Analysis Of Heavy Metal Pollution In Farmland Soil And Crops In J County Of Shandong Province

In the field of environment,soil is one of the basic environmental factors,which is closel y related to climate and other environmental factors.Due to the impact of industrialization an d human activities,a large number of water,gas and solid wastes harmful to the environment have been produced.These substances enter the soil in various ways.In the process of crop gr owth,it will not only absorb nutrients in the soil,but also absorb pollutants in the soil.After l ongterm accumulation,the content of pollutants in crops is increasing.To a certain extent,it will i nevitably affect the quality of crops.In order to evaluate the ecological risk of heavy metals in farmland soils and crops,98 soils and 6 crops,wheat,corn,tomatoes,cucumber,celery and potatoes,were collected in J county.The contents of heavy metals such as chromium,arsenic,lead,cadmium and mercury in soils and crops were determined according to the relevant methods of national standards.The single pollution index method and the comprehensive pollution index method were used to judge the pollution of these five heavy metals to agricultural products and farmland soil.In addition,in order to understand the capacity of different crops to enrich heavy metals,four kinds of agricultural products,wheat,corn,tomato and cucumber,were selected as research objects,and the enrichment coefficient of heavy metals was used to reflect the enrichment effect of crops on different heavy metals.The main conclusions are as follows:1.From the average content of heavy metals in soil,the order of heavy metals content is chromium > lead > arsenic > cadmium > mercury.The single pollution index of heavy metals such as chromium,lead and mercury in soil samples is less than 1,and the content of heavy metals is less than the standard value;the over-standard rate of heavy metals arsenic is about 1%,while the over-standard amount of heavy metals cadmium in soil samples is more,and the over-standard rate is about 10%.Therefore,cadmium has the greatest safety risk to soil.From the comprehensive pollution index,the index value of most soil samples is less than 0.7,and the soil is in a relatively safe state.2.Detection of heavy metal content in agricultural products showed that the order of heavy metal content in wheat and maize was chromium > lead > arsenic > cadmium > mercury;the order of heavy metal content in potatoes and tomatoes was arsenic > chromium > lead > cadmium > mercury;the order of heavy metal content in celery and cucumber was lead > chromium > arsenic > cadmium > mercury.In addition,from the point of view of single pollution index and comprehensive pollution index,the comprehensive pollution index of nearly half of the wheat samples is more than 0.7,and a few samples are heavily polluted,some of which contain excessive heavy metals such as chromium and lead;the contents of all heavy metals in maize are not exceeding the standard,and the whole situation is relatively safe;most of the tomato samples were seriously polluted,and the content of arsenic,chromium and lead exceeded the standard.Potato samples were heavily polluted and arsenic content was severely exceeded.Celery samples were heavily polluted because of excessive chromium and lead content.3.The enrichment ability of heavy metals in different kinds of crops is different.The results showed that wheat had a strong ability to enrich cadmium,chromium and mercury,maize had a strong ability to enrich cadmium and mercury,tomato had a strong ability to enrich arsenic,cadmium and lead,and cucumber had a strong ability to enrich lead and chromium.