title: [Assessment of shallow groundwater nitrate concentrations in typical terrestrial ecosystems of Chinese Ecosystem Research Network (CERN) during 2004-2009].
abstract: The nitrate-N (NO3(-) -N) concentrations of 38 shallow groundwater wells from 31 of the typical terrestrial ecosystems on Chinese Ecosystem Research Network (CERN) were assessed using the monitoring data from 2004 to 2009. The results showed that the average values of NO3(-) -N concentrations were significantly higher in the agricultural (4.85 mg x L(-1) +/- 0.42 mg x L(-1)), desert (oasis) (3.72 mg x L(-1) +/- 0.42 mg x L(-1)) and urban ecosystems (3.77 mg x L(-1) 0.51 mg x L(-1)) than in the grass (1.59 mg x L(-1) +/- 0.35 mg L(-1)) and forest ecosystems (0.39 mg x L(-1) +/- 0.03 mg x L(-1)). Nitrate was the major form of nitrogen, with between 56% to 88% of nitrogen in the nitrate-N form in the shallow groundwater of desert (oasis), urban and agricultural ecosystems. Nitrate-N concentrations for some agricultural ecosystems (Ansai, Yanting, Yucheng) and desert (oasis) ecosystems (Cele, Linze, Akesu) analysis exceeded the 10 mg x L(-1) World Health Organization drinking water standards between 14.3% and 84.6%. Significant seasonality was found in Ansai, Fengqiu, Yanting agricultural ecosystems and the Beijing urban ecosystem using the relatively high frequency monitoring data, with the higher nitrate concentrations usually found during summer and winter months. The monitoring results indicated that the shallow groundwater of agricultural ecosystems was contaminated by agricultural management practices, i.e. fertilization, while the shallow groundwater of forest ecosystems was under natural condition with no contamination from human activities.
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China. xuzw389@163.com
authors.forename: Zhi-Wei
authors.initials: ZW
authors.lastname: Xu
authors.forename: Xin-Yu
authors.initials: XY
authors.lastname: Zhang
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: Sun
authors.forename: Guo-Fu
authors.initials: GF
authors.lastname: Yuan
authors.forename: Sheng-Zhong
authors.initials: SZ
authors.lastname: Wang
authors.forename: Wen-Hua
authors.initials: WH
authors.lastname: Liu
mesh_terms: D002681:China; D018556:Crops, Agricultural / Q000254:growth & development; D017753:Ecosystem; D004784:Environmental Monitoring; D060587:Groundwater / Q000032:analysis*; D009566:Nitrates / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis; D014197:Trees / Q000254:growth & development; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009566:Nitrates; D014874:Water Pollutants, Chemical; D009584:Nitrogen