摘要
"三氮"也就是氨氮、硝酸盐氮、亚硝酸盐氮,其污染已成为地下水污染的常见形式,研究"三氮"的迁移转化机理对浅层地下水"三氮"的污染控制有重要意义。以海口南渡江周边地区砂壤土为研究介质,通过室内土柱淋滤试验,研究在pH 6.5、5.5、4.5的条件下,用100 mg/L氮肥溶液淋滤,"三氮"的迁移转化情况。结果表明:在pH 6.5和5.5时,从1号采样点到3号采样点NH_4^+-N、NO_2^--N、NO_3^--N的浓度总体趋势是下降,土壤对"三氮"的去除作用包括土壤的吸附作用和硝化及反硝化作用。在pH 6.5时NH_4^+-N、NO_2^--N、NO_3^--N的去除效率分别为57.2%、65.3%、91.6%。在pH 5.5时,NH_4^+-N、NO_2^--N、NO_3^--N的去除效率为46.3%、61.2%、60.4%。pH 6.5在吸附作用、硝化作用和反硝化作用的最佳pH范围内,因此对"三氮"去除效率最高。在pH 4.5时NO_2^--N浓度由141.3μg/L增至147μg/L。NO_3^--N的含量由11.3 mg/L增至34.56 mg/L,说明在pH 4.5时,受到酸性环境的抑制硝化作用和反硝化作用减弱,且土壤对NO_2^--N和NO_3^--N吸附效果较小,可能导致土壤中NO_2^--N和NO_3^--N的积累。海南地区土壤呈酸性,应适时监测地下水"三氮"的含量并采取相应的控制措施。
＂Three nitrogen＂pollution including ammonia nitrogen, nitrate nitrogen and nitrite nitrogen, whichhas become a common form of groundwater pollution. Study on the migration and transformation mechanism of＂three nitrogen＂is important to control shallow groundwater pollution. Sandy loam of surrounding areas inHaikou Nandu River was taken as the research medium, migration and transformation of＂three nitrogen＂werestudied under 100 mg/L nitrogen solution leaching under the pH value of 6.5, 5.5 and 4.5 by soil columnleaching experiment. The results showed that the concentration of NH_4~＋-N, NO_2^--N and NO_3^--N decreasedfrom No.1 to No.3 sampling point under pH 6.5 and 5.5, which was mainly due to the adsorption of soil andnitrification and denitrification. The removal efficiencies of NH_4~＋-N, NO_2^--N and NO_3^--N were 57.2%, 65.3%and 91.6%, respectively, under pH 6.5, but they were 46.3%, 61.2% and 60.4%, respectively, under pH 5.5.pH 6.5 was in the optimal pH range of adsorption, nitrification and denitrification, and it had the highestremoval efficiency of＂three nitrogen＂. The concentration of NO_2^--N increased from 141.3 g/L to 147 g/L at pH4.5, and the concentration of NO_3^--N increased from 11.3 mg/L to 34.56 mg/L, it indicated that nitrificationand denitrification were inhibited by acid environment, and the absorption efficiency was week, which mightlead to the accumulation of NO_2^--N and NO_3^--N in soil. The soil in Hainan area was acidic, the concentrationof＂three nitrogen＂in groundwater should be monitored timely and corresponding measures should be taken tocontrol the pollution.
出处
《中国农学通报》
2017年第30期56-60,共5页
Chinese Agricultural Science Bulletin
基金
海南医学院科研培育基金"浅层地下水中亚硝酸盐迁移转化机理实验研究"(HY2012-017)
海南医学院创新创业训练计划实验项目"海南乐东地下水硝酸盐含量调查及分析"(HYCX2015040)
关键词
“三氮”
迁移转化
淋滤试验
地下水
土壤柱
＂three nitrogen＂
migration and transformation
leaching experiment
groundwater
soil column
