The POPs described in this Assessment Report are characterized by their lipophilicity, persistence and semi-volatility. These characteristics pre-dispose these substances to long environmental persistence and to long range transport. These substances are also known for their ability to biomagnify and bioconcentrate under typical environmental conditions, thereby potentially achieving toxicological relevant concentrations. The semi-volatility of these substances facilitates their long range transport to and accumulation in the cooler and polar regions of the world, far removed from any source of use.
A number of the substances described in this report have been implicated in a broad range of adverse human health and environmental effects including impaired reproduction and endocrine dysfunction, immunosuppression and cancer. In many cases, the substances are considered as possible human carcinogens by the International Agency for Research on Cancer.
Many of the substances described in this report are still in use in at least some countries. The paucity of reliable data regarding use and disposal has meant that it has not been possible to accurately determine the quantities still in use, where they are used, the specific crops to which the pesticidal substances are being applied, and the direction and initiatives underway to eliminate these substances throughout the world. Where data does exist, it is plagued with a variety of limitations making it difficult to develop comprehensive and accurate use profiles.
While convincing substantive evidence exists for the actual and potential toxic impact of these substances to both human health and the environment, a comprehensive, accurate and reliable inventory of global manufacture, use and disposition, must be developed to allow the effective and efficient elimination of these substances throughout the world.
Several risk reduction strategies are available for the POPs. They involve greater use of alternatives to substances still in use and proper disposal of POPs in storage or in closed systems (e.g. PCBs). As this is a global problem, these strategies need to be coordinated on a global level and must be tailored to the socio-economic considerations of user nations.