Chunli Su , Jiaqi Jiang , Xianjun Xie , Zhantao Han , Mengzhu Wang , Junxia Li , Huijian Shi
{"title":"典型农业湖盆稳定同位素及水化学揭示的氮源与循环过程","authors":"Chunli Su , Jiaqi Jiang , Xianjun Xie , Zhantao Han , Mengzhu Wang , Junxia Li , Huijian Shi","doi":"10.1016/j.apgeochem.2023.105662","DOIUrl":null,"url":null,"abstract":"<div><p><span>Increased exposure to nitrate has been reported in many arid and semi-arid areas where groundwater is used as the drinking water<span> source, presenting a major public health threat. Groundwater nitrate pollution is becoming serious due to intensive agricultural activities in the Nansi Lake Basin, Shandong Province, Northern China, through which the trunk line of the South-to-North Water Diversion Project passes. This study characterized potential nitrogen pollution sources by combined analysis of hydrochemical components and stable nitrate isotopes (δ</span></span><sup>15</sup>N–NO<sub>3</sub><sup>-</sup>, δ<sup>18</sup>O–NO<sub>3</sub><sup>-</sup><span>); the contribution of different sources was estimated using the SIAR<span> model. The results show groundwater nitrate contamination in the Nansi Lake Basin is widespread both west (NSW) and east (NSE) of the lake. Manure and sewage (M&S), soil nitrogen<span> (SN), and chemical fertilizer (CF) are potential NO</span></span></span><sub>3</sub><sup>−</sup>-N sources in the study area, with the order of contribution being M&S (78.38%) > SN (15.02%) > CF (6.60%) in areas west of the lake and M&S (59.40%) > SN (30.38%) > CF (10.22%) in areas east of the lake, indicating the significant impact of human activities. The relationship between d-excess and δ<sup>15</sup>N–NO<sub>3</sub><sup>-</sup> suggests irrigation practices increase soil moisture, resulting in more N from <sup>15</sup><span><span><span>N-depleted soils leaching into the groundwater, increasing the contribution of SN. The predominant processes of the </span>nitrogen cycle<span><span> in the basin are different in the NSW and NSE areas. In the upper-middle reaches of the NSW area, nitrification dominates the nitrogen cycle due to aerobic conditions and elevated </span>salinity<span>; however, denitrification occurs in local downstream aquifers at depths ranging from 10 to 50 m. In contrast, SN plays a bigger role in the NSE, where the mineralization of soil organic nitrogen is the predominant process, followed by nitrification of M&S and CF nitrogen sources due to rapid groundwater flow in the carbonate and </span></span></span>metamorphic rock aquifers.</span></p></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"156 ","pages":"Article 105662"},"PeriodicalIF":3.1000,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":"{\"title\":\"Sources and cycling processes of nitrogen revealed by stable isotopes and hydrochemistry in a typical agricultural lake basin\",\"authors\":\"Chunli Su , Jiaqi Jiang , Xianjun Xie , Zhantao Han , Mengzhu Wang , Junxia Li , Huijian Shi\",\"doi\":\"10.1016/j.apgeochem.2023.105662\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p><span>Increased exposure to nitrate has been reported in many arid and semi-arid areas where groundwater is used as the drinking water<span> source, presenting a major public health threat. Groundwater nitrate pollution is becoming serious due to intensive agricultural activities in the Nansi Lake Basin, Shandong Province, Northern China, through which the trunk line of the South-to-North Water Diversion Project passes. This study characterized potential nitrogen pollution sources by combined analysis of hydrochemical components and stable nitrate isotopes (δ</span></span><sup>15</sup>N–NO<sub>3</sub><sup>-</sup>, δ<sup>18</sup>O–NO<sub>3</sub><sup>-</sup><span>); the contribution of different sources was estimated using the SIAR<span> model. The results show groundwater nitrate contamination in the Nansi Lake Basin is widespread both west (NSW) and east (NSE) of the lake. Manure and sewage (M&S), soil nitrogen<span> (SN), and chemical fertilizer (CF) are potential NO</span></span></span><sub>3</sub><sup>−</sup>-N sources in the study area, with the order of contribution being M&S (78.38%) > SN (15.02%) > CF (6.60%) in areas west of the lake and M&S (59.40%) > SN (30.38%) > CF (10.22%) in areas east of the lake, indicating the significant impact of human activities. The relationship between d-excess and δ<sup>15</sup>N–NO<sub>3</sub><sup>-</sup> suggests irrigation practices increase soil moisture, resulting in more N from <sup>15</sup><span><span><span>N-depleted soils leaching into the groundwater, increasing the contribution of SN. The predominant processes of the </span>nitrogen cycle<span><span> in the basin are different in the NSW and NSE areas. In the upper-middle reaches of the NSW area, nitrification dominates the nitrogen cycle due to aerobic conditions and elevated </span>salinity<span>; however, denitrification occurs in local downstream aquifers at depths ranging from 10 to 50 m. In contrast, SN plays a bigger role in the NSE, where the mineralization of soil organic nitrogen is the predominant process, followed by nitrification of M&S and CF nitrogen sources due to rapid groundwater flow in the carbonate and </span></span></span>metamorphic rock aquifers.