Department of Chemistry & Biochemistry, Utah State University, Logan, USA.
Department of Chemistry, University of Otago, Dunedin, New Zealand.
Environ Pollut. 2019 Nov;254(Pt A):112973. doi: 10.1016/j.envpol.2019.112973. Epub 2019 Jul 29.
New Zealand uses more than a ton of pesticides each year; many of these are mobile, relatively persistent, and can make their way into waterways. While considerable effort goes into monitoring nutrients in agricultural streams and programs exist to monitor pesticides in groundwater, very little is known about pesticide detection frequencies, concentrations, or their potential impacts in New Zealand streams. We used the 'Polar Organic Chemical Integrative Sampler' (POCIS) approach and grab water sampling to survey pesticide concentrations in 36 agricultural streams in Waikato, Canterbury, Otago and Southland during a period of stable stream flows in Austral summer 2017/18. We employed a new approach for calculating site-specific POCIS sampling rates. We also tested two novel passive samplers designed to reduce the effects of hydrodynamic conditions on sampling rates: the 'Organic-Diffusive Gradients in Thin Films' (o-DGT) aquatic passive sampler and microporous polyethylene tubes (MPTs) filled with Strata-X sorbent. Multiple pesticides were found at most sites; two or more were detected at 78% of sites, three or more at 69% of sites, and four or more at 39% of sites. Chlorpyrifos concentrations were the highest, with a maximum concentration of 180 ng/L. Concentrations of the other pesticides were generally below 20 ng/L. Mean concentrations of individual pesticides were not correlated with in-stream nutrient concentrations. The majority of pesticides were detected most frequently in POCIS, presumably due to its higher sampling rate and the relatively low concentrations of these pesticides. In contrast, chlorpyrifos was most frequently detected in grab samples. Chlorpyrifos concentrations at two sites were above the 21-day chronic 'No Observable Effect Concentration' (NOEC) values for fish and another two sites had concentrations greater than 50% of the NOEC. Otherwise, concentrations were well-below NOEC values, but close to the New Zealand Environmental Exposure Limits in several cases.
新西兰每年使用超过一吨的农药；其中许多是移动的、相对持久的，并且可以进入水道。尽管在监测农业溪流中的营养物质方面做了大量工作，并且存在监测地下水农药的计划，但对于新西兰溪流中农药检测的频率、浓度或其潜在影响知之甚少。我们在 2017/18 年澳大拉西亚夏季稳定的溪流流量期间，使用“极性有机化学综合采样器”（POCIS）方法和抓水采样调查了怀卡托、坎特伯雷、奥塔哥和南地 36 条农业溪流中的农药浓度。我们采用了一种新的方法来计算特定地点的 POCIS 采样率。我们还测试了两种新的被动采样器，旨在减少水动力条件对采样率的影响：“有机扩散梯度薄膜”（o-DGT）水相被动采样器和填充 Strata-X 吸附剂的微孔聚乙烯管（MPT）。大多数地点都发现了多种农药；78%的地点检测到两种或两种以上，69%的地点检测到三种或三种以上，39%的地点检测到四种或四种以上。毒死蜱浓度最高，最高浓度为 180ng/L。其他农药的浓度通常低于 20ng/L。个别农药的平均浓度与溪流中的营养物质浓度没有相关性。大多数农药在 POCIS 中检测到的频率最高，可能是因为它的采样率较高，而且这些农药的浓度相对较低。相比之下，毒死蜱在抓样中检测到的频率最高。两个地点的毒死蜱浓度高于鱼类 21 天慢性“无观察效应浓度”（NOEC）值，另有两个地点的浓度高于 NOEC 的 50%。在其他情况下，浓度远低于 NOEC 值，但在几种情况下接近新西兰环境暴露限值。
