小尺度区域红壤重金属含量背景值及其环境质量评价

在小尺度范围内均匀密集布点采样的基础上,从268个土壤样品中挑选其中“清洁”红壤48个和“清洁”水稻土78个进行统计分析后,提出了江西省鹰潭红壤Hg含量的背景值为0.050 mg/kg、Cd为0.105mg/kg、As为10.4 mg/kg、Cr为47.9 mg/kg、Cu为24.1 mg/kg、Pb为25.7 mg/kg;水稻土Hg含量的背景值为0.063 mg/kg、Cd为0.100 mg/kg、As为4.3 mg/kg、Cr为42.3 mg/kg、Cu为25.7 mg/kg、Pb为27.1 mg/kg;与以前研究提出的背景值相比,本研究提出的鹰潭红壤Cd和Cu含量的背景值分别提高了61.5%和31%,Hg降低了35.9%,其它元素相近;水稻土除Cu稍有提高外,其余5种重金属元素都显著降低。同时,不同作物利用土壤重金属环境质量评价结果表明:鹰潭地区50%旱地红壤、20%菜地、15%水稻土和30%果园地的土壤达到清洁标准。

Assessment of Environmental Quality and Background Concentrations of Red Soil Heavy Metals on Small Scale

The background concentrations of red soil heavy metals such as Hg,Cd,As,Cr,Cu and Pb in small areas of Yingtan City,Jiangxi Province,were investigated.About 48 red soil samples and 78 paddy soil samples taken from the areas without pollution of heavy metals were selected from the total whole 268 soil samples.After analyzing samples with strict quality assure and quality procedures,heavy metal concentrations in the soils were calculated statistically.The background concentrations of red soil were 0.050 mg/kg for Hg,0.105 mg/kg for Cd,10.4 mg/kg for As,47.9 mg/kg for Cr,24.1 mg/kg for Cu,25.7 mg/kg for Pb;and of paddy soil to be 0.063 mg/kg for Hg,0.100 mg/kg for Cd,4.3(mg/kg) for As,42.3 mg/kg for Cr,25.7 mg/kg for Cu,27.1 mg/kg for Pb,respectively.Compared with the concentrations suggested by China national environmental monitor center(CNEMC) in 1990,the Cd and Cu concentrations in red soil in present study are about 61.5% and 31.0% higher than those of CNEMC,the Hg is lower 35.9% than that of CNEMC,others are similar;the Cu concentrations in paddy soil in present study is little higher than that of CNEMC,the others are obviously lower than that of CNEMC;meanwhile,environmental quality results of soil heavy metals in different crop utilization testify that 50% of dryland red soil,20% of vegetables soil,15% of paddy soil and 30% of fruit soil in Yingtan reach the soil criterion without pollution of heavy metals.