Polychlorinated biphenyls

PCB; formula: C12H10-xClx

Persistent and toxic chlorinated compounds

Polychlorinated biphenyls are a class of 209 chlorinated hydrocarbons which share a common biphenyl structure but vary in number and position of chlorine atoms (congeners). The identification of the single congeners is facilitated by numbers whereby higher numbers are normally associated with a higher degree of chlorination. The degree of chlorination determines the physico-chemical properties of the compound, e.g. with increasing degree of chlorination, viscosity and lipophilicity increase but vapour pressure and water solubility decrease.

Commercial products always contain mixtures of 50-70 different congeners. Depending on the degree of chlorination they are thin or viscous oils.
Until the 1980s PCBs were widely used, e.g. as hydraulic fluids, lubricating oils, cooling and insulating fluids in transformers and capacitors, plasticisers and flame retardants in paints, plastics, sealing compounds and insulates.

Due to their wide application and high persistence, PCBs are ubiquitous. In the atmosphere they can be transported over long distances.
PCBs are accumulated by organisms and enriched in the food web (biomagnification). Furthermore, they are of high chronic toxicity and are suspected to be carcinogenic, teratogenic, reproductive toxic and developmental toxic and to act as endocrine disruptors.

Since 1983, PCB production is banned in the Federal Republic of Germany. When the Stockholm Convention entered into force in 2004, PCBs were banned worldwide.

For practicability reasons, analysis of PCB in samples is mostly restricted to six so called indicator-congeners (PCB-28, -52, -101, -138, -153, -180). These were chosen according to toxicological aspects.
Furthermore, PCB-118 is often analysed as representative of the dioxin-like PCBs.

Substances

  • PCB 101
    PCB 101 is a low chlorinated, relatively volatile PCB. Together with other low chlorinated congeners (e.g. PCB 28 and PCB 52) it stands for acute contamination of the ambient air. It degrades rather fast and accumulation in organisms is lower compared to higher chlorinated congeners.
  • PCB 118
    PCB 118 belongs to the toxicologically relevant group of dioxin-like PCBs (also known as WHO-PCBs) that have molecular-biological properties resembling those of dioxins and furans. They are highly toxic. Technical mixtures of PCB contain only trace amounts of dioxin-like PCB. They can occur as by-products of incineration processes.
  • PCB 138
    PCB 138 is a higher chlorinated PCB. It is hardly degradable and accumulates strongly in organisms and the food web. Together with other high chlorinated congeners (e.g. PCB 153 and PCB 180) it stands for long-term contamination mainly through food.
  • PCB 153
    PCB 153 is a higher chlorinated PCB. It is hardly degradable and accumulates strongly in organisms and the food web. Together with other high chlorinated congeners (e.g. PCB 138 and PCB 180) it stands for long-term contamination mainly through food.
  • PCB180
    PCB 180 is a higher chlorinated PCB. It is hardly degradable and accumulates strongly in organisms and the food web. Together with other high chlorinated congeners (e.g. PCB 138 and PCB 153) it stands for long-term contamination mainly through food.
  • PCB 77
    PCB 77 belongs to the toxicologically relevant group of dioxin-like PCBs (DL-PCBs, also known as WHO-PCBs) that have molecular-biological properties resembling those of dioxins and furans.Toxic equivalency factor according to WHO(2005) (WHO-TEF(2005)): 0.0001
  • PCB 81
    PCB 81 belongs to the toxicologically relevant group of dioxin-like PCBs (DL-PCBs, also known as WHO-PCBs) that have molecular-biological properties resembling those of dioxins and furans.Toxic equivalency factor according to WHO(2005) (WHO-TEF(2005)): 0.0003
  • PCB 126
    PCB 126 belongs to the toxicologically relevant group of dioxin-like PCBs (DL-PCBs, also known as WHO-PCBs) that have molecular-biological properties resembling those of dioxins and furans.Toxic equivalency factor according to WHO(2005) (WHO-TEF(2005)): 0.1
  • PCB 169
    PCB 169 belongs to the toxicologically relevant group of dioxin-like PCBs (DL-PCBs, also known as WHO-PCBs) that have molecular-biological properties resembling those of dioxins and furans.Toxic equivalency factor according to WHO(2005) (WHO-TEF(2005)): 0.03
  • PCB 105
    PCB 105 belongs to the toxicologically relevant group of dioxin-like PCBs (DL-PCBs, also known as WHO-PCBs) that have molecular-biological properties resembling those of dioxins and furans.Toxic equivalency factor according to WHO(2005) (WHO-TEF(2005)): 0.00003
  • PCB 114
    PCB 114 belongs to the toxicologically relevant group of dioxin-like PCBs (DL-PCBs, also known as WHO-PCBs) that have molecular-biological properties resembling those of dioxins and furans.Toxic equivalency factor according to WHO(2005) (WHO-TEF(2005)): 0.00003
  • PCB 123
    PCB 123 belongs to the toxicologically relevant group of dioxin-like PCBs (DL-PCBs, also known as WHO-PCBs) that have molecular-biological properties resembling those of dioxins and furans.Toxic equivalency factor according to WHO(2005) (WHO-TEF(2005)): 0.00003
  • PCB 156
    PCB 156 belongs to the toxicologically relevant group of dioxin-like PCBs (DL-PCBs, also known as WHO-PCBs) that have molecular-biological properties resembling those of dioxins and furans.Toxic equivalency factor according to WHO(2005) (WHO-TEF(2005)): 0.00003
  • PCB 157
    PCB 157 belongs to the toxicologically relevant group of dioxin-like PCBs (DL-PCBs, also known as WHO-PCBs) that have molecular-biological properties resembling those of dioxins and furans.Toxic equivalency factor according to WHO(2005) (WHO-TEF(2005)): 0.00003
  • PCB 167
    PCB 167 belongs to the toxicologically relevant group of dioxin-like PCBs (DL-PCBs, also known as WHO-PCBs) that have molecular-biological properties resembling those of dioxins and furans.Toxic equivalency factor according to WHO(2005) (WHO-TEF(2005)): 0.00003
  • PCB 189
    PCB 189 belongs to the toxicologically relevant group of dioxin-like PCBs (DL-PCBs, also known as WHO-PCBs) that have molecular-biological properties resembling those of dioxins and furans.Toxic equivalency factor according to WHO(2005) (WHO-TEF(2005)): 0.00003
  • WHO(2005)-PCB TEQ excl. LOQ
    Sum of dioxin-like PCBs (DL-PCBs), expressed as WHO toxic equivalent (TEQ) using the WHO-TEFs(2005), calculation by using lowerbound concentrations: lowerbound concentrations are calculated on the assumption that all the values of the different congeners below the limit of quantification (LOQ) are zero.
  • WHO(2005)-PCB TEQ incl. LOQ
    Sum of dioxin-like PCBs (DL-PCBs), expressed as WHO toxic equivalent using the WHO-TEFs(2005), calculation by using upperbound concentrations: upperbound concentrations are calculated on the assumption that all the values of the different congeners below the limit of quantification (LOQ) are equal to the limit of quantification.

Specimen

Sampling area

Sampling period

1985 - 2019