煤矸石等组成的无土栽培基质重金属污染及蔬菜安全评价

利用煤矸石、油菜秸秆等废弃资源为原料,按（煤矸石：腐熟秸秆）体积比为2：8、3：7、4：6、5：5和6：4的比例配制成5种混合基质,在人工光照室内以盆栽的方法栽培白菜、生菜、苋菜、菠菜、茄子、番茄、辣椒和萝卜8种蔬菜,采用尼梅罗综合污染指数和Hakanson潜在生态风险指数法对5种混合基质以及其上生长的8种蔬菜的重金属污染和潜在生态风险进行了综合评价。结果表明,5种混合基质中,煤矸石含量较少的T1、T2、T3基质的重金属污染程度较小,潜在生态风险程度较低,在这3种基质上栽种的蔬菜重金属综合污染评价等级为优良或安全,符合蔬菜绿色食品标准。重金属对混合基质产生的污染中,Cd和Hg是主要的重金属污染及潜在生态风险因子,其他重金属的污染能力较小。另外,在评价由煤矸石为无机原料组成的有机生态型无土栽培基质的重金属污染及潜在生态风险时,应选择国家土壤环境质量一级标准作为参比值,且煤矸石在混合基质中所占的体积比一般不应超过1/2。

Evaluation on Heavy Metal Contamination and Vegetable Security in Soilless Culture Medium Containing Coal Gangue

Five types of soilless culture mediums,containing coal gangue and rape stalk with the volume ratios of 2：8,3：7,4：6,5：5 and 6：4,respectively,were prepared for vegetable cultivation.On such mediums,8 species of vegetable crops,Brassica chinensis L.,Lactuca sativa,Amarantus mangostanus L.,Spinacia oleracea L.,Solanum melongena,Lycopersicon esculentum,Capsicum frutescens L.,Raphanus sativus L.,were cultivated in the pot in the biotron.The state of heavy metals contamination and the potential ecological risks in the cultivation systems were assessed using single factor contaminant indexes,nemerow pollution indexes and hakanson indexes,respectively.The results showed that 3 of the 5 types of mediums,containing less coal gangue,named T1,T2,T3,exhibited low levels of heavy metal contamination and less potential ecological risks.All of the 8 species of vegetable crops cultivated on these 3 types of mediums were evaluated as quality or safe for heavy metals contamination assessments,and meet the standards for green food vegetables.However,the mediums of T4 and T5,with slightly elevated levels of heavy metals contamination,exhibited relatively high potential of ecological risks.The 8 species of vegetable crops cultivated on these mediums were evaluated as safe or lightly heavy metals contamination.The main heavy metals contaminants in the compound mediums were Cd and Hg,which contribute to 35.64%～36.50% and 51.78%～42.94% to the RI according to the national soil environment first-level quality standards.So,Cd and Hg were the major pollutants and potential ecological risk factors in the mediums,while other heavy metals had relatively low levels of pollution capabilities.Additionally,the national soil environment first-level quality standards should be adopted as the control in evaluation the overall heavy metals contamination and potential ecological risks of soilless culture with coal gangue as inorganic constituents,and the volume ratios of coal gangue in the compound mediums should be less than half of the total volumes.