Toward ecosystem‐based sediment quality guidelines for polychlorinated biphenyls (PCBs)

Abstract

To investigate whether Sediment Quality Guidelines (SQGs) for polychlorinated biphenyls (PCBs) in Canada and British Columbia achieve their objective of protecting ecosystems, we measured and compiled concentrations of PCB congeners in sediments, bivalves, crustaceans, fish, and marine mammals from 3 areas off the Pacific coast of British Columbia, Canada. The concentration data showed that whereas PCB concentrations in sediments were predominantly below the SQG of 20 µg/kg dry weight, large fractions of the PCB concentrations in fish and shellfish species exceeded the tissue residue guideline for the consumption of fish and shellfish by wildlife (i.e., 50 µg/kg wet weight [ww]) but were below the tissue residue guideline for the consumption of fish and shellfish by human populations (i.e., 2000 µg/kg ww). Also, PCB concentrations in marine mammals exceeded toxicity reference concentrations. The concentration data were used to develop species- and location-specific Biota-Sediment Accumulation Factors (BSAF = Cbiota /Csediment ), that were used to estimate PCB concentrations in wildlife species that may exist if the PCB concentration in sediments are equal to the SQGs. The results show that if the PCB concentration is equal to the SQGs, then PCB concentrations in most wildlife species can be expected to exceed the tissue residue guideline for the consumption of fish and shellfish by wildlife species and by humans, as well as toxicity reference concentrations for marine mammals. A methodology for developing SQGs for PCBs that are protective of the health of different wildlife species and human consumers of fish and shellfish from general Canadian and coastal First Nations populations was developed and applied. The proposed guidelines may provide useful guidance to establish SQGs for PCBs that can account for the ecological diversity in coastal environments and that better achieve the intent of the guidelines to protect ecosystems. The proposed methodology for guideline development may also be useful in the development of SQGs for other bioaccumulative substances.

First Assessment of the Benthic Meiofauna Sensitivity to Low Human-Impacted Mangroves in French Guiana

“…By referring to the official guideline concentrations for assessing toxicity hazards (i.e., effects range low (ERL) and effects range median (ERM; NOAA, 2012)), we have seen that organic contaminants and metals concentrations remained low. The most toxic PCB in our analyses were dioxin-like polychlorinated biphenyl 169 with a total concentration of 19.1 µg.kg −1 being just below the official used threshold [71] which does however depend on various intrinsic sediments parameters as the OM content. The most abundant pesticide was hexachlorobenzen found at station 2 at a concentration below the level of 17 ng/g that is calculated to be a predicted no effect HCB concentration for chronic exposure (PNEC chronic ) for organisms living in sediments [72].…”

Environmental Sources, Chemistry, Fate, and Transport of Per‐ and Polyfluoroalkyl Substances: State of the Science, Key Knowledge Gaps, and Recommendations Presented at the August 2019 SETAC Focus Topic Meeting

“…As mentioned in the previous section, PFAS are not a monolith in terms of environmental risk , there are large differences in hazard potential among compounds within the PFCAs and PFSAs. This is not unlike the orders‐of‐magnitude differences among bioaccumulation potential of individual PCB congeners that are considered when one is evaluating the risk potential of PCBs as a group (Arblaster et al, 2015; Gobas & Arnot, 2010). Assuming the same behavior (e.g., bioaccumulation, toxicity) without quantitative understanding of potential differences among individual chemicals has the potential to mismanage the risk of PFAS that share structural similarities (but not necessarily risk potential) with comparatively well‐studied PFAS. There are currently no PFAS quantitative structure–activity relationship (QSAR) models : Simply counting the number of fluorine atoms or perfluorocarbons in a molecule will not provide a simple short cut to characterizing the risk of an individual PFAS.…”

A chemical activity approach to exposure and risk assessment of chemicals

“…In many cases, the methodology for guideline development varies between environmental media (e.g., water, sediment, soil, animal tissue). This approach tends to produce a patchwork of medium‐specific guideline values that are often not internally consistent and sometimes fail to achieve the objective of consistently protecting environmental and human health (Arblaster et al ). A chemical activity approach allows toxicity data to be evaluated for a safe chemical activity value that can be applied to all relevant environmental media irrespective of the route of intake by the organism.…”

“…The laws of thermodynamics ensure that when chemical concentrations in environmental media are held at or below the safe activity value, environmental quality standards are achieved. This approach cannot be applied to chemicals that can biomagnify, and other approaches should be considered (Alava et al ; Arblaster et al ). However, the great majority of chemicals in commerce do not biomagnify, and the application of chemical activity may serve as a simple, pragmatic strategy to develop environmental quality criteria for chemicals in multiple environmental media of varying composition.…”