Introduction: Due to rapid urbanization, Malaysia is currently undergoing extensive amount of construction activities and significant rise in the construction waste. Improper construction wastes management practices have led to rise in the waste open dumping sites which may significantly affect the environment and public health. This study was undertaken to assess air pollution in such a site and the impact to the respiratory health of children studying in a nearby school. Methods: A comparative cross-sectional study was conducted in Sungai Buloh (exposed) and Kuala Selangor (comparative). Concentration of PM10 was monitored at the open dumping site (n=15), a nearby primary school (n=45) and a comparative primary school (n=12). Parents who gave consent (n=229) answered a questionnaire related to child’s respiratory health whereas their children participated in lung function assessment. Results: Concentration of PM10 at the dumping site, exposed school and comparative school was 0.245±0.048mg/ m3 , 0.270±0.020mg/m3 and 0.051±0.016mg/m3 respectively, with the first two significantly exceeded the 24-hour Malaysian Air Quality Standard (MAQS) for PM10 (0.150mg/m3 ). Besides, PM10 concentration in the exposed school was similar to the dumping site (p>0.05) and many folds higher than the comparative school (p
Mental health outcome among teachers has become an escalating problems in many countries. Mental health now- adays has becoming a public health issue. Teachers were not an exclusion from this issue. Several studies did point out teachers with poor mental health status has become an increasing problems in many countries. A total of 272 teachers from the urban, rural and industrial areas participated in this cross sectional study in the Klang Valley. The objective was to determine the risk factors associated with mental health among primary school teachers. The teachers’ mental and physical health status were measured using questionnaires. Respondents were given a set of questionnaire which consisted 5 parts, namely socio-demographic and background status, occupational information and medical history obtained from the first part of questionnaire. The other part consisted of the General Health Questionnaire, Teachers’ Stress Inventory, Modified Nordic Questionnaire and American Thoracic Society for Adult. There was no difference in the background of the groups of teachers except for the educational level (p
A cross-sectional study was conducted on 83 female electronics factory workers. The respondents comprised 50 exposed workers who use lead alloy solder and 33 unexposed workers. The objective of this study was to assess the lead exposure of these workers. Breathing zone were sampled using air sampling pumps. Dust samples were collected by wipe method. Venous blood collected and blood pressure were measured. All lead analyses were carried out with Graphite Furnace Atomic Absorption Spectrophotometer. The mean air lead for exposed workers (57 0. ± 0.93 μg/m³) was significantly higher than the unexposed workers (0.0067 ± 0.0045μg/m³) (p
A cross sectional study to determine the exposure of heat and its biological effects on the workers in a plastic factory located in the Shah Alam Industrial Estate, Selangor, Malaysia. Forty five respondents from the polymer section in the factory were selected as the respondents. Variables measured were the environmental temperature (WBGTin), air velocity, relative humidity, body temperature, average heart and recovery heart rate. QUESTEMP°34 Area Heat Stress Monitor was used to measure the environmental temperature in °C (WBGTin) and relative humidity (%). Velocicheck Model TSI 8830 was used to measure the air velocity in meter per second (m/s) while the OMRON Blood Pressure Monitor Model T3, was used to measure average heart rate and recovery heart rate. Body temperature (°C) was measured by the Instant Ear Thermometer-OMRON Gentle Temperature Model MC509. Interviews using questionnaires were used to determine respondents’ socioeconomic background, previous risk factors on heat exposure and other information related to heat stress. Results showed that the mean environmental temperature for the exposed group was 28.75°C, the mean air velocity was 0.15 m/s and the mean relative humidity was 58.1%. These production workers were exposed occasionally to heat when loading plastic powder into the molds as well as demolding the finished plastic products from the molds. The average time of monitoring was 2 hours for intermittent exposure and 8 hours duration for overall exposure. Maximum demand for work load was measured 1 minute after work activities were stopped at the demolding section. There was a significant difference between body temperature and average heart rate before work, after 2 hours of work and after 8 hours of work ( p < 0.001). The mean recovery heart rate after 1 min was 88.0 ± 12.0 beat per min. (bpm), indicating that there is no excessive physiological demand. Body temperature (36.8 ± 0.40°C) and average heart rate after 8 hours (78 ± 12 bpm) indicated a good body control of heat exposure. Five out of six workplaces monitored had temperatures of greater than 28°C (ACGIH TLV). The workers were exposed to moderate heat stress during the study period, however, body temperature and average heart rate measurement did not reach unacceptable level of physiologic strain.
