[Groundwater quality in an arid area of Morocco: impact of pollution on the biodiversity and relationships between crustaceans and bacteria of health interest]. / Qualité des eaux souterraines dans une région aride du maroc: impact des pollutions sur la biodiversité et relations crustacés--bactéries d'intérêt sanitaire.

In the north of Marrakesh (Morocco), the high anthropogenic activity and the permeable nature of the geological ground makes the water of Jbilet vulnerable to contamination. The results of physico-chemical analyses conducted in 2006 showed that two groups of wells could be distinguished. Groundwater of wells located on the right bank of the Tensift River, which are far from any source of pollution, is of fairly good quality, well oxygenated, at neutral pH and with rather weak levels of organic compounds. In contrast, in the other wells in the area of the landfill of the city of Marrakesh and those in the peri-urban area demonstrate deteriorated water quality. The nutriment and organic matter content is quite high. Results of bacteriological analyses of water showed a fairly high faecal contamination. In this area the soil is highly permeable and promotes infiltration of organic pollutants and minerals as well as of pathogen and opportunistic bacteria into groundwater. After their penetration, these microorganisms form films around grain particles. The movements of the stygofauna in the interstices allow bacteria to settle on their exoskeleton and seep into their gut, thus being a potential source of groundwater contamination. An analysis of bacterial flora showed that the rate of bacteria is high in the digestive tract of two crustacean species of the stygobites Typhlocirolana haouzensis and Metacrangonyx spinicaudatus, and that it depends on the species and the bacteria. Bacteria may be one of the potential nutritional resources for stygobites.

[Impact of olive oil wastewater on the physicochemical and biological quality of groundwater in the Haouz plain, south of Marrakesh (Morocco)]. / Impact des effluents des huileries d'olive sur la qualité physico-chimique et biologique des eaux souterraines dans la plaine du Haouz au sud de Marrakech (Maroc).

Olive Oil Waste Water (OOWW) is acidic water known for its antibacterial and phytotoxic effects. In Morocco, these effluents are generally drained into the surrounding environment without any treatment or are collected and retained in large evaporation basins, which can constitute a source of potential pollution of groundwater. The analysis of water from 14 wells, in an agricultural zone, where there are four storage basins of OOWW coming from various types of oil mills, showed that their physicochemical and biological quality is largely influenced by the presence of these basins. Indeed, high values of COD (400 mg O2 L(-1)), polyphenols (180 mg l(-1)) and electrical conductivity (1.89 mS cm-') were recorded in P5 water. This well is located only 5 m from a storage basin of OOWW coming from the H4 oil mill which rejects OOWW charged with organic matter (more than 290 g of O2 L(-1) of COD, on average). However, the settlement of a basin, dug close to a modern oil mill (H3), which produces large OOWW volumes but is loaded with low organic pollutant concentration (100 g of O2L(-1) of COD), reduced notably the effect of the OOWW infiltration on groundwater. This resulted in the improvement of the groundwater physicochemical quality near this basin (P7 and P8); the organic matter contents expressed by COD vary from 26.7 mg l(-1) to 30 mg l(-1) and the polyphenol contents are on average between 41 mg l(-1) and 47.6 mg l(-1). The analysis of the total well water fauna showed a great taxonomic richness with variations in time and space. The biodiversity decreases in groundwater polluted by the oil mill waste and the underground fauna disappears completely if the degree of contamination of groundwater is high.

[Groundwater quality in two arid areas of Morocco: impact of pollution on biodiversity and paleogeographic implications]. / Qualité des eaux souterraines dans deux régions arides du Maroc: impact des pollutions sur la biodiversité et implications paléogéographiques.

The biodiversity and the quality of subterranean waters have been comparatively studied in the Haouz plain near Marrakesh and in the Tafilalet, in south-eastern Morocco. For this purpose, physicochemical and faunistic analyses were carried out on the water of ten wells and springs located in the area of Marrakesh, and in Errachidia area respectively. In the wells of Marrakesh, the average stygobiologic diversity is relatively high in the wells located upstream the dumping from the city where the ground water presents low contents of nitrates and orthophosphates. In contrast, the wells located in the spreading zone of Marrakesh wastewaters are characterized by the scarcity or the absence of stygobitic species; in these latter wells, the water is highly polluted. It is rich in nitrates, nitrites, ammonium, and the conductivity is rather high. In the area of Errachidia the faunistic inventory gathers some ten species, some of which are living in hot springs. The subterranean water is highly mineralised. In the two studied areas, the biodiversity decreases when well water is locally polluted, and the subterranean fauna completely disappears if the degree of contamination is important. This relation between the biodiversity and water quality which had already appeared in surface water, is confirmed within the wells of Marrakech. The groundwater fauna of both two areas presents similarities in relation to their geological history, mainly the various marine cycles of marine transgressions-regressions, which were at the origin of the settlement of the ancestors of the extant species, and the Atlasic orogenesis which separated the common ancestral populations into two separated stocks, involving a different evolution of the ancestors and a resulting speciation by vicariance.