Biological Traits and the Transfer of Persistent Organic Pollutants through River Food Webs

Freshwater organisms remain at risk
from bioaccumulation and biomagnification
of persistent organic pollutants (POPs), but factors affecting their
transfer through food webs are poorly understood. Here, we investigate
transfer pathways of polychlorinated biphenyls, polybrominated diphenyl
ethers, and organochlorine through a river food web, assessing the
distribution and flux between basal resources (n =
3), macroinvertebrates (n = 22), and fish (n = 1). We investigate the effects of biological traits
on the observed patterns and use trait-based models to predict POP
bioaccumulation. Transfer pathways differed among POPs and traits
such as habitat affinity, feeding behavior, and body size explained
some variation in POP burdens between organisms. Trait-based models
indicated that relationships between POPs, trophic transfers, and
traits were relatively well conserved across a wider array of river
food webs. Although providing more consistent predictions of POP bioaccumulation
than steady-state models, variability in bioaccumulation across food
webs limited the accuracy of trait-model predictions. As some of the
first data to illustrate how ecological processes alter the flux of
pollutants through river food webs, these results reveal important
links between POPs and contrasting energetic pathways. These data
also show the utility of trait-based methods in the assessment of
persistent contaminants, but further field validations are required.

淡水生物仍面临持久性有机污染物（Persistent Organic Pollutants, POPs）的生物蓄积（bioaccumulation）与生物放大（biomagnification）风险，但目前学界对其沿食物网传递的影响机制仍知之甚少。本研究以河流食物网为研究对象，探究多氯联苯（polychlorinated biphenyls）、多溴二苯醚（polybrominated diphenyl ethers）及有机氯污染物（organochlorine）的传递路径，评估基础食物资源（n=3）、大型无脊椎动物（macroinvertebrates，n=22）与鱼类（n=1）间的污染物分布与通量特征。我们分析了生物性状对观测到的污染物累积模式的影响，并采用基于性状的模型（trait-based models）预测POP的生物蓄积过程。不同POP的传递路径存在差异，而生境偏好、摄食行为与体型等生物性状可解释生物间POP负载量的部分差异。基于性状的模型结果显示，POP、营养级传递与生物性状间的关联在更多样化的河流食物网中相对保守。尽管相较于稳态模型（steady-state models），基于性状的模型对POP生物蓄积的预测更为一致，但不同食物网间生物蓄积的差异仍限制了该模型预测的准确性。作为首批阐明生态过程如何改变污染物沿河流食物网通量的研究数据之一，本研究结果揭示了POP与不同能量流动路径间的重要关联。本数据集同时证实了基于性状的方法在持久性污染物评估中的应用价值，但仍需开展进一步的野外验证工作。