天津市农区地下水硝酸盐污染现状调查与评价

Investigation and Evaluation on Nitrate Concentration Status of Groundwater in Rural Areas of Tianjin

硝酸盐含量是衡量地下水水质的重要指标，直接关系到人类的健康。大量研究表明，地下水硝酸盐污染已成为普遍问题。为了摸清天津市地下水硝酸盐污染现状，2011年对天津市10个涉农区县的地下水进行了取样调查及硝酸盐含量监测，对地下水硝酸盐污染现状进行了分析研究。结果表明，天津市地下水NO3^--N含量总体较低，平均值为7．11mg／L，约12．06％的地下水样超过中国地下水质量标准。取样时间、取样区域、地下水埋深的不同，均导致了地下水硝酸盐含量的差异。雨季后地下水硝酸盐含量（6．89mg／L）低于雨季前（7．33mg／L）；受地下水埋深影响，0～30m、30～100m和≥100m地下水硝酸盐含量分别为47．66、13．5、0．18mg／L，受作物种植类型、施肥习惯以及地形等因素的共同影响，不同地区间地下水硝酸盐含量差异明显，西青、蓟县2个地区地下水硝酸盐含量高于10mg／L，武清、宝坻、静海3个地区地下水硝酸盐含量在6．95-9．82mg／L，津南、北辰等5个地区地下水硝酸盐含量低于5mg／L，宁河、东丽以及滨海新区地下水水质最好，未出现污染现象。

Nitrate content is an important index to evaluate the quality of groundwater which affects human health directly. As to evaluate the nitrate contamination in groundwater in Tianjin, an investigation and watersampling analysis on nitrate concentration in Tianjin groundwater was performed in 2011, and the nitrate pollution status was studied. The results showed that： the average 7.11 mg/L, and about 12.06% samples exceeded the criterion of concentration of groundwater was affected obviously by concentration of NO3^--N in groundwater was national drinking water quality. The nitrate sampling period, sampling area and sampling depth. The nitrate concentration in groundwater after raining period （6.89 mg/L） was lower than that before raining period （7.33 mg/L）. The nitrate concentrations in groundwater of 0-30 m, 30-100 m and ≥100 m depth were 47.66 mg/L, 13.5 mg/L and 0.18 mg/L respectively. As being affected by cultivation system, fertilizer application and landform, there were obvious differences between the nitrate concentrations of different areas. The nitrate concentrations of Xiqing and Jixian were exceeded 10 mg/L, higher than other districts; the nitrate concentrations of Wuqing, Baodi and Jinghai were between 6.95 mg/L and 9.82 mg/L. The nitrate concentrations of other 5 districts were under 5 mg/L.