Kurek Joshua, Fraser Meghan P, Nakamoto Bobby J, Kidd Karen A, Edge Christopher B
Department of Geography and Environment, Mount Allison University, Sackville, NB, Canada.
Department of Biology, Mount Allison University, Sackville, NB, Canada.
PLoS One. 2025 Apr 21;20(4):e0320665. doi: 10.1371/journal.pone.0320665. eCollection 2025.
To manage defoliation from insect outbreaks, about half of the forested land in New Brunswick, Canada, was treated with dichlorodiphenyltrichloroethane (DDT) between 1952 and 1968. Aerial applications of DDT have thus likely increased the risk of chronic effects in aquatic ecosystems from this legacy insecticide given its high persistence in soil and sediments and its bioaccumulation potential within the food web. We investigated DDT and its metabolites (total ΣDDTs = ∑ DDT + ∑ DDD + ∑ DDE) in Brook Trout (Salvelinus fontinalis) associated with geospatial data of historical applications to lake watersheds and sedimentary measures of DDT and its metabolites from five "impact" and two "reference" study lakes. Total ΣDDTs in recent lake sediments were significantly correlated with cumulative DDT applied aerially to the lake's watershed. Brook Trout muscle tissue showed total ΣDDTs that were significantly higher from impact lakes than reference lakes. On average, total ΣDDTs in Brook Trout from impact lakes exceeded ecological guidelines for consumers of aquatic biota by about ten times. Most legacy DDT in Brook Trout and lake sediments were the metabolites ΣDDE and ΣDDD, which suggests the importance of environmental conditions and transport of weathered sources of this organochlorine insecticide to biota. Stable isotopes from fish and common invertebrate prey also suggested that Brook Trout were at a similar trophic position among all study lakes and thus storage pools of legacy DDT likely explain contamination levels within biota. Our findings clearly demonstrate that chronic effects of historical DDT applications likely persist throughout aquatic environments in north-central New Brunswick.
为应对昆虫爆发导致的落叶问题，1952年至1968年间，加拿大新不伦瑞克省约一半的林地都喷洒了二氯二苯三氯乙烷（DDT）。鉴于DDT在土壤和沉积物中具有很高的持久性及其在食物网中的生物累积潜力，通过空中喷洒DDT可能增加了这种遗留杀虫剂对水生生态系统产生慢性影响的风险。我们研究了溪鳟（Salvelinus fontinalis）体内的DDT及其代谢物（总ΣDDTs = ∑ DDT + ∑ DDD + ∑ DDE），并将其与湖泊流域历史喷洒的地理空间数据以及来自五个“受影响”和两个“参考”研究湖泊的DDT及其代谢物的沉积测量数据相关联。近期湖泊沉积物中的总ΣDDTs与空中喷洒到该湖流域的累积DDT量显著相关。溪鳟肌肉组织中的总ΣDDTs显示，受影响湖泊中的含量明显高于参考湖泊。平均而言，受影响湖泊中溪鳟体内的总ΣDDTs超过了水生生物消费者的生态准则约十倍。溪鳟和湖泊沉积物中大多数遗留的DDT是代谢物ΣDDE和ΣDDD，这表明环境条件以及这种有机氯杀虫剂风化源向生物群的迁移的重要性。鱼类和常见无脊椎动物猎物的稳定同位素也表明，所有研究湖泊中的溪鳟处于相似的营养级，因此遗留DDT的储存库可能解释了生物群体内的污染水平。我们的研究结果清楚地表明，历史上使用DDT的慢性影响可能在新不伦瑞克省中北部的整个水生环境中持续存在。
