Nabil M. Fayad

Effect of Water Quality Parameters on the Migration of Vinyl Chloride Monomer from Unplasticized PVC Pipes

The migration of vinyl chloride monomer (VCM) from unplasticizedpolyvinyl chloride (uPVC) pipes was investigated using locallymanufactured pipes. Specimens of 33 cm long were used throughoutthe research. The investigation was carried out under differentconditions of water temperature, pH and total dissolved solidsconcentration and at different durations of exposure. The VCMconcentration in the water was evaluated using the gaschromotography (GC)/head-space technique. A VCM concentration ofmore than 2.5 ppb was detected after 30 days of exposure at45 °C. The initial VCM concentration in the uPVC pipewas predicted using equations derived from Ficks first law ofdiffusion. Water tenperature did not affect the migration ofVCM, unless it was raised to high values (i.e. 45 °C).Total dissolved solids (TDS) and pH of water were found toaffect the release of VCM from uPVC pipes. Diffusion rate of VCMwas predicted as a function of pH or TDS values.

Analysis of drinking water for the detection of trihalomethanes

Drinking water of the Dammam metropolitan area is a blend of raw well water and desalinated water obtained from the Al-Azizia seawater desalination plant. Chlorination is the only disinfection method applied to the blended water before the water is pumped into the distribution system. Chlorination of water containing organic compounds results in the formation of trihalomethanes. In general, the known carcinogenic and physiological effects of THMs other than chloroform are limited. However, based on their structural similarity to chloroform, these compounds can be considered health hazards. The present study was carried out in order to determine the extent of the occurrence of THMs in finished drinking water in some of the major cities of the Eastern Province of Saudi Arabia.

Migration of vinyl chloride monomer (VCM) and additives into PVC bottled drinking water

Abstract The migration of vinyl chloride monomer (VCM) and plasticizers, especially adipate and phthalate esters, from polyvinyl chloride (PVC) packaging materials into bottled drinking water was investigated. The study has shown that the concentrations of VCM in various brands of bottled‐water were below 0.6 ppb, which is far below the 2 ppb maximum contamination limit set by the United States Environmental Protection Agency for VCM in drinking water. Exposure of the bottled‐water to sunlight did not result in a measurable increase in the VCM concentration levels. However, several volatile and semi‐volatile organic compounds were tentatively identified by GC‐MS in the bottled‐water after exposure to sunlight. 2,3‐Dichloro‐l‐propanol and dichloroacetic acid were the volatile compounds repeatedly identified, moreover, the presence of benzene was confirmed in some bottled‐water samples. Di‐n‐octyl adipate and bis(2‐ethylhexyl) phthalate were the major semi‐volatile organic compounds identified. Migration of...

Chlorination byproducts of Arabian Gulf seawater

Some researchers have related the toxicity of chlorinated seawater to the residual chlorine contents of the water. This has resulted in the establishment of guidelines for reducing the chlorine levels in the discharged water. However, when chlorine is added to seawater, a great proportion of it is consumed in the oxidation of the naturally occurring organic and inorganic materials of the water. Therefore, the harmful effects of the chlorinated discharges can most probably be attributed to the reaction by-products. Very little information is available about these by-products.

Survey of Saudi Arabian drinking water for trihalomethanes

Formation of trihalomethanes (THMs) as a result of drinking water chlorination is well documented. The presence of THMs in drinking water may adversely affect human health. The objectives of this study are to determine the concentration levels of THMs in drinking water of eight major cities in Saudi Arabia and to compare these concentrations with Saudi Arabian Water standards, as well as with THMs concentrations reported in drinking water in other parts of the world.

Effects of solvent and humic materials in fluorimetric determination of oil hydrocarbons in marine sediments

Abstract Serious interferences were found to occur during the fluorimetric determination of oil hydrocarbons in marine sediments. The presence of trace quantity of methylene chloride in the sediment extracts was found to considerably enhance the fluorescence intensity of chrysene. While the presence of humic materials, naturally existing in sediment, in some cases completely quench the fluorescence. This study suggests that a great precaution should be taken when fluorescence spectroscopy is applied to such determinations.

Trihalomethanes (THMs) formation in a distillation process

Abstract In this study, the fate of THMs formation in seawater distillation process and the rates of THMs formation in the chlorinated blended distillate were examined under various experimental conditions. The following general equation was obtained empirically: Log (THM) = A * Log (Cl2) + B * Log (TOC) + C (THM) is the concentration of total THMs in μg/l, (Cl2) and (TOC) are the concentration of chlorine doese and total organic carton in mg/l, A,B, and C are estimated parameters. The results showed that THMs level increases with the increase of both chlorine and initial humic substances concentrations. Increase in temperature and contact time also increased THMs concentrations. On the other hand, pre-chlorination and aeration step of the seawater resulted in a reduction of THMs concentrations in the blended distillate.

Development of a simple monitoring technique for oil pollution in sediment

Abstract In this study an attempt was made to develop a reliable method for the estimation of total oil hydrocarbons in sediments. The method developed involved an HPLC technique using a group separation. The oil was separated into saturates, aromatics and polar compounds after removing the asphaltenes gravimetrically. Determination was carried out by quantifying the aromatics and polar hydrocarbon fractions of a reference oil (Arabian light), against which the unknown was assayed. Linear calibration curves were obtained for the aromatics and polar fractions over the range 1–12 mg/mL and 0.1–1 mg/mL, respectively. The reproducibility for the aromatics fraction was acceptable with a maximum error of 2.8 % (n=3) and recovery rate was 89.3% (n=3). Similar results were obtained for the polar fraction. The method was compared with an existing Spectrofluorometric method.

N-Alkanes in Air Particulates of the Eastern Province of Saudi Arabia

Abstract Oil hydrocarbons represent a great proportion of organic compounds in the atmosphere. Information about these compounds in the atmosphere of the Eastern Province of Saudi Arabia is lacking. In this study, n-alkanes and polynuclear aromatic hydrocarbons in air particulates were determined. The highest median concentration levels of n-alkanes in three urban areas and three areas near oil production centers were 121 ng/m3 and 42.9 ng/m3, respectively. Polynuclear aromatic hydrocarbons were also detected, although they are present in too low concentration for reliable quantitative measurement by GC and GC/MS techniques. A positive correlation was found between the concentration levels of n-alkanes in air particulates and the total suspended particulates measured at most locations. The carbon preference index (CPI) and the presence of the unresolved complex envelope suggested an anthropogenic origin for the n-alkanes.