[Toxicological risks of cohabitation with wild landfills: the case of the Akouedo landfill (Abidjan, Ivory Coast).] / Risques toxicologiques de la cohabitation avec une décharge : cas d'Akouédo en Côte d'Ivoire.

INTRODUCTION: The objective of this study is to evaluate the health risks associated with metal exposure (Pb, Cd, Hg and Cr) in the populations living around the Akouédo landfill. METHOD: This evaluation required the use of the most recent reference toxicological data relating to human exposure to these pollutants and the results of measurements in the environment. Crossing these two data sources using the CalTOX simulation allowed for the calculation of daily exposure, through the consumption of soil dust, contaminated water and foodstuffs. RESULTS AND DISCUSSION: Exposure levels to lead (1.05-1.34 ppm) and mercury (1.46 ∙ 10–2-2.16 ∙ 10–2 ppm) appear highest. The danger quotients are also high and are on average 220 and 54 Toxicological Reference Values (TRVs). In addition, lead exposure for infants presents a danger quotient 15 times TRVs. The calculation of the health impact due to chromium gives 9 cases of cancer that would be reported per year. The comparison of the theoretical values with those estimated by calculation gives overvalued theoretical danger ratios for the four pollutants (Cd, Pb, Hg, Cr). An overvaluation that would be related to uncertainties in measurements and calculations. However, it is clear that people living around the landfill are exposed to the poisoning of the pollutants indicated. This zone is therefore a major public health problem. CONCLUSION: Consequently, prevention means such as closure and rehabilitation of the site must be taken urgently. Also, the construction in the area, of a hospital center specific to the treatment of the pathologies resulting from the intoxication with the indicated pollutants would be desirable.

Microbiological risk infection assessment using QMRA in agriculture systems in Côte d'Ivoire, West Africa.

Poor wastewater management that results from a lack of appropriate sanitation infrastructure contributes to increasing health risks in urban areas in Côte d'Ivoire. We assessed the health risks associated with the use of wastewater for watering salad destined for human consumption, to help local authorities in developing appropriate risk mitigation measures for Yamoussoukro, the political capital of Côte d'Ivoire. We applied a stochastic approach based on quantitative microbiological risk assessment (QMRA), focusing on wastewater for farming activities and salad consumption at the household level. Farming activities rely on a large degree on contaminated water and are conducted without any protection. The QMRA highlights that the poor quality of watering water increased the microbiological risk of the two assessed groups of urban farmers and individual households. The annual risk of infection due to watering wastewater in the city is estimated at 0.01 per person per year (pppy) for Giardia lamblia and 0.2 pppy for Escherichia coli O157:H7. The annual risk from salad consumption is 0.01 pppy for G. lamblia and 0.9 pppy for E. coli O157:H7. Both the annual risks from farming activities and salad consumption were higher than the tolerable standard of risk of 10-4 pppy as defined by the World Health Organization. There is a need to conduct a risk analysis and a cost-effectiveness study on intervention to improve public health and the livelihoods of the producers which are women in majority in Yamoussoukro.

Ecohealth approach to urban waste management: exposure to environmental pollutants and health risks in Yamoussoukro, Côte d'Ivoire.

Poor waste management is a key driver of ill-health in urban settlements of developing countries. The current study aimed at assessing environmental and human health risks related to urban waste management in Yamoussoukro, the political capital of Côte d'Ivoire. We undertook trans-disciplinary research within an Ecohealth approach, comprised of a participatory workshop with stakeholders and mapping of exposure patterns. A total of 492 randomly selected households participated in a cross-sectional survey. Waste deposit sites were characterised and 108 wastewater samples were subjected to laboratory examinations. The physico-chemical parameters of the surface water (temperature, pH, conductivity, potential oxidise reduction, BOD5, COD, dissolved oxygen, nitrates, ammonia and total Kendal nitrogen) did not comply with World Health Organization standards of surface water quality. Questionnaire results showed that malaria was the most commonly reported disease. Diarrhoea and malaria were associated with poor sanitation. Households having dry latrines had a higher risk of diarrhoea (odds ratio (OR) = 1.8, 95% confidence interval (CI) 1.2-2.7) compared to latrines with septic tanks and also a higher risk for malaria (OR = 1.9, 95% (CI) 1.1-3.3). Our research showed that combining health and environmental assessments enables a deeper understanding of environmental threats and disease burdens linked to poor waste management. Further study should investigate the sanitation strategy aspects that could reduce the environmental and health risks in the study area.

Using fluorescence spectroscopy EEM to evaluate the efficiency of organic matter removal during coagulation-flocculation of a tropical surface water (Agbo reservoir).

This study evaluate the use of fluorophores A, C and T fluorescence intensities to access the coagulation efficiency for removing dissolved organic carbon (DOC) in the raw water from Agbo reservoir in Ivory Coast. A coagulation-flocculation was conducted with aluminium sulphate as coagulant and DOC residual and fluorescence intensities were acquired. The consistency of fluorescence data was evaluated to ensure that no inner-effect, quenching or enhanced intensities affect the data. Fluorescence-inferred DOC removal was then calculated in percentage terms from the decrease in organic matter fluorescence intensity for each peak between raw and clarified water and correlated with measured DOC removal. The results indicate a high significant correlation between measured DOC removal and fluorescence-inferred DOC removal calculated for peak A (R(2)=0.91), peak C (R(2)=0.89), peak T (R(2)=0.92) indicating a strong linear relationship between DOC removal and fluorescence intensities. Furthermore, tryptophan-like (peak T) was found to be the least eliminated and thus, may be considered as an indicator of DOC residual after coagulation-flocculation process. This result shows that fluorescence spectroscopy offers a robust analytical technique to be used to evaluate DOM removal efficiency in water treatment.