The histological alterations in gills and liver of Tilapia guineensis exposed to common drilling fluids in the delta of river Niger

This study investigated the histological changes on gill and liver of fry, fingerling and post-fingerlings of Tilapia guineensis exposed to sublethal concentrations of drilling fluid for 12 weeks. The concentrations used were 0.32%, 0.63%, 1.25% and 2.5% vol/vol (Note 1% = 1000ml/L). The results revealed that little or no lesions were observed in the gills and liver with the exception of those exposed to the highest concentration. The gill filaments of the fish exposed to the highest concentration of the toxicants (2.5%) had mild lesion which was characterized by epithelial lifting and hyperplasia of the gill lamellae, while the liver exhibited mild vacuolations, presence of macrophages and slight sloughing of the cell. Although toxic responses had been identified in the tissues of fish exposed to acute concentrations of drilling fluids, the subtle changes identified in the tissues of the exposed fish divulge regenerative response in terms of functions and histology. This implies that drilling fluids released even at low concentrations are capable of inducing changes in the tissues of fishes endemic in the delta.Keywords: Drilling, Niger Delta, medial lethal concentration (LC50), median lethal time (LT50

Comparative analysis of municipal solid waste (MSW) composition in three local government areas in Rivers State, Nigeria

Rivers State is one of the major oil producing States in Nigeria. Its capital, Port Harcourt and sub-urban areas have witnessed an increased influx of migrants in recent time. Consequently, the consumption of goods and services has also increased leading to generation of unprecedented quantities of municipal solid waste. Previous efforts by relevant authorities to contain this increase in waste generation have proved abortive due largely to among other reasons, inappropriate and unsustainable municipal solid waste (MSW) management systems. The first step in a sustainable MSW management is to understand the types, composition and variation that exist in the waste generated in time and space. Previous reports have been concentrated on the characteristics of waste in Port Harcourt. This present work evaluated solid waste composition in three LGAs in Rivers State with a view of an integrated approach in MSW management in the State. Waste characteristics varied with the different locations studied. Generation rate was 0.45, 0.98 and 1.16 kg/capita/day for Emougha, Obio/Akpor and Port Harcourt, respectively. Most prominent categories were organic waste, paper and nylon. Mean percentage composition was 65, 65.5 and 59% for organic waste, 13, 11 and 6% for paper and 12, 16 and 14% for nylon in Port Harcourt, Obio/Akpor and Emougha LGAs, respectively. It is believed that given the characteristics of these waste streams, a sustainable management strategy could have several benefits including resources recovery and energy generation.Key words: Municipal solid waste (MSW), characterization, Rivers State, integrated MSW management