农田土壤中微囊藻毒素污染特征及风险评价

蓝藻水华释放的微囊藻毒素(MCs)通过灌溉、堆肥沤田等途径进入农田土壤造成污染.采用固相萃取-高效液相色谱串联质谱方法(HPLC-MS/MS)研究了滇池周边35个代表性农田土壤样品中3种典型微囊藻毒素(MC-LR、MC-RR、MC-YR)的含量、分布特征及风险水平.结果表明,MCs检出率为85.7%,总含量为n.d.~7.8μg/kg,平均含量为1.6μg/kg,其中MC-RR检出率(82.9%)和含量(n.d.~5.3μg/kg)最高.3种MCs的健康风险和生态风险均在可接受范围内,健康风险以MC-YR最大,生态风险以MC-LR最大.儿童以口腔暴露MCs为主,成人以皮肤暴露MCs为主,儿童暴露MCs的健康风险高于成人.

Investigation and risk evaluation of microcystins in agricultural soils

Microcystins (MCs) released from cyanobacterial blooms may be transferred to agricultural soil via irrigation water and cyanobacterial compost. Concentration distribution and risk evaluation of three commonly found MCs (including MC-LR, MC-RR, and MC-YR) in 35 soil samples from vegetable fields around heavy eutrophic Dianchi Lake were studied using solid phase extraction and liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Results indicated that MCs were detected in 85.7% of the samples and the total concentrations of MCs ranged from n.d. (below LOQ) to 7.8μg/kg with the average concentration of 1.6μg/kg. MC-RR appeared the highest detection rate (82.9%) and concentration (n.d.~5.3μg/kg), followed by MC-LR and MC-YR. Both the health and ecological risks of the three MCs were acceptable. MC-YR displayed the highest health ecological risk, while MC-LR showed the highest ecological risk. Oral intake and dermal contact were primary exposure pathway of MCs to children and adults, respectively. Children suffered higher health risk than adults.