BOX 3-1

Accomplishments of the NAWQA Program

National assessment of chemicals in the nation’s surface water: NAWQA has provided a national picture of surface water quality.

National assessment of chemicals in the nation’s groundwater: This picture extends to the quality of the nation’s groundwater, giving the scientific and regulatory communities and the public an understanding of the nation’s water quality. Specific to groundwater, NAWQA has demonstrated the utility of groundwater age determination in water-quality studies, especially mixing of old and young waters.

Incorporation of biological indicators of water quality into assessments: NAWQA has integrated measures of indicator organisms into water-quality monitoring and has examined relationships among biological, chemical, hydrological, and land-use parameters using uniform methods at a national scale.

National synthesis reports: These reports synthesize robust data sets using descriptive statistics to draw broad conclusions for the nation to help answer the question that led to the program’s development—what is the state of the nation’s water-quality?

Continuity and consistency in study methods and design: NAWQA uses standardized sampling regimes, network design, and analytical techniques to enable cross-site comparisons, as well as intensive site-specific and constituent-specific sampling to meet local and regional stakeholder needs, and national water-quality assessments.

pesticides, organics, and their breakdown products, which are often just as prevalent as the parent compounds. Contaminant occurrence is not limited to compounds currently in use: polychlorinated biphenyls, chlordane, dieldrin, and other organochlorine compounds that are now restricted still persist in streams and sediments. Spatiotemporal patterns in contamination correspond with the timing of chemical application, hydrologic events (e.g., snowmelt) and land management practices. Thus, NAWQA provided a picture of water quality nationwide, giving the scientific and regulatory communities and the public an idea of the nation’s water quality.

NAWQA’s continuing focus on pesticides built on the assessment of pesticides in the nation’s surface waters and groundwaters from 1991 to 2001 (Gilliom et al., 2006). More recent analyses identify trends in pesticide and herbicide concentrations in streams and rivers in the Corn Belt from 1996 to 2006 (Sullivan et al., 2009). Regulatory and economic



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