土壤中7种典型PPCPs的分布特征及其影响因素分析

药物和个人护理产品(PPCPs)的环境残留问题在全世界范围内受到了越来越多的关注。利用高效液相色谱与质谱联用技术(LCMS)检测了研究区域土壤样品中7种典型PPCPs的质量比,分析了PPCPs在不同区域和不同深度土层中的分布特征,通过相关性研究探寻了影响这类物质分布的关键理化因子。检测采用正离子模式,以甲醇和水为流动相梯度洗脱,7种PPCPs的线性决定系数大于0.99,加标回收率为71.2%~140%,相对标准偏差RSD为6.7%~22%。结果表明,除美托诺尔和咖啡因未被检出外,其余5种药物的检出率在13%~100%。采样点ΣPPCPs的平均质量比为9.91 ng/g dw,质量比范围为2.23~26.07 ng/g dw。DEET是研究区质量比最高的PPCPs,平均质量比达7.88 ng/g dw,检出率为100%。区域分布表明,垃圾渗沥液及驱虫剂的喷洒可能导致土壤中DEET质量比偏高。DEET的GUS指数为3.65,淋溶迁移性和潜在环境风险高。垂直分布显示,随土层深度增加,DEET质量比总体呈现下降趋势。相关分析结果显示,DEET质量比与土壤有机质呈显著的正相关关系(r=0.6746,p0.01),与土壤的p H值呈显著的负相关关系(r=-0.5761,p0.01)。

Distribution characteristics and influential factors of 7 typical pharmaceutical and personal care products left-over in the soil

This paper is aimed at investigating and analyzing the influential factors affecting the distribution of PPCPs.It has also made a careful test and measurement in the positive ion mode by using methanol and water as its gradient elution solutions,for such products tend to exhibit very strong persistence,biological activity and bioaccumulation trend,which can bring about serious negative effects on the environment protection.Particularly speaking,there exist 7 kinds of typical PPCPs in the soils we have collected from the different areas at various depths,including trimethoprim (TP),caffeine (CF),metoprolol tartrate (MTP),propranolol hydrochloride (PPN),nalidixic acid (NA),carbamazepine (CNZ) and N,N-diethyl-3-methyl benzoyl amide (DEET),which can be analyzed by means of high-performance liquid chromatography mass spectrometry (LC-MS).The linear correlation coefficient of the said 7 PPCPs proves greater than 0.99 and the ratio of the standard addition recovery turns out to be equal to 71.2％-140％ with a relative standard deviation (RSD) of 6.7％-22％.The investigation results have thus shown that the detectable rate of 5 PPCPs is supposed to be between 13％-100％,though we have failed to detect any metoprolol in whatsoever efforts.More accurately speaking,the average rate of ∑PPCPs in the sampling spots stands about 9.91 ng/g dw with a range from 2.23 ng/g dw to 26.07 ng/g dw,whereas DEET serves as the most abundant PPCP,on average 7.88 ng/g dw,and then the detectable rate can be made as high as by 100％.The distribution regularity indicates that the landfill leachates and the use of the insecticides may account for the high concentration of DEET in the soil,whereas the groundwater ubiquity score (GUS) and the score of DEET signifying the leachability and the potential toxicity to the environment stands at about 3.65.Moreover,the vertical distribution data proves that the concentration of DEET tends to decrease with the increase of the depth of the sample spots.The difference in the soil among the various regions should be gradually reduced,which can be resulted probably from a number of uncertainties in the topsoil from the frequent interference of the natural and human-interference factors.Nevertheless,on the contrary,in the great depth of the soil layers wherein the conditions of the environment tend to be more isolated and insensitive to the external effects,the physical and chemical properties of the soil may be likely to have impact on the distribution of PPCPs.Thus,the correlation analysis may demonstrate a significantly positive linear correlation between the concentration rate of DEET and the rate of the organic compounds in the soils (r =0.6746,p ＜ 0.01).And,therefore,there ought to be exist a negative linear correlation with pH value of the soil (r =-0.5761,p ＜0.01).