Worldwide seagrass declines have been observed due to multiple stressors. One of them is the mixture of pesticides used in intensive agriculture and boat antifouling paints in coastal areas. Effects of mixture toxicity are complex and poorly understood. However, consideration of mixture toxicity is more realistic and ecologically relevant for environmental risk assessment (ERA). The first aim of this study was to determine short-term effects of realistic herbicide mixture exposure on physiological endpoints of Zostera noltei. The second aim was to assess the environmental risks of this mixture, by comparing the results to previously published data. Z. noltei was exposed to a mixture of four herbicides: atrazine, diuron, irgarol and S-metolachlor, simulating the composition of typical cocktail of contaminants in the Arcachon bay (Atlantic coast, France). Three stress biomarkers were measured: enzymatic activity of glutathione reductase, effective quantum yield (EQY) and photosynthetic pigment composition after 6, 24 and 96 h. Short term exposure to realistic herbicide mixtures affected EQY, with almost 100% inhibition for the two highest concentrations, and photosynthetic pigments. Effect on pigment composition was detected after 6 h with a no observed effect concentration (NOEC) of 1 μg/L total mixture concentration. The lowest EQY effect concentration at 10% (EC) (2 μg/L) and pigment composition NOEC with an assessment factor of 10 were above the maximal field concentrations along the French Atlantic coast, suggesting that there are no potential short term adverse effects of this particular mixture on Z. noltei. However, chronic effects on photosynthesis may lead to reduced energy reserves, which could thus lead to effects at whole plant and population level. Understanding the consequences of chemical mixtures could help to improve ERA and enhance management strategies to prevent further declines of seagrass meadows worldwide.
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http://dx.doi.org/10.1016/j.envpol.2016.12.021 | DOI Listing |
Environ Sci Pollut Res Int
December 2024
EPHE-PSL, Sorbonne Université, CNRS, UMR 7619 METIS, 75005, Paris, France.
Freshwater environments are biodiversity hotspots under multiple pressures, including pesticide exposure. S-metolachlor, a widely used herbicide, can induce genotoxic, cytotoxic and physiological effects in captive fish, but we have a limited understanding of the effects of exposure to S-metolachlor in free-living vertebrates. We carried out an original field experiment using integrative approaches across biological levels and temporal scales.
View Article and Find Full Text PDFMar Pollut Bull
December 2024
Coastal and Marine Research Centre, Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, QLD 4222, Australia.
Multiple anthropogenic stressors degrade ecosystems globally. A key knowledge gap in multiple stressor research is how variability in stressor intensity (i.e.
View Article and Find Full Text PDFJ Environ Qual
November 2024
Department of Crop Sciences, University of Illinois, Urbana, Illinois, USA.
The evolution and spread of antibiotic resistance are problems with important consequences for bacterial disease treatment. Antibiotic use in animal production and the subsequent export of antibiotic resistance elements in animal manure to soil is a concern. Recent reports suggest that exposure of pathogenic bacteria to glyphosate increases antibiotic resistance.
View Article and Find Full Text PDFDrug Chem Toxicol
October 2024
Laboratorio de Ecotoxicología, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.
Chemosphere
September 2024
College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China. Electronic address:
Due to past massive usage and persistent nature, pentachlorophenol (PCP) residues are prevalent in environments, posing a potential threat to various organisms such as sessile filter-feeding bivalves. Although humoral immunity and its crosstalk with cellular one are crucial for the maintaining of robust antimicrobic capability, little is known about the impacts of PCP on these critical processes in bivalve mollusks. In this study, pathogenic bacterial challenge and plasma antimicrobic capability assays were carried out to assess the toxic effects of PCP on the immunity of a common bivalve species, blood clam (Tegillarca granosa).
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