RESUMO
Acid rain is widely believed to be responsible for acidifying soil and water in areas of North America and northern Europe. However, factors commonly considered to make landscapes susceptible to acidification by acid rain are the same factors long known to strongly acidify soils through the natural processes of soil formation. Recovery from extreme and widespread careless land use has also occurred in regions undergoing acidification. There is evidence that acidification by acid rain is superimposed on long-term acidification induced by changes in land use and consequent vegetative succession. Thus, the interactions of acid rain, acid soil, and vegetation need to be carefully examined on a watershed basis in assessing benefits expected from proposed reductions in emissions of oxides of sulfur and nitrogen.
RESUMO
The concentration of phosphorus in parts per billion (ppb) in 33 Connecticut lakes was predicted from information on land use and simple models for concentration decreases in lakes. The best predictions were obtained from [Formula: see text] where P is the concentration of phosphorus in ppb, Q is the water load on the lake in meters per year, D is the water export from the entire watershed in meters per year, and U, A, and W are the fractions of urban, agricultural, and wooded land, respectively, in the watershed. The phosphorus export coefficients and SEM, estimated by least squares regression, were 170 +/- 21 mg per m(2)/yr for urban, 54 +/- 15 mg per m(2)/yr for agricultural, and 10 +/- 3 mg per m(2)/yr for wooded land. P +/- (SEM) 6.9 ppb was predicted.