Introduction This paper aims to investigate the potential pesticide dermal contamination
among the agricultural community by observing the microenvironmental and
macroactivity interaction between farm children and adult farmer.
Methods A 24 hours timeline activity was observed and recorded in the agricultural
farming village, Kuala Selangor. In this study, 2 homes were monitored for 2
days following a pesticide application. A total of 2 adult farmers and 5
children (7-10 year old) were recruited to participate in this study. Twentyfour
hour videotape segments and time-activity diaries were collected during
the study.
Results The microenvironment and macroactivity interaction were modelled in this
study. By considering only the potential dermal exposure pathway, the
different biological vulnerability and exposure pattern to pesticides were
observed. Finding showed a greater extent of interaction between human and
its environment, where adult farmers are the main contributor of
environmental contaminants, and children is one of the vulnerable receivers
of the contaminants’ residuals from the environment.
Conclusion The daily activities and behaviors practiced by the agricultural community
were among the contributing factors which help to highlight the pesticide
dermal contamination pathway in the farming village. This study
recommends the necessary to consider the microenvironment and
macroactivity of the target community when assess their exposure levels to
the environment contaminants.
Bauxite mining activities in Felda Bukit Goh, Kuantan, has been in operation since early 2013. The uncontrolled min- ing activities created dusty environment which led to health complaints from the surrounding residence. The mining activities had also caused anxiety and stress among the community due the noise which disturb their well-being and their sleep (1). The objectives of this study were to determine and relate selected heavy metal levels (As, Cd, Cr, Ni, Pb and Al) in the dust in the classrooms of a school located near to the mines with the respiratory health symptoms reported by the parents of the selected school children. A cross-sectional study was conducted on 121 students randomly selected from the Primary 4 and 5 clusters. Questionnaires were used to collect information on their back- ground and their respiratory health symptoms. Environmental sampling for 16 dust samples consisted two samples (window and corridors) from each of the eight classes (four from each Primary 4 and 5) were collected using 400W vacuum cleaner with special filter from these classrooms. The dust samples were analyzed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Results showed that the levels of heavy metal in the dust were high in both the Primary 5 and Primary 4 classes. The mean heavy metal levels in the dust from the classroom area varied signifi- cantly and decreased in the order of: Al > Cr > Ni > Pb > As > Cd. The mean ranges were as follows: Al (39360.15- 110824.1 mg/kg); Cr (2364.84- 4726.009 mg/kg); Ni (699.9606-1443.36 mg/kg); Pb (434.3067- 1650.76 mg/kg); As
(200.7891-454.7241 mg/kg); and Cd (10.9107-34.9902 mg/kg) respectively. The levels were higher at the corridor than the window. Nasal congestion (45.5%) was the highest respiratory symptoms experienced by the school chil- dren. There was a significant correlation between the respiratory health symptoms reported with absenteeism in the year 2015 when the mining activities were at the peak. There was a significant correlation between dust Pb levels with respiratory reported symptoms of the school children. Other risk factors which contributed to the respiratory symptoms reported were the close location of their houses to the mining areas, young age and low family income.
