Baseline survey of marine sediments collected from the Kingdom of Bahrain: PAHs, PCBs, organochlorine pesticides, perfluoroalkyl substances, dioxins, brominated flame retardants and metal contamination

Spatial and temporal analysis of the risks posed by metal contamination in coastal and marine sediments of Bahrain

“…Cd can affect sensitive benthic taxonomic groups like mollusca, polycheata, echinodermata, crustacea and platyhelminthes already at low concentrations (0.0014 mg kg −1 of Cd affect 5% of sensitive organisms, whilst over 90% were affected at 1.0 mg kg −1 according to Leung et al ( 2005 ). The low Cd concentration in the sediment measured in this study and recently confirmed by Bersuder et al ( 2020 ) would indicate that there is a low risk of Cd accumulating in the food chain and impacting some of the higher trophic fauna (e.g. dugongs and turtles) that graze on the extensive sea grass beds around Bahrain’s coast (Burt et al, 2013 ; Naser, 2015 ).…”

“…The results of these sites indicate that the ongoing pollution needs continued monitoring. This was addressed in a recent study by Bersuder et al ( 2020 ), who conducted a detailed survey of sediments around the Refinery Area and found that metal contamination was relatively localised around the Refinery Area station and not widespread within that region of coast. More detail on which metal exceeded the relevant AC in the last sampled year and which trends for a specific metal are increasing or decreasing at a specific station can be seen in Table 4 .…”

“…Bahrain does not yet have formally adopted sediment quality guidelines (SQGs) (Abdulla & Naser, 2021 ), so the available data were assessed against a range of internationally adopted AC (Table 2 ). The AC used in this manuscript were recently described by Bersuder et al ( 2020 ), which include OSPAR Background Assessment Concentrations (BACs; OSPAR, 2008 ), United States Environmental Protection Agency Effects Range Low (US EPA ERL; Long & MacDonald, 1998 ), US EPA Effects Range Median (ERM; Long & MacDonald, 1998 ), Canadian Interim Sediment Quality Guidelines (ISQG; Canadian Council of Ministers of the Environment, 2001 ) and Probable Effect Levels (PEL; Canadian Council of Ministers of the Environment, 2001 ). Generally, OSPAR BACs are said to be ‘near-background’ (based on samples collected from the North-East Atlantic region) and concentrations below this AC do not pose harm to the marine environment.…”

“…Concentrations above the ERL or ISQG indicate that small effects may occur to organisms living in or near the assessed sediments, whilst concentrations above the ERM or PEL suggest that some effects are likely to occur to bottom-dwelling organisms (Bersuder et al, 2020 ; Nicolaus et al, 2015 ). These standards were established for European and American sediment backgrounds and should be adopted with care, as some baseline metal concentrations observed in the Arabian Gulf region are above various sediment quality guidelines (SQGs; Al-Sarawi et al, 2015 ; Alshemmari et al, 2010 ; Bersuder et al, 2020 ; Lyons et al, 2015 ). Al-Abdali et al ( 1996 ) proposed metal background concentration for the Arabian Gulf region (Table 2 ) which was taken into consideration in the discussion.…”

“…This coastal development, which includes petrochemical, power generation and desalination industries, discharges significant volumes of effluent into Bahrain’s marine waters. Consequently, a variety of contaminants have been reported in biota, sediment and water samples, including petroleum hydrocarbons, organohalogens, metals and nutrients from sewage treatment plants (Bersuder et al, 2020 ; de Mora et al, 2010 ; Naser, 2011 ; Tolosa et al, 2005 ). These contaminant inputs pose a risk to Bahrain’s marine habitats, which serve as a feeding and nursery ground for many ecologically and economically important species like dugongs and green turtles (Abdulqader, 1999 ; Zainal et al, 2007 ; Moore & Peirce, 2013 ; Arab Regional Centre for World Heritage & Supreme Council for Environment, 2017 ).…”