Marine Pollution near Shipwrecks in Iraq
The IAEA-MESL recently collaborated with the United Nations Development Programme (UNDP), the Regional Organisation for the Protection of the Marine Environment (ROPME) and the Department for International Development (DFID, UK) on a survey of shipwrecks in Kuwait and Iraq waters. IAEA experts supervised the collection of sediment samples (Figure 1), together with the subsequent analysis of several contaminants and data interpretation for pollution assessment.
Figure 1 IAEA experts Mekki Azzouz (left) and Stephen de Mora (right) aboard the Ain Zalah.
Divers collected 198 sediments samples from the vicinity of 35 wrecks, together with 5 mid-channels sites. The samples were partially processed onboard the survey vessel, Halul 32 and shipped to Monaco for chemical analyses. Several metals and uranium isotopes (235, 238) were determined in all samples. Also, all samples were screened for total oil content, expressed as both chrysene and ROPME oil equivalents. A set of 24 samples was further subjected to detailed chemical analyses of petroleum hydrocarbons and chlorinated compounds, including PCBs and several pesticides. Some of the wrecks are very close to the shipping lane to the Iraqi port of Umm Qasr (Figure 2). Apart from potential pollution hazards like oil in tankers (Figure 3), the wrecks may contain dangerous cargo and stores (Figure 4), as well as unexploded munitions.
Figure 2 Ramaila in the shipping channel leading to Umm Qasr, Iraq (Photograph by SJ de Mora)
Figure 3 Tanks on the Ain Zalah still contain oil (Photograph by SJ de Mora)
Figure 4 Halon gas cylinders aboard the Ramaila (Photograph by SJ de Mora)
Pollutant concentrations were compared to North American sediment quality criteria in the absence of local standards. Cadmium and mercury (Figure 5) concentrations are generally low. This is also true for lead, except for one sample collected inside a wreck. For arsenic, copper and zinc, sporadic samples exceeded the sediment quality guideline values, but represented no pollution threat when considering the average metal content in the sediments around these wreck sites. Both chromium and nickel exhibited consistently high concentrations, interpreted to be due to the mineralogy of the suspended sediment in the river. The uranium concentrations were consistent with the crustal abundance and 235U:238U ratios (Figure 6) also reflected a natural source for this element.
Figure 5 Mercury concentrations in sediments never exceeded eth sediment quality guideline value of 0.15 µg g-1.
Figure 6 Uranium concentrations and 235U:238U rations reflected natural origins, with no evidence of enrichment or depletion.
As indicated in Figure 7, the shipwrecks with the highest total oil content in adjacent sediments were W9b (11 Ardar), W18 (dredger), W22 (navy tug 2), W24 (fuel barges 1, 2, 3), and W27 (small tug 01), together with the mid channel sample BG03-9. Of these sites, the most contaminated location was W22, the navy tug with concentrations up to 386 and 2930 µg g-1 for chrysene and ROPME oil equivalents, respectively, which represents an extremely contaminated site.
Figure 7 Oil contamination near shipwrecks in Iraq and Kuwait.
Based on 24 sediment samples, the distribution for Σ PAHs differed to that of total oil. Two samples (W01-2 and W30-9) had concentrations that exceeded North American guideline value and must be classified as contaminated. Notably, these sites were not remarkable in terms of total oil contamination. With respect to organochlorinated compounds, there was no evidence of pollution in the 24 samples that were analysed. The concentrations were generally low for both a wide range of chlorinated pesticides and several PCB congeners. Total levels of DDTs and PCBs, together with the Aroclor 1254 mixture, did not surpass North American sediment quality guideline values.
