Heavy Metals Contamination and what are the Impacts on Living Organisms

Heavy metals are toxic metals having density five times greater than water. They are toxic for all living organisms. In humans they enter into body through various ways like ingestion, absorption etc. They become harmful when their accumulation rate is more than their discharge. They accumulate gradually in body over a long time and are toxic. Heavy metal contamination is a major problem in environment and of medium sized cities due to anthropogenic activities. Human activities may contribute largely in their production such as burning of fossil fuel, mining and use of many chemical for crop growth etc. Waste water also contains heavy metal and when it is applied to crops it can cause threat to soil and plants growing in that soil. Waste water health risks can be determined by different indices. Generally, heavy metals cannot be removed from waste water and when they enter into the soil, interfere with the plant roots -these plants when eaten by animals or humans they enter into food chain. Plants along with other nutrients also uptake lead and cadmium; their accumulation may be effected by the concentration time of exposure and climatic factor. Heavy metals affect the quality and production of crop and influence atmospheric and water quality. These contamination are important and of concern because of increasing demand for food safety. There are different sources for heavy metal such as natural and manmade, as industries and air borne sources. These heavy metals have severe effects on plants, animals, humans and ultimately on environment.