Groundwater Pollution of the Quaternary Aquifer in Northern United Arab Emirates

Abstract

Natural conditions and human activities have caused serious quality degradation of the Quaternary aquifer in the north of the United Arab Emirates (UAE). The aquifer within Ajman City is unconfined, receiving limited recharge (12 542 m 3 / day) from the east and large pollutants flux (4,800 m 3 / day) from land surface. Field survey and laboratory analyses revealed anomalies in groundwater salinity (TDS), total hardness (TH), dissolved oxygen (DO), cations (Ca 2+ , Mg 2+ , Na + and K + ), anions (HCO À 3 , SO 2À 4 , Cl − and NO À 3 ) and trace elements (Fe, Pb, Cd and Cr), which can be correlated to point and nonpoint pollution sources. Concentrations of trace elements are more responsive to anthropogenic sources than natural ones. High Fe and Pb levels were measured close to the untreated sewage disposal site, while high Cd and Cr contents were observed near hospitals and clinics. Iso-concentration maps of salinity and major ions, in addition to hydrochemical profiles were used to define the seawater-groundwater interface in Ajman City. The potentiometric surface map of the Quaternary aquifer within the study area shows that groundwater flows from the east towards the Arabian Gulf in the west. The proposed landfill site is suitable because it lies within a topographic low, receiving groundwater flow from all directions.

Impact of small municipal solid waste landfill on groundwater quality

“…The results of tests confirmed that leachate from the municipal landfill site under review constituted a source of contamination of the water environment, which was also shown by Kanownik and Policht-Latawiec (2016). Other researchers also proved the impact of municipal solid waste landfills on the deterioration of groundwater quality with varying degrees of pollution (Han et al 2016; Al-Hogaraty et al 2008).…”

Seasonal variation in chemical properties and degradability by anaerobic digestion of landfill leachate at Benowo in Surabaya, Indonesia

“…Seawater intrusion into the aquifer below the coastal area has been reported at depths as shallow as 1e2.5 m (Al-Hogaraty et al, 2008). Because the depth to water in our sampling sites ranged from 0.7 to 2.4 m, seawater could have contaminated the water collected at many of the sampling sites.…”

Land Use/Land Cover Changes Impact on Groundwater Level and Quality in the Northern Part of the United Arab Emirates

“…With distance away from the mountainous areas, TDS concentration in groundwater increases and the groundwater becomes more saline (Figure 12). The dissolution of evaporates, leakage of saline water, and circulation of flow irrigation of the groundwater aquifer are also sources of TDS in groundwater [55][56][57][58][59][60][61]. However, population growth and density have a strong impact on TDS concentration in groundwater in the NUAE.…”

“…The spatial relationship shows that the areas affected by high NO3 concentration and groundwater depletion are, at the same time, the areas that have the greatest need for water, including the irrigated agricultural areas (Figures 15 and 16). The impact of vegetation, as part of LULC, on groundwater recharge and groundwater level can be both negative and positive by facilitating the surface water infiltration and transpiration obtained from the rooted soil profile [61][62][63][64][65]. While the irrigated agricultural areas and water demand in the study area increase depletion in the groundwater level and the rate of evapotranspiration (2-3 m/year), the built-up areas decrease water infiltration and the recharge rate (< 4% /year) due to their impervious surfaces [12,13,66].…”

“…The high TDS and Clconcentration in the groundwater are also positively associated with intensive urbanisation. This phenomenon can be explained by the fact that groundwater level depletion due to overpumping is mainly responsible for groundwater level depletion, and thus seawater intrusion as indicated by the Na/Cl ratio map [49,50,61] (Figure 16d). The low value (<1) for the Na/Cl ratio in the groundwater indicates seawater intrusion and regional brine and sabkha impacts [11,19,49,54,61,62].…”