The objective of this study aims to evaluate the physicochemical quality of surface and well water based on measurements of Temperature (T°C), pH, Electrical Conductivity (EC), Suspended Matter (MES), Calcium (Ca2+), Magnesium (Mg2+), Sodium (Na+), Potassium (K+), Bicarbonates (HCO3-), nitrates (NO3-), nitrites (NO2-), ammonium (NH4+), Chlorides (Cl-), sulfactes (SO42-), orthophosphates (PO43-) in the Loka watershed. The physical parameters pH, EC and T were measured in situ with a WTW 3111 pH meter, a WTW 3110 conductivity meter and a WTW3110 oximeter. Chemical parameters, major elements, nutrient salts and heavy metals were all analyzed at the CIAPOL laboratory. The analysis of these parameters was carried out according to the protocol of Rodier 1994. The suspended solids (MES) were obtained by filtration on a fiberglass filter. The physicochemical analysis of the Loka watershed shows that the surface waters have an average temperature of 26.43°C. pH values vary between 5.5 and 6.8. Summary The objective of this study aims to evaluate the physicochemical quality of surface and well water based on measurements of Temperature (T°C), pH, Electrical Conductivity (EC), Suspended Matter The coductivity content is between 29 ÿS/cm and 116.2 ÿS/cm, which reflects weakly mineralized waters. Nitrate concentrations observed in surface waters vary from 0.24 mg/L to 1.95 mg/L. Also, well water has a pH varying between 6.55 and 8.9 with an average of 7.35. These waters are also weakly mineralized and have nitrate contents of between 0.2 mg/L and 1.04 m/L. The average values of the different physicochemical parameters are generally below WHO quality standards. As a result, surface and well water on the whole can be used for the supply of drinking water but environmental monitoring remains important.

Located in central-eastern Côte d’Ivoire, the department of Dimbokro has for the past ten years been faced with the illegal and clandestine development of artisanal and small-scale gold mining (ASGM), commonly known as gold panning. This activity is having a huge impact on the environment and especially on natural resources (deforestation, loss of arable land). The aim of this study is to detect changes in land cover in the Dimbokro department using Landsat TM (1988), ETM+ (2002) and OLI (2021) images. The supervised or directed classification method with maximum likelihood and the diachronic comparison method were used. The areas of the classes obtained after the diachronic analyses were used to highlight the average annual rates of spatial expansion. This expansion between 1988 and 2021 is either progressive or regressive. A regression was observed for the dense forest (-2.99%), degraded forest (-2.32%), crop (-0.82%) and water (-1.65%) classes. In terms of change over this period (33 years), there has been an increase in the surface area of savannah (+2.67%) and buildings/bare ground (+4.12%). This study shows that changes in the landscape of the Dimbokro department are linked to a high level of human activity, leading to the degradation of natural resources in a context of climatic variability.