Heavy Metals and Total Microbial Load in Industrial Wastewater Treated with Moringa Seed: Implication on Clarias lazera Fish Farming

Abstract

Fish farming is gaining more attention in Nigeria; Clarias sp. can be reared in any type of water including waste water. Fish especially Clarias lazera is a very important source of protein and nutritional value of unsaturated fatty matter, in developing countries. Bioaccumulation of heavy metals and rapid loss of quality that might occur very rapidly after catch, especially in hot climates and tropical areas are a huge source of concern. The aim of this study was determination of the heavy metals and total microbial load in waste water treated with Moringa seed and used in the rearing of Clarias lazera. Standard procedures were used for the analyses. Atomic Absorption Spectrophotometer was used for the determination of heavy metals. Nickel was below detection limit in all water samples. Chromium and nickel was below detection limit in gills and flesh of the fish samples. In the gills cadmium ranged between 0.01 and 0.08mg/l and reduced to 0.02mg/l in the flesh in treated water. Lead and chromium increased in waste water and treated water. Moringa seed was able to remove the following microorganisms from the wastewater E. coli, Staphylococcus aureus, Salmonella spp., Shigella spp., Vibrio spp., Cladosporum spp., Bacillus spp. But two new microorganisms were found in the fish samples which were Aeromonas spp., Clostridium lockleadii. The microbial count was reduced in the fish samples reared in moringa treated water as compared to the count in waste water: total Bacteria count by 1.6 x 107 Cfu/ml, Fungal count 0.5 x 105 Cfu/ml, Salmonella Count 0.9 x 105 Cfu/ml, Vibrio Count by 1.4 x 104 Cfu/ml and Total Coliform Count by 3.3 x 101 Cfu/ml. The implication was that Moringa seed can be used in remediating microbial contaminated industrial wastewater but not very active in remediating water polluted by heavy metals as it may not be able to remove lead and chromium from the sample.