Histopathological Responses of Tympanotonus Fuscatus (Brackish Periwinkle) Exposed to Leachate from the Olusosun Landfill in the Lagos Lagoon, Southwestern Nigeria

Abstract

The disposal of solid waste in non-engineered landfills remains a widespread waste management practice in many developing countries. However, the generation and discharge of landfill leachate pose significant environmental and public health concerns due to the presence of toxic contaminants. Therefore, the objective of this study was to investigate the histopathological responses of Tympanotonus fuscatus (brackish periwinkle) following exposure to leachate from the Olusosun landfill in Lagos Lagoon, southwestern Nigeria, using standardized laboratory procedures. A total of 1,296 benthic macrofaunal individuals were identified, representing 3 phyla, 4 classes, 9 orders, 10 families, 10 genera, and 11 species. Tympanotonus fuscatus was the dominant species, accounting for 32.56% of the total abundance, whereas Iphigenia truncata was the least abundant species, contributing only 1.16%. The low abundance of sensitive bivalve species and the reduced occurrence of Pachymelania aurita indicated environmental stress within the lagoon ecosystem. Histopathological assessment revealed severe tissue necrosis in T. fuscatus exposed to landfill leachate, demonstrating its toxic effects. These findings highlight the ecological risks associated with landfill leachate contamination and emphasize the need for effective environmental management strategies to protect benthic biodiversity and maintain the ecological integrity of the Lagos Lagoon.