Geochemical Characterization of Soil and Water From a Wastewater Treatment Plant in Gaza

The aim of the study was to determine the interaction between the natural geochemistry and the anthropogenic effects through trace element profiles in one of the environmentally significant areas of the Gaza Strip. Five boreholes were dug in the area of the Gaza wastewater treatment plant. The geology, mineralogy, and geochemistry of the soil profiles were studied, and the geochemistry of wastewater, sludge, soil, and groundwater was identified by several analytical techniques. The study introduced the environmental baselines and the infrastructure needed for further research for the first time: the natural infiltration potential, the artificial recharge, and the agricultural activities of water and wastewater. The results of the geochemical investigations confirmed that the upper 40 cm of soil was found to be the affected zone by wastewater and sludge. Among 26 elements analyzed, only a few metals (As, Cd, Cr, Hg, Zn, and to a lesser extent Pb) showed relevance from the human health point of view. The metal accumulations in the soils were characterized by a large spatial variability, with some “hot spots” of Cu and Zn reaching topsoil concentrations of up to 240 and 2005 mg/kg, respectively. In spite of that, the results of the groundwater revealed that none of them was detected at concentrations that exceeded the WHO (World Health Organization) standards. Moreover, it was shown that both anthropogenic activities as well as seawater intrusion caused the high levels of nitrate and salinity.