Ali A.Z. DouAbul

Vegetation Response to Re-flooding in the Mesopotamian Wetlands, Southern Iraq

Wetlands in the Mesopotamian Plain in southern Iraq were extensively drained in the 1990s. Re-flooding of drained areas commenced in 2003, and included parts of the Central marsh between the Euphrates and Tigris Rivers. New vegetation in the re-flooded areas of the Central marsh was studied in 2006. Most of the wetland plant species and communities widely distributed prior to drainage have reappeared, but there were some species and communities that did not re-establish. Aboveground plant biomass is recovering in some communities, but in most of the new communities, biomass and diversity were low. Post-flooding sites were characterized by higher concentrations of chloride and bicarbonates in surface water and higher percent organic matter in sediment than those prior to drainage. Comparisons among the three study sites in the re-flooded areas and those between pre-drainage and post-flooding sites suggests that differences in water quality, including more saline conditions in the re-flooded wetlands, might be hindering the biomass recovery. The water source being limited to only the Euphrates River, a much more subdued seasonal fluctuation in the quantity of water input and output, and inputs of contaminated waters appear to be responsible for the delay in vegetation recovery in the Central marsh.

Trace element geochemical associations in the Arabian Gulf

A sequential extraction procedure is utilized to determine the geochemical fractionation of Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn in surficial sediments from the NW Arabian Gulf. It has been established that there are no strong variations in the concentration of total trace elements among different locations within the studied area. The mean concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn in the lithogenous fraction were 0.19, 88, 25, 5868, 1158, 456, 10, 116 and 33 μg g−1 respectively, whereas in the non-lithogenous fraction they were 0.17, 6.2, 6.78, 1828, 755, 91, 4, 22 and 3 μg g−1 respectively. In the non-lithogenous fraction the easily or freely leachable and exchangeable fraction is not geochemically significant, thus having only 11% Cu, 9% Mn, 2% V and 3% Zn of the total non-lithogenous metals. The carbonates and Fe-Mn oxides and hydroxides fractions appear to be the most dominant phases in the non-lithogenous fraction containing 100% Cd, 35.5% Cr, 50% Cu, 33% Fe, 80% Mn, 40% Ni, 42.5% Pb, 33% V and 45% Zn in the former and 21% Cr, 35% Cu, 59% Fe, 6% Mn, 14% Ni, 57.5% Pb, 35% V and 45% Zn in the latter. This observation has been attributed to the scavenging affinity of Fe-Mn oxides and to the carbonate-rich sediments of the Arabian Gulf. On the other hand, the organics and sulphides fraction contains the following percentages of the total non-lithogenous metals: 43.5% Cr, 4% Cu, 8% Fe, 5% Mn, 46% Ni, 30% V and 7% Zn.

Trace metals in Shatt al-Arab River, Iraq

Abstract The distribution of 10 trace metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn have been determined along the northern section of the Shatt al-Arab River, Iraq. Analyses were carried out, employing a flameless AAS instrument. The mean concentrations of the dissolved species were as follows (expressed in μg l −1 ): 0.25 Cd, 0.9 Cu, 716 Fe, 1.3 Mn, 0.3 Pb, 0.2 V and 1.8 Zn. Mean concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn in the particulate matter were 55.2, 6.0, 188, 77, 31 472, 1731, 3807, 93, 207 and 77 μg g −1 respectively. In the exchangeable fraction of the sediment were 0.15, 5.5, 11.1, 11.9, 1625, 482, 42, 30.5, 25.7 and 6 μg g −1 , whereas in the residual were 0.025, 11.5, 96.1, 22, 5176, 258, 613, 3.9, 162 and 56.8 μg g −1 respectively. Thus, the exchangeable trace metals represent the following mean percentage of the total; 75% Cd, 33% Co, 10% Cr, 34% Cu, 24% Fe, 63% Mn, 7% Ni, 74% Pb, 14% V and 23% Zn. The concentration of Ni and V were relatively high, this was attributed to the petroleum-rich deposits of the region. The concentrations observed for other metals were lower or equal to those reported for control sites except for Pb which was slightly higher. The data obtained were subjected to simple linear regression analysis and expressed in the form of correlation coefficients. It was found that the inter-elemental relationships are rather complex.

Seasonal variations of oil residues in water of Shatt al-Arab river, Iraq

The distribution and seasonal variations of petroleum residues in the Shatt al-Arab water column have been determined spectrofluorometrically. Their concentrations were found to vary between 1.7 to 35.4 μg L−1 Kuwait crude oil equivalents. The results suggested that petroleum hydrocarbons present in this river originated from diverse sources. Hydrocarbon amounts tend to be highest in winter (averaged 17.4 μg L−1) and lowest in summer (averaged 3.1 μg L−1).

The Shatt al-Arab River: A nutrient salt and organic matter source to the Arabian Gulf

The distribution of dissolved reactive phosphate, nitrate and nitrite in the waters as well as total organic carbon, total phosphorus and Kjeldahl nitrogen in the sediments of the Shatt al-Arab Estuary and the NW Arabian Gulf were studied from November 1979 to April 1980. The Shatt al-Arab waters contain 0.18 to 0.70 µg-at P-POinf4sup3−l−1, 26.12 to 52.39 µg-at N-N0inf3sup−l−1 and 0.53 to 0.70 µg-at N-NOinf2sup−l−1, indicating that this river should be considered a source of nutrients to the Arabian Gulf. It is concluded that most of the nitrate is supplied in dissolved form, while an appreciable amount of phosphate is absorbed to fine suspended particles and released at higher salinities. Total organic carbon in surficial sediments was found to vary between 0.14% and 0.96%. These rather low values are attributed to dilution by dust fallout, which is a major cource of sediments in this area.

