| 高原湖泊周边浅层地下水:氮素时空分布及驱动因素 |
| 摘要点击 2037 全文点击 601 投稿时间：2021-09-23 修订日期：2021-10-29 |
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| 中文关键词 浅层地下水 氮(N) 时空分布 驱动因素 高原湖泊 |
| 英文关键词 shallow groundwater nitrogen(N) spatiotemporal distribution driving factor plateau lake |
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| 中文摘要 |
| 高原湖泊周边浅层地下水作为当地重要的生产和生活水源之一，由于受到地表氮素投入负荷、降雨和灌溉等因素驱动下，浅层地下水NO3--N污染较为严重，威胁着高原湖泊水质安全.2020~2021年雨季和旱季从云南8个高原湖泊周边农田和居民区的水井中采集了463个浅层地下水样，分析了地下水中氮的污染特征及驱动因素.结果表明，浅层地下水中ρ（TN）、ρ（NO3--N）、 ρ（ON）和ρ（NH4+-N）平均值分别为24.35、15.15、8.41和0.79 mg·L-1，8个湖泊周边近32%的浅层地下水样NO3--N浓度超过地下水Ⅲ类水质要求（GB/T 14848），其中，洱海、杞麓湖和滇池湖泊周边地下水NO3--N浓度超标率最高，其次是星云湖、阳宗海和异龙湖，最小为抚仙湖和程海.土地利用和季节变化影响着浅层地下水中各形态N浓度及其组成，农田区浅层地下水中各形态N浓度高于居民区，除NH4+-N外，雨季浅层地下水中各形态N浓度高于旱季.NO3--N是TN的主要形态，占TN的质量分数为57%~68%，ON占TN的质量分数为27%~38%.浅层地下水中EC、DO、ORP和T是反映或影响浅层地下水中各形态N浓度的关键因子，而土壤因子对浅层地下水中各形态N浓度影响较弱. |
| 英文摘要 |
| Shallow groundwater around plateau lakes is one of the important sources of production and potable water. Shallow groundwater NO3--N pollution driven by factors such as surface nitrogen input load, rainfall, and irrigation is serious and threatens the water quality of plateau lakes. In order to identify the characteristics of nitrogen pollution and its driving factors in shallow groundwater, 463 shallow groundwater samples were collected from wells in farmland and residential areas around eight plateau lakes of Yunnan in the rainy and dry seasons in 2020 and 2021. The results showed that the average values of ρ(TN), ρ(NO3--N), ρ(ON), and ρ(NH4+-N) in shallow groundwater were 24.35, 15.15, 8.41, and 0.79 mg·L-1, respectively. Nearly 32% of the shallow groundwater samples around the eight lakes failed to meet the groundwater Class Ⅲ water quality requirements (GB/T 14848) of 20 mg·L-1 for NO3--N. Among them, the NO3--N concentration in the shallow groundwater around Erhai Lake, Qiluhu Lake, and Dianchi Lake had the highest rate of exceeding the standard, followed by that around Xingyunhu Lake, Yangzonghai Lake, Yilonghu Lake, Fuxianhu Lake, and Chenghai Lake as the smallest. Land use and seasonal changes affected the concentration and composition of various forms of nitrogen in shallow groundwater. The concentration of various forms of nitrogen in shallow groundwater in the farmland area was higher than that in the residential area. The nitrogen concentration in shallow groundwater in farmland was higher than that in residential areas. Except for NH4+-N, the concentration of various forms of nitrogen in shallow groundwater in the rainy season was higher than that in the dry season. NO3--N was the main nitrogen form in shallow groundwater; the fraction of TN was 57%-68%, and the fraction of ON was 27%-38%. The EC, DO, ORP, and T in shallow groundwater were the key factors reflecting or affecting the concentration of various forms of nitrogen in shallow groundwater, whereas soil factors had a weak impact on the concentration of various forms of nitrogen in shallow groundwater. |
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