</span></p></div>\",\"PeriodicalId\":8064,\"journal\":{\"name\":\"Applied Geochemistry\",\"volume\":\"156 \",\"pages\":\"Article 105662\"},\"PeriodicalIF\":3.1000,\"publicationDate\":\"2023-09-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"2\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Applied Geochemistry\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0883292723001075\",\"RegionNum\":3,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Geochemistry","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0883292723001075","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Sources and cycling processes of nitrogen revealed by stable isotopes and hydrochemistry in a typical agricultural lake basin
Increased exposure to nitrate has been reported in many arid and semi-arid areas where groundwater is used as the drinking water source, presenting a major public health threat. Groundwater nitrate pollution is becoming serious due to intensive agricultural activities in the Nansi Lake Basin, Shandong Province, Northern China, through which the trunk line of the South-to-North Water Diversion Project passes. This study characterized potential nitrogen pollution sources by combined analysis of hydrochemical components and stable nitrate isotopes (δ15N–NO3-, δ18O–NO3-); the contribution of different sources was estimated using the SIAR model. The results show groundwater nitrate contamination in the Nansi Lake Basin is widespread both west (NSW) and east (NSE) of the lake. Manure and sewage (M&S), soil nitrogen (SN), and chemical fertilizer (CF) are potential NO3−-N sources in the study area, with the order of contribution being M&S (78.38%) > SN (15.02%) > CF (6.60%) in areas west of the lake and M&S (59.40%) > SN (30.38%) > CF (10.22%) in areas east of the lake, indicating the significant impact of human activities. The relationship between d-excess and δ15N–NO3- suggests irrigation practices increase soil moisture, resulting in more N from 15N-depleted soils leaching into the groundwater, increasing the contribution of SN. The predominant processes of the nitrogen cycle in the basin are different in the NSW and NSE areas. In the upper-middle reaches of the NSW area, nitrification dominates the nitrogen cycle due to aerobic conditions and elevated salinity; however, denitrification occurs in local downstream aquifers at depths ranging from 10 to 50 m. In contrast, SN plays a bigger role in the NSE, where the mineralization of soil organic nitrogen is the predominant process, followed by nitrification of M&S and CF nitrogen sources due to rapid groundwater flow in the carbonate and metamorphic rock aquifers.
期刊介绍：
Applied Geochemistry is an international journal devoted to publication of original research papers, rapid research communications and selected review papers in geochemistry and urban geochemistry which have some practical application to an aspect of human endeavour, such as the preservation of the environment, health, waste disposal and the search for resources. Papers on applications of inorganic, organic and isotope geochemistry and geochemical processes are therefore welcome provided they meet the main criterion. Spatial and temporal monitoring case studies are only of interest to our international readership if they present new ideas of broad application.
Topics covered include: (1) Environmental geochemistry (including natural and anthropogenic aspects, and protection and remediation strategies); (2) Hydrogeochemistry (surface and groundwater); (3) Medical (urban) geochemistry; (4) The search for energy resources (in particular unconventional oil and gas or emerging metal resources); (5) Energy exploitation (in particular geothermal energy and CCS); (6) Upgrading of energy and mineral resources where there is a direct geochemical application; and (7) Waste disposal, including nuclear waste disposal.
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