million is being spent every year on 

 U. S. marine environmental monitoring, 

 but that most of it is devoted to compli- 

 ance monitoring, i.e., testing wastewa- 

 ters and other materials prior to dis- 

 charge, or making measurements near 

 discharge points as prescribed by regu- 

 lation. Since compliance monitoring, 

 by design, covers very small spatial 

 scales, national programs such as 

 NOAA's NS&T Program are the only 

 ones focusing on wider public concerns. 

 It is on this wider scale that national 

 benefits should be derived from expend- 

 ing billions of dollars to control direct 

 and indirect chemical discharges to 

 coastal and marine waters. 



The Mussel Watch Project was designed 

 to describe chemical distributions over 

 national and regional scales. Therefore, 

 it is important for sampling sites to be 

 representative of large areas rather than 

 the small-scale patches of contamina- 

 tion commonly referred to as "hot spots." 

 To this end, no sites were knowingly 

 selected near waste discharge points. 

 Furthermore, since the Mussel Watch 

 Project is based on analyzing indig- 

 enous mussels and oysters, a site must 

 support a sufficient population of these 

 mollusks to provide annual samples. 



NS&T sampling sites are not uniformly 

 distributed along the coast. Within estu- 

 aries and embayments. they average 

 about 20 kilometers (km) apart, while 

 along open coastlines the average sepa- 

 ration is 70 km. Almost half of the sites 

 were selected in waters near urban 



areas, wjthin 20 km of population cen- 

 ters in excess of 100.000 people. This 

 choice was based on the assumptions 

 that chemical contamination is higher, 

 more likely to cause biological effects, 

 and more spatially variable in these 

 waters than in rural areas. 



In 1986 and 1987, 145 Mussel Watch 

 sites were sampled. In 1988, a few sites 

 were added on the East Coast to fill in 

 large spatial gaps between sites, and one 

 was added in Hawaii to provide a third 

 sampling site for an oyster species that is 

 not sampled elsewhere. Also in 1988, 

 20 new sites were selected in the Gulf of 

 Mexico for the specific purpose of gath- 

 ering samples closer to urban centers. 



Results from the initial sampling showed 

 that the highest chemical concentrations 

 were near urban areas on the East and 

 West Coasts, and that few sites in the 

 Gulf of Mexico could be considered 

 contaminated. Since urban centers along 

 the Gulf are further inland than those 

 near other coasts, an attempt was made 

 to sample as close to them as possible. 

 The major limitation on sampling fur- 

 ther inland is that oysters are not found 

 at salinities below about 10 parts per 

 thousand. By 1990, 234 sites had been 

 sampled, with further additions made to 

 test the representativeness of earlier sites. 



Figures la through le indicate the loca- 

 tions of all sites sampled in the NS&T 

 Mussel Watch Project in the contiguous 

 United States. Three sites are located in 

 Hawaii, and two in Alaska. Locations of 



