Miller Lana L, Isaacs Meghan A, Martyniuk Christopher J, Munkittrick Kelly R
Environmental Protection Division, BC Ministry of Environment, Prince George, British Columbia, Canada.
Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada.
Environ Toxicol Chem. 2015 Oct;34(10):2335-46. doi: 10.1002/etc.3064. Epub 2015 Sep 11.
Canadian fish-based environmental effects monitoring programs use individual and population-level endpoints to assess aquatic health. Impacts of coal mining and selenium (Se) exposure were assessed in slimy sculpin (Cottus cognatus) from reference streams located both inside and outside of a coal zone, and from 1 stream with a history of coal mining, using traditional environmental effects monitoring endpoints. In addition, physical characteristics of the streams and benthic macro-invertebrate communities were assessed. To determine whether the assessment of effects could be improved by including molecular markers, real-time polymerase chain reaction assays were optimized for genes associated with reproduction (vtg, esr1, star, cyp19a1, and gys2), and oxidative and cellular stress (sod1, gpx, gsr, cat, and hsp 90). Water Se levels exceeded guidelines in the stream with historical mining (4 μg/L), but benthic macroinvertebrates did not exceed dietary thresholds (2-3 μg/g dry wt). Whole-body Se levels were above British Columbia's tissue guideline in fish from all streams, but only above the draft US Environmental Protection Agency (USEPA) criterion (7.91 μg/g dry wt) at the reference stream inside the coal zone. Some markers of cellular and oxidative stress were elevated in fish liver at the exposed site (sod1, gpx), but some were lower (cat, sod1, gpx, gsr, hsp90) in the gonads of fish inside the coal zone. Some of the differences in gene expression levels between the reference and impacted sites were sex dependent. Based on benthic macroinvertebrate assessments, the authors hypothesize that traditional and molecular differences in slimy sculpin at impacted sites may be driven by food availability rather than Se exposure. The present study is the first to adapt molecular endpoints in the slimy sculpin for aquatic health assessments.
加拿大基于鱼类的环境影响监测项目使用个体和种群层面的指标来评估水生生物健康状况。利用传统环境影响监测指标，对来自煤炭产区内外参考溪流以及一条有煤矿开采历史溪流中的粘背杜父鱼（Cottus cognatus）进行评估，以了解煤矿开采和硒（Se）暴露的影响。此外，还评估了溪流的物理特征和底栖大型无脊椎动物群落。为了确定纳入分子标记是否能改进影响评估，针对与繁殖（vtg、esr1、star、cyp19a1和gys2）以及氧化和细胞应激（sod1、gpx、gsr、cat和hsp 90）相关的基因，优化了实时聚合酶链反应检测方法。历史开采溪流中的水体硒水平超过了指导标准（4 μg/L），但底栖大型无脊椎动物未超过饮食阈值（2 - 3 μg/g干重）。所有溪流中鱼类的全身硒水平均高于不列颠哥伦比亚省的组织指导标准，但仅煤炭产区内参考溪流中的鱼类高于美国环境保护局（USEPA）草案标准（7.91 μg/g干重）。在暴露位点的鱼肝中，一些细胞和氧化应激标记物有所升高（sod1、gpx），但煤炭产区内鱼类性腺中的一些标记物则较低（cat、sod1、gpx、gsr、hsp90）。参考位点和受影响位点之间基因表达水平的一些差异具有性别依赖性。基于底栖大型无脊椎动物评估，作者推测受影响位点粘背杜父鱼的传统差异和分子差异可能由食物可获得性而非硒暴露驱动。本研究首次将粘背杜父鱼的分子指标应用于水生生物健康评估。
