The element fluorine has long been recognised to have benefits for dental health: low-fluoride intake has been linked to development of dental caries and the use of fluoride toothpastes and mouthwashes is widely advocated in mitigating dental health problems. Fluoridation of water supplies to augment naturally low fluoride concentrations is also undertaken in some countries. However, despite the benefits , optimal doses of fluoride appear to fall within a narrow range. The detrimental effects of ingestion of excessive doses of fluoride are also well documented. Chronic ingestion of high doses has been linked to the development of dental fluorosis, and in extreme cases, skeletal fluorosis. High doses have also been linked to cancer (Marshall 1990), although the association is not well-established (Hamilton 1992).

Fluoride in Natural Waters

Fluoride contamination in water is a major problem across the globe, with health hazards such as dental and skeletal fluorosis. Most earlier studies are confined to local or regional scales. As the problem has serious socioeconomic implications, there is a need for a global perspective. Thus, here we review worldwide research for nearly a century on fluoride contamination in water. We investigated the distribution of fluoride contamination in water, its sources, mobilization and association. The major findings are: (1) Anomalous fluoride concentration in groundwater is mainly confined to arid and semiarid regions of Asia and North Africa. (2) The geogenic sources of fluoride in water are mainly fluorine-bearing minerals in rocks and sediments, whereas anthropogenic sources of fluoride in water are mainly pesticides and industrial waste. (3) Fluoride mobilization from geogenic sources is mainly controlled by alkalinity and temperature. (4) Fluoride occurrence in water is associated with ions such as sodium, arsenic chloride and bicarbonate. There are few associations of fluoride in water with calcium and magnesium.

Worldwide contamination of water by fluoride

Fluoride contamination, health problems and remediation methods in Asian groundwater: A comprehensive review.

Fluoride is one of the most widespread groundwater pollutant. More than 200 million people, from 25 nations, are suffering from fluorosis. This review presents an overview of fluoride distribution in groundwaters, and defluoridation techniques. Adsorption is the most common technique; however, the efficiency, sorbate disposal and continuous supply of efficient sorbates are still problematic. Membrane processes are quite efficient but not economical for developing communities. This article therefore highlights the importance of further research on efficient and cost-effective defluoridation for the rural developing communities not only to be used for household filtration units but also for use in community water supply schemes.

Fluoride in the environment: sources, distribution and defluoridation

Groundwater is the major source for various purposes in most parts of the world. Presence of low or high concentration of certain ions is a major issue as they make the groundwater unsuitable for various purposes. Fluoride is one such ion that causes health problems in people living in more than 25 nations around the world. Fluoride concentration of atleast 0.6 mg/l is required for human consumption as it will help to have stronger teeth and bones. Consumption of water with fluoride concentration above 1.5 mg/l results in acute to chronic dental fluorosis where the tooth become coloured from yellow to brown. Skeletal fluorosis which causes weakness and bending of the bones also results due to long term consumption of water containing high fluoride. Presence of low or high concentration of fluoride in groundwater is because of natural or anthropogenic causes or a combination of both. Natural sources are associated to the geological conditions of an area. Several rocks have fluoride bearing minerals like apatite, fluorite, biotite and hornblende. The weathering of these rocks and infiltration of rainfall through it increases fluoride concentration in groundwater. Fluoride which is present in high concentration in volcanic ash is readily soluble in water and forms another natural source. Anthropogenic sources of fluoride include agricultural fertilisers and combustion of coal. Phosphate fertilisers contribute to fluoride in irrigation lands. Coal which is a potential source of fluoride is used for combustion in various industries and in brick kilns. The aerial emission of fluoride in gaseous form during these activities reaches the surface by fall out of particulate fluorides and during rainfall they percolate with the rainwater thus reaching the groundwater table. Also the improper disposal of fly ash on ground surface contributes to fluoride in groundwater. Since ingestion of high fluoride has a long term effect on human health it is essential to monitor its concentration in groundwater used for drinking periodically and take steps to bring them within the permissible range of 0.6 to 1.5 mg/l. There are several methods available for the removal of fluoride from groundwater which is insitu or exsitu. To dilute the groundwater contaminated with fluoride, artificial recharging structures can be built in suitable places which will decrease its concentration. Rainwater harvesting through existing wells also will prove effective to reduce the groundwater fluoride concentration. Exsitu methods which are conventional treatment methods like adsorption, ion exchange, reverse osmosis, electrodialysis, coagulation and precipitation etc can be practiced at community level or at households to reduce fluoride concentration before ingestion. But the choice of each method depends on the local conditions of the region such as the quality of groundwater and the source of contamination whether it is natural or anthropogenic. Fluoride contamination being a prominent and widespread problem in several parts of the world and as causes for this are mostly natural and unpreventable, educating the people and defluorinating the groundwater before consumption are essential for a healthy world.

