Kissinger Jennifer A, Gregory Braden R B, Clarkson Chloe, Libera Nell, Eickmeyer David C, Kimpe Linda E, Kurek Joshua, Smol John P, Blais Jules M
Department of Biology, University of Ottawa, 30 Marie Curie Pvt., Ottawa, ON, Canada.
Paleoecological Environmental Assessment and Research Laboratory, Department of Biology, Queen's University, Kingston, ON, K7L 3N, Canada.
Environ Pollut. 2023 Oct 15;335:122307. doi: 10.1016/j.envpol.2023.122307. Epub 2023 Aug 3.
Eutrophication, which remains one of the greatest threats to water quality worldwide, is particularly acute in agricultural areas. Here we assessed long-term drivers of potential pollution inputs to lakes in southwest Nova Scotia (Canada), a region marked by fur farming (mainly mink) and other agricultural activities. We used a BACI (before-after-control-impact) study design with sediment cores collected from 14 lakes selected based on their proximity to mink farms. We combined economic data, mink faecal samples, and a series of geochemical markers in dated sediment cores, including sterols, δN, visible reflectance spectroscopy (VRS)-inferred chlorophyll-a, and heavy metals, to relate changes in sediment geochemistry to the growth of mink farms in the region. Sterol biomarkers (cholesterol and β-sitosterol) measured in a range of samples (i.e. mink faeces and feed, aquaculture feed), were elevated where mink farms were located close to each study lake. Mink-related sterols (cholesterol, β-sitoserol), δN measurements, VRS chlorophyll-a, and heavy metals As, Cu, Sr increased in the 1980s coeval with a ∼400% increase of mink farms in the region, especially near Nowlans Lake. Agricultural impacts were subtler in other lakes. Our study expands on prior applications of geochemical fingerprinting in forensic paleolimnology when direct monitoring data are incomplete. This multi-proxy approach has promising applications for environmental pollution assessments in other lake ecosystems experiencing water quality issues.
富营养化仍然是全球水质面临的最大威胁之一，在农业地区尤为严重。在这里，我们评估了加拿大新斯科舍省西南部湖泊潜在污染输入的长期驱动因素，该地区以水貂养殖（主要是貂）和其他农业活动为特征。我们采用了一种BACI（前后对照影响）研究设计，从14个根据与水貂养殖场的距离选择的湖泊中采集了沉积物岩芯。我们将经济数据、水貂粪便样本以及一系列年代测定的沉积物岩芯中的地球化学标志物相结合，包括甾醇、δN、可见反射光谱（VRS）推断的叶绿素a和重金属，以将沉积物地球化学的变化与该地区水貂养殖场的发展联系起来。在一系列样本（即水貂粪便和饲料、水产养殖饲料）中测量的甾醇生物标志物（胆固醇和β-谷甾醇），在靠近每个研究湖泊的水貂养殖场所在位置有所升高。与水貂相关的甾醇（胆固醇、β-谷甾醇）、δN测量值、VRS叶绿素a以及重金属砷、铜、锶在20世纪80年代有所增加，与此同时该地区水貂养殖场数量增加了约400%，尤其是在诺兰斯湖附近。其他湖泊的农业影响则较为细微。我们的研究扩展了在直接监测数据不完整时地球化学指纹识别在法医古湖沼学中的先前应用。这种多指标方法在其他面临水质问题的湖泊生态系统的环境污染评估中具有广阔的应用前景。
