Scientific Center of Zoology and Hydroecology NAS RA, 7 P. Sevak Str., Yerevan 0014, Armenia.
National Institute of Chemical Physics and Biophysics, Laboratory of Environmental Toxicology, Akadeemia tee 23, Tallinn 12618, Estonia.
Ecotoxicol Environ Saf. 2024 Sep 15;283:116855. doi: 10.1016/j.ecoenv.2024.116855. Epub 2024 Aug 10.
Globally, monitoring of the surface waters is largely limited to the physico-chemical analysis of water in rivers and lakes. Sediment state in the aquatic systems including sediment chemical content or the structure and diversity of benthic communities or ecotoxicological studies with natural sediments remains largely overlooked by the monitoring programs. Hence we assessed the potential toxicity of three riverine sediments on the life-cycle traits (emergence and reproduction) of midge Chironomus riparius via an ecotoxicological testing method over two generations (according to OECD test 233 guidelines). In addition, the riverine sediments were spiked with polyamide (nylon) microplastic particles (1 g kg) to analyze an additive effect of microplastic on the sediment toxicity. As model river systems, three rivers (Karchaghbyur, Gavaraget, Argichi) in the Lake Sevan basin (Armenia) were selected. Results of ecotoxicity testing were compared with the indices of water quality (derived from the physico-chemical analysis) and the indices of the ecological status of the rivers (derived from the analysis of benthic communities). The results of testing demonstrated an unexpectedly low emergence of midges after the first generation exposed to the sediment of the river having ''good ecological status'' - the Argichi. Sediments of the Karchaghbyur and Gavaraget rivers impeded the emergence and reproduction of midges after the second generation. An addition of polyamide particles to the sediments did not significantly affect the life-cycle traits of C. riparius indicating the primary effect of the sediments' condition. The discrepancy of biotesting result with that of the other two methods (which indicated ''average water quality'' and "good ecological status") underlies the importance of designing more comprehensive monitoring programs for better assessment and protection of aquatic systems and resources.
全球范围内，对地表水的监测主要局限于对河流和湖泊水质的理化分析。水生系统中的沉积物状况，包括沉积物的化学含量或底栖群落的结构和多样性，或者对天然沉积物的生态毒理学研究，在监测计划中基本上被忽视了。因此，我们通过两代（根据 OECD 测试 233 指南）的生态毒理学测试方法，评估了三种河流沉积物对摇蚊 Chironomus riparius 生命周期特征（出现和繁殖）的潜在毒性。此外，还在河流沉积物中添加了聚酰胺（尼龙）微塑料颗粒（1g/kg），以分析微塑料对沉积物毒性的附加效应。作为模型河流系统，选择了塞凡湖盆地（亚美尼亚）的三条河流（Karchaghbyur、Gavaraget、Argichi）进行研究。生态毒性测试的结果与水质指数（源自理化分析）和河流生态状况指数（源自底栖群落分析）进行了比较。测试结果表明，在第一代暴露于具有“良好生态状况”的河流沉积物后，摇蚊的出现率出人意料地低——Argichi。Karchaghbyur 和 Gavaraget 河流的沉积物阻碍了摇蚊的出现和繁殖，经过第二代后。向沉积物中添加聚酰胺颗粒并没有显著影响 C. riparius 的生命周期特征，表明主要是沉积物状况的影响。生物测试结果与另外两种方法（指示“平均水质”和“良好生态状况”）的结果不一致，这表明需要设计更全面的监测方案，以更好地评估和保护水生系统和资源。
