摘要
采用14C同位素示踪技术和野外Lysimeter试验,进行了小麦种植条件下多环芳烃萘(naphthalene)的环境归趋的定量化研究。结果表明,气态损耗是土壤中外源萘含量减少的主要途径,其中矿化损失约占气态损耗的84.41%,作物的存在可显著促进萘的气态损耗,矿化速率和挥发速率可分别提高43.51%和190.32%,其原因可能与植物的根系分泌活动有关。经过一个小麦生长周期,土壤表层残留14C占施入量的1.73%;对土壤柱样的分层分析和土壤渗滤放射性强度测定发现,萘存在明显的纵向迁移现象并可能影响地下水水质,渗滤损失约占施入总量的0.043%;收获期萘在小麦体内含量仅占外源施入量的0.003%,但小麦籽粒已明显检测到14C的存在,浓度约为0.16mg·kg-1,因此农田环境中多环芳烃残留对食品安全的影响也应引起重视。
Outdoor lysimeter with wheat plant growth was used to investigate the environmental fate of ^14C-labeled naphthalene in soil. Results showed that gaseous loss was the main pathway to reduce the naphthalene in soil, and 84.4% of initially applied ^14C was evaporated from soil as ^14CO2. Wheat plants markedly enhanced the gaseous loss, by 43.5% and 190.3% for mineralization and volatilization loss, respectively. After a growth cycle of wheat, 1.7% of initial applied ^14C remained in the soil. Determination of the vertical distribution of the radioactivity showed that the highest content was located in the top 10 cm soil layer, followed by the 10-20 cm soil layer. In view of the detectable radioac- tivity found in the leachate, vertical migration of naphthalene could result in serious contamination of ground water. The wheat plants contained 0.003% of the initial ^14C, while the radioactivity detected in the wheat grains corresponded to 0.16 mg.kg^-1 of naphthalene contamination in the grains, indicating the adverse effect of polyaromatic hydrocarbons （ PAHs ） in soil on food safety.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2009年第8期1557-1561,共5页
Journal of Agro-Environment Science
基金
国家自然基金重点项目(20637030)
土壤中持久性有机有毒污染物的迁移转化规律及对地下水的影响资助项目
