Physico-chemical quality of the Medjerda River in Tunisia and suitability for irrigation during the moist and the dry seasons

Abstract

Surface waters are usually exposed to industrial, urban, and agricultural wastes. This study assessed the water and the sediments quality of the important primary watercourse in Tunisia and the principal source of domestic and irrigation purposes, the Medjerda River. Water samples were analyzed for total suspended solids, calcium, magnesium, total hardness, carbonates, bicarbonates, residual sodium hazard, and magnesium hazard. They were collected from five sampling sites along the Medjerda watercourse from upstream to downstream through two campaigns, one at the end of the moist period and the other at the half of the dry one in line with irrigation. The presence of high concentrations of (i) magnesium, which varied from 25.51 to 61.65 mg l-1 for the moist period and from 27.58 to 133.10 mg l-1 for the dry one; (ii) carbonates that varied from 18.0 mg l-1for the two campaigns to respectively 49.8 and 66.0 mg l-1 for the humid and the dry periods and (iii) total hardness that varied from 646.5 to 1043.0 mg l-1 for the moist period and from 503.0 to 741.0 mg l-1 for the dry one could in the future pose threats and toxicity to soil and plants when the water will be continuously used for irrigation. Sediments samples were also collected, and their contamination by heavy metals was assessed through two indicators: contamination factor (CF) and pollution load index. Results depicted severe metal contamination mainly from cadmium, of which CF varied from 3.33 to 22.66. Protection of Medjerda River and its tributaries is compulsory to prevent the apparent deterioration of its water quality.

Non-Lethal Assessment of Land Use Change Effects in Water and Soil of Algerian Riparian Areas along the Medjerda River through the Biosentinel Bufo spinosus Daudin

“…For these reasons, these anthropogenic activities are the main drivers for high enrichment and contamination indices, as also reported by Napoletano et al [23]. Particularly interesting is also the comparison with the results of Ben Ayed et al [61], who reported particularly high contamination with Pb and Cd in five industrial areas along the Medjerda River. In addition, URB was the second most polluting land use due to it being affected by vehicular emissions and open burnings that released contaminants, especially Pb [62].…”