Toxicity evaluation and environmental risk assessment of 2-methyl-4-chlorophenoxy acetic acid (MCPA) on non-target aquatic macrophyte Hydrilla verticillata

• Published in: Environmental science and pollution research international 2018-10, Vol.25 (30), p.30463-30474
• Main Authors: Weerakoon, Hewa Pathirannahelage Athri Thathsarani, Atapaththu, Keerthi Sri Senarathna, Asanthi, Hewa Bandulage
• Format: Article
• Language: English
• Subjects: 2-Methyl-4-chlorophenoxyacetic Acid - administration & dosage; 2-Methyl-4-chlorophenoxyacetic Acid - toxicity; Acetic acid; Agricultural land; Agricultural management; Agrochemicals; Aquatic ecosystems; Aquatic environment; Aquatic plants; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Biomarkers; Chlorophenoxyacetic acids; Chlorosis; Dose-Response Relationship, Drug; Earth and Environmental Science; Ecological risk assessment; Ecosystem integrity; Ecosystem management; Ecotoxicology; Environment; Environmental assessment; Environmental Chemistry; Environmental Health; Environmental risk; Environmental science; Exposure; Herbicides - toxicity; Hydrilla verticillata; Hydrocharitaceae - drug effects; Hydrogen Peroxide; Landscape; Oxidation-Reduction; Oxidative stress; Oxidative Stress - drug effects; Peroxidase; Peroxidases - metabolism; Pigments; Plant growth; Research Article; Risk analysis; Risk Assessment; Toxicity; Waste Water Technology; Water Management; Water Pollutants, Chemical - toxicity; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-018-3013-z

Aquatic plants in agricultural landscapes play a vital role in maintaining the ecological integrity within the aquatic systems while facing an array of disturbances. Among them, information on herbicide exposure on non-target aquatic plants is scarce. The present study was designed to fill this information gap by detecting the impacts of 2-methyl-4-chlorophenoxyacetic acid (MCPA) on Hydrilla verticillata using morpho-anatomical and physiological biomarkers and assessing the environmental risk of MCPA to the non-target environment. H. verticillata was exposed to different MCPA concentrations (10, 100, 500, 1000 μg/L) and control (0 μg/L) for 7 days. At the end of the experiment, plant growth, pigments, H 2 O 2 content, peroxidase activity (POD) and plant anatomy were compared. The environmental risk was assessed using predicted environmental concentration/predicted no effect concentration (PEC:PNEC) ratio, hazard quotient (HQ) and hazard index (HI). Control plants exhibited the highest growth, and a growth decline was noted in parallel to MCPA exposure, where a similar trend was detected for the plant pigment contents. MCPA induced chlorosis and oxidative stress in H. verticillata . Risk analysis detected high values for PEC:PNEC ratios (3–9), HQ (1.92–5.79) and HI (28.15). MCPA-exposed H. verticillata could recover once those plants received natural conditions. Overall, present findings showed the negative impacts of MCPA on non-target aquatic plant H. verticillata . These findings will be useful to clarify the interaction between agrochemicals and non-target aquatic plants. Such information would benefit to decide the criteria in aquatic ecosystem management.