基于DIN测试的场地土壤PAHs生物可给性及健康风险研究

为了解决目前基于总量风险评估导致土壤PAHs修复目标过严的问题，采用德国标准研究院（Deutsches Institut für Normung）的方法（DIN 19738）研究了北京某焦化厂（BJ）、山东某钢铁厂（SD）、北京某钢铁厂（BG）和大连某农药厂（DL）4个不同地区大型典型污染场地中荧蒽（FLT）、芘（PYR）、苯并b]荧蒽（BBF）、苯并a]芘（BAP）和茚并1，2，3-cd]芘（IPY）5种PAHs的生物可给性，并探究了禁食及进食（奶粉、苹果）状态下生物可给性的变化.结果表明:①5种PAHs生物可给性随模拟胃肠液添加食物及种类的不同而有所不同.添加奶粉时BJ、SD、BG和DL场地土壤中FLT、PYR、BBF、BAP、IPY 5种PAHs的生物可给性范围分别为1.2%~4.2%、5.5%~15.7%、11.2%~18.0%、15.3%~68.5%，添加苹果时依次为0.2%~1.3%、0.8%~6.1%、1.3%~11.9%、21.7%~82.8%，禁食状况下依次为0.2%~1.4%、0.6%~5.2%、0.7%~10.6%、20.8%~73.6%.②基于考虑和不考虑生物可给性计算了4个污染场地土壤中5种PAHs经口摄入途径的土壤暴露量、致癌风险、非致癌危害商及风险控制值，结果显示，在考虑生物可给性情况下，4个场地土壤中BAP、BBF、IPY 3种致癌PAHs的经口暴露量均降低1~2个数量级，风险控制值则会相应提高.其中，BJ场地土壤中5种PAHs风险控制值提高最为显著（22.9~82.5倍）；SD和BG场地土壤中BAP、BBF、IPY土壤风险控制值分别提高了13.5~17.2倍和6.3~7.9倍，而2种非致癌物质FLT和PYR的风险控制值提高程度接近，在4.6~6.3倍之间；DL场地土壤中5种PAHs风险控制值提高大多在1倍左右.研究显示，在考虑PAHs生物可给性的情况下进行健康风险评估，可以在一定程度上克服现有技术导则计算土壤PAHs修复目标过于严格的问题. 

Bioaccessibility and Health Risk of PAHs in Site Soil Based on DIN Test

In order to solve the problem of the excessively stringent remediation target values based on total PAHs in risk assessment, the bioaccessibility of five PAHs (fluoranthene(FLT), pyrene(PYR), benzob]fluoranthene(BBF), benzoa]pyrene(BAP) and indeno1,2,3-cd]pyrene(IPY)) in the soil samples collected from a coking plant in Beijing(BJ), a steel coking plant in Shandong(SD), a steel coking plant in Beijing(BG), and a pesticide plant in Dalian(DL), were tested using the German Standards Institute(Deutsches Institut für Normung)method(DIN 19738). The changes of the bioaccessibility of the five PAHs were determined by additing different foods (milk powder, apple). The results showed that the bioaccessibility of the five PAHs varied with the addition of food typesin the simulated gastrointestinal fluid. When milk powder was added, the bioaccessibility of FLT, PYR, BBF, BAP and IPY in the soils of the BJ, SD, BG and DL ranged from 1.2% to 4.2%, 5.5% to 15.7%, 11.2% to 18.0% and 15.3% to 68.5%, respectively. When apples were added, the bioaccessibility of the five PAHs in BJ, SD, BG and DL ranged from 0.2% to 1.3%, 0.8% to 6.1%, 1.3% to 11.9% and 21.7% to 82.8%, respectively. In the fasting states, the bioaccessibility of the five PAHs in BJ, SD, BG and DL ranged from 0.2% to 1.4%, 0.6% to 5.2%, 0.7% to 10.6% and 20.8% to 73.6%, respectively. The soil exposures, carcinogenic risks, non-carcinogenic hazard quotients and risk control value of the five PAHs in the four contaminated soils were subsequently calculated with or without considering the bioaccessibility. The results showed that the oral exposures of BAP. BBF, and IPY in the four sites reduced by 1 to 2 orders of magnitude with the considering of bioaccessibility, and the risk control value increased correspondingly. Among them, BJ had the most significant improvement in the risk control value (22.9-82.5 times). The soil risk control value of SD and BG of the three carcinogens BAP, BBF and IPY increased by 13.5-17.2 times and 6.3-7.9 times, respectively, while the risk control values of the two non-carcinogenic PAHs FLT and PYR had an improvement of 4.6-6.3 times. The improvement of the risk control value of the five PAHs in DL was about 1 times. The research results show that health risk assessments that take into account the bioaccessibility of PAHs can, to a certain extent, overcome the problem that the existing technical guidelines for calculating soil PAHs remediation targets are too strict.