Advanced removal of pesticides, herbicides, and pharmaceutical residues from surface water.

This work is interested in studying the removal of 27 harmful pollutants from drinking water in the Rosetta branch of the River Nile by advanced treatment processes (i.e. photo-catalysis under natural conditions and normal pH of surface water). The concentration levels of the selected pesticides (11 compounds) in raw water by the spiking method ranged from 1.57-0.40 µg/L, while the concentration of pharmaceuticals (10 compounds) ranged from 41.56-5.95 µg/L and the herbicides (6 compounds) in the range of 1.89-1.37 µg/L. For this purpose, TiO2-Hombikat/alumina (T/A) was prepared by a two-step method; sonication followed by the hydrothermal method. Cu/TiO2-Hombikat/alumina was prepared hydrothermally (H-Cu/T/Al) and by the wet impregnation method (Ma-Cu/T/Al). The prepared materials were characterized by XRD and SEM. The use of advanced treatment could successfully remove selected pollutants. In the case of pharmaceutical residues, the prepared catalysts showed a powerful efficiency in the complete removal of sulfamethazine, while only (T/A) and (H-Cu/T/Al) showed such an efficiency in the complete removal of diclofenac sodium. On the other hand, lower efficiencies were observed with caffeine (17.99% (T/A) and 24.05% (H-Cu/T/Al)). In the case of pesticides, a high removal of pendimethalin (93.77%) using (H-Cu/T/Al) and 86.03% by using (Mb-Cu/T/Al), whereas lower efficiencies were observed for T/A toward the degradation of aldicarb (15.6%) (l) and H-Cu/T/Al (26.07%). In the case of herbicides, the catalysts showed no more than 57% efficiency in the removal of these pollutants.

Multi-exposure human health risks assessment of trihalomethanes in drinking water of Egypt.

The present study aims to assess the probable lifetime cancer and non-cancer risks of exposure to the trihalomethanes in Egypt's drinking water through ingestion, dermal contact, and inhalation. A total of 1667 drinking water samples were collected from twenty-three Egyptian governorates over a three-years period. The concentrations of total trihalomethanes ranged between 29.07 and 86.01 µg/L and were always below the maximum contamination level recommended by the Egyptian standards (100 µg/L). Chloroform was the most prominent trihalomethanes species, while bromoform was rarely detected. The cancer risk study revealed that, among the investigated paths, inhalation poses the greatest risk. And bromodichloromethane had the highest impact to cancer (69%), followed by chlorodibromomethane (28%). Geographically, the highest cancer risk value was found in Matruh governorate (42.2 × 10-6) and the lowest was in Minya governorate (1.0 × 10-6). The cancer risk for the studied governorates, except Minya governorate, was higher than the level recommended by the USEPA (1.0 × 10-6). Hazard index (HI) study revealed that the ingestion pathway caused higher HI values than the dermal pathway and that chloroform had the highest contribution to HI value. However, the values of HI were below unity in all studied governorates demonstrating that there would be negligible non-cancer risk.

Hazardous inorganic disinfection by-products in Egypt's tap drinking water: Occurrence and human health risks assessment studies.

This study is the first that monitored the presence and levels of chlorite, chlorate and bromate in tap drinking water of Egypt. Three hundred and eight samples were collected from 22 governorates across Egypt and were analyzed using a standardized ion chromatography method. Forty-seven samples were contaminated by one or more of the inorganic disinfection by-products (DBPs) and only 12 samples exceeded the admissible maximum contamination levels (MCLs). The ratio of samples detected, and exceeding the MCLs were low relative to the global literature. Chlorate was the most prevalent inorganic DBPs (40 samples; concentration <12-4082 µg/L) followed by bromate (12 samples; concentration <3-626 µg/L) then chlorite (5 samples; concentration <12-123 µg/L). Chlorite was always below the MCL and had no human health risk even for the worst-case scenario. Bromate is a real challenge as it poses a significant cancer risk even for the median concentrations. None of the inorganic DBPs was detected in the tap drinking water of Beheira, Cairo, Gharbia, Giza, Kafr El Sheikh, Luxor, Monufia, and Suez governorates. This study manifested the importance of routine monitoring, and implementing counter measures to control the levels of the hazardous inorganic DBPs in tap drinking water.

The occurrence and risk assessment of phenolic endocrine-disrupting chemicals in Egypt's drinking and source water.

This is the first nationwide survey of bisphenol A (BPA), methylparaben, ethylparaben, propylparaben, butylparaben, and o-phenylphenol, in Egypt's water. Five hundred fifty-five water samples were collected from source water (SW, 109 samples) and drinking water (DW, 446 samples) of twenty-three Egyptian governorates. These chemicals were determined by direct ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis of a filtered aliquot of samples. The impacts of the measured concentrations on the aquatic organisms and human health were evaluated as well. BPA, methylparaben, propylparaben, and butylparaben were frequently detected in SW and DW, while ethylparaben and o-phenylphenol were not detected whatsoever. The most frequently detected endocrine-disrupting chemical (EDC) was BPA in SW and methylparaben in DW. The recorded highest concentrations of BPA and methylparaben in SW and BPA and methylparaben, propylparaben, and butylparaben in DW were the highest worldwide. Of the investigated twenty-three governorates, the SW and DW of Aswan, Red Sea, Cairo, Sharqia, and Damietta were free of the studied EDCs. Contrarily, BPA, MeP, PrP, and BuP were detected in Sohag's SW and DW. A detection ratio > 70% was recorded in SW of Faiyum, Dakahlia, and Ismailia, and > 90% in DW of Sohag, Port Said, Dakahlia, and Faiyum. The environmental risk assessment results excluded any human health risk even in the worst-case scenario and showed that BPA represents the highest risk to the aquatic organisms.