Dissolved petroleum residues and alkylbenzene photo-oxidation products in the upper arabian gulf

Abstract Lipophilic dissolved material was concentrated by in-situ liquid-solid adsorption on Amberlite XAD-2 resin from glass-fibre-filtered coastal seawater in the upper Arabian Gulf in the fall of 1986. 10% aqueous acetone was used for countercurrent desorption under reflux. In the concentrated eluate petroleum components were characterized and quantified by GC-MS as were ketonic photo-oxidation products of alkylbenzenes. Concentrations of the latter exceeded those of unaltered petroleum components by roughly a factor of 10.

Residues of organochlorine pesticides in fish from the Arabian Gulf

High-resolution electron capture gas chromatography was used to determine residue levels of organochlorine pesticides in 13 commercially important fish species collected from the NW Arabian Gulf. While most of the residues were below the detection limit of 1 μg kg−1 wet weight, relatively low concentrations of ΣDDT, endrin and dieldrin were detected in the edbile tissue of these fishes. The ΣDDT residue levels ranged from 2 to l 1μg kg−1 wet weight, endrin ranged from none detected (nd) to 45 μg kg−1 and dieldrin from nd to 5 μg kg−1. A definite correlation was established between total organochlorine pesticide residues and lipid content (r = 0.6) for the NW Arabian Gulf fishes. Comparison with fish from Hor-al-Hammar Lake (an area that used to be sprayed with pesticides) has shown that the latter contained significantly higher residue levels. The ΣDDT residue levels ranged from 5 to 45 μg kg−1 wet weight, endrin from 3 to 83 μg kg−1 and dieldrin from nd to 4 μg kg−1 Based upon the observation that the original DDT (p, p′-DDT) was identified in the NW Arabian Gulf fishes, it has been concluded that there was a recent input of DDT to this region. Since DDT application has been banned in Iraq, consequently it was assumed that DDT must originate from a more remote source.

Occurrence and sources of polar lipid tracers in sediments from the Shatt al-Arab River of Iraq and the northwestern Arabian Gulf.

Shallow surface sediment samples from the southern part of the Shatt al-Arab River estuary of Iraq and the northwestern Arabian Gulf were analyzed for polar lipid compounds including n-alkanoic acids, n-alkanols, steroids and triterpenoids. The results showed that the n-alkanoic acids, methyl n-alkanoates and n-alkanols typically ranged from C12 to C32 with total concentrations of 3.2 to 108.2 μg g(-1)dwt sample, from C12 to C30 with totals of 1.1 to 18.9 μg g(-1)dwt sample, and from C14 to C32 at 1.8 to 112.6 μg g(-1)dwt sample, respectively. Steroids and triterpenoids were detected and included stenols, stanols, stenones, stanones, tetrahymanol, tetrahymanone and extended ββ-hopanes. The total steroid concentrations ranged from 2.8 to 78.4 μg g(-1)dwt sample, whereas the triterpenoids varied from 0.05 to 7.6 μg g(-1)dwt sample. The simple regression analysis of the results and the spatial distribution patterns of the identified organic tracers indicated that the inter-compound relationships were related mainly to their major sources. Cluster analysis and principal component analysis (PCA) of data set showed that the sampling sites are similar. These sources were allochthonous (terrestrial vegetation), autochthonous (plankton residues and bacteria in the sediments) and anthropogenic (sewage and petroleum).

Phosphorus and nitrogen budgets of the Al-Hawizeh marshland after re-flooding

The ecological function of the Mesopotamian marshlands was severely damaged during their desiccation from 1993 to 2003 and, as a result, the marshes became a main target for restoration after their re-flooding in April 2003. In this study, the phosphorus (P) and nitrogen (N) budgets for a portion of the Mesopotamian marshlands at Al-Hawizeh (Iraq) are reported. Al-Hawizeh appears to play a strong role in regulating P and N. Total P input and output were both dominated by dissolved organic P, while total N input and output were dominated by particulate organic N, suggesting that N is in greater demand than P. Al-Hawizeh acts as source for N and sink for P; this has an important function in altering their export downstream (Shatt Al-Arab River) and subsequently into the Arabian Gulf. However, investigating P and N fractions helped in understanding the role of Al-Hawizeh in transforming, storage and release of P and N fractions.

Restoration of heavily polluted branches of the Shatt Al-Arab river, Iraq

Abstract In view of the desire to improve the water quality of the heavily polluted branches of the Shatt al-Arab River at the City of Basrah, it was proposed to maintain effective flushing as well as contracting sewerage system. The present study was conducted in order to examine the water quality of these branches in an attempt to evaluate the effectiveness of the proposed flushing system. It has been found that their waters contained very low levels of dissolved oxygen and relatively high amounts of both COD and BOD 5 . The annual average water quality parameters for Basrah Branches were: dissolved oxygen 3.4 ppm; pH 7.67; hydrogen sulphide 1.4 ppm; ammonia 97 μ g-at. N l −1 ; COD 15.9 mg l −1 ; BOD 5 12.7 mg l −1 ; dissolved silicates 202 μ g-at. Si l −1 ; dissolved reactive phosphate 13.4 μ g-at. P-PO 4 3− l −1 ; nitrate 10.4 μ g-at. N-NO 3 − l −1 ; nitrite 2.1 μ g-at. N-NO 2 − l −1 and chlorophyll- α 14.3 mg m −3 . Based on our calculations, it has been concluded that the proposed system is effective, thus within a flushing cycle all of the above mentioned parameters will become within the acceptable values of the Shatt al-Arab water quality. Moreover, this system has no appreciable effect upon the water quality characteristics of the Shatt al-Arab River due to the fact that it discharges a high volume of water annually. However, It has been recommended to dredge the deposited sludge to a minimum depth of 50 cm.