Distribution of Ecosystem Health Indicators for Biomonitoring of Oil Pollution in the Western Niger Delta, Nigeria

Abstract

As a result of the limitations of physical and chemical methods for monitoring pollution, interest on the more reliable biological monitoring intensified over the past four decades. Soil microarthropods, specifically the free-living mites (Cryptostigmata, Mesostigmata, Prostigmata) and Collembolans were used as monitor (ability to withstand pollutants) and indicator (sensitive to pollutants) species in the Eastern Niger Delta. Study was undertaken in the Western Niger Delta (Delta State) across three eco-vegetational zones (freshwater swamp forest, Mangrove swamp forest, Lowland rainforest) in the area to determine if these ecosystem health indicators were widely distributed in these zones. Collections were made during the rainy season over a 4-month period. A modified Berlese-Tullgren funnel was used for extraction of microarthropds. Free-living mites: Cryptostigmata (Oribatida) – Archogozettes magnus, Opiida sp., Annecticarus sp., Bicyrthermania negeriana, Cephalida sp., Scheloribates sp., Galumnida sp., Mesostigmata (Gamasida) - Asca sp., Trichuropodida and Collembolan – Paronella sp., were widely distributed across the eco-vegetational zones. Oribatids were most abundant across eco-vegetational zones. These mesofauna contained the full complement of monitor and indicator species. It is therefore possible to use these mesofauna for biomonitoring of oil pollution across the Niger Delta (eastern and western sectors), Nigeria.