[ARCHIVED] Potential Human Health Effects of Perfluorinated Chemicals (PFCs)
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Perfluorinated chemicals (PFCs), including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are stain, water and grease repellent chemicals found in a wide range of consumer products. Almost everyone has detectable levels of PFOS, PFOA, and other PFCs in their blood. Although levels of PFOS and PFOA in human serum have declined in the US and Europe over the past decade, levels of PFNA (perfluorononanoic acid, the nine carbon version of PFOA) have increased. Serum PFOS levels have also increased exponentially in some areas of China over the past few years, likely reflecting increased PFOS production in China. PFCs have been linked to many health effects in animal studies, but often at higher exposure levels than are found in people. Few human health studies of PFCs have been conducted in the general population. To date, associations have been found between PFOS or PFOA levels in the general population and reduced female fertility and sperm quality, reduced birth weight, attention deficit hyperactivity disorder (ADHD), increased total and non-HDL (bad) cholesterol levels, and changes in thyroid hormone levels. Some results are inconsistent across studies and further work is needed to confirm these initial findings. In a highly exposed community living near a chemical plant, PFOS and PFOA have been associated with pre-eclampsia (pregnancy-induced hypertension), birth defects (PFOA only), and increased uric acid levels – a marker of heart disease. Occupationally-exposed workers may have increased risk of prostate and bladder cancer. The production of PFOS, PFOA, and some of their precursors is being phased out in many parts of the world, but PFOS production has increased dramatically in China since 2003. Many other PFCs and precursors remain in commercial use worldwide. Humans are exposed to many chemicals in addition to PFCs. The long-term health effects of multiple, low-level exposures are poorly understood. Chemical exposures to the developing fetus, infants, and children are the greatest concern; these periods are the most sensitive stages of human development.