Discussion On The Risk Control Division And Countermeasures Of Heavy Metal Pollution In Paddy Field And Rice In A County

In order to explore the risk management and control categories of heavy metal pollution in paddy soil and rice in a certain county,take paddy soil in a certain county as the research object,collect 326 pairs of soil and rice samples,analyze and test 5items of cadmium,mercury,arsenic,lead and chromium in soil and rice samples Heavy metal content,evaluate the heavy metal pollution of paddy soil and rice in a certain county,conduct correlation analysis,and classify the risk control category of paddy soil in a certain county.In view of the different risk categories of paddy soil,the soil utilization protection countermeasures were discussed,in order to provide technical measures for paddy soil protection and utilization in a certain county.The main conclusions are as follows:(1)The average contents of cadmium,mercury,arsenic,lead,and chromium in paddy soil are 0.57mg/kg,0.53mg/kg,19.04mg/kg,49.68mg/kg,76.83mg/kg,5element single-factor pollution The risk result is that the risk of cadmium pollution is the highest,followed by arsenic,and the risk of mercury,lead,and chromium pollution is extremely low.The comprehensive factor pollution risk evaluation result is no pollution risk>light pollution risk>medium pollution risk>severe pollution risk,and the soil is generally free of pollution risk.(2)The average content of cadmium,mercury,arsenic,lead,and chromium in rice is 0.072mg/kg,0.004mg/kg,0.108mg/kg,0.037mg/kg,0.150mg/kg,and the average content of 5 elements is low It is the limit value of food safety standards.The over-standard rates of cadmium,mercury,arsenic and lead content were 9.82%,0.61%,0.31%,0.61%,and the chromium content did not exceed the standard.Rice mainly has no pollution risk,and the risk of rice being polluted by 5 heavy metals is extremely small.(3)Among all tested samples,there is a positive correlation between soil and rice cadmium,mercury,and arsenic,and there is a negative correlation between lead and chromium,and the correlation does not reach a significant level.When p H≤5.5,there is a positive correlation between soil and rice cadmium,mercury,arsenic,lead,and chromium;when 5.5<p H≤6.5 and 6.5<p H≤7.5,there is a positive correlation between soil and rice cadmium,mercury,arsenic,and chromium When p H>7.5,there is a positive correlation between soil and rice mercury,arsenic,and chromium,and there is a negative correlation between cadmium and lead,and the correlation does not reach a significant level.(4)The area of the five-element single-factor risk control category of paddy soil is priority protection category>safe use category>strict control category;the areas of priority protection category,safe use category,and strict control category of the comprehensive factor risk control category of paddy soil are respectively 212,700 acres,71,500 acres,and 2,400 acres,accounting for 74.2%,24.9%,and 0.8% of the total paddy soil area respectively.(5)Priority protection paddy soil is distributed throughout the county.It is recommended that priority protection paddy soil be designated as permanent basic farmland to ensure that the area and quality are not reduced.The safe use of paddy soil is mainly distributed in CG,LG,NL,FS,LM,GZ,HF,HL,JZ,NJ,YW,LS,SL and other townships in a county.It is recommended to adopt low accumulation varieties,lime adjustment,optimized fertilization,Safe use measures such as moisture regulation,in-situ passivation,organic material regulation,and foliar resistance control technology.Strictly controlled paddy soils are scattered in CG,LS,MP,NMD,SL and other villages and towns.It is recommended to take control measures such as planting structure adjustment and fallow,and increase monitoring efforts to ensure rice safety and control.