【摘要】 本研究调查了广西高镉异常区水田土壤中重金属Cd的含量水平,评估其对环境的潜在生态风险.通过初步筛查和详细调查两部分,分批次采集高镉异常区土壤样品共912件,测定土壤Cd含量,并运用单因子污染指数法和潜在风险指数法对水田土壤Cd污染程度及潜在风险进行评价.结果表明:①初查中自然土壤、水田土壤和旱地土壤Cd几何均值分别为0. 915、0. 591和0. 593 mg·kg^-1.②详查中土壤p H为4. 6～8. 7,介于酸性和弱碱性间.若以《土壤环境质量标准》（GB15618-2018）为标准,平果县、天等县、大新县、隆安县和柳城县水田土壤样点Cd超标严重,融水县水田土壤样点无污染;以土壤基线值为评价标准,田东县、柳城县和融水土壤样点中Cd均为无污染状态;田阳县、平果县、天等县、大新县、隆安县和融安县水田土壤Cd处于轻度-中度污染的比例分别为:4. 2%、3. 7%、14. 9%、2. 6%、7. 1%和1. 4%.③9个县市水田土壤中Cd呈现不同级别潜在生态风险.天等县、大新县和隆安县部分水田土壤样点Cd处于高等生态风险,比例为4. 3%、2. 6%、2. 4%;田阳县、平果县、融安县和柳城县水田土壤Cd表现为中-中高等潜在风险;田东县和融水县处于低潜在生态风险.总体上,研究区水田土壤中Cd整体偏高,长此以往可能会对水稻安全种植产生影响,最终对当地居民产生健康威胁,应引起重视.建议开展对研究区土壤镉生物有效性和水稻镉累积状况研究,以便科学合理地评估其生态风险和健康风险.更多还原

【Abstract】 To investigate the levels of heavy metal Cd in paddy soils in high cadmium anomaly areas in Guangxi,and to assess their potential ecological risks to the environment. Through preliminary screening and detailed investigation,912 pieces of soil samples from high-cadmium abnormal area were collected in multiple batches to determine the soil Cd content. The single-factor pollution index method and potential risk index method were used to control the Cd pollution degree of paddy soil. Potential risks were evaluated. The results showed that: ① The average Cd values of natural soil,paddy soil,and dryland soil in the initial screening were 0. 915,0. 591,and 0. 593 mg·kg^-1,respectively. ② In the detailed investigation,the soil p H is 4. 6-8. 7,which is between acidic and weakly alkaline. If the Soil Environmental Quality Standard（ GB 15618-2018） is used as the evaluation standard,the Cd of the soil sample in Pingguo County,Tiandong County,Long’an County,and Liucheng County is seriously exceeded,and the soil sample in the paddy field of Rongshui Country is not polluted. Based on the soil baseline value,the Cd in the soil samples of Tiandong County,Liucheng County,and Rongshui County were non-polluting. In the paddy soils of Tianyang County,Pingguo County,Tianxian County,Daxin County,Long’an County,and Rong’an County,the proportion of Cd in mild to moderate pollution was 4. 2%,3. 7%,14. 9%,2. 6%,7. 1%,and 1. 4%,respectively. ③ Cd in paddy soils of nine counties and cities presents different levels of potential ecological risks.The soil Cd of some paddy fields in Tiandeng County,Daxin County,and Long’an County was at a high ecological risk ratio of 4. 3%,2. 6%,and 2. 4%. The soil Cd of Tianyang County,Pingguo County,Rong’an County,and Liucheng County was medium-Middle and high potential risks. Tiandong County and Rongshui County are at low potential ecological risks. In conclusion,the overall Cd in the paddy soil of the study area is high,which may affect the safe planting of rice in the long-term. It will eventually pose a health threat to local residents and should be taken care of. It is recommended to carry out research on soil cadmium bioavailability and rice cadmium accumulation in the study area in order to assess its ecological risk and health risk more scientifically and reasonably.更多还原