摘要
多氯联苯(PCBs)是一类化学性质非常稳定的氯化芳烃化合物,本文揭示了手性PCBs在玉米中的污染水平、分布特征和累积规律,测定并计算了玉米样品中的7种手性PCBs含量和对映体百分数值(enantiomer fractions,EF)。结果表明,玉米不同器官中总手性PCBs的浓度范围为87.6—294.3 ng·g^(-1),PCB91、PCB95、PCB136和PCB149在采集的玉米样品中均有检出,除了穗期和花粒期茎中手性PCBs,5种手性PCBs在玉米不同生长时期不同部位的浓度水平均为PCB95>PCB132>PCB136>PCB91>PCB149。从不同生长期时间变化上看,玉米中手性PCBs单体和总量在植物中的浓度均随着生长的延长而降低,即苗期>穗期≈花粒期。玉米中PCB91、PCB95、PCB132、PCB136和PCB149的EF均值分别为0.584±0.010、0.574±0.008、0.363±0.014、0.389±0.012和0.449±0.006。在全部可检出手性PCBs的玉米样品中全部的PCB95、PCB132、PCB136和90.9%的PCB91,81.8%的PCB149具有非外消旋特征,玉米中的手性PCBs对映体选择性累积作用随着植物的生长而不断增强。上述结果说明,该地区玉米样品受到了手性PCBs的污染,手性PCBs从土壤进入玉米的过程中发生了生物转化,本研究为准确评价其对人类健康和生态环境风险提供基础数据。
Polychlorinated biphenyls(PCBs)are a class of chemically stable chlorinated aromatic compounds.This paper revealed the pollution levels,distribution characteristics and accumulation rules of chiral PCBs in maize.The concentrations of 7 kinds of chiral PCBs in maize samples,the enantiomeric concentrations and enantiomer fractions(EF)were measured.The results showed that the levels of total chiral PCBs in different organs of maize ranged from 87.6—294.3 ng·g^(−1).PCB91,PCB95,PCB136 and PCB149 were all detected in the collected maize samples.In addition to the chiral PCBs in the stems at the heading and flowering stages,the concentration levels of the 5 chiral PCBs in different parts of the maize at different growth stages from high to low were PCB95>PCB132>PCB136>PCB91>PCB149.The concentration of monochiral PCBs and total chiral PCBs in plants decreased with the growth of the plant,and the concentration levels showed that seedling stage>ear stage≈flowering stage.The average EF of PCB91,PCB95,PCB132,PCB136 and PCB149 in maize were 0.584±0.010,0.574±0.008,0.363±0.014,0.389±0.012 and 0.449±0.006,respectively.In all maize samples,all PCB95,PCB132,PCB136,90.9%PCB91 and 81.8%PCB149 had non-racemic characteristics,the selective enantioselective accumulation of chiral PCBs in maize increased with the growth of plants.The results indicated that maize samples in this area were contaminated with chiral PCBs,and biotransformation occurred during the process of chiral PCBs entering the maize from the soil.This study provided basic data for accurately assessing PCBs risks to human health and ecological environment.
作者
朱帅
劳昌玲
刘世东
ZHU Shuai;LAO Changling;LIU Shidong(Key Laboratory of Eco-geochemistry,Ministry of Natural Resources,National Research Center for Geoanalysis,Beijing,100037,China;China University of Geosciences,Wuhan,430074,China)
出处
《环境化学》
CAS
CSCD
北大核心
2021年第8期2371-2377,共7页
Environmental Chemistry
基金
国家自然科学基金(21607033)
中国地质科学院基本科研业务费(CSJ201905,CSJ-2021-03)资助.
