Geo-environmental impact assessment of rock-cutting activities on the mountainous urban areas, western Saudi Arabia

This study evaluates the geo-environmental impacts of ongoing rock-cutting activities on the environment and the health of the residents in Makkah city, Saudi Arabia. The total quantity of rock-cuttings from one site was estimated using satellite data, a special algorithm, and mathematical models as 280,000 m3, which represents a large amount of rock debris from one excavation site. These debris were ultimately dumped into arid valleys. Rock-cutting processes also release a high percentage of silica dust particles (crystalline silica) and, in some cases, radon and some radioactive elements that cause alarming air pollution. Air pollutants percentage (PM2.5) reached 624 ppm and noise levels were estimated as 81 dB, which is above the acceptable limits. The total radiation intensity in the rock-cutting process areas showed normal levels, in the range of 34 milli-Roentgen/h. Conversely, inhaled dust in Mina area ranged between 35 and 190 μg/m3. The results showed also that the silica concentrations in Mina area ranged between 0.8 and 14 μg/m3, with an average concentration of 7.8 μg/m3. Medical geological and geo-biological simulations of the air pollutant hazards on human enzymes showed a notable 3B75 co-crystal form, which was characterized as glycated human hemoglobin. The ground-penetrating radar (GPR) surveys at the rock-cutting sites showed cracks and joints in the subterranean layering near the excavated areas, which were most likely caused by rock-cutting processes.