Environmental Science
N.J. Mensah; S. Antwi-Akomeah; E.J.D. Belford; G.E. Sebiawu; R. Aabeyir
Abstract
BACKGROUND AND OBJECTIVES: The vulnerability of the Sankana dam to organochlorine pesticide contamination is a major cause for concern. Indigenes rely on the dam for drinking water and irrigation of their farmlands as well as for fish and other aquatic delicacies. Virtually there exists no study on the ...
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BACKGROUND AND OBJECTIVES: The vulnerability of the Sankana dam to organochlorine pesticide contamination is a major cause for concern. Indigenes rely on the dam for drinking water and irrigation of their farmlands as well as for fish and other aquatic delicacies. Virtually there exists no study on the residual levels of organochlorine or other pesticide contaminants in the dam despite its susceptibility to pesticide contamination. In the present study, the levels of organochlorine residues in fish and sediments from the Sankana dam were assessed.METHODS: Pesticide residue extraction was achieved using acetonitrile containing 1% (v/v) acetic acid in the presence of sodium acetate, sodium citrate and magnesium sulphate followed by purification over activated florisil and sodium sulphate. Identification and quantification of residue extracts was done using a gas chromatograph conjugated with mass spectrometer.FINDING: In all, varying levels of 13 organochlorine residues were detected, 11 of which were found in fish and 12 in sediment. Average mean levels of organochlorine residues found in fish ranged from 0.001 - 0.277 mg/kg. Residual levels of beta-hexachlorocyclohexane, delta-hexachlorocyclohexane, gamma-hexachlorocyclohexane, endosulfan-A and dichlorodiphenyldichloroethane in fish were relatively higher than their respective levels in sediment. Organochlorine residues found in sediment also ranged from 0.001 - 0.091 mg/kg. Dichlorodiphenyldichloroethylene, aldrin, dieldrin, endrin, methoxychlor, heptachlor, gamma-chlordane and endosulfan-B residual levels in sediment were higher than the corresponding levels in fish.CONCLUSION: The study provides a baseline for continuous/regular monitoring of organochlorine contaminants in the Sankana dam and other waterbodies upstream and downstream. Where organochlorine residues exceeded their recommended permissible thresholds typically suggests possible recent/continuous use of such pesticides within the catchment area. There is therefore the need for appropriate measures and/or need to strengthen existing policies that bans the importation, sale and use of organochlorine pesticides via strict enforcement.
S. Antwi-Akomea; B. Fei-Baffoe; E.J.D. Belford; M. Borigu
Abstract
The present study investigated the coupling effect of biodegradation and media filtration in treating hydrocarbon contaminated water. The study recorded reductions in total petroleum hydrocarbon, total dissolved solids, turbidity and microbial load. The study was essentially a simulated pump and treat ...
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The present study investigated the coupling effect of biodegradation and media filtration in treating hydrocarbon contaminated water. The study recorded reductions in total petroleum hydrocarbon, total dissolved solids, turbidity and microbial load. The study was essentially a simulated pump and treat process that involved the pumping of hydrocarbon contaminated water for treatment in a locally designed multi-stage bioreactor incorporated with media filtration. A mixed consortium of hydrocarbon-eating microbes was applied in the study. Hydrocarbon-eating microbes were isolated from hydrocarbon contaminated soils obtained from selected mechanic workshops. Bamboo chips and coconut husk chips were applied as support media for microbial attachment within the bioreactor compartment of the treatment setup. Applied support media were approximately 2-4 cm in size. Media filters applied comprised three locally manufactured candle filters two of which were respectively impregnated with granular activated charcoal and sand. The coupling effect of biodegradation and media filtration recorded over 99 % (> 8.7 mg/L) total petroleum hydrocarbon removal. Microbial load reduction ranged from 3.57±0.11E+20 to 7.45±0.26E+20 Colony forming unit/mL, total dissolved solids reduction from 30.00±5.66 to 131.00±0.00 mg/L and turbidity reduction from 39.00±1.41 to 123.50±0.71 nephelometric turbidity units. Biodegradation accounted for 69.70±0.63 and 90.72±2.36 % total petroleum hydrocarbon removal respectively for bamboo chips and coconut husk chips.