Source Apportionment and Carcinogenic Risks Assessment of 238U and 232Th in the Haihe River Using Monte Carlo Simulation
In order to research the environmental carcinogenic risks and sources of 238U and 232Th in the water of the Haihe River,Concentrations of 238U and 232Th were measured by ICP-MS.The pollution levels and carci-nogenic risks of 238U and 232Th in the water of the Haihe River were evaluated based on a Monte Carlo simula-tion combined with the Nemerow Index and Carcinogenic Risk models.The source apportionment was ful-filled by Spearman's rank correlation coefficient method and the Positive Matrix Factorization model(PMF 5.0).The results showed that the activity concentrations of 238U and 232Th were(36.5±25.2)mBq/L and(0.041±0.037)mBq/L in the water of the Haihe River,respectively.Activity concentrations of 238U were much higher than 232Th.238U activity concentrations were highest in January,followed by April and October,with a mini-mum in July.The concentrations of 238U and 232Th in the middle and lower reaches were higher than those in the feeding rivers and upper reaches.The probabilities of pollution of 238U and 232Th were less than 20%in April,July,and October.However,there was a high risk of pollution in January.The probabilities of pollution in the feeding river and the upper reaches were extremely low.The risk of pollution occurring in the both mid-dle and lower reaches ranged from 11%to 14%.The carcinogenic risk index in the Haihe River is between 10-4 and 10-6,suggesting that there was a potential risk of cancer.The order of total carcinogenic risks was Children,Adults and Teenagers.The results of source apportionment showed that there were four pollution sources for 238U,namely,agricultural,industrial,cosmic rays,and soil.Their contributions were 61.4%,12.6%,8.9%and 17.1%,respectively.There were three pollution sources for 232Th,that was,industrial,cosmic rays,and soil,with contributions of 18.1%,59.8%,and 22.1%,respectively.The scientific based for the pre-vention of uranium and thorium pollution in the Haihe River are provided from this work.
Haihe River238U and 232Thpollution characteristicscarcinogenic risksource apportionment
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