The physicochemical and bacteriological quality of groundwater was assessed to show the impact of the agriculture and human activities in the Triffa Plain located in North-East of Morocco. The current levels of contamination of the groundwater were estimated by analysing electrical conductivity, nitrate, nitrite, ammonia, orthophosphate, and indicators of faecal pollution content.

Water samples from 55 locations were collected during two period of time, the wet and the dry season of the year 2016. Result obtained indicated that most samples are highly contaminated. The electrical conductivity varied from 800 to 9 100 μS∙cm–1. Nitrate levels ranged from 25 to 216 mgꞏdm–3, with 78% of samples exceeding the critical level value set at 50 mgꞏdm–3. Nitrate concentrations are slightly higher during the wet period in 73% of studied cases. Nitrite rarely exceeded the normal rate fixed by World Health Organization and reached 0.90 mgꞏdm–3. Ammonia and orthophosphate contents do not exceed these norms.

The study revealed a wide contamination of groundwater by microbial agents such as, total coliforms, faecal coliforms and faecal streptococci, with content ranged from 0 to 14 000, 0 to 5 000 and 0 to 5 000 CFUꞏ(100 cm3)–1 respectively, con-firming the impact of septic tanks, wastewater discharge into rivers without treatment, and the use of animal waste on the ground water vulnerability.Samplings and measurements were carried out according to the international standard ISO 13395, ISO 11732 and ISO 15681-2 for chemical compounds and ISO 9308-1 and ISO 7899-2 for microbiological numerations.

The rainfall irregularity in the Al-Hoceima area places the Ghis-Nekor coastal aquifer as a primary resource for water supply. However, it is of paramount priority to adopt management and optimization plans that can mitigate the effects of the irrational use of the resource and the deterioration of its quality in the region of our study. In order to study the alteration aspects of this aquifer, 26 wells were sampled and their suitability for irrigation was assessed. The sodium adsorption rate (SAR) values indicate that most groundwater samples fall into the risk classes of high salinity and low sodium (C3-S1) and high salinity and medium sodium (C3-S2). The results also show a medium to high alkalinity risk due to the high concentration of HCO3–. The excess of salts is largely due to the intensive exploitation of groundwater and to the phenomenon of salt-water intrusion into the coastal karst aquifer. As a result, the quality of groundwater is not adapted to sustainable agricultural production and soil balance, which requires controlled monitoring to ensure its rational use with a view to the sustainable development of the region.