2011-2014年宝鸡市农田土壤铅、镉污染检测

Detection of lead and cadmium pollution in the agricultural soil of Baoji City,2011-2014

目的了解宝鸡市农村土壤环境重金属铅、镉的污染状况,为当地土壤污染状况的评价及治理提供科学依据。方法 2012-2014年,根据地貌和方位,随机选取宝鸡市3个县50个镇(街道)的农田土壤进行采样,用石墨炉原子吸收分光光度法检测铅、镉含量,并分析评价其污染状况。结果采集检测农田土壤样品200份,铅平均含量(20.33±12.26)mg/kg、镉平均含量(0.33±0.54)mg/kg。不同年度土壤铅、镉含量差异有统计学意义(P<0.05),铅含量2014年最高(24.26±5.77 mg/kg)、2012年最低(11.88±6.83 mg/kg),2012年显著低于其它各年(P<0.05);镉含量2011年最高(0.59±1.11 mg/kg)、2012年最低(0.16±0.11 mg/kg),2011年显著高于其它各年(P<0.05)。不同县土壤铅、镉含量差异无统计学意义(P>0.05)。铅含量达到一级土壤标准195份(97.5%)、二级5份(2.5%),镉含量达到一级土壤标准94份(47.0%)、二级48份(24.0%)、三级48份(24.0%)、超三级10份(5%)。不同年度、不同县的土壤铅污染分级构成差异无统计学意义(P>0.05),镉污染分级构成差异有统计学意义(P<0.05)。结论宝鸡市农田土壤总体已受到重金属污染,污染程度低于全国平均水平。应根据污染状况采取综合防控措施,降低土壤重金属污染。

Objective To investigate the pollution status of lead （Pb） and cadmium （Cd） in rural soil of Baoji City so as to provide scientific evidence for evaluation and management of local soil pollution. Methods According to landform and orientation, agricultural soil samples were randomly collected from 50 towns （streets） of 3 counties in Baoji City during 2012 - 2014. The concentration of Pb and Cd in the soil was determined by graphite furnace atomic absorption spectrophotometry （GFASS）, and the pollution was analyzed and evaluated. Results For the 200 soil samples detected, the average levels of Pb and Cd were （20.33 ± 12.26）mg/kg and （0.33 ±0.54）mg/kg respectively. The concentration of Pb and Cd was different among soil samples collected in different years （P〈0.05）. The concentration of Pb in the soil collected in 2014 [ （24.26 ±5.77）mg/kg] was the highest, while that in 2012 [ （11.88 ±6.83）mg/kg] was the lowest, significantly lower than that in the other years （P 〈 0.05） . The concentration of Cd in the soil collected in 2011 [ （0.59 ± 1.11 ）mg/kg] was the highest and was significantly higher than that in the other years （P 〈 0.05）, while that in 2012 was the lowest [ （0.16 ±0.11）mg/kg]. No statistically significant differences were found in the concentration of Pb and Cd among soils collected from different counties （ P 〉 0.05）. As for Pb concentration, 195 （97.5 % ） soil samples met the standard of level- Ⅰ soil and 5（2.5 % ） met the standard of level- Ⅱ. As for Cd concentration, 94（47.0% ）, 48（24.0% ）, 48（24.0% ）, 10（5% ） soil samples respectively met the standards of level - Ⅰ, level - Ⅱ , level - Ⅲ and super level - Ⅲsoil. Grading composition of Pb pollution of soils collected in different years and different counties had no statistical differences （ P 〉 0.05 ）, while that of Cd pollution differed significantly （ P 〈 0.05 ）. Conclusions Agricultural soil in Baoji City has been polluted by heavy metals, but the pollution levd is lower than the national average level. It is necessary to adopt comprehensive prevention and control measures according to the pollution situation so as to decrease the heavy metal pollution.