Duan Baoling, Zhang Wuping, Zheng Haixia, Wu Chunyan, Zhang Qiang, Bu Yushan
College of Resources and Environment, Shanxi Agricultural University, Taigu, Shanxi 030801, China.
College of Forestry, Shanxi Agricultural University, Taigu, Shanxi 030801, China.
Int J Environ Res Public Health. 2017 Oct 8;14(10):1194. doi: 10.3390/ijerph14101194.
To compare the human health risk of heavy metals and As in sewage sludge between adults and children, samples were collected from five wastewater treatment plants (WWTPs) located in the urban district of Taiyuan, the capital of Shanxi. Heavy metals and As in sewage sludge can be ranked according to the mean concentration in the following order: Cu > Cr > Zn > Pb > As > Hg > Cd. Compared with the concentration limit set by different countries, the heavy metals contents in sewage sludge were all within the standard limits, except for the content of As, which was higher than the threshold limit established by Canada. A health risk assessment recommended by the United States Environmental Protection Agency (USEPA) was used to compare the non-cancer risk and cancer risk between adults and children. Based on the mean and 95% upper confidence limit (UCL) of the average daily dose (ADD), heavy metals and As can be ranked in the order of Cu > Cr > Zn > Pb > As > Hg > Cd for adults, and Cu > Cr > Zn > Pb > Hg > As > Cd for children. Moreover, results of ADD and ADD indicated that ingestion was the main pathway for heavy metals and As exposure for both adults and children, and the sum of ADD implied that the exposure to all heavy metals and As for children was 8.65 and 9.93 times higher, respectively, than that for adults according to the mean and 95% UCL. For the non-carcinogenic risk, according to the hazard quotient (HQ), the risk of Cu, Hg and Cr was higher than the risk of Zn and Pb. The hazard index (HI) for adults was 0.144 and 0.208 for the mean and 95% UCL, which was less than the limit value of 1; for children, the HI was 1.26 and 2.25, which is higher than the limit value of 1. This result indicated that children had non-carcinogenic risk, but adults did not. Furthermore, ingestion was the main pathway for non-carcinogenic risk exposure by the HQ and HQ. For the carcinogenic risk, Cd and As were classified as carcinogenic pollutants. The values of RISK for the mean and 95% UCL for adults and children all exceeded the limit value of 1 × 10, which implied that adults and children had a carcinogenic risk, and this risk was higher for children than for adults. The results of RISK for As and Cd implied that As was the main pollutant for carcinogenic risk. Moreover, the results of RISK and RISK indicated that ingestion was the main pathway. Uncertainty analysis was performed, and the risk ranges of it were greater than certainty analysis, which implied that uncertainty analysis was more conservative than certainty analysis. A comparison of the non-carcinogenic risk and carcinogenic risk for adults and children indicated that children were more sensitive and vulnerable than adults when exposed to the same pollutant in the environment.
为比较成人和儿童接触污水污泥中重金属及砷的人体健康风险，从山西省省会太原市市区的五个污水处理厂采集了样本。污水污泥中的重金属及砷按平均浓度排序如下：铜＞铬＞锌＞铅＞砷＞汞＞镉。与不同国家设定的浓度限值相比，除砷含量高于加拿大设定的阈值外，污水污泥中的重金属含量均在标准限值内。采用美国环境保护局（USEPA）推荐的健康风险评估方法，比较成人和儿童的非致癌风险和致癌风险。基于平均日剂量（ADD）的均值和95%上置信限（UCL），成人接触重金属及砷的顺序为铜＞铬＞锌＞铅＞砷＞汞＞镉，儿童为铜＞铬＞锌＞铅＞汞＞砷＞镉。此外，ADD和ADD的结果表明，摄入是成人和儿童接触重金属及砷的主要途径，ADD总和表明，根据均值和95% UCL，儿童接触所有重金属及砷的量分别比成人高8.65倍和9.93倍。对于非致癌风险，根据危害商（HQ），铜、汞和铬的风险高于锌和铅。成人的危害指数（HI）均值为0.144，95% UCL为0.208，均小于限值1；儿童的HI为1.26和2.25，高于限值1。这一结果表明儿童存在非致癌风险，而成人不存在。此外，摄入是HQ和HQ导致非致癌风险暴露的主要途径。对于致癌风险，镉和砷被列为致癌污染物。成人和儿童的RISK均值及95% UCL值均超过1×10的限值，这意味着成人和儿童均存在致癌风险，且儿童的风险高于成人。砷和镉的RISK结果表明，砷是致癌风险的主要污染物。此外，RISK和RISK的结果表明摄入是主要途径。进行了不确定性分析，其风险范围大于确定性分析，这意味着不确定性分析比确定性分析更保守。成人和儿童非致癌风险和致癌风险的比较表明，在环境中接触相同污染物时，儿童比成人更敏感、更易受影响。
