02/06/2018 | Press release | Distributed by Public on 02/06/2018 02:56
MSc. Elijah Ngumba defends his doctoral dissertation in Environmental Science 'Occurrence and control of selected antibiotics and antiretroviral drugs in urban hydrological cycles'. Opponent Dr Jerker Fick (Umeå University, Sweden) and custos Professor Tuula Tuhkanen (University of Jyväskylä).
The focus of this study was to study the occurrence and control of antibiotics and antiretroviral drugs in urban hydrological cycles of Nairobi-Kenya, Lusaka-Zambia and Jyväskylä-Finland. The pharmaceuticals were analyzed in municipal wastewater, surface water, groundwater and urine diverting dry toilets source separated urine. The study revealed widespread contamination in Nairobi and Lusaka with concentration of individual pharmaceuticals of up to 50 µg/l in surface water, 56 µg/l in wastewater effluents, 12800 µg/l in source separated urine and 1 µg/l in groundwater. The concentrations of the majority of the pharmaceuticals in Lusaka and Nairobi compared to Jyväskylä were up to 1000 times higher in surface water and 100 times higher in wastewater effluents. The main reasons for the high pharmaceutical loads in the Nairobi and Lusaka are the lack of adequate wastewater collection and treatment facilities as well as high prevalence of diseases such as HIV/AIDS. The management of HIV/AIDS involves multiple lifelong daily medications mostly comprising of several antiretroviral drugs and antibiotics. Thus, the amount of pharmaceuticals excreted to the environment is significantly high especially in areas with high HIV prevalence. The wastewater treatment plants in the three hydrological cycles were found to be a major point source of antibiotic and antiviral contamination to surface waters. Some non-biodegradable and water soluble pharmaceuticals can pass the treatment process while some are degraded or attached to sludge formed during the wastewater treatment process.
How serious is the problem?
At elevated concentrations, antibiotics and antiretroviral drugs can be toxic to various classes of organisms. Other than the toxicological effects, antibiotics in sub-inhibitory concentrations have the potential to promote the development antibiotic resistance which currently has been identified by the scientific community as one of the most serious global health threats. Further, pharmaceuticals compounds are released to environment as mixtures and long term cocktail effects remain largely unknown. Thus, the high concentrations measured in developing and middle income countries such as in Zambia and Kenya calls for establishment of effective risk identification, management and communication strategies as a priority.
What are the possible control options?
In the study, we observed that the most critical primary barrier in controlling of pharmaceutical residues reaching the water bodies is access to improved sanitation coupled with proper collection, treatment and disposal of excreta. The high concentration of pharmaceuticals measured in source separated urine was an indicator of the great potential of source separation as a critical barrier to environmental contamination. The use of source separation sanitation techniques also allows efficient nutrient recycling in a closed-loop fertility cycle. Removal of residual pharmaceuticals in areas with existing centralized convectional wastewater collection and treatment systems can be enhanced by addition of advanced post-treatment techniques. However, the end-of-pipe post-treatment technologies are not economically feasible in a majority of wastewater treatment facilities due to the high cost of energy, chemicals and additional infrastructure. Overall, in order to protect human and environmental health, there is need to establish critical control points throughout the whole cycle of a pharmaceutical products-from cradle to grave.
Since the majority of studies on the occurrence and fate of pharmaceuticals in the environment have been done in developed countries with only limited information available for developing countries, this dissertation aims at bridging some the existing knowledge gaps and gives ideas for development of robust and cost-effective decentralized sanitation systems as primary barriers to environmental contamination.
Elijah Ngumba, puh. 0466210371, [email protected]
Elijah Ngumba is from Nairobi, Kenya. He graduated with BSc. Chemistry in 2006 and MSc. Chemistry in 2011 from Jomo Kenyatta University of Agriculture and Technology, Kenya. Previously he worked in Jomo Kenyatta University of Agriculture and Technology as a teaching and research assistant. He has been doctoral student in the University of Jyväskylä in 2014-2018
The dissertation is published in the series Jyväskylä Studies in Biological and Environmental Science number 341, 70 p., Jyväskylä 2018, ISSN: 1456-9701, ISBN 978-951-39-7343-8 (print), ISBN 978-951-39-7344-5 (PDF). Permanent link to this publication: http://urn.fi/URN:ISBN:978-951-39-7344-5