Assessment of Groundwater Aquifer Impact from Artificial Lagoons and the Reuse of Wastewater in Qatar

Qatar relies on groundwater for farming activities. Animal fodder crops are irrigated during summer, and different types of vegetables are grown in winter. Qatar has been using lagoons in different parts of the country to dispose of treated wastewater. Some of those lagoons are near farms and residential areas. Thus, understanding the groundwater quality and the lagoons' impact on them is important for future human and environmental health. Lagoons (n = 14) and wells (n = 56) were sampled in both summer and winter of 2018/2019. A good correlation between Cl-, Na+, Li+, SO42-, S, Sr2+ and Ca2+ suggests salinization of the aquifers. Gypsum dissolution is active in the Qatar aquifers and lagoons system during both summer and winter. A few elements in groundwater exceeded the Qatar irrigation guidelines, indicating a degradation of groundwater quality. Lagoon water was found to be similar to groundwater but with lower values of salinity. General linear model analysis shows a correlation between lagoon proximity to the wells and the concentrations of elements in the groundwater. Isoconcentration maps visualize marine intrusion and the impact of lagoons on groundwater quality. Increasing concentrations of nitrate and decreasing chloride and sulphate concentrations were observed in the groundwater in winter, indicating recharge following winter rainfall.

Automated summary

Qatar's reliance on groundwater for agriculture is affected by the presence of lagoons used for wastewater treatment. The study found salinization of the aquifers and degradation of groundwater quality, with some elements exceeding irrigation guidelines. The proximity of lagoons to wells was found to affect the concentrations of elements in groundwater. Isoconcentration maps showed the impact of lagoons on groundwater quality, including marine intrusion.