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通过对福州市郊14片蔬菜基地的120个蔬菜样品、16个田面水样和11个地下水样的检测,并引用相关评价标准,分析了福州市郊菜地氮磷面源污染现状。结果表明:(1)处于严重污染(NO3-≥3100mg·kg-1)的蔬菜样品占检测总数的13.33%,处于重度污染(NO3-≥1440mg·kg-1)以上的蔬菜样品占检测总数的32.5%,处于中度污染(NO3-≥785mg·kg-1)以上的蔬菜样品占检测总数的50.83%。(2)氨氮含量超过地表水Ⅲ类(1mg·L-1)和Ⅴ类(2mg·L-1)水质标准的菜地田面水样数量分别占调查总量的62.5%和56.25%;硝态氮含量超过国家集中式生活饮用水地表水标准(10mg·L-1)的菜地田面水样数量占调查总量的12.5%;总氮平均含量和最高含量分别为10.99和33.80mg·L-1,分别是地表水Ⅴ类水质氮标准(2mg·L-1)的5.5和16.9倍;总磷平均含量和最高含量分别为4.75和12.75mg·L-1,分别是地表水Ⅴ类水质磷标准(0.4mg·L-1)的11.9和31.9倍。(3)氨氮含量超过Ⅴ类水质标准(0.5mg·L-1)的地下水样数量占调查总量的18.18%;硝态氮含量处于超标级别(≥10mg·L-1)以上的地下水样数量占调查总数的54.55%,处于严重超标级别(≥20mg·L-1)以上的地下水样数量占调查总量的27.27%;总氮含量全部超过Ⅴ类水质标准(2mg·L-1,GB3838—2002),超标率为100%;总磷含量超过Ⅴ类水质标准(0.4mg·L-1,GB3838—2002)的占调查总量的81.82%。
Based on the detection of 120 vegetable samples, 16 surface water samples and 11 groundwater samples from 14 vegetable bases in the suburbs of Fuzhou, the status quo of nitrogen and phosphorus non-point source pollution in suburbs of Fuzhou was analyzed with reference to relevant evaluation criteria. The results showed that: (1) The vegetable samples with serious pollution (NO3-> 3100mg · kg-1) accounted for 13.33% of the total number of samples tested, and the vegetables with heavy pollution (NO3- ≥1440mg · kg-1) 32.5% of the total samples, and those in the medium pollution level (NO3-≥785mg · kg-1) accounted for 50.83% of the total. (2) The amounts of surface water samples of vegetable fields whose ammonia nitrogen content exceeded the water quality standards of Grade 1 (1 mg · L-1) and Grade 2 (2 mg · L-1) of surface water accounted for 62.5% and 56.25% of the total respectively; The amount of surface water samples of vegetable fields whose nitrogen content exceeded the national standard of centralized drinking water surface water (10 mg · L-1) accounted for 12.5% of the total surveyed amount; the average content and the highest content of total nitrogen were 10.99 and 33.80 mg · L- 1, respectively 5.5 and 16.9 times of the nitrogen level of Grade V of surface water Ⅴ (2.mg · L-1). The average content and maximum content of total phosphorus were 4.75 and 12.75 mg · L-1, respectively, 11.9 and 31.9 times the standard (0.4 mg · L-1). (3) The amount of groundwater samples with ammonia nitrogen exceeding Grade V (0.5 mg · L-1) accounted for 18.18% of the total surveyed quantity; the amount of groundwater samples with nitrate content exceeding the standard (≥10 mg · L-1) Accounting for 54.55% of the total number of surveyed cases. The total amount of groundwater samples above 27% and 70% of the total surveyed cases exceeded the Class V water quality standard (2mg · L-1 and GB3838- 2002). The exceeding standard rate was 100%. The total phosphorus content exceeded the Grade V water quality standard (0.4mg · L-1, GB3838-2002) accounting for 81.82% of the total surveyed quantity.