Introduction: Water based Metalworking fluids (MWF) are commonly used in machining industries and are excellent media for microorganism growth. The study aimed at determining the relationship between the airway inflammation as indicated by fractional exhaled nitric oxide (FeNO) with the microbial contaminants of MWF in aerosol and bulk sample as well as the workers’ reported respiratory health symptoms. Methods: This cross sectional study was carried out on 138 machining workers. Their FeNO were measured using NIOX-MINO instrumentation. The microbial as- sessments of bacteria and fungus were carried out on the MWF bulk samples and the aerosol using a sampler DUO SAS SUPER 360TM. Results: Findings showed significant difference in the FeNO levels in workers from various job sections (p=0.01). Significant relationships found between high FeNO levels with their closeness to the machines (p=0.03), high number of machines in the workplaces (p=0.02), high environmental bacteria colonies (p=0.04), lon- ger employment years (p
Introduction: Bauxite ore contain various heavy metals especially aluminum, if exposed excessively is detrimental to the respiratory system. Objective: This study aimed at determining the PM10 and its Al, As, Cd, Cr, Ni and Pb con- tent and assessing the inhalation health risk assessment (HRA) among the community. Method: This cross-sectional study was conducted in Kuantan on 162 randomly selected respondents in three residential areas; Felda Bukit Goh (FBG), Jalan Besar Bukit Goh (JBBG) and Kuantan Port Consortium Flat (KPCF). Questionnaires were used to obtain the background information and health symptoms. PM10 with its heavy metals were subsampled for 24 hours using air
sampling pumps in 42 randomly sub-sampled households from the 3 areas. Results: PM10 exceeded 150 µg/m and
3
the Al, Cd, As, Cr, Ni and Pb levels exceeded the standard limit. The hazard quotient (HQ) of Cd in JBBG (4.13), Cr in FBG (74.06), JBBG (84.41), KPCF (76.87) and Ni in FBG (60.53), JBBG (66.95) and KPCF (58.81) exceeded the HQ
value of 1. The lifetime cancer risk (LCR) exceeded the level of 0.0000001 for Cr in FBG (0.0252), JBBG (0.0288) and KPCF (0.0262), as well as for Ni in the FBG (0.000184), JBBG (0.000204), and KPCF (0.000179) areas. Conclusion: The PM10 levels exceeded the USEPA guidelines while Al, Cd, As, Cr, Ni and Pb exceeded the ATSDR limit. The Cd, Cr and Ni posed non-carcinogenic and carcinogenic health risks. Therefore, health risks from the PM10, Cd, Cr and Ni exposures were found in this study.
Cr0ss»sectional studies on lung functions of 100 smokers and 100 non-smokers was conducted among a university student population. The objectives of the studies were to determine the correlation between the lung functions with smoking frequency and duration among smokers as well as to compare the lung functions with non-smokers. The smokers’ mean age was 20.74 years, their smoking initiation age was 16.18 years, the smoking duration was 4.41 years and the smoking frequency was 8.72 cigarettes per day. Among smokers, signqicant inverse correlation was shown between FEV] predicted and the smoking frequency (number of cigarette per day) (ri-0.241, p=0.016). Multiple regression confirmed the relationship between FEV]% predicted with respondent’s age (p=0.013) and smoking frequency (p=0.002), FVC% predicted with age (p=0.005) and smoking frequency (p=0.009). The FEV;/FVC% predicted was signyicantly related to phlegm symptoms (p=0.03), while the FEFZ5.y5% predicted was signdicantly related to age (p=0.005), height (p=0.043) and smoking duration (p=0.046). The lung functions (FEV1% predicted, FVC% predicted and FEV]/FVC% predicted ) for smokers were not statistically dyferent from non-smokers. This study showed that the lung functions for the smokers were still quite normal due to their short smoking duration, their low number of cigarette smoked per day and their young age.