Fluoride in Groundwater: Causes, Implications and Mitigation Measures

Fluoride dynamics in the granitic aquifer of the Wailapally watershed, Nalgonda District, India

The groundwater of Nalgonda district is well known for its very high fluoride content for the past five decades. Many researchers have contributed their scientific knowledge to unravel causes for fluoride enrichment of groundwater. In the present paper, an attempt has been made to relate the high fluoride content in the groundwater to hydrogeochemical characterization of the water in a fracture hard rock terrain—the Wailpally watershed. Groundwater samples collected from all the major geomorphic units in pre- and post-monsoon seasons were analyzed for its major ion constituents such as Ca2 + , Mg2 + , Na + , K + , CO
 $_{3}^{-}$
 , HCO
 $_{3}^{-}$
 , Cl − , SO
 $_{4}^{-2}$
 , NO
 $_{3}^{-}$
 , and F − . The groundwaters in the watershed have the average fluoride content of 2.79 mg/l in pre-monsoon and 2.83 mg/l in post-monsoon. Fluoride concentration in groundwater does not show perceptible change neither with time nor in space. The ionic dominance pattern is in the order of Na +  > Ca2 +  > Mg2 +  > K −  among cations and HCO
 $_{3}^{-}\:\,>$
 Cl −  > SO
 $_{4}^{-2} >$
 NO
 $_{3}^{-} >$
 F −  among anions in pre-monsoon. In post-monsoon, Mg replaces Ca2 +  and NO
 $_{3}^{-}$
 takes the place of SO
 $_{4}^{-2}$
 . The Modified Piper diagram reflect that the water belong to Ca + 2–Mg + 2–HCO
 $_{3}^{-}$
 to Na + –HCO
 $_{3}^{-}$
 facies. Negative chloralkali indices in both the seasons prove that ion exchange between Na +  and K +  in aquatic solution took place with Ca + 2 and Mg + 2 of host rock. The interpretation of plots for different major ions and molar ratios suggest that weathering of silicate rocks and water–rock interaction is responsible for major ion chemistry of groundwater in Wailpally watershed. Chemical characteristics and evolution of this fluoride-contaminated groundwater is akin to normal waters of other hard rock terrain; hence, it can be concluded that aquifer material play an important role in the contribution of fluoride in to the accompanying water. High fluoride content in groundwater can be attributed to the continuous water–rock interaction during the process of percolation with fluorite-bearing country rocks under arid, low precipitation, and high evapotranspiration conditions.

Hydrogeochemical characterization of fluoride rich groundwater of Wailpalli watershed, Nalgonda District, Andhra Pradesh, India

Metastasis to gastrointestinal (GI) tract from breast cancer is rare Commonly affected organ in GI tract is stomach, followed by colon and then rectum The authors report a case of a 61-year-old woman who had a mastectomy for lobular carcinoma of the breast 17 years ago and was referred to colorectal clinic with increased frequency of stools Colonoscopy showed a stricture in the rectum, but biopsy was inconclusive As she was symptomatic, she had a Hartmann’s resection 5 months after she initially presented to the clinic Histopathology of the resected specimen showed it to be metastasis from lobular carcinoma of the breast Awareness of potential long delays in the presentation of metastatic breast cancer especially lobular carcinoma helps in the earlier diagnosis and clinical management

/pdf/rectal-metastasis-from-breast-cancer-an-interval-of-17-years-19s8qetdmz.pdf

Rectal metastasis from breast cancer: an interval of 17 years

This study aims to determine the role of positron emission tomography (PET)/computed tomography (CT) in changing the management plan in patients with metastatic or recurrent colorectal cancer (CRC) and to evaluate the role of PET/CT in patients with an unexplained rise in carcinoembryonic antigen (CEA). A total of 60 consecutive patients with CRC, who had PET/CT, were identified between 2008 and 2010. All patients had CT scans prior to the PET/CT. Data were collected from clinic letters, CT and PET CT reports and pathology results and cross-checked with the patient’s notes. Patients were aged between 43 and 85 years [33 males, 27 females]. CEA was raised in 37 patients and normal in 23. Results of PET/CT were compared with that of CT scan and 33 out of the 60 patients (55 %) had PET/CT results which were different to that of CT scan and 27 patients (45 %) had similar PET/CT and CT results. PET scan appropriately altered the management in 23/60 patients (38 %) and avoided unnecessary surgery in 14 patients. PET/CT had a sensitivity of 86 % and specificity of 84 %. In patients with an unexplained rise in CEA, PET/CT was positive in only one out of ten (10 %) patients. PET/CT is valuable in deciding the management outcome in patients with metastatic or recurrent colorectal cancer. Unnecessary surgery might be avoided by careful use of PET/CT scanning in colorectal cancer patients. PET/CT might not be of value in patients with an unexplained rise in CEA.

Unnecessary Surgery Can Be Avoided by Judicious Use of PET/CT Scanning in Colorectal Cancer Patients

Metastatic lesions to the mandible are rare, comprising less than 1% of all malignancies. A 75-year-old gentleman presented to ENT outpatient with a 3-week history of numbness over his lower lip on the right side followed by a rapidly growing swelling in his right mandibular region. The patient was diagnosed with an obstructing sigmoid tumour with metastasis to the liver and retroperitoneal adenopathy, 5 months ago. A colonic stent was inserted for the sigmoid tumour and patient was undergoing palliative chemotherapy. CT scan of the mandibular region showed mass lesion invading the ascending ramus of mandible and involving the right inferior alveolar nerve. Trucut biopsy confirmed metastatic adenocarcinoma.

/pdf/lower-lip-numbness-in-a-patient-with-colorectal-cancer-3exo6tv3cv.pdf

Anil Reddy

Papers

Fluoride dynamics in the granitic aquifer of the Wailapally watershed, Nalgonda District, India

Hydrogeochemical characterization of fluoride rich groundwater of Wailpalli watershed, Nalgonda District, Andhra Pradesh, India

Rectal metastasis from breast cancer: an interval of 17 years

Unnecessary Surgery Can Be Avoided by Judicious Use of PET/CT Scanning in Colorectal Cancer Patients

Lower lip numbness in a patient with colorectal cancer.