DDT (dichlorodiphenyltrichloroethane) is probably the most well-known of the organochlorine (OC) insecticides due to its environmental legacy. DDT was banned for use in the U.S. in 1972, with subsequent bans of other OCs (chlordane, dieldrin, endosulfan, hexachlorocyclohexane, etc.). DDT is considered one of the most insoluble and persistent pesticides ever synthesized, and it readily bioaccumulates. These chemicals persist in the environment but are not as toxic as many of the current-use pesticides
Polychlorinated Biphenyls (PCBs) were used in hundreds of industrial and commercial applications including electrical, heat transfer and hydraulic equipment, plasticizers in paints, plastics and rubber products, and pigments, dyes and carbonless copy paper. They were manufactured domestically until 1979, but because of their stability, they can remain in the environment for long periods, cycling between air, water, and soil. PCBs bioaccumulate in organisms at the lower end of the food web, and bioconcentrate in higher trophic levels.
Between 2008 and 2022, majority of the 90 sites showed stable/no trends for Chlordane, DDT and PCBs (96%, 91%, 95% of sites, respectively). In 2023, organochlorine monitoring was focused on 40 tier II urban sites. Out of these sites, 70-90% showed either stable or no trends for all three OCs. In order to minimize the effects of temporal analytical variability on trend analyses, the charts and tables below include data collected between 2012 and 2023. Trends shown below were identified for total chlordane (sum of five compounds), total DDT (the sum of six compounds) and sum of PCB congeners. No significant statewide trends are detected for any of the OCs at 40 sites between 2012 and 2023. Concentrations of chlordane and PCBs are significantly related to urban land use. The number of sites showing upward or downward OC trends are ≤5.
Polychlorinated Biphenyls (PCBs) were used in hundreds of industrial and commercial applications including electrical, heat transfer and hydraulic equipment, plasticizers in paints, plastics and rubber products, and pigments, dyes and carbonless copy paper. They were manufactured domestically until 1979, but because of their stability, they can remain in the environment for long periods, cycling between air, water, and soil. PCBs bioaccumulate in organisms at the lower end of the food web, and bioconcentrate in higher trophic levels.
Between 2008 and 2022, majority of the 90 sites showed stable/no trends for Chlordane, DDT and PCBs (96%, 91%, 95% of sites, respectively). In 2023, organochlorine monitoring was focused on 40 tier II urban sites. Out of these sites, 70-90% showed either stable or no trends for all three OCs. In order to minimize the effects of temporal analytical variability on trend analyses, the charts and tables below include data collected between 2012 and 2023. Trends shown below were identified for total chlordane (sum of five compounds), total DDT (the sum of six compounds) and sum of PCB congeners. No significant statewide trends are detected for any of the OCs at 40 sites between 2012 and 2023. Concentrations of chlordane and PCBs are significantly related to urban land use. The number of sites showing upward or downward OC trends are ≤5.
