br b Type in bold indicates potential cancer risk
b Type in bold indicates potential cancer risk (all are presented in units of per million).
c Significant diﬀerences were determined by the analysis of variance and the multiple comparison tests were performed by Tukey Test, and the same letter on the same column are not significantly diﬀerent.
For the highest cancer risk—female adults, the ILCR values were greater than 1 × 10−6 at 16 sites of these 33 soil. They were con-tributed by Datong, Shuozhou, Xinzhou, Changzhi, Linfen and Yuncheng cities, suggesting that people living and farming in these areas suﬀered from the low cancer risk. Subsequently, in order to dis-tinguish the diﬀerences between them statistically, the analysis of variance was performed by averaging ILCR among the diﬀerent cities. As showed in Table 4, the total ILCR values between Datong and five cities (Taiyuan, Yangquan, Jinzhong, Lvliang and Jincheng) were all in very significant diﬀerences (n = 3, p < 0.05). Furthermore, the total ILCR value in Xinzhou was much significantly higher than those of Lvliang, Jinzhong, Jincheng and Taiyuan (n = 3, p < 0.05), while those of remains (Changzhi, Shuozhou, Linfen and Yuncheng) were at the median levels. These results indicated that the significantly higher cancer risk occurred at Datong and Xinzhou cities. Similarly, from the analysis of variance of the significant diﬀerences for age and gender, the significant diﬀerences of age were observed between each other, and their average values were 1.74 ± 1.64, 1.03 ± 0.96, and 0.35 ± 0.32 per million for adulthood, childhood, and adolescence, respectively (n = 66, p < 0.05). But for gender, no significant diﬀer-ences were observed because the values were 1.09 ± 1.32 and 0.98 ± 1.17 (n = 99, p < 0.05) for female and male, respectively.
As the previously reported, the cancer risks of PAHs were assessed in other areas of China. For instance, most of the areas of suburban in Beijing were at a safe level for inhabitation, but a few areas aﬀected by previously industrial activities or point sources should be of concern (Peng et al., 2016). In Shanghai, average ILCR values of direct ingestion for children and adults were 1.23 × 10−4 and 9.28 × 10−5, respec-tively. This result suggested that they Exendin4 had potential cancer risk (Jia et al., 2017). In a township from Southern Jiangsu province, the cancer risk of PAHs in 2014 decreased by 8.6% relative to 2009 (Cao et al., 2017). In Xi'an, The mean values of ILCR in the urban soils were higher than the acceptable risk level (10−6), indicating that the urban soils from the three functional areas possessed potential cancer risk (Bao et al., 2018). But in Chengdu, the total cancer risk of PAHs among the diﬀerent age groups were 1.10 × 10−4, 4.20 × 10−5 and 2.30 × 10−5 for adult, child and teen, respectively, which showed the adults suﬀered the moderate risk (Zheng et al., 2018). In conclusion, cancer risk of Ecotoxicology and Environmental Safety 182 (2019) 109381
PAHs in surface soil in China descended on the urban–suburban–rural gradient except for point sources.
145 (Man et al., 2013), or even 600 ng/g (CCME, 2010) for human cancer risk. While BaPeq concentrations in the present study were 58, 285, and 96 ng/g for adulthood, childhood, adolescence, respectively. These results were accordant to assess cancer risk to some extent. Based on the BaPeq threshold, human cancer risks of PAHs were also assessed in Shanxi, for instance, the average BaPeq concentrations were 89 (8–1462) ng/g for Xiangfen in Shanxi (Tao et al., 2017), 933 ng/g for industrial district (Jiao et al., 2017) and 151 (Nd–1683 ng/g) for agri-cultural soil in Changzhi (Liu et al., 2017), and 44.6 (17.1–85.6 ng/g) for Midland in Shanxi (Duan et al., 2015). In addition, six of the 247 soil samples had concentrations above the safe BaPeq value (600 ng/g) in agricultural soils from Xinzhou near the coal production area (Zhao et al., 2014), and about 28% of the soil samples exceeded this 600 in the vicinity of a chemical plant from the southeast of Shanxi (Liu et al., 2016). In addition to PAHs, polychlorinated biphenyls (PCBs) and heavy metals (e.g. Cr, Cd, As, Ni, Pb, and Hg) were listed in the In-ternational Agency for Research on Cancer (IARC, 2017). Heavy metal pollution from As and its carcinogenic risk for human were reported on Shanxi’ mines (Li et al., 2014). And children suﬀered from the potential cancer risk from soils contaminated by heavy metals As, Cr, and Ni in a typical county of Shanxi, China (Pan et al., 2016). Sum up, some re-sidents suﬀered from the potential low or moderate cancer risk in Shanxi, China. r>