Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
Environment and Climate Change Canada, Wildlife Research Division, Delta, British Columbia, Canada.
Environ Toxicol Chem. 2021 Dec;40(12):3379-3391. doi: 10.1002/etc.5220. Epub 2021 Nov 10.
Dichlorodiphenyldichlorethane (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) (DDT) is an organochlorine insecticide that was widely used from the late 1940s to the 1970s in fruit orchards in the Okanagan valley, British Columbia, Canada, and in the process, contaminated American robin (Turdus migratorius) food chains with the parent compound and metabolite dichlorodiphenyldichloroethylene (1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene) (p,p'-DDE). In the present study, we examined the biological fate of these DDT-related (DDT-r) compounds at the same sites/region 26 years after a previous study by: (1) collecting soil, earthworms, and American robin eggs from apple, cherry, and pear orchards; (2) characterizing the diet and trophic positions of our biota using stable isotope analyses of δ C and δ N; and (3) estimating fugacity, biota-soil-accumulation factors (BSAFs), and biomagnification factors (BMFs). Mean p,p'-DDE concentrations (soil: 16.1 µg/g organic carbon-lipid equivalent; earthworms: 96.5 µg/g lipid equivalent; eggs: 568 µg/g lipid equivalent) revealed that contamination is present at elevated levels similar to the 1990s and our average soil DDE:DDT ratio of 1.42 confirmed that DDT is slowly degrading. American robins appeared to feed at similar trophic levels, but on different earthworms as indicated by egg stable isotope values (mean δ N = 8.51‰ ± 0.25; δ C = -26.32‰ ± 0.12). Lumbricidae and Aporrectodea worms shared a roughly similar δ N value; however, Lumbricus terrestris showed a markedly enriched δ C isotope, suggesting differences in organic matter consumption and physiological bioavailability. Biota-soil-accumulation factors and BMFs ranged over several orders of magnitude and were generally >1 and our fugacity analyses suggested that p,p'-DDE is still thermodynamically biomagnifying in American robin food chains. Our results demonstrate that DDT-r in fruit orchards remains bioavailable to free-living terrestrial passerines and may pose a potential toxicological risk. Environ Toxicol Chem 2021;40:3379-3391. © 2021 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Environment and Climate Change Canada.
滴滴涕（1,1,1-三氯-2,2-双（对氯苯基）乙烷）（DDT）是一种有机氯杀虫剂，于 20 世纪 40 年代末至 70 年代在加拿大不列颠哥伦比亚省奥肯那根山谷的果园中广泛使用，在此过程中，滴滴涕的母体化合物和代谢物滴滴滴（1,1-二氯-2,2-双（4-氯苯基）乙烯）（p,p'-DDE）污染了美洲知更鸟（Turdus migratorius）的食物链。在本研究中，我们通过以下方式检查了 26 年前之前研究在同一地点/区域内这些滴滴涕相关（DDT-r）化合物的生物命运：（1）从苹果、樱桃和梨园采集土壤、蚯蚓和美洲知更鸟的蛋；（2）使用 δ C 和 δ N 的稳定同位素分析来描述我们生物群的饮食和营养水平；（3）估算逸度、生物-土壤积累因子（BSAF）和生物放大因子（BMF）。p,p'-DDE 的平均浓度（土壤：16.1μg/g 有机碳-脂质当量；蚯蚓：96.5μg/g 脂质当量；蛋：568μg/g 脂质当量）表明，污染仍处于类似 20 世纪 90 年代的高水平，而我们的平均土壤 DDE:DDT 比值为 1.42，证实 DDT 正在缓慢降解。美洲知更鸟似乎处于相似的营养水平，但从卵的稳定同位素值（平均 δ N=8.51‰±0.25；δ C=-26.32‰±0.12）可以看出，它们的食物来源不同。Lumbricidae 和 Aporrectodea 蚯蚓具有相似的 δ N 值；然而，Lumbricus terrestris 的 δ C 同位素明显富集，表明它们在有机物消耗和生理生物利用度方面存在差异。生物-土壤积累因子和 BMF 的范围跨越几个数量级，通常大于 1，我们的逸度分析表明，p,p'-DDE 仍在美洲知更鸟食物链中热力学上具有生物放大作用。我们的研究结果表明，果园中的 DDT-r 仍然对自由生活的陆地雀形目动物具有生物可利用性，可能构成潜在的毒理学风险。环境毒物化学 2021；40:3379-3391。©2021 加拿大女王陛下以其自身和加拿大环境与气候变化部的名义。环境毒物化学由 Wiley Periodicals LLC 代表 SETAC 出版。经加拿大环境与气候变化部许可转载。
