Clean Air, Cleaner Water

The link between air quality and water quality was first popularized in the early1960's when Rachel Carson warned of the dangers of the indiscriminate spraying of pesticides in Silent Spring. Overthe years, the evidence of contamination from the air crossing media into water bodies through atmospheric deposition has dramatically increased. From PCBs to acid rain to mercury, dioxins,and lead, chemicals that were once thought of as strictly air pollutants, are now prime suspects in the cross-contamination of rivers, lakes, and streams around the globe. The air pollutants that affect water quality can result from both natural and anthropogenic sources, some sources, thousandsof miles away from the receiving watershed and waterbodies. This paper presents an overview of theimpacts of air contaminants on water quality, the transport process that brings the pollutants fromtheair to the surface, the pollutants of concern, the various monitoring networks established tomeasure the levels of the atmospheric deposition and pollutant loading to watersheds, and the modeling techniques used to estimate the impacts.