Trace metal and TBT pollution in the Gulf and Oman: spatial variation and hot spots.

This review assesses trace metal concentrations in nearshore and offshore bottom sediments in the Arabian Gulf and Oman focusing particularly on targeted monitoring studies of point sources of contamination near industrial zones (sometimes with ports) and desalination and power plants (often co-located). Concerns have been raised about harmful impacts from accumulation of metals in the semi-enclosed Gulf. The sediment trace metal contaminants of the greatest concern are highlighted with maximum levels of toxic trace metals such as As, Cd, Cu, Pb, Hg, Ni, Zn, and TBT recorded near port and ship repair yards/dry docks as well as industrial and power/desalination plant discharge outfalls. The levels of metals such as Cd, Pb, and Hg exceeding sediment quality guidelines at identified hot spots are of concern. Efforts to mitigate future impacts are recommended.

Petroleum hydrocarbon pollution in sediments from the Gulf and Omani waters: Status and review.

This review presents the spatio-temporal distribution of petroleum hydrocarbons including total petroleum hydrocarbon (TPH), total organic carbon (TOC), total aliphatics, unresolved complex mixture (UCM), polycyclic aromatic hydrocarbons (PAHs), and total aromatic hydrocarbons in marine sediments of the Gulf (Iraq, Iran, Kuwait, Saudi Arabia, Bahrain, Qatar, United Arab Emirates and Oman). The TPH ranged between 0.134 and 48,018 µg g-1 dw where 10-15 µg g-1 dw was considered as a background concentration. The TOC levels were between 0.04 and 14.96% with a mean concentration of 1.154 ±â€¯0.523%. Total aliphatic hydrocarbon levels were reported between 0.1 and 76 µg g-1, the 2005 levels that had the largest spatial coverage were between 0.1 and 4.4 µg g-1. The unresolved complex mixture was very variable post Gulf War but by 2005 most of the Gulf War artifacts had decreased and the levels were between 1.5 and 73.5 µg g-1. The Æ©PAHs in bottom sediments by 2005 were between 0.3 and 3450 ng g-1. The total aromatics were limited in spatial extent and varied between 1.0 and 14,000 µg g-1. Most of the locations with elevated contamination levels were near point sources, e.g. oil facilities and ports, and these sites could be categorized as chronically contaminated by oil. This review highlights the paucity of the data both in terms of the spatial extent and temporal coverage, and with several Gulf states undergoing large-scale coastal developments and offshore oil exploration, it will be prudent to undertake regular monitoring of the petroleum hydrocarbons to ensure effective ecosystem functioning as well as seafood and drinking water safety in the Gulf region. The spatial distribution also highlights the lack of uniformity in assessments and the need to support marine pollution assessments in the Gulf countries.

Ciguatera in the Indian Ocean with Special Insights on the Arabian Sea and Adjacent Gulf and Seas: A Review.

The dinoflagellates of the genus Gambierdiscus are found in almost all oceans and seas between the coordinates 35° N and 35° S. Gambierdiscus and Fukuyoa are producers of ciguatoxins (CTXs), which are known to cause foodborne disease associated with contaminated seafood. The occurrence and effects of CTXs are well described in the Pacific and the Caribbean. However, historically, their properties and presence have been poorly documented in the Indian Ocean (including the Bay of Bengal, Andaman Sea, and the Gulf). A higher occurrence of these microorganisms will proportionately increase the likelihood of CTXs entering the food chain, posing a severe threat to human seafood consumers. Therefore, comprehensive research strategies are critically important for developing effective monitoring and risk assessments of this emerging threat in the Indian Ocean. This review presents the available literature on ciguatera occurrence in the region and its adjacent marginal waters: aiming to identify the data gaps and vectors.