Water-based metalworking fluid (MWF) provides a suitable environment for microbes to grow. This study aimed at identifying the level and species of microbial contamination of MWF in a metal machining factory and to determine the corresponding Immunoglobulin G (IgG) levels in the workers’ blood samples. Methods: Total of 298 workers in the production section of a metal machining factory, the production section using MWF as coolant fluid, were involved in this study. The Analytical Profile Index system was used to identify the species of microbes isolated from MWF bulk and air samples. Tryptone soya agar was used to incubate unknown bacteria, and sabouraud dextrose agar was used for unknown fungi. The level of IgG antibodies in workers’ blood were measured as an indicator of the exposure to the microbes isolated from MWF, corresponded to the microbial species isolated from MWF. Results: The most dominant microbes isolated from the channels were Candida albicans, Klebsiella pneumoniae, E. coli and Pseudomonas aeruginosa. A total of 21 (34.4%) workers were positively exposed to E. coli, 30 (42.2%) to Pseudomonas aeruginosa, and 45(75%) exposed to Candida albicans. Also, the mean level of optic density of IgG to Klebsiella pneumoniae was 0.415 (0.02). Conclusion: Water-based metalworking fluid in this metal machining factory was contaminated with bacteria and fungi. The workers in the production section were exposed to MWF as well as the microbes present in MWF. The level of IgG in blood was the biomarkers for occupational exposure to microbial contaminant MWF.
This study compares the mean blood lead concentration and its association with the mean neurobehavioral scores between 2 groups of workers. The exposed group was made up of 50 male workers from 2 battery manufacturÂing factories and the comparative group was made up of 40 male adminisÂtrative workers from a local university. The neurobehavioral test was carried out by using a modified World Health Organization Neurobehavioral Core Test Battery (NCTS). The NCTS consists of 7 tests, which are made up of the Benton Visual Retention Test, Digit Symbol, Digit Span, Pursuit Aiming Test, Reaction Time, Santa Ana Manual Dexterity Test and Trail Making Test. Blood samples were collected by venous puncture method. Blood lead concentrations were determined by the Graphite Furnace Atomic Absorption Spectrophotometer (GFAAS). The mean blood lead concentration of the exposed group (38.5 μg/dL) is higher than the comparative group (5.6 μg/dL). Results show significant difference in the mean blood lead concentration between the 2 groups (p<0.001). There are also significant differences in the mean scores of each NCTS test such as Benton Visual Retention Test (p = 0.001), Digit Span Test (p< 0.001), Digit Symbol Test(p< 0.001), Pursuit Aiming Test (p< 0.001), Reaction Time Test (p< 0.001), Santa Ana Manual Dexterity Test (p< 0.001), Trail Making Test (p<0.001) (p< 0.001) and the overall NCTS test (p<0.001) between the 2 groups. There are significant inverse correlation between blood lead concentrations with each and overall NCTS scores when the two groups are combined. There are significant inverse correlations between blood lead concentrations with educational years and income for all respondents. Statistical tests show that blood lead, age, years of formal education, total income, years of work, and ethnicity contributes to the overall NCTS scores. The GLM model shows that 56.9% of the mean NCTS scores are influenced by the variability in the contributing factors mentioned before.
Introduction: Pesticides may influence the physicochemical properties of soil and the water quality parameters, which is vital in maintaining soil fertility and producing high quality crops. Objective: This study aims to determine the relationship between the concentration of pesticides, the physicochemical properties of the paddy soil samples and the water quality parameters of paddy water samples. Methods: A total of 72 soil and 72 water samples were collected in Tanjung Karang, Malaysia. The paddy soil and water were extracted using Quick, Easy, Cheap, Efficient, Rugged and Safe (QuEChERS) and solid phase extraction (SPE) techniques respectively. The concentrations of pesti- cides were analysed in ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The relationship of the concentration of target pesticides and the paddy soil and water physicochemical properties were studied using Spearman correlation. Results: In paddy soil, the concentration of propiconazole shows moderate positive correlation with manganese (Mn) (r = 0.587) (p 0.01). Meanwhile buprofezin-total organic carbon (TOC) (r = -0.55) (p 0.01), imidacloprid-cation exchange capacity (CEC) (r = -0.519) (p 0.01), pymetrozine-sodium (Na) (r = -0.588) (p 0.01), and trifloxystrobin-calcium (Ca) (r = 0.566) (p 0.01) showed moderate negative correlation. Whereas in water, trifloxystrobin showed significant positive correlation with turbidity (r = 0.718) (p 0.01) and te- buconazole showed negative correlation to dissolved oxygen (DO) (r = 0.634) (p 0.01). Conclusion: The presence of pesticides in paddy field may influence the soil and water quality, thus regular monitoring of pesticides usage and nutrient management in soil is deemed important.
