to diazinon and aniline (72nd and 90th percentile, respectively). The 96-h LC(50) for naphthalene was estimated at 10 mg/l, based on 50% mortality in the highest concentration. Based on a comparison with LC(50)s for four other fish species, ranging from 2.0 to 6.6 mg/l, lamprey ammocoetes were relatively insensitive to naphthalene. A 96-h LC(50) could not be derived for lindane, with 12.5% mortality in the highest test concentration of 2.68 mg/l. LC(50)s for numerous other fish species ranged from 0.001 to 0.24 mg/l, indicating that lamprey ammocoetes were relatively insensitive to lindane. The study concluded that the use of surrogate species in the ecological risk assessment for Portland Harbor would be protective of lamprey ammocoetes.