Geoenvironmental approach to investigate surface and groundwater pollution-related problems in water-sensitive regions.

The desert environment is a clean, dynamic system due to its remoteness from human interventions. Yet, sometimes it is approached by anthropogenic activities that change its balanced ecosystem. The present study states that the non-planned construction of wastewater plants has affected the environment and led to water resource deterioration. The presented approach is based on the integration of hydrogeologic data together with remote sensing and GIS applications as well as statistical, chemical, biochemical, and bacteriological analyses of water samples. The groundwater showed high salinity values (up to 13,236 mg/l) where it is extracted from two coastal aquifers; the Middle Miocene aquifer represents the main one, while the Pleistocene aquifer is of limited use. The obtained results reveal the existence of pollution indicators in both stored rainwater and groundwater where the colony bacteria, NO3, chemical and biological oxygen demands, and total organic carbon exceed the permissible limits. The satellite images acquired between 2003 and 2021 demonstrated a land use change through the construction of a wastewater plant with two forests that led to the spreading of the partially treated water over the Marmarica Plateau. The photogeological lineaments are extracted where the plateau is affected by many faults (NE-SW, NW-SE, and E-W) that facilitate surface-groundwater interaction. The results indicate that the studied groundwater becomes vulnerable to the existing pollution sources, with the possibility of being affected by climate change and saltwater intrusion. Therefore, this integrated approach is presented to assess the current environmental problems and suggests a strategy to mitigate the pollution hazards.

Satellite observations for monitoring atmospheric NO2 in correlation with the existing pollution sources under arid environment.

Monitoring of air pollutants using satellite data has been largely improved over the past few decades, which can provide deeper insights into the effects of anthropogenic activities on the air quality. The observations and measurements of atmospheric NO2 are poorly investigated in North Africa, therefore, the current study applied a multi-proxy approach to better understand of the ambient environment. This approach is based on satellite observations, chemical and biological analyses, and investigative information during fieldworks. The Aura satellite provides the basic data for the current study with fine resolution of atmospheric NO2 and O3 concentrations. The obtained results reveal noticeable increases of atmospheric NO2 values since the 2011, where its emission reaches the peak during summer season that is characterized by high anthropogenic activities. The study area has many sources for NO2 emissions, such as the urban region, traffic, as well as the NH3 emission that is in turn converted to NO2. Although the discharged and spreading wastewater (80,000 m3/day in summer) has a limited role in NO2 emissions, it represents an indicator of the anthropogenic activities. The wastewater analyses confirm the occurrence of nitrate (NO3 -), nitrite (NO2 -), and ammonia (NH4 +), which provide an appropriate condition for NO2 release. The analyses of multi-climate datasets (previous records and the expected scenarios) reveal an increase of temperature accompanied by decrease of precipitation which confirmed the existence of climate change. Therefore, the study presents a set of suggestions to mitigate the release of NOx gases and achieve Net-Zero emissions.