Threat To People and Wildlife
According to a study by the Environmental Directorate of the OECD "PFOS is persistent, bioaccumulative and toxic to mammalian species."
It has been shown to affect the immune system of male mice at a blood serum concentration of ~90 parts per billion, raising the possibility that highly exposed people and wildlife are immunocompromised. Chicken eggs dosed at 1 milligram per kilogram (or 1000 parts per billion) of egg weight developed into juvenile chickens with an average of ~150 parts per billion in blood serum—and showed effects such as brain asymmetry and decreased immunoglobulin levels. Occupationally exposed individuals have an average level of PFOS over 1000 parts per billion, and a small segment of individuals in the upper range of the general population are also over the 91.5 parts per billion level. A variety of wildlife species have had PFOS levels measured in egg, liver, kidney, serum, and plasma samples and some of the highest recorded values as of January 2006 are listed below.
| Species | Geography | Year | Sample | PFOS (ppb) |
|---|---|---|---|---|
| Bald Eagle | Midwestern USA | 1990–93 | plasma | 2,200 |
| Brandt's Cormorant | California, USA | 1997 | liver | 970 |
| Guillemot | Baltic Sea | 1997 | egg | 614 |
| Carrion Crow | Tokyo Bay, Japan | 2000 | liver | 464 |
| Red-throated Loon | North Carolina, USA | 1998 | liver | 861 |
| Polar Bear | Sanikiluaq, Nunavut | 2002 | liver | 3,100 |
| Harbor Seal | Dutch Wadden Sea, Denmark | 2002 | muscle | 2,725 |
| Bottlenose Dolphin | Charleston, South Carolina, USA | 2003 | plasma | 1,315 |
| Common Dolphin | Mediterranean Sea, Italy | 1998 | liver | 940 |
| Mink | Michigan, USA | 2000–01 | liver | 59,500 |
The levels observed in wild animals are considered sufficient to "alter health parameters". In people, the highest exposures to PFOS in blood are 12,830 parts per billion for occupational exposure and 656 parts per billion—or possibly 1,656 parts per billion—in a consumer.
In animal studies PFOS also causes cancer, physical development delays, endocrine disruption, and neonatal mortality; neonatal mortality might be the most dramatic result of laboratory animal tests with PFOS. Female mice with blood levels of PFOS within ranges found in wildlife and humans demonstrated higher mortality when infected with influenza A. PFOS reduces the birth size of animals; in humans, correlations between PFOS levels and reduced fetal growth are inconsistent.
PFOS is detected in the blood serum of almost all people in the U.S., where concentrations are decreasing; by contrast, blood levels of PFOS appear to be rising in China. PFOS levels in pregnant women have been associated with preeclampsia. Levels have also been associated with altered thyroid hormone values and an increased risk of high cholesterol. Levels in US children aged 12–15 were associated with an increased risk (60% over the interquartile range) of attention deficit hyperactivity disorder (ADHD).
Read more about this topic: Perfluorooctanesulfonic Acid
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