**2.5 Pollution**

Anthropogenic pollution is a reality in the Maghreb and it is undermining the socioeconomic and ecological basis of life in the region. The fastest growing population, urbanization and effects of climate change are all factors influencing the anthropogenic CO2 and air pollutant emissions across the Maghreb region. Major types of pollution sources in the region include dust storms, sandstorms and gases from various industries. Air pollution and stress on agriculture play a major role in water pollution and realize high number of pollutants (pesticides, herbicides and insecticides) into water bodies and these pollutants not only harm water but also, they treat the biodiversity of the plant and animal life that depend on water to survive.

Algeria—Surface water in Algeria including Tafna, Macta, Cheliff and Seybous River basins are polluted by industrial wastewater and also by organic fertilizers (nitrate, potassium and phosphates) used in agriculture. Groundwater quality in Algeria was generally good. However, this quality has been affected by anthropogenic factors such as pesticides and fertilizers [28]. People in the North part of Algeria consumes more water than others; where the most of its groundwater is non-saline; salinity ≤1 (g/l). Nevertheless, certain coastal aquifers in Mitidja and Bas Sebaou are particularly at risk due to intrusion of salty marine water (overexploitation). In the

southern Sahara, there are important aquifers, that meet ~96% of water consumption, having salinity ≤9 g/l in the Complex treatment terminal. Additionally, saline lakes with salinity ≥3 g/l are impacted as the quality of surrounding freshwater aquifers and their salinity may increase [29].

Morocco—The increase of water demands in Morocco combined with climate change have led to water deficit which have forced farmers to use wastewater in irrigation and thus affecting the water quality of many water bodies such as streams and groundwater (contamination with a large quantity of nitrogen and phosphates, due to fertilizer runoff from agriculture areas). Also, pressure on groundwater resources in Morocco has been increasing over the last decades which causes a dramatic decline in groundwater levels and degradation in its quality (seawater intrusion, nitrate pollution and natural salinity changes).

Tunisia—Generally, pollution of freshwater water in Tunisia comes from wastewater discharge, industrial waste and agricultural activities. However, Tunisia has the highest access rates to water services and sanitation in the Maghreb region. In the northern coastal region, there is relatively abundant rainfall. In the arid central reason, surface watercourses are ephemeral, flowing only for a few days or weeks a year. Nevertheless, in the South part of Tunisia, surface flows are rare and small. Groundwater is the principal source of water—both shallow renewable and deep, with often non-renewable groundwater resources. The overexploitation of shallow and deep aquifers in this country has led to water-level declines and seawater intrusion.

Libya has very limited freshwater and Libyan people rely heavily on groundwater located underneath the country's vast deserts; about 98% of the total water use [25]. Generally, the water pollution in Libya comes from the combined impact of sewage, oil by products, and industrial effluents. The exploitation of groundwater reserves in Libya has become very crucial in the last decades, especially in coastal areas which compose the only geographic area receiving more than 100 millimeters of rainfall a year and accounts for less than 5% of Libya's land area. In fact, the overexploitation of coastal aquifers reduces freshwater outflow to the sea, and cause a high depletion in piezometric level of these aquifers as much as 25 m below mean sea level which has led to the progressive seawater intrusion in the coastal aquifers since the 1930s [30].

Mauritania lies almost entirely within the Sahara Desert. The only perennial river in the country is the Senegal River, which forms its southern border. The region receives very low rainfall and the only the coastal zone is received significant seasonal rainfall. Several recurrent years of droughts have caused rapidly declined with people settling in rural areas and in shantytowns in cities (where access to clean water and sanitation is scarce). This climate variability put the region in water crisis "water availability" (quantity and quality) and particularly Nouakchott (Capital of Mauritania) at near-constant risk of flooding because it is below sea level and therefore prone to frequent floods caused by rising sea levels and resulting a very water-poor.
