Phytoremediation of pesticide-contaminated freshwaters by aquatic plants: a meta-analysis.

In the last decade, water contamination by pesticides has become a global concern, and phytoremediation has gained increasing attention. This approach is cost-effective and ecologically beneficial, revealing the abilities of plants to remove, detoxify, or immobilize environmental contaminants. Despite the growing number of publications, some questions remain: (i) How effectively do aquatic plants reduce pesticides in water? (ii) How is the effectiveness of water phytoremediation influenced by plant characteristics, pesticide properties, and environmental/experimental conditions? To answer those questions, we conducted a meta-analysis with 405 extracted pairs of data points from 56 studies to systematically analyze and explore the efficiency of pesticide removal by aquatic plants. We found that, compared to the control without plants, aquatic vegetation increases pesticide removal from water by 38.86 % (95 % CI = 31.50-46.21 %). We conducted subgroup and meta-regression analyses to identify factors influencing the global effect size. The taxonomy (order) and the life form of the plants did not significantly influence the degree of pesticide removal. The removal efficiency was influenced by pesticides' type/mode of action, with insecticides being less efficiently removed than other pesticides. Additionally, we observed higher phytoremediation efficiency with increasing log KOW (lipophilicity), molecular mass, and in experiments conducted with contaminant mixtures. Environmental conditions also influenced removal efficiency, with higher temperatures and light intensity enhancing phytoremediation. Our results provide insights into the key factors determining the success of phytoremediation in aquatic environments contaminated by pesticides, thereby guiding decision-making on using this technology and directing new research toward developing strategies to enhance its effectiveness.