Mohmed Abdilhmid Sayed, PhD

Decontamination of wastewater as efficiently and as cost-effectively as possible, is very important. There are several widely used techniques to decontaminate waste water from heavy metals: chemical precipitation, extraction, sorption, ion exchange and membrane separation. Adsorption is one of the most commonly used techniques for removing organic and inorganic pollutants from wastewater, which involves the adsorption of ions and molecules on to the surface of the adsorbent solid particles. Removal of heavy metals using White Cement, Portland cement and Lime Gypsum were studied in order to apply it for industrial wastewater decontamination, for neutralization of acidic wastewaters and for removal of heavy metals ions such as Pb2+, and Cd2+. The interaction of different additives of cement with water solutions of lead and cadmium salts formation of compounds, maximal capacity and the ability of the different additives to remove these heavy metals to the Egyptian Standard Low 44–2000 on discharge consent levels (DCL) has been studied. Metal removal was investigated using synthetic solutions at initial different concentrations of individual metals (Cd2+, and Pb2+). The removal efficiency was determined at different contact time. The optimum contact time for removal of Cd, and Pb2+ was 2h for both Cement types. At initial concentration 50 mg Pb2+ l-1, the maximal capacity to remove Pb2+ of different additives after 24h interaction was 50 mg g-1 of White Cement, 47.5 mg g-1 of Lime Gypsum and 34.2 mg g-1 of Portland cement. The maximum capacity to remove Cd2+ was ordered as White Cement > Portland cement > Lime Gypsum. The results suggested that as the cement is a cheap by-product of the cement industry; it is promising for decontamination of electroplating rinsing waters or similar non-concentrated heavy metal solutions.

Grains of rice and wheat are important food as acereal crop in Egypt as in the world. Recently, the lead (Pb) content of soils and plants increased as a result of different pollutant sources causing negative environmental impacts. Therefore, this study aimed to es-timate the level of Pb in the soils, rice and wheat plants of Damiet-ta governorate cultivated area and evaluate its impact on human health. Results shows that soil total Pb in the surface layer (26.7 ± 11.1 mg kg-1) are higher than the subsurface layers (1.27 ± 0.13-fold) due to its low mobility with soil depth. The DTPA extractable Pb in the surface layers (0.69±0.50 mg kg-1) are also higher than subsurface (1.35 ± 0.42-fold) and represents a small fraction from total (2.39 ± 1.1%). Moreover, DTPA extractable Pb shows significant positive correlation with total soils Pb (r2 = 0.73) and organic matter content (r2 = 0.82), on the other hand, a negative correlation with the soil pH (r2= - 0.76). Rice grain Pb concentrations (0.09 ± 0.02 mg kg-1) is lower than straw (0.72 ± 0.12 mg kg-1), which represents 12.6% ± 1.70-fold. A significant correlation is found between rice grains and straw Pb content (r2 = 0.95) that also increasing soil DTPA extract-able Pb rice straw (r2 = 0.91) and grains (r2 = 0.93).On the other hand, wheat grain Pb concentrations (0.08 ± 0.024 mg kg-1) is lower than straw (0.63 ± 0.19 mg kg-1), which represents 11.9% ± 1.74-fold. However, a significant correlation is found between wheat grain and straw Pb concentrations (r2 = 0.92) that also by increasing soil DTPA extractable Pb wheat straw (r2 = 0.82) and grains (r2 = 0.75).Rice and wheat grains Pb concentrations are lower than the permissible limits according to WHO/FAO and EU (0.20 mg kg-1) and no potential human health risk is concluded yet.

Keywords: Egypt; Grains; Rice (Oryza sativa L.); Lead; wheat (Trit-icum aestivum L.)