Sharma Rajesh Kumar, Agrawal Madhoolika
Ecology Research Laboratory, Department of Botany, Banaras Hindu University, Varanasi, India.
J Environ Biol. 2005 Jun;26(2 Suppl):301-13.
Heavy metals constitute a very heterogeneous group of elements widely varied in their chemical properties and biological functions. Heavy metals are kept under environmental pollutant category due to their toxic effects on plants, animals and human being. Heavy metal contamination of soil results from anthropogenic as well as natural activities. Anthropogenic activities such as mining, smelting operation and agriculture have locally increased the levels of heavy metals such as Cd, Co, Cr, Pb, As and Ni in soil up to dangerous levels. Heavy metals are persistent in nature, therefore get accumulated in soils and plants. Heavy metals interfere with physiological activities of plants such as photosynthesis, gaseous exchange and nutrient absorption, and cause reductions in plant growth, dry matter accumulation and yield. Heavy metals also interfere with the levels of antioxidants in plants, and reduce the nutritive value of the produce. Dietary intake of many heavy metals through consumption of plants has long term detrimental effects on human health.
重金属是一类非常 heterogeneous 的元素，其化学性质和生物学功能差异很大。由于重金属对植物、动物和人类具有毒性作用，因此被归类为环境污染物。土壤中的重金属污染源于人为活动和自然活动。采矿、冶炼作业和农业等人为活动已在局部地区将土壤中镉、钴、铬、铅、砷和镍等重金属的含量提高到危险水平。重金属具有持久性，因此会在土壤和植物中积累。重金属会干扰植物的生理活动，如光合作用、气体交换和养分吸收，并导致植物生长、干物质积累和产量下降。重金属还会干扰植物中抗氧化剂的水平，并降低农产品的营养价值。通过食用植物摄入多种重金属对人类健康具有长期的有害影响。
