Complications of Chemical Mixtures

Fish advisories often mention concerns with mercury and PCBs for the same species in the same water bodies. PCBs affect the thyroid, which controls brain development.²³ Mercury binds to brain tissue and may cause other problems. Both PCBs and mercury can pass through the placenta. ²⁴ Therefore, their combination may pose a greater risk to a developing fetus than either alone. Current epidemiological studies are exploring this linkage, and further study is warranted.