太子河流域莠去津的空间分布及风险评价

Spatial Distribution and Risk Assessment of Atrazine in Taizi River Basin, China

应用气相色谱-质谱联用仪(gas chromatograph-mass spectrometer,GC-MS),分析了莠去津(atrazine,AT)在太子河流域地表水、悬浮物和地下水中的含量水平,以及AT在该流域水体环境中的分布特征与环境行为,并对地表水中的AT污染程度进行了初步评价.结果表明,太子河流域地表水中ρ(AT)为0~734.0 ng·L-1,悬浮物中ω(AT)为0~1 496.6 ng·g-1,地下水中ρ(AT)为30.0~245.0 ng·L-1,其算术平均值分别为335.3 ng·L-1、382.9 ng·L-1和104.4 ng·L-1.AT在太子河流域地表水中水相-悬浮物相的有机碳标准分配系数(lg koc)介于3.50~4.14,表明悬浮物的吸附是水体中AT迁移的一个重要途径.AT在太子河流域地表水体中(水相和悬浮物相)的通量介于1.5~184.7 mg·s-1之间,最高值出现在中游地区.风险评价结果显示,地表水中AT的生态风险很小,95%以上的物种能够得以保护,但太子河流域地表水中AT的残留水平可能具有一定的潜在危害.

Atrazine( AT) has been detected in surface water and groundwater in many countries and regions around the world. Concentrations of AT in surface water,suspended particulate matter( SPM) and groundwater samples collected from the Taizi River basin,in northeast China,were analyzed using a gas chromatograph-mass spectrometer( GC-MS) in order to clarify their spatial distribution and environmental behavior,and to assess their potential ecological risk. Concentrations of AT varied from 0-734. 0 ng·L- 1 for surface water,0-1 493. 6 ng·g- 1for SPM and 30. 0-245. 0 ng·L- 1for groundwater,with averages of 335. 3 ng·L- 1,382. 9 ng·L- 1, and 104. 4 ng·L- 1,respectively. The logarithm in situ SPM-water partition coefficients( lg koc) of AT were in the range of 3. 50-4. 14 indicating that adsorption of AT from the aqueous phase to SPM plays an important role in dissipating AT in surface water. Fluxes of AT in surface water ranged from 1. 5-184. 7 mg·s- 1in the basin,calculated based on the measured flow velocity and concentrations in surface water and SPM. The maximum value of AT flux was found in the middle stream of the Taizi River( S7). The risk assessment suggested that the ecological risk of AT in surface water was low,with more than 95% of the species protected from risk in the Taizi River basin. However,the residue levels of AT in surface water of the Taizi River basin may cause potential environmental risks.