Bridging the Gap: Advancing Ecological Risk Assessment from Laboratory Predictions to Ecosystem Reality

Advancing aquatic ecological risk assessment of imidacloprid in global surface water with mesocosm-based thresholds

Aquatic ecological risk posed by neonicotinoids has become a growing concern due to their widespread use and documented environmental impacts. However, current risk assessments predominantly rely on laboratory-based toxicity data, which often lack ecological relevance and may introduce substantial biases. In this study, we addressed a critical knowledge gap in neonicotinoid risk assessment by establishing the first global-scale comparison between traditional laboratory-based and ecologically realistic mesocosm-derived toxicity thresholds. Analysis of literature-reported concentrations revealed significant regional variations in imidacloprid pollution at a global scale, with the highest median concentrations detected in Oceania, followed by Asia, Africa, America, and Europe, although extreme concentrations were observed in America. The mesocosm-based hazard concentration for 5 % of species (HC5) was determined to be 0.013 μg/L, which was significantly lower than the laboratory-based HC5 of 0.086 μg/L. Risk assessment using the laboratory-based threshold identified 1.2 % of the 1378 freshwater samples as high risk (risk quotient, RQ>10) and 7.1 % as medium risk (1 Collapse

Key Words

• Land use
• Mesocosm
• Neonicotinoids
• Regional distribution
• Regulatory thresholds
• Species sensitivity distribution

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MESH Headings

• Neonicotinoids
• Risk Assessment
• Nitro Compounds/toxicity
• Nitro Compounds/analysis
• Water Pollutants, Chemical/toxicity
• Water Pollutants, Chemical/analysis
• Imidazoles/toxicity
• Environmental Monitoring
• Fresh Water
• Animals

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Affiliation(s)

Huizhen Li Guangdong Key Laboratory of Environmental Pollution and Health, College of Environment and Climate, Jinan University, Guangzhou 511443, China
Lingzhi Xie Guangdong Key Laboratory of Environmental Pollution and Health, College of Environment and Climate, Jinan University, Guangzhou 511443, China
Zewei Xu Guangdong Key Laboratory of Environmental Pollution and Health, College of Environment and Climate, Jinan University, Guangzhou 511443, China
Fei Cheng State Key Laboratory of Advanced Environmental Technology, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
Jing You Guangdong Key Laboratory of Environmental Pollution and Health, College of Environment and Climate, Jinan University, Guangzhou 511443, China.

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Ecological impacts of treated effluent on multitrophic biodiversity and their interactions

The reuse of water, particularly treated effluent from wastewater treatment plants (WWTPs), is a crucial and sustainable strategy for mitigating water scarcity, especially in megacities with high water demand and limited resources. However, the ecological risks associated with effluent discharge into receiving waterbodies have gained significant global attention. Understanding the dynamic effects of WWTP effluent on multi-trophic groups and their interactions is essential for assessing ecological impacts in aquatic ecosystems and informing management strategies. In this study, we examined five taxonomic groups representing different trophic levels of the freshwater food web - bacteria (decomposers), algae (primary producers), zooplankton (primary consumers), and benthic macroinvertebrates and fish (predators) - across two rivers to elucidate ecological responses to WWTP effluent from a multi-trophic perspective. Our results revealed significant but variable biological responses among these groups, depending on river conditions and trophic level. In the nutrient-rich river, primary consumers (zooplankton) were most affected, whereas in the nutrient-poor river, primary producers (algae) exhibited the strongest responses primarily derived from environmental disturbances. Notably, interactions between environmental variables and taxa were highly diverse, with trophic dynamics influenced by both bottom-up and top-down processes in the nutrient-rich river, whereas bottom-up effects dominated in the nutrient-poor river. Furthermore, niche overlap in algae-zooplankton networks was higher in the nutrient-rich river than in the nutrient-poor river. This study underscores the importance of integrating multi-trophic biodiversity profiling and trophic interaction analyses to comprehensively assess the ecological effects of WWTP effluent in receiving aquatic ecosystems with contrasting environmental contexts. Our findings highlight the importance of conservation and sustainable management practices, especially in urban aquatic ecosystems located in (semi-)arid regions that experience prolonged periods of low precipitation.

Emerging contaminants in Taihu lake Basin: Multi-dimensional prioritization, colloidal adsorption, and trophic-level disruptions

Emerging contaminants (ECs) pose significant threats to aquatic ecosystems across multiple trophic levels. This year-long study in China's Taihu Lake Basin investigated the spatiotemporal distribution, environmental behavior, and ecological impacts of ECs in diverse aquatic systems. Key findings revealed strong spatiotemporal heterogeneity, with industrial areas exhibiting the highest EC concentrations (mean: 1888.28 ng/L), dominated by perfluorinated compound. Seasonal variations showed spring EC levels twice those of other seasons, linked to intensified industrial activity. Colloidal adsorption played a critical role in EC fate, contributing 0.74-45.48 % to pollutant distribution, particularly for antibiotics and bisphenols. A multidimensional prioritization framework integrating concentration, detection rate, colloidal adsorption, toxicity, persistence, and bioaccumulation identified nine priority ECs, including erythromycin, tetrabromobisphenol A (TBBPA), and perfluorooctanoic acid (PFOA). ECs significantly disrupted plankton communities, with zooplankton diversity experiencing stronger suppression than phytoplankton, indicating trophic-level-dependent impacts. This study underscores the need for integrated monitoring strategies and regulatory thresholds to mitigate EC risks in complex aquatic ecosystems.

Pesticide Pollution Reduces the Functional Diversity of Macroinvertebrates in Urban Aquatic Ecosystems

Urbanization accelerates innovation and economic growth but imposes significant ecological challenges, particularly to aquatic biodiversity and ecosystem functionality. Among urban stressors, pesticide-driven chemical pollution represents a critical, yet under-recognized, global threat. Quantifying the causes and consequences of pesticides on biodiversity loss and ecosystem degradation is vital for ecological risk assessment and management, offering insights to promote sustainable societal development. This study evaluated anthropogenic stressors and macroinvertebrate communities at 42 sites across two major drainages in Beijing using chemical analysis and environmental DNA (eDNA), focusing on macroinvertebrate responses to pesticide exposure in the context of multiple anthropogenic stressors. Pesticides significantly impacted the α- and β-functional diversity of macroinvertebrates, accounting for 18.46 and 14.6% of the total observed variation, respectively, underscoring the role of functional groups in pesticide risk assessment. Land use and flow quantity directly influenced pesticide levels, which in turn affected macroinvertebrate functional diversity, while basic water quality had a less pronounced effect. These results provide empirical evidence of pesticide pollution's impact on macroinvertebrate functional diversity at the watershed scale under field conditions in a highly urbanized area. The findings highlight the importance of considering multiple stressors and sensitive taxa in pesticide risk assessment and management for urban aquatic ecosystems.