Organochlorines

Organochlorines are a broad class of organic compounds that contain carbon–chlorine bonds. They encompass many pesticides, industrial chemicals, solvents, and flame retardants. The term includes legacy pollutants such as DDT and polychlorinated biphenyls (PCBs) as well as a variety of chlorinated solvents and other additives.

Most organochlorines are synthetic, though some chlorinated natural products occur in trace amounts. They are typically relatively stable and lipophilic, leading to low water solubility and persistence in the environment. These properties promote long-range transport via air and water and cause bioaccumulation in fatty tissues, with concentrations often increasing up the food chain (biomagnification).

Health and ecological effects vary by compound but can be significant. Many organochlorines are toxic to aquatic life and can affect wildlife reproduction and development. In humans, exposure has been linked to neurodevelopmental effects, endocrine disruption, immunotoxicity, and, for some compounds, cancer risk. The severity of outcomes depends on the specific chemical, exposure route, dose, and duration.

Regulatory actions have aimed to reduce production and use due to persistence and toxicity. The Stockholm Convention on Persistent Organic Pollutants targets several organochlorines for elimination or restriction, including DDT, lindane, chlordane, heptachlor, aldrin, dieldrin, endrin, mirex, hexachlorobenzene, toxaphene, and PCBs. Some countries continue limited uses under exemptions or for essential purposes.

Ongoing monitoring, risk assessment, and remediation of contaminated sites are important to manage the environmental and health impacts of organochlorines.