Heavy Metal Levels in Insect Species Collected from Enyigba Community with Mining Activities in Southeast Nigeria

Abstract

Insects are the largest and most diverse group of organisms which are typically the overwhelming dominant invertebrate faunal group extensively used in biomonitoring and bioassessment. The aim of this paper was to evaluate the heavy metals levels in insect species collected from Enyigba Community with mining activities in Southeast Nigeria using appropriate standard methods.  In this study, three sites namely: Upper Inyia-(SA), Lower Inyia (SB) and the Control Site (SC) were selected and insect specimens were collected and evaluated from July 2022 to February, 2023. The insect groups used were Reticulitermes flavipes (termite), Zonocerus elegans (grasshopper), Acraea acrita (butterfly) and Cremtogaster sp. (Ant). The selected insects’ samples were analyzed using atomic absorption spectrophotometer (AAS). The results showed heavy metal accumulations on the selected insects particularly the toxic metals such as Cadmium (Cd), Copper (Cu), Manganese (Mn) and Mercury (Hg). Insects examined were Reticulitermes flavipes, Zonocerus elegans, Acraea acrita, and Crematogaster sp. collected from Enyigba mines. High concentrations of Cd was recorded in Zonocerus elegans at SA (0.13±0.042) and SB (0.17±0.007) which is far above WHO/FAO permissible limit. The result further revealed that there was also high Cd concentration (0.21±0.011) in Reticulitermes flavipes, which is also far above WHO/FAO permissible limit. Grasshopper, termites and butterfly had the highest accumulation of heavy metals among the studied insect groups, highlighting the challenges of mining on agriculture and food security in the region.