黄海北部河口区活性磷酸盐含量分布动态与环境质量评价

Distribution of active phosphates and assessment of the ambient water quality in estuary of the northern Yellow Sea

1999～2000年对黄海北部重要河口海域活性磷酸盐的连续监测分析,结果表明,春夏季是江河等陆源排放活性磷酸盐的高峰期,秋季呈下降趋势,但沿岸的降水能延迟下降的时间表;总体区域分布为大洋河口以东偏高。1999年椅圈、大洋河口、碧流河口、鸭绿江口和庄河口活性磷酸盐含量的最高值出现在3～5月,分别达0.059mg/L、0.047mg/L、0.046mg/L、0.041mg/L和0.039mg/L;2000年椅圈、庄河口最大值出现在7月,为0.049mg/L和0.042mg/L,分别超过四类和三类海水标准,并超过引发赤潮的磷酸盐阈值;最低值全区多出现在9月。

The results of continuous monitoring on the active phosphates in the estuaries of North Yellow Sea during 1999-2000 were discussed. It showed that the discharges of the active phosphates from terrestrial sources were higher in spring and summer through the river water flowing,and it decreased in autumn. The decrease was delayed because rainfall in land. The active phosphate content in east estuary of Dayanghe River was higher than that in the west. The peak values and minimum values of the active phosphate content appeared in March to May, July or September in 1999, respectively. The highest concentrations of active phosphates in the seawaters near Yiquan, the estuaries of Dayang River and Biliu River were 0.059 mg/L, 0.047 mg/L and 0.046 mg/L, respectively in 1999, which were 31.1%, 4.4 %and 2.2 % higher than the criterion of fourth-class seawater. While the highest concentrations of the active phosphates in the seawaters around the estuaries of Yalu River and Zhuanghe River were 0.041 mg/L and 0.039 mg/L, respectively, which were 36.7% and 30.0 % higher than the criterion of third-class seawater. The minimum values of the active phosphate content in all area appeared in September, and the highest values in the seawaters appeared near Yiquan, and the estuaries of Zhuanghe River appeared in July, which were 0.049 mg/L and 0.042 mg/L in 2000, which were 8.9% and 40.0% higher than the criterion of fourth-class and third-class seawater respectively. Besides all these values of the active phosphate content exceeded the threshold values, which may cause the alga blooming.