Assessment of public health risk associated with consumption of dominant edible animal species of the Lagos Lagoon, Nigeria

Abstract

Heavy metals bio-accumulated in edible aquatic animal species pre-dispose final consumers to adverse health effects of these toxins. Edible animal species were collected from the Lagos lagoon, Nigeria where elevated concentrations of heavy metals have been documented over the years. The concentrations of heavy metals in the animal species were determined and the potential health risk to three age groups of the population, associated with consumption of these species was assessed by calculating Daily Intake of Metals (DIM) and Health Risk Index (HRI). The levels of heavy metals recorded in the tissues of the animal species were below Food and Agricultural Organization (FAO) recommended limits in food, except for Zn (47.60 ppm) in Tympanotonus fuscatus. FAO recommended limits for Zn in food is 30.00 ppm. The DIM and HRI for all heavy metals analyzed were < 1 (unity) in the three animal species and for all age groups indicating that utilization of the species as a protein source does not currently pose serious health risk to consumers. The relative safety associated with utilization of edible animal species from the Lagos lagoon as a protein source reported in this study can only be maintained if heavy metal concentrations in the lagoon are kept within acceptable limits by setting effective effluent limitation standards and enforcing the set standards.

Keywords: Bio concentration, Heavy Metals, Pollution, Risk indices, Public Health