Assessment of the impact of coastal development on the water quality, sediment and macrobenthic infauna in the Dubai coastal environment

Alshaer, Hamdan (2021) Assessment of the impact of coastal development on the water quality, sediment and macrobenthic infauna in the Dubai coastal environment. (PhD thesis), Kingston University, .


Over the last few decades, industrial and urban activities have contributed to the accumulation of trace metals and other contaminants in the marine environment, thereby impacting coastal ecosystems. Dubai has undergone incredible economic, social and industrial developments, resulting in a significant increase in anthropogenic impacts such as dredging, land reclamation, industrial and sewage effluents, desalination discharges, and oil pollution causing environmental degradation of Dubai's marine ecosystem. Sites were selected along the nearshore, offshore, creeks and port locations that characterise distinct environmental features within the marine environment of Dubai. Sediment, water and macro benthic samples were collected from fifty sampling stations in the coastal environment of Dubai during December 2013 (winter) and August 2014 (summer). The study of sediment, water and macro benthic revealed different types of pollution, identifying certain areas of concern. The status of trace metals in the sediment along the Dubai coast is principally influenced by the anthropogenic activities in the proximity of ship maintenance, ports and industrial areas (Dry Dock, Jaddaf, Jebel Ali Port, Wharfage, Hamriya and DUBAL). Copper and zinc were the major trace constituents found to affect these areas, with some trace metal hot spots (e.g., Dry Dock, Wharfage, Jebel Ali Port, Jaddaf and Sanctuary) identified including some contaminated stations, Jebel Ali Port, Dry Dock, Hamriya N and Jaddaf. The ecological risk indices showed that all stations were free from potential ecological risk, except for moderate ecological risk at Dry Dock because of its elevated sediment metal levels. The results of the water quality index (WQI) illustrated that the water quality at most stations, except STP (sewage treatment plant), Jaddaf and Sanctuary, was excellent with a score of >90. The low score (69.9-74.0) in STP, Jaddaf, and Sanctuary is linked to anthropogenic influences, as these stations are situated near the STP discharge and ship lifting yard in the upper region of Dubai creek. This upper area of Dubai creek is a partially enclosed lagoon and more vulnerable to organic pollution and severe environmental incidents such as fish mortality, algal blooms and eutrophication. The elevated levels of NO3-N, PO4-P and NH4-N associated with anthropogenic inputs (sewage effluent) are evident in this area, due to regular inputs of secondary treated effluents from the STP outfall. The macro benthic biomass along the Dubai coastal environment was found to be considerably lower than the biomass of the Arabian Gulf, also showing a decline from the soft-bottom substrate of the Arabian Gulf. This indicates the poor status of macro benthic ecology in terms of standing stock (biomass) and population, hence, the stressed state of macro benthic ecology, which could be linked to a variety of anthropogenic activities such as dredging, reclamation, organic and trace metal contamination along Dubai's coast. The distribution of the macrobenthic community along the Dubai coastal environment is characterised in several zones such as extreme and high severity, moderate and healthy areas. Signs of extreme severity (dead zone) were evident along the upper area of Dubai creek due to organic pollution, whereas high severity in macro benthic communities was also evident in Hamriya and Jebel Ali Ports. Based on this study’s findings, a coastal zone management (CZM) plan for Dubai is needed to ensure access to safe and healthy water quality and ecosystems that sustain the coastal economy. Rigorous and systematics environmental monitoring programme along Dubai coastline for water quality, sediment and marine ecology is required with proper control and remedial measures in hot spot areas.

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