Investigation of heavy metal contamination and ecological and health risks in farmland soils from southeastern phosphate plateaus of Khouribga (Morocco)

The present study was conducted in the SE area of phosphate plateaus (Khouribga) located in central Morocco. It attempted to assess the heavy metal (HM) (Cd, Cr, Cu, Pb, Zn) contamination in the farmland soils and their potential ecological hazard and non-non-carcinogenic risks using various pollution indices, magnetic susceptibility (MS), and Geographical Information System (GIS) methods. A total of 41 soil samples were collected and analyzed for pH, electrical conductivity (EC), grain-size, organic matter (OM), calcium carbonate (CaCO3), and MS and HM elements. The results showed a mean dominance order of Zn>Cr>Cu>Pb>Cd where mean concentrations of HMs, except Pb, exceeded their local background and Food and Agriculture Organization (FAO) and World Health Organization (WHO) permissible guidelines. The values of geo-accumulation index (Igeo), nemerow pollution index (PI), and pollution load index (PLI) revealed significant high level of HM contamination in soils. The MS values showed a spatial distribution pattern similar to those of HMs, attesting the ability of the MS method for mapping the contaminated soils. Agricultural and mining activities and geologic materials were the main sources of HM accumulation. According to the potential ecological risk index (RI) (195.93<RI<1092.53), the soil samples had moderate (65.85%) to high ecological (34.15%) risk. The hazard index (HI) showed that adults and children are not exposed to non-carcinogenic risk from the studied HMs, apart from two soil samples where Cd posed health risks to children compared to the other studied HMs. The statistical results revealed that soils are polluted by anthropogenic activities. Accordingly, effective agricultural practices that respect the environment, including the reduction of inputs as fertilizers, pesticides, herbicides, and fungicides should be required to guarantee the safety of cropland and the residents in the studied area. Hence, the findings from this study provided some useful information for soil pollution control and management in the study area

Remote sensing approach to assess salt-affected soils in the north-east part of Tadla plain, Morocco

Recently, the remote sensing technologies have been used increasingly in various domains in order to explain or detect different phenomena in a rapid manner and covering large areas. This study aims to use Landsat 8 Oli imagery product to elaborate a map of soil salinity in the north-east part of Tadla plain, by implication of spectral reflectance and electrical conductivity (EC) measured in the laboratory. Based on salinity Index (SI), the Normalized Differential Salinity Index (NDSI), and Landsat bands, we carried out a statistical study via the JMP13 software to determine the most correlated bands with EC measured. The obtained results were very satisfactory with an R2 = 71.3% and root mean square error (RMSE) of 0.084. The elaborated map showed that the salinity is high near Oum Er Rbia River and the two cities of Beni-Mellal and Ouled Yaich, which is due to saline waters of Oum Er Rbia River and Béni-Moussa-East (Dir) groundwater used for irrigation. These results signify that the combination of remote sensing and laboratory EC measurements would be a suitable method for predicting soil salinity

Multivariate statistical analysis for spatial evaluation of physicochemical properties of agricultural soils from Beni-Amir irrigated perimeter, Tadla plain, Morocco

Soil surveying and mapping is an important operation in soil science, and characterization of their properties is a key step in understanding soil quality . This study was undertaken to investigate the spatial variability of selected soil properties, such as soil pH, electrical conductivity (EC1:5), carbonate content (CaCO3) and total organic matter (TOM) and soil texture using different conventional analytical methods. Spatial distribution of these soil properties was elaborated by using the kriging method. The obtained results showed that the soil is alkaline, soil pH ranges from  7.20 to 8.78. TOM varies from 0.11 to 1.05 dS/m, and its texture varied from sand to loam content. Nonetheless, EC values fall within the slight, moderate and strong degrees of salinity. According to these results, it can be concluded that the soil is saline. Interrelationships between the parameters analyzed and the different samples were investigated by multivariate analyses, principal component analysis (PCA), and hierarchical cluster analyses (HCA). HCA classified the five groups, which were compared to PCA visualizations. The Box-plots show that the values fractions (sand, silt, clay) were very variable. Pearson correlation coefficient indicates a high correlation between carbonate content and pH, organic matter and silt fractio