The purpose of this study was to determine the fluoride levels in water, soil and tea, and to identify the major fluoride minerals in soil that supply water with fluoride ions. Another aim was to study the prevalence of dental fluorosis in permanent dentition of the school children of the Gaza Strip. Monitoring of fluoride levels in 73 groundwater wells and 20 topsoil samples for the last three years revealed a general trend of increasing from north to south of the Gaza Strip. A linear regression analysis found a correlation coefficient of r=0.93 between the fluoride concentrations in groundwater and soil for the same geographic areas. However, the X-ray diffraction technique (XRD) results showed that none of the four major fluoride minerals were detected in the tested soil samples; the PHREEQC model showed that fluorite (CaF2) was the main donating mineral of fluoride ions to groundwater. A high positive correlation was found between fluoride concentrations in groundwater and occurrence of dental fluorosis. Among 353 school children of the five geographic areas of the Gaza Strip the prevalence of dental fluorosis was 60%, and 40% had no signs of fluorosis in their permanent dentitions. The highest occurrence, 94%, was in Khan Yunis, followed by 82% in Rafah, 68% in the middle area, 29% in Gaza and the lowest occurrence of 9% was in the northern area. These percentages were directly proportional to the average content of fluoride in groundwater of each area: 2.6, 0.9, 1.7, 1.2, and 0.7 ppm, respectively. The exception was Rafah where people drank from new groundwater wells that have been dug in the last 10 years. The occurrence of the disease was due to intake of high amounts of fluorides in drinking water, tea and fish. Communication with population indicated a heavy intake of tea starting from a very young age; not uncommonly tea is put in nursing bottles. No significant correlation was found between prevalence figures and gender or age groups. This high prevalence indicates a need to examine other sources of F including diet.

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A Geographical Information System (GIS) tool was used to construct thematic maps for groundwater quality in the Gaza Strip. Environmental data were integrated and an overall picture about the spatial variation in the groundwater quality of the Gaza Strip was defined. The integrated spatial maps helped to refine information on land use, soil types, depth to groundwater table, environmental “hot spots”, and contaminant concentra-tions of the study area. The groundwater quality maps have been derived from the results of an eight-year monitoring program for major anions, cations and heavy metals. An environmental hot-spots map was de-rived from potential contaminating sources, showed direct and indirect influences on groundwater quality. The GIS maps showed not only contaminant distributions but also illustrated the need to improve the groundwater quality management methods. Several contaminants pose great problems in the water of Gaza. Integration of water data and GIS maps for all parameters revealed that there is probably no drinking water in Gaza according to the WHO standards. Moreover, the new maps of 2008 could be used as base-line for water planners and policy makers as well as guidelines for the Palestinian people to manage and protect their groundwater. Increased water demand from population and economic growth, environmental needs, land use changes, urbanization, groundwater mining, deterioration of water quality, pollution from local and diffuse sources, environmental hot-spots and impacts on public heath and ecosystems are all factors that can create a severe water quality crisis as well as water shortage problems

Water and sediment samples were collected from 18 sampling stations in Wadi Gaza for two successive years in order to: (1) Establish a baseline condition of the geochemistry of surface water and sediments; (2) assess the impact of seasonal variation on distribution of heavy metals and major ions; and (3) identify possible natural and anthropogenic sources of pollution. The heavy metal concentrations in the sediments of the lake (downstream) were higher than those of the eastern eight stations(upstream) where the water was shallower. Shallower areas showed greater temporal variation than deeper areas. Several elements (P, Fe, Mn and As) showed the greatest temporal variability. For example, in the winter rainy season these elements decreased 2-10 times compared to their values in summer. Moreover, Ca, Na, Cl, PO 4 , and NO 3 decreased3, 3, 5, 2, 4 times, respectively. Some of the trace metals were more abundant in these waters compared to the domestic wastewaters of the study area. The averages of Cd and Co were 6 and 43 lg/l, respectively and they were 50 times higher than the domestic wastewater results. The discharge of olive oil mill wastewater was recorded in the Ca, Na, Mg, K and P concentrations in sediments of one of the sampling stations.

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