...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Environmental Science & Technology >Saturated Zone Denitrification: Potential for Natural Attenuation of Nitrate Contamination in Shallow Groundwater Under Dairy Operations
【24h】

Saturated Zone Denitrification: Potential for Natural Attenuation of Nitrate Contamination in Shallow Groundwater Under Dairy Operations

机译：饱和区反硝化：乳业运营下浅层地下水中硝酸盐污染的自然衰减潜力

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We present results from field studies at two central California dairies that demonstrate the prevalence of saturated-zone denitrification in shallow groundwater with ~3H/~3He apparent ages of < 35 years. Concentrated animal feeding operations are suspected to be major contributors of nitrate to groundwater, but saturated zone denitrification could mitigate their impact to groundwater quality. Denitrification is identified and quantified using N and 0 stable isotope compositions of nitrate coupled with measurements of excess N_2 and residual NO_3~- concentrations. Nitrate in dairy groundwater from this study has δ~(15)N values (4.3-61 per thousand), and δ~(18)O values (-4.5-24.5per thousand) that plot with δ~(18)O/δ~(15)N slopes of 0.47-0.66, consistent with denitrification. Noble gas mass spectrometry is used to quantify recharge temperature and excess air content. Dissolved N_2 is found at concentrations well above those expected for equilibrium with air or incorporation of excess air, consistent with reduction of nitrate to N_2. Fractionation factors for nitrogen and oxygen isotopes in nitrate appear to be highly variable at a dairy site where denitrification is found in a laterally extensive anoxic zone 5 m below the water table, and at a second dairy site where denitrification occurs near the water table and is strongly influenced by localized lagoon seepage.
机译：我们提供了来自加利福尼亚中部两个奶牛场的现场研究结果，这些结果证明了〜3H /〜3He表观年龄小于35岁的浅层地下水中饱和区反硝化的普遍性。怀疑动物集中饲养是硝酸盐对地下水的主要贡献者，但是饱和区反硝化可以减轻其对地下水质量的影响。使用硝酸盐的N和0稳定同位素组成以及过量N_2和残留NO_3〜-的测量值来确定和量化反硝化作用。这项研究中的乳业地下水中的硝酸盐具有δ〜（15）N值（4.3-61 /千）和δ〜（18）O值（-4.5-24.5 /千），与δ〜（18）O /δ对应〜（15）N斜率为0.47-0.66，与反硝化一致。稀有气体质谱法用于量化补给温度和过量空气含量。发现溶解的N_2浓度远高于与空气平衡或掺入过量空气所预期的浓度，这与硝酸盐还原为N_2相一致。在奶场中硝酸盐中氮和氧同位素的分馏因子似乎高度可变，奶场中反硝化作用发生在地下水位下方5 m的横向广泛缺氧区中，而第二个奶场中，反硝化作用发生在地下水位附近，并且受局部泻湖渗漏的强烈影响。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号