Ecological assessment of physico-chemical properties in mangrove environments along the Arabian Gulf and the Red Sea coasts of Saudi Arabia

Urban expansion along the coastal sites is one of the major causes of the deterioration of mangrove habitats. This study aimed to report the current status of different mangrove environments in Saudi Arabia. Mangrove soil and sediment–water samples were collected from the coasts of the Arabian Gulf and the Red Sea for their physical, chemical, and heavy metal analysis. The mean values (n = 42) of heavy metals in the soil showed that Fe (2200 ppm) > Mn (91.9 ppm) > Zn (66.11 ppm) > Cr (62.40 ppm) > Ni (33.64 ppm) > Cu (31.06 ppm) > Pb (30.69 ppm) > Co (27.06 ppm). While the mean values (n = 15) of heavy metals in the sediment–water were as follows; Cr (0.1978 ppm) > Fe (0.1016 ppm) > Pb (0.0792 ppm) > Co (0.0706 ppm) > Mn (0.0356 ppm) > Cu (0.0317 ppm) > Ni (0.0215 ppm). The average values of Zn, Ni, Cu, Pb, and Co were greater than those reported previously in the Red Sea and Arabian Gulf coastal sediments. At the same time, Mo and Cd were not detected in any studied soil sample. The correlation analysis revealed that the EC of mangrove soil was positively correlated with SOM, Ca, Mg, Na, and K, while the EC of sediment–water was positively correlated with Na, K, and Cu. Landfilling, sewage pollution, mismanagement of solid waste, and contamination due to other anthropogenic activities may lead to heavy metal hazards and the loss of large areas of mangrove plants in this region. Therefore, the findings of this study should be considered to understand and design the management strategy of mangrove forests in the area of study.