Fluorides in groundwater, soil and infused black tea and the occurrence of dental fluorosis among school children of the Gaza Strip

Abstract

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.

Dietary behaviours and dental fluorosis among Gaza Strip children

“…The highest (3.19 cups) was in Rafah and the lowest (2.4 cups) was in Bani Suhila. Consistent with our results, Shomer et al demonstrated that children in Gaza Strip were consuming tea in an early age [5]. We found that 44.1% of children were given tea since the first year of age.…”

“…In 1999, the prevalence of dental fluorosis in 7th grade (12-year-old children) in Rafah (60.0%) was the highest, followed by Khan Younis (50.5%), while in North Gaza, where the fluoride concentration was very low in drinking water, it did not exceed 7.1% [4]. Recently, a high prevalence of dental fluorosis (60%) was detected among children of school age in the Gaza Strip [5].…”

Correlation among fluoride and metals in irrigation water and soils of Ethiopian Rift Valley

“…Except the value reported by US NAS [25], Washington DC, America and Smith and Hodge [26], fluoride in American soil is lower than this study, while others such as Toma et al [27], Moldova; Shomar et al [28], Israel; Zhang et al [29], China and others have comparable value of total fluoride with this study. The water soluble content of soil in this study is a bit higher than that of reported in literature, but comparable values also reported in America [25] and New Zealand [30].…”

Water usage in the Gaza Strip: recommendations from a literature review and consultations with experts

“…Of these, 87 relevant original articles were identified and classified under 11 thematic areas. Only nine studies (15)(16)(17)(18)(19)(20)(21)(22)(23) examined the association between water quality and health effects (Table 1). In the literature describing contaminants in the water supply in the Gaza Strip, salt was the most notable cause of decreased water quality, followed by nitrates and infectious organisms.…”