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Objective Soil contamination by heavy metals is a pervasive issue, and this paper investigates the spatial distribution of Pb, As, and Cd in the groundwater-soil-rice system in the Changshou district of Chongqing. We also assess their exposure risk and predict their potential changes in the future. Method Geostatistical techniques, ArcGIS, and the target hazard quotients (THQ) methods were used to assess the risk of the three metals entering food chain. Based on these results, we predicted their potential changes and distribution up to 2036. Result Pb, As, and Cd in groundwater, soil and rice co-existed spatially, with their concentrations higher in the southwest than in the northeast. The THQ model did not showed risk of rice consumption for adults (THQ (As, Pb, and Cd) <1), but showed that there was slight risk of Cd (THQCd=1.12) and Pb (THQPb=1.05) for children. The model predicted substantial differences in the content of Pb, As, and Cd between different three management scenarios: ideal, no human intervention, and severe pollution until 2036. While the contents of the heavy metals were predicted to decrease by 4% to 8% under the ideal scenario in 2036 compared to the current level in 2021, allowing severe pollution to continuously happen is expected to increase heavy metal content by 1.51 to 1.72 times the current level.Conclusion Industries are the primary source of heavy metal pollution in Changshou district. Regarding the exposure risk to children and vulnerable people, and current pollution level, strict measures, including controlling discharge of industrial waste into soils and remediating contaminated soils are essential to reducing heavy metal contents in soil and alleviating them entering food chain. [ABSTRACT FROM AUTHOR]

[Objective] The paper provides references for the prevention of heavy metal pollution and the protection of cultivated soil environ- ment through exploring the content characteristics and the risk of heavy metals elements of paddy soil in Chongqing. 【Method】230 paddy soil samples were collected from 7 major and typical rice-growing regions in Chongqing, and the pH and the content of 5 heavy metal elements in- cluding Cd, Hg, As, Pb and Cr in paddy soil samples were analyzed. The Nemero pollution index evaluation method and the land accumula- tion index evaluation method were used to analyze the degree of pollution, and compared with the background value of heavy metals in Chongqing soil and the risk screening value of agricultural land soil. The characteristics of heavy metal pollution in Chongqing paddy soil were analyzed and evaluated. Then, the possible sources of heavy metal pollution in soil were explored through Pearson correlation analysis and cluster analysis. 【Result】 The average contents of Pb, Cd, Cr, As and Hg in the paddy soil of the research area were 25.4, 0.312, 66. 8, 4.71 and 0.0827 mg/kg, respectively. Through the analysis of single factor pollution index and Nemero pollution index evaluation methods, 19.57% of the paddy soil sites in the study area were in the state of Cd light pollution, 0.43% was in the state of Hg medium pol- lution, and the remaining points were in the state of no pollution. According to Geo-accumulation index, the paddy soil was lightly polluted by Cd, while the remaining heavy metal elements were at a non-polluted level. However, there were very few soils with extremely high ground accumulation index of Hg (4.03, belonging to the level of strong to extremely strong pollution). It was found that the content of Cd and Hg elements exceeded the background value of Chongqing soil, 2. 84 times and 1.38 times of the background value, respectively, with a cumulative effect; The content of Pb, Cr, As elements was slightly lower than the background value of Chongqing soil, and there was basi- cally no enrichment. The average content of heavy metals in the surveyed paddy soil was lower than the corresponding agricultural land soil risk screening value. Correlation and cluster analysis showed that heavy metal pollution mainly originated from soil formation processes and human factors. [Conclusion] The paddy soil in Chongqing is generally in a clean state, but there is a risk of Cd and Hg contamination. [ABSTRACT FROM AUTHOR]

[Objective)Through monitoring the water and sediment in Chongqing section of Jialing River, the present paper aimed to understand the current situation of eutrophication of water, pollution status of heavy metal elements in water and sediment. [ Method J 4 monitoring points we set up in the Chongqing section of Jialing river and tested twice in May and August, Water monitoring indicator B included TP, TN, NH3-N, CODmn, SD, Chl. a, DO, pH, etc.; Monitoring indication for heavy metal elements included Cu, As, Pb, Cd, Hg and Zn. The national standard ( GB 3838-2002) was used to determine the type of water quality, the Carlson Comprehensive Nutritional Status Index ( TLl) we used to evaluate the eutrophication of water bodies, and the limiting factors affecting phytoplankton growth was determined by the nitrogen and phosphorus ratio( N/P) ; The geo accumulation index( Igeo) was used to quantify the concentration of heavy metals in the sediment. [ Result)The water quality of Chongqing section of Jialing river was between III-V water in dry season and III-IV water in wet season. The water was less polluted by heavy metal elements, except Hg which was a potential pollutant, all other heavy metal elements met the requirements of grade I surface water and met the requirements of China Fishery Water Quality Standard ( 1989) and domestic drinking water sanitation standard ( 2006 ) . The variation range of heavy metal elements in sediment was Luger than that in water, and the lgeo of As, Cd existed light pollution in the range of O - 2, Zn, Hg and Cu had almost no pollution. [ Conclusion) The water quality in Chongqing section of Jialing river was between 111-V, the degree of eutrophication was between moderate nutrition and mild eutrophication, the water was less polluted by heavy metal elements, and the sediment was polluted by heavy metal elements Cd, As and Pd. Phosphorus was the main nutrient limiting factor of phytoplankton. [ABSTRACT FROM AUTHOR]