Main Anson R, Headley John V, Peru Kerry M, Michel Nicole L, Cessna Allan J, Morrissey Christy A
School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Aquatic Contaminants Research Division, Water Science and Technology Directorate, Environment Canada, Saskatoon, Saskatchewan, Canada.
PLoS One. 2014 Mar 26;9(3):e92821. doi: 10.1371/journal.pone.0092821. eCollection 2014.
Neonicotinoids currently dominate the insecticide market as seed treatments on Canada's major Prairie crops (e.g., canola). The potential impact to ecologically significant wetlands in this dominantly agro-environment has largely been overlooked while the distribution of use, incidence and level of contamination remains unreported. We modelled the spatial distribution of neonicotinoid use across the three Prairie Provinces in combination with temporal assessments of water and sediment concentrations in wetlands to measure four active ingredients (clothianidin, thiamethoxam, imidacloprid and acetamiprid). From 2009 to 2012, neonicotinoid use was increasing; by 2012, applications covered an estimated ∼11 million hectares (44% of Prairie cropland) with >216,000 kg of active ingredients. Thiamethoxam, followed by clothianidin, were the dominant seed treatments by mass and area. Areas of high neonicotinoid use were identified as high density canola or soybean production. Water sampled four times from 136 wetlands (spring, summer, fall 2012 and spring 2013) across four rural municipalities in Saskatchewan similarly revealed clothianidin and thiamethoxam in the majority of samples. In spring 2012 prior to seeding, 36% of wetlands contained at least one neonicotinoid. Detections increased to 62% in summer 2012, declined to 16% in fall, and increased to 91% the following spring 2013 after ice-off. Peak concentrations were recorded during summer 2012 for both thiamethoxam (range: <LOQ--1490 ng/L, canola) and clothianidin (range: <LOQ--3110 ng/L, canola). Sediment samples collected during the same period rarely (6%) contained neonicotinoid concentrations (which did not exceed 20 ng/L). Wetlands situated in barley, canola and oat fields consistently contained higher mean concentrations of neonicotinoids than in grasslands, but no individual crop singularly influenced overall detections or concentrations. Distribution maps indicate neonicotinoid use is increasing and becoming more widespread with concerns for environmental loading, while frequently detected neonicotinoid concentrations in Prairie wetlands suggest high persistence and transport into wetlands.
作为加拿大主要草原作物（如油菜籽）种子处理剂，新烟碱类目前在杀虫剂市场占据主导地位。在这个以农业为主的环境中，新烟碱类对具有生态意义的湿地的潜在影响在很大程度上被忽视了，而其使用分布、污染发生率和污染水平仍未得到报告。我们结合对湿地水和沉积物浓度的时间评估，模拟了三个草原省份新烟碱类使用的空间分布，以测量四种活性成分（噻虫胺、噻虫嗪、吡虫啉和啶虫脒）。2009年至2012年期间，新烟碱类的使用量在增加；到2012年，施用面积估计达到约1100万公顷（占草原农田的44%），活性成分超过21.6万千克。按质量和面积计算，噻虫嗪是主要的种子处理剂，其次是噻虫胺。新烟碱类使用量高的地区被确定为高密度油菜籽或大豆产区。在萨斯喀彻温省四个农村自治市的136个湿地（2012年春季、夏季、秋季和2013年春季）进行了四次水样采集，同样在大多数样本中检测到了噻虫胺和噻虫嗪。在2012年春季播种前，36%的湿地至少含有一种新烟碱类。2012年夏季检测率升至62%，秋季降至16%，2013年春季解冻后升至91%。2012年夏季记录到噻虫嗪（范围：<最低定量限-1490纳克/升，油菜籽）和噻虫胺（范围：<最低定量限-3110纳克/升，油菜籽）的峰值浓度。同期采集的沉积物样本很少（6%）含有新烟碱类浓度（未超过20纳克/升）。位于大麦、油菜籽和燕麦田的湿地中，新烟碱类的平均浓度始终高于草原湿地，但没有单一作物单独影响总体检测结果或浓度。分布图显示，新烟碱类的使用在增加且分布越来越广泛，这引发了对环境负荷的担忧，而在草原湿地中频繁检测到的新烟碱类浓度表明其具有高持久性并能传输到湿地中。
