Fluoride Action Network


Fluoride plays a fundamental part in human health. However, continued ingestion of excessive fluoride may cause significant negative health effects on people, ranging from mild dental fluorosis to crippling skeletal fluorosis, depending on the level and time of exposure to fluorides. In provincial areas, the presence of fluoride in well water may be due to natural factors or human activities. The reason for our work was to evaluate the level of tainting of groundwater by fluorides from various areas in Morocco situated in rural and agricultural areas, where the main wellspring of consumable water is well water, and the reasons for fluorosis in this area. The 44 samples were taken in seven Moroccan regions: Had Soualem-Berrechid, Kenitra, Fez, Tit Mellil, Sidi Slimane-Sidi Kacem-Zirara, Larache, and Brachoua, and 12 samples of tea were taken from different souks and commercials in Morocco. Fluoride dosing measurements in well water were performed using the potentiometric technique using the fluoride-specific ion electrode (HI-4110) at room temperature, while the determination of fluorine in tea is done by the spectrophotometric method. The results of fluoride levels revealed in different well waters from different regions range from 0.2 to 6.58 mg/l. For the green and black tea samples, the fluorine content varies between 0.48 and 1.60 mg/l for the 10 min infusion and between 0.93 and 2.7 mg/l for the 30 min infusion. These results make it possible to warn the population facing the risk of developing dental fluorosis by limiting the amount of fluoride ingested by the consumed foods.

*The full-text study is online at https://www.sciencedirect.com/science/article/pii/S2214785322049999#!


Table 1. Fluoride (mg/l) content of well water samples in the different regions.

Sample Region Location Fluoride (mg/l)
P1 Had Soualem-Berrechid Had Soualem 1.400
P2 Had Soualem-Berrechid Had Soualem 6.580
P3 Had Soualem-Berrechid Harcha 0.400
P4 Had Soualem-Berrechid Ouled Bouziri 2.550
P5 Kenitra Douar Bourhma 0.790
P6 Kenitra Douar Bourhma 0.530
P7 Kenitra Douar Bourhma 1.660
P8 Kenitra Kenitra 0.530
P9 Kenitra Kenitra 0.290
P10 Fez Douar Bsais 0.730
P11 Fez Douar Bsais 0.680
P12 Fez Douar Chejeaa 0.450
P13 Fez Douar Chejeaa 1.640
P14 Fez Taaounyat Birda, Btamat Boujlafa 0.770
P15 Fez Taaounyat Elfarah 0.970
P16 Fez Taaounyat Ghalya 0.980
P17 Fez Moulay Yacoub 0.850
P18 Fez Moulay Yacoub 0.870
P19 Fez Moulay Yacoub 0.090
P20 Fez Moulay Yacoub 0.140
P21 Fez Moulay Yacoub 0.180
P22 Tit Mellil Tit Mellil 1.290
P23 Tit Mellil Tit Mellil 1.470
P24 Tit Mellil Tit Mellil 0.500
P25 Sidi Kacem-Sidi Slimane Lkhawass 4.110
P26 Sidi Kacem-Sidi Slimane Lkhawass 2.060
P27 Sidi Kacem-Sidi Slimane Zirara 1.170
P28 Sidi Kacem-Sidi Slimane Zirara 0.270
P29 Sidi Kacem-Sidi Slimane Sidi Kacem 0.200
P30 Larache Oulad Hamou Lghaba 0.750
P31 Larache Oulad Hamou Lghaba 0.013
P32 Larache Oulad Hamou Lghaba 0.004
P33 Larache Oulad Hamou Lghaba 0.090
P34 Larache Oulad Khssiss 0.200
P35 Brachoua Enakhlat 0.650
P36 Brachoua Enakhlat 0.790
P37 Brachoua Enakhlat 0.330
P38 Brachoua Enakhlat 0.460
P39 Brachoua Brachoua 0.870
P40 Brachoua Brachoua 0.270
P41 Temara Jammat sbah, wladhbri 0.240
P42 Temara Jammat sbah, wladhbri 0.250
P43 Temara Jammat sbah, oulad mssoun rkhokha 0.220
P44 Temara Jammat sbah, oulad mssoun rkhokha 0.040

Table 2. Fluoride level in green and black teas (10 and 30 mintes of infusion).

Sample Nature F mg/l (preparation 10 min) F- mg/l (preparation 30 min)
1 Green tea 0.92 2.70
2 Green tea 1.17 2.20
3 Green tea 0.80 0.93
4 Green tea 1.40 1.93
5 Green tea 1.62 2.40
6 Green tea 0.50 1.94
7 Green tea 1.28 1.50
8 Green tea 0.69 2.55
9 Black tea 1.09 1.37
10 Black tea 1.26 1.75
11 Black tea 0.48 1.35
12 Black tea 1.26 1.36

2.2. Methods

Fluoride dosing has been made utilizing the potentiometric technique using the Fluoride specific ion electrode (HI-4110) at room temperature. HI-4110 is an ISE fluoride combination ideal for detecting free fluoride in drinking water, soft drinks, wine, plants, emulsion food products, and electrodeposition acids. The HI-4110 allows accurate measurement of the total concentration of fluoride.

The levels of fluoride in tea extracts (in duplicate tests) are determined by the Belcher-West colorimetric method with Alizarin complexone in polyethylene tubes [12]. In the presence of Alizarin complexone, lanthanum nitrate gives a red coloration in an aqueous medium. In the presence of F-anion, a blue-colored complex is formed. The new complex is soluble in acetone and was determined by spectrophotometry at 618 nm. The absorbance of the samples is subtracted from that of a control in which the tea extract is replaced by distilled water. The fluoride concentration of the samples is calculated by analysis against the calibration curve.

*The full-text study is online at https://www.sciencedirect.com/science/article/pii/S2214785322049999#!