Ecotoxicological evaluation of the effectiveness of natural adsorbents in the infiltration-percolation treatment of leachate

Waste management involves the operation of landfills, producing leachates that pose a threat to humans and surrounding ecosystems. The objective of this study is to evaluate the effectiveness of the treatment of leachate from the Taza landfill by an infiltration-percolation process. Seven natural adsorbents were used: sawdust of Juniperus phoenicea L., sawdust of Cedrus atlantica, sawdust of Arundo donax L. roots, coal slag, clayey soils, beach sand and Oued sand. The effectiveness of each treatment was carried out via the dosage of ten metallic trace elements: arsenic, cadmium, lead, chromium, nickel, copper, zinc, iron, aluminum and tin, the evaluation of phytotoxicity using 4 tests (Hordeum vulgare, Lactuca sativa, Raphanus sativus and Lepidium sativum) and cytotoxicity using the brine shrimp test (Artemia salina). The results reveal the toxic effect of raw leachate from the uncontrolled Taza landfill on animal and plant organisms. They also show the effectiveness of using natural adsorbents to reduce trace metal content, in particular clinker (D) and clay soil (E). This translates into a moderate reduction in phytotoxicity and cytotoxicity after treatment. Principal component analysis allowed us to categorize three groups of filtrates differing in trace element content and toxicity.