- WEB EXCLUSIVE
- PE COFFEEHAUS
Contrasting with the results of a previous study, a new critical evaluation of sediment effect concentrations (SECs) of polychlorinated biphenyls questioned the degree of trust in those determinations.
According to a press release from the Society of Environmental Toxicology and Chemistry (SETAC), researchers of a new study concluded that the SECs for polychlorinated biphenyls (PCBs) should be used only in the screening-level evaluations that typically precede more direct assessments of sediment toxicity at individual study sites. The study is published in the latest issue of the society's publication, Integrated Environmental Assessment and Management.
In 2000, according to the release, a set of SECs was published for evaluating the toxicity of PCBs in freshwater, estuarine, and marine sediments. According to the developers, these consensus-based SECs reconcile existing sediment quality guidelines (SQGs) that have been developed using various approaches, reflect causal rather than correlative effects, and can be used to determine the spatial extent of injury to sediment-dwelling organisms.
In the present study, a critical evaluation of those consensus-based SECs was based on the original documents and databases used to develop the underlying SQGs as well as the original documents and data sets used to determine the predictive ability of the SECs. Results indicated that the SECs were simple mathematical constructs that share the same limitations as their underlying SQGs. The SECs were questionable "consensus" values because many of their underlying SQGs were dissimilar, misclassified, or redundant with other SQGs.
On the basis of this critical evaluation, researchers D. Scott Becker and Thomas Ginn concluded that the SECs for PCBs should be used only in the screening-level evaluations that typically precede more direct assessments of sediment toxicity at individual study sites, and should not be used to predict sediment toxicity. Contrary to the conclusions of the SEC developers, Becker and Ginn found that the SECs do not reconcile existing SQGs, do not reflect causal effects, and should not be used to determine the spatial extent of injury to sediment-dwelling organisms.
To read the entire study, Critical Evaluation of the Sediment Effect Concentrations for Polychlorinated Biphenyls (D Scott Becker and Thomas C Ginn), visit www.allenpress.com/pdf/i1551-3793-4-2-156.pdf