土壤学报2025，Vol.62Issue(3)：791-800,10.DOI:10.11766/trxb202401290047
生菜对燃煤排放大气颗粒物沉降重金属的叶面吸收
Lettuce Foliar Uptake of Heavy Metals Directly from the Deposition of Atmospheric Particulate Matter Emitted from Coal Combustion
摘要
Abstract
[Objective]The combustion of fossil fuels such as coal emits a large amount of particulate matter and heavy metals into the atmosphere,which are then significant sources of input into the agricultural environment by dry and wet deposition.These pollutants will directly influence crop growth and heavy metal accumulation,and indirectly threaten human health through the food chain.Atmospheric particulate matter rich in heavy metals can enter the plant through two pathways:deposition into the soil followed by root absorption or direct foliar uptake of dry deposition on the crop leaf surface.However,the respective proportions and specific mechanisms of these pathways remain elusive.[Method]An open-side(covered with fine particulate matter filter membranes)transparent chamber was designed for vegetable pot experiments,simulating the actual dry deposition flux of atmospheric particulate matter in diverse coal-burning regions.This quantitative study systematically compared the effects of fly ash from two representative coal-fired power plants in southern and northern China on lettuce(Lactuca sativa L.)growth and the leaf accumulation of typical heavy metals through deposition into soil and leaf surface,respectively.[Result]The results indicated that atmospheric deposition is a significant source of Cd,Pb,Cr,and As in crops.The heavy metal contents in lettuce leaves increased with the fly ash deposition.The proportion of deposited Cd accumulated by the edible above-ground parts of lettuce through the foliar uptake is 40.9%-84.2%and the proportion of Pb can be 62.3%-85.6%.This indicates that direct foliar uptake is the main pathway for lettuce leaf accumulation of Cd and Pb in atmospheric particulate matter,especially for metals with high content(Pb)or bioavailability(Cd)in particulates,and if the amount of particle deposition does not exceed the foliar uptake capacity.However,when the atmospheric deposition flux is high or the bioavailability is low,heavy metals such as As in particulate matter are mainly accumulated by leaves through the traditional pathway of soil-root migration,absorption,and transport.Because of the higher contents of most heavy metals and stronger bioavailability in the soil-lettuce system,the southern fly ash induced higher accumulation of heavy metals by the leaf,and stronger toxic effects translated to lower photosynthetic activity and less biomass.[Conclusion]Consequently,comprehensive pollution control measures such as source prevention and reduction of heavy metal deposition input from the emissions of atmospheric particulate matter like coal combustion,as well as suppression of leaf dust retention,are of great environmental and health significance for ensuring crop growth and the quality and safety of leafy vegetables in coal burning areas.关键词
大气颗粒物污染/粉煤灰/重金属/植物叶面吸收/农产品质量安全Key words
Atmospheric particulate pollution/Fly ash/Heavy metals/Plant foliar uptake/Quality and safety of agricultural products分类
资源环境引用本文复制引用
刘欣,童欣,陈志怀,张婷婷,郭豪华,罗小三..生菜对燃煤排放大气颗粒物沉降重金属的叶面吸收[J].土壤学报,2025,62(3):791-800,10.基金项目
国家自然科学基金项目(41471418)资助 Supported by the National Natural Science Foundation of China(No.41471418) （41471418）
