What it is:

  • PCBs are a group of synthetic organic chemicals containing 209 individual compounds, which are known as congeners.
  • They have no smell or taste and are can either be oily liquids or solids.
  • The name Arochlor is also used to reference PCBs in the U.S. For example, Arochlor 1345, which means there are 13 carbon atoms and 45 percent chlorine weight.
  • They do not burn easily and are used as good insulating material.
  • Due to toxicity, production was banned in the U.S. in 1977. The Environmental Protection Agency (EPA) banned most uses of PCBs in 1979. Current releases are due mainly to PCB cycling from soil to air to soil again.

Occurrence:

  • PCBs come into the environment as mixtures that contain a variety of individual components and there are no known natural resources of PCBs in the environment.
  • They have been used as coolants, lubricants/dielectrics in transformers, capacitors and other electrical equipment.
  • Since PCBs were banned, they usually only occur due to releases mainly from cycling from soil to air to soil again.

Health effects

  • PCBs can cause skin irritations, such as acne and rashes when exposed for a period of time.
  • PCBs found in the work place may cause irritation of the nose and lungs according to studies.
  • Short-term exposures well above the EPA maximum contaminant level, or MCL, potentially cause: Acne-like eruptions and pigmentation of the skin, hearing and vision problems and spasms.
  • Long-term exposures well above the MCL potentially cause: Effects similar to acute poisonings, irritation of nose, throat and gastrointestinal tracts, changes in liver function, problems with thymus gland, immune deficiencies or reproductive or nervous system difficulties.

Regulation:

  • In public water supplies: EPA has listed PCBs as a primary drinking water contaminant, with an enforceable MCL of 0.0005 milligrams per liter (mg/L), or 500 parts per trillion (500 ppt).
  • The MCLG for PCBs in drinking water set by the EPA is zero.

Water treatment:

  • Reduction readily with carbon adsorption or finer membrane filtration (such as RO or nanofiltration), and even reduction by conventional coagulation, flocculation, sedimentation, filtration, because PCBs are hydrophobic and the readily bind to particulates; some types of advanced oxidation have been known to break down the PCB molecule.

Sources: Environmental Protection Agency, Pollution Issues, Eco-USA, World Health Organization.