Organic pollutants are chemical substances that contain carbon and originate from biological materials or synthetic organic compounds, which can contaminate water, soil, and air and pose risks to environmental and human health. In stormwater management, organic pollutants are commonly transported by runoff from urban, agricultural, and industrial areas into receiving waters.
Organic pollutants include a wide range of substances, both natural and man-made. Natural organic pollutants may consist of decomposing plant material, animal waste, and organic debris, while synthetic organic pollutants include petroleum hydrocarbons (such as oils and fuels), pesticides, herbicides, solvents, and industrial chemicals. Many of these compounds are characterized by their persistence in the environment, toxicity, and ability to accumulate in living organisms.
In stormwater systems, organic pollutants are often associated with impervious surfaces such as roads, parking lots, and industrial sites, where materials like oil, grease, and chemical residues accumulate and are washed off during rainfall events. They may also be attached to sediment particles or dissolved in water, allowing them to be transported through drainage systems.
The presence of organic pollutants can have several adverse impacts. Some compounds are toxic to aquatic organisms, while others contribute to oxygen depletion as they are broken down by microorganisms, affecting dissolved oxygen levels. Certain organic pollutants, such as pesticides and hydrocarbons, can also bioaccumulate in the food chain, posing long-term ecological and health risks.
Stormwater management practices aim to reduce organic pollutant loads through a combination of source control, filtration, adsorption, and biological treatment. Practices such as vegetated systems, infiltration practices, and constructed wetlands are particularly effective, as they promote microbial transformation and degradation of organic compounds.
Organic pollutants are a significant component of stormwater contamination, requiring careful management to protect water quality and ecosystem health.