Determination of selected persistent organic pollutants in wastewater from landfill leachates, using an amperometric biosensor

► The POPs inhibited HRP enzyme activity, reduced activity was proportional to concentration. ► Detection limits ranged 0.014 for BDE-100 to 0.022μgl−1 for PBB-1. ► Concentration ranges in μgl−1; BDE-100 (0.424–25.8) to (0.930–27.1) for PCB-101. ► The inhibition mechanism, competitive for PBDEs; non...

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Published in:Physics and chemistry of the earth. Parts A/B/C 2012, Vol.50-52, p.252-261
Main Authors: Nomngongo, Philiswa N., Catherine Ngila, J., Msagati, Titus A.M., Gumbi, Bhekumuzi P., Iwuoha, Emmanuel I.
Format: Article
Language:English
Subjects:
Amperometric biosensor
Biosensors
Electrical measurements
Enzyme activity
Enzyme inhibition
Enzymes
Horseradish peroxidase
Inhibition
Landfills
Leachate
Persistent organic pollutants
Pollutants
Waste water
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Summary:► The POPs inhibited HRP enzyme activity, reduced activity was proportional to concentration. ► Detection limits ranged 0.014 for BDE-100 to 0.022μgl−1 for PBB-1. ► Concentration ranges in μgl−1; BDE-100 (0.424–25.8) to (0.930–27.1) for PCB-101. ► The inhibition mechanism, competitive for PBDEs; non-competitive for biphenyls (PCBs, PBBs). ► The leachate contained PCB-28 (0.28±0.03μgl−1) and PCB-101 (0.31±0.02μgl−1). Landfill leachates that contain persistent organic pollutants (POPs) are a big threat to groundwater systems and are projected to have hazardous effects in the long term if proper management strategies of the landfills are not put in place by those responsible. Monitoring the levels of POPs in landfill leachates is very crucial. This work presents an amperometric biosensor for determination of selected POPs in landfill leachates. The biosensor is based on kinetic inhibition of horseradish peroxidase (HRP). The enzyme was immobilised by electrostatic attachment on a polyaniline-modified Pt electrode surface. Selected POPs inhibited HRP enzyme activity and the decrease in the enzyme activity was used to determine these environmental pollutants. Selected polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs) and polychlorinated biphenyls (PCBs) were the analytes of choice because they are commonly found in South Africa water systems. Limits of detection for the amperometric biosensor were established as 0.014, 0.018, 0.022, 0.016 and 0.019μgl−1 for BDE-100, PBB-1, PCB-1, PCB-28 and PCB-101, respectively. The HRP biosensor system gave different linear ranges for; BDE-100 (0.424–25.8μgl−1), PBB-1 (0.862–13.4μgl−1), PCB-1 (0.930–18.1μgl−1), PCB-28 (0.730–15.7μgl−1) and PCB-101 (0.930–27.1μgl−1). Inhibition studies on HRP biosensor response toward the reduction of H2O2 in the absence and presence of the selected POPs were carried out to investigate the inhibition kinetics and its mechanism. The results obtained indicated that the inhibition mechanism was competitive for PBDEs and non-competitive for biphenyls (PCBs and PBBs). The application of the biosensor was tested on wastewater samples obtained from landfill leachate for determination of selected POPs. The leachate samples were found to contain PCB-28 (0.28±0.03μgl−1) and PCB-101 (0.31±0.02μgl−1). The samples were also analysed by GC–MS as a cross-check method and the two sets of results were in close agreement.
ISSN:1474-7065
1873-5193
DOI:10.1016/j.pce.2012.08.001