Estrogenicity of environmental PCBs.

Estrogenicity of Environmental PCBs The paper by Bergeron, Crews, and McLachlan, "PCBs as Environmental Estrogens: Turtle Sex Determination as a Biomarker of Environmental Contamination" (EHP 102:780-781) presents data on the estrogenic activity of 11 chlorinated biphenyls or diphenyl ethers, or hydroxylated derivatives thereof, selected so as to represent a variety of structural types. Some of the PCB types examined (e.g., compounds A, C, D, E, and J) arise from PCB congeners actually detectable in the commercial Aroclors (1) and hence also in environmental samples, whereas other PCB types (e.g., those with heavily uneven chlorination of the two rings, as in compounds F,G, and L) arise from PCB congeners that are not detectable in either the Aroclors themselves (1) or even environmentally transformed PCB compositions (2). It is noteworthy that the only compounds found to have statistically significant estrogenic activity (compounds F and G) both represented 4-hydroxylation products of PCB congeners belonging to the nonenvironmental group, whereas the five compounds representative of PCB structures actually present in the environment were all negative. In short, the results present zero evidence that environmental PCBs present risk of estrogenic activity. This is hardly what the authors claim, however. In their discussion they state (p. 781):