Nitrogen contamination in the Yangtze River system, China

The data at 570 monitoring stations during 1990 were studied. The results i ndicate as follows: (i) the contents of nitrogen in the Yangtze mainstream has a raising trend from the upper reaches to the lower reaches; (ii) total nitrogen content at a lot of stations during the middle 1980s is 5-10 time s more than that during the 1960s; (iii) seasonal variances of nitrogen con tent vary with watersheds; and (iv) the difference of nitrogen contaminatio n level is related to the regional population and economic development. (C) 2000 Elsevier Science B.V. All rights reserved.