Study On Screening Of Alternative Crops In Cultivated Land For Safe Utilization

In recent years,the remediation of cultivated land contaminated by heavy metal has gradually attracted public attention,and the elevated content of heavy metals in agricultural products has become a focus of public.By 2020,It had been taken the completing the classification of cultivated land environmental quality in Henan Province.There was a certain amount of safe utilization and also strict control of cultivated land cross the province,and posed certain risks in food security.Thus,it is urgent to solved.For high-risk cultivated land,soil remediation,low accumulation crop varieties,leaf amendment,and deep plowing could not fully guarantee the safe production for staple food.In view of this,this study was conducted by heavy metal cadmium,lead,and arsenic analysis in a total of 663 alternative edible crop samples and 214 soil samples in the risk area.According to the "National Food Safety Standards for Food Pollutants Limits"(GB 2762-2017)and the "Chinese Pharmacopoeia",alternative edible crops were evaluated through regression analysis to select appropriate alternative crop and establish soil thresholds for achieving safe production in the area studied and to provide data support for safe utilization in cultivated land.The conclusions of this study are as follows:(1)According to cadmium limit values for vegetables in the GB 2762-2017 standard,the safety status was in the order: eggplants>legumes>leafy vegetables> rhizomes.In this study,more than 90% of the edible parts of eggplant and legume vegetables had cadmium content far below the limit.Therefore,eggplant and legume vegetables could be used as alternative edible crops in cultivated land for safe utilization.For leafy vegetables,up to 85% of the samples could be lower than the limit standards,and leafy vegetables could achieve safe production when the soil cadmium content was lower than 2.57 mg·kg-1;Spicy rhizome vegetables(garlic,onions)are severely exceeding the standard,so it could not be recommended to use as alternative edible crops.(2)For oilseed crops,referring to the peanut cadmium limit(0.50 mg·kg-1)in the GB 2762-2017 standard,the cadmium content in rape seed samples ranged from 0 to 2.60 mg·kg-1,with a standard-reaching rate of over 80%.The transfer rate of heavy metal cadmium from rape seed to oil during pressing could be less than 10%.The warning value of cadmium content in soil which could realize the safe production of rapeseed was 14.58 mg·kg-1 by regression equation.Therefore,in cultivated land sites for safe utilization and some sites for strictly controlled,safe production could also be achieved.(3)For Chinese herbal medicine,it refers to the cadmium limit(1.00 mg·kg-1)in the standard of the Chinese Pharmacopoeia.This Chinese herbal medicine sample involves two cities in northwest Henan,both significantly exceeded the standard.Among them,cities with heavy soil pollution was more obvious,making it difficult to achieve safe production.Further verification is needed for the cadmium content threshold of Chinese herbal medicine in in cultivated land for safe utilization.(4)For lead additionally,according to the limit value of lead content invegetables in GB 2762-2017,95% of the edible parts of various vegetables could be lower than the limit value,and achieve safe production.referring to the standard for peanut lead content limit in GB 2762-2017,and Oil crops samples such as rape seed with lead content below the limit account for over 85%.As for alternative crops for cultivated land contaminated by heavy metal in Henan Province,the primary concern is cadmium.Alternative crops that achieved safe production for cadmium could also achieve safe production for lead.