Human Health Implications of POPs

The implications of chronic and acute exposure to POPs are not fully understood. Laboratory investigations and environmental impact studies in the natural environment have indicated that POPs exposure can result in endocrine disruption, reproductive and immune dysfunction, brain and nervous system disorders, developmental disorders and cancer. Some organochlorine chemicals are likely carcinogenic by promoting the formation of tumours. PCBs are classified as probably carcinogenic to humans, while an additional eight of the 12 other POPs identified in the Stockholm Convention are classified as possibly carcinogenic to humans. The remaining three - endrin, dieldrin and aldrin are classified by WHO as highly hazardous (class 1b) on the basis of their acute toxicity to experimental animals.

Fetuses and infants are particularly vulnerable to POPs exposure due to the transfer of POPs from the mother during critical stages of development. Exposure during development has been linked to reduced immunity (and increased infections), developmental abnormalities, brain and nervous system impairment, and cancer and tumour induction or promotion in infants and children. There may also be a link to human breast cancer.

Cancer Risk

The International Agency for Research on Cancer identifies most of the 12 POPs targeted by the Stockholm Convention as presenting a potential carcinogenic risk to humans, as described in the table below.

IARC Classification


Group 1: The agent (mixture) is carcinogenic to humans

2,3,7,8-Tetrachlorodibenzo-para-dioxin (TCDD)

Group 2A: The agent (mixture) is probably carcinogenic to humans

Mixtures of polychlorinated biphenyls (PCB)

Group 2B: The agent (mixture) is possibly carcinogenic to humans

Toxaphene (mixtures of Polychlorinated camphenes)

Group 3: The agent (mixture or exposure circumstance) is unclassifiable as to carcinogenicity in humans

Polychlorinated dibenzo-para-dioxins (other than TCDD)
Polychlorinated dibenzofuran

Table Source:




Adapted from Stober, J, 1998. Health effects of POPs, Proceedings of the Subregional Awareness Raising Workshop on Persistent Organic Pollutants (POPs) Kranjska Gora, Slovenia, 11-14 May 1998

Recreational fishing at Xuan Lake, Viet Nam
Source: Hatfield 2007
Hatfield Consultants The World Bank funded by the Canadian POPs Trust Fund through the      
Canadian International Development Agency
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