Heat stress is a serious problem among agricultural workers. Workers who are exposed to the extreme heat or work in hot environments may be at risk of heat stress. The physiological changes and heat related symptoms could occur due to heat stress. The objective of this cross-sectional study was to determine the impact of heat on the health and productivity of cassava farm workers in Kratie province of Cambodia. The sampling method was a convenient sampling with some inclu- sive criteria. A total of 125 cassava farm workers were selected to participate in this study. The information was collected through a face to face interview using a questionnaire form. Questions were asked on heat exposure during work and heat related symptoms. The environmental heat was measured using heat stress monitor WBGT and data logger for 2 hours for each day. Automatic blood pressure monitor was used to measure blood pressure and heart rate, while ear thermometer measured the body temperature. All measurements of physiological changes were conducted during the rest and work time of the workers. Observations were conducted to determine the production hourly output of workers by using productivity forms. The productivity was determined by calculating the total of cassava roots harvested per hour, which started from
9.00 a.m. to 11.00 a.m. The results indicated that the highest average of heat stress index were 32.11°C and 32.36°C re- spectively whereby the daily exposure to heat during work, exceeded the threshold limit value (TLV) of 27.5°C for heavy metabolic workload level with 75% work, 25% rest regimen. Meanwhile, the highest prevalence of heat related symptoms reported among workers were tiredness/weakness (84.4%), followed by heavy sweating (82.4%) and headache (61.6%). The blood pressure, heart rate and core body temperature were below the standard, indicated that the workers were fully acclimatized. There was no significant difference in the physiological changes between male and female during the resting and working period. Heavy sweating, heat, BMI and working time were the factors that were significantly related with productivity. In conclusion, the cassava farm workers in Kratie, Cambodia were exposed to high level of heat stress, which reduced their work productivity.
To achieve rapid economic development, many countries including Malaysia resort various activities to exploit nat- ural sources such as mining. As a consequence, mining are an important economic activity which has the potential to contribute to the development of areas endowed with the ore. Studies have been carried out in countries where the impact were on the environment and health. However, fewer studies have been carried out on the effects of min- ing on health especially the children. This paper provides a review of the process description, properties of bauxite, bauxite production and the potential health effects of heavy metals from mining ores on children’s health. The aims of this article are to evaluate the most frequently reported effect towards health and heavy metals levels in biomark- ers such as blood, urine, hair and toenail among children mining areas. Respiratory problems were most commonly reported effects associated with mining activities. Heavy metals such as lead, aluminum, chromium, nickel are also elevated from normal levels due to mining activities. Specific mitigated measures need to be taken in order to solve the problems and protect the public health especially children as they are vulnerable and represent the non-occupa- tionally exposed population.
The generation of municipal solid waste (MSW) in South East Asian and developing countries has become a serious concern worldwide. Population growth, urbanization, economic productivity and demand for consumption had accelerated the amount of waste generation each year. This paper presents a short definition of MSW landfill, an overview of current status of MSW landfills in Malaysia and generation of solid waste in Malaysia and other neigh- bouring countries.
A study on 30 asthmatic children was conducted in Kuala Lumpur. The objective of this study was to study the relationship between respirable particulate (PM10), sulphur dioxide, ozone and various meteorological factors such as humidity, level ofrainfall and temperature with asthma attacks. This study was conducted from 1st September to 31 December 1994. Patients were selected from the Paediatric Unit, Kuala Lumpur Hospital. Questionnaires were used to obtain information from their parents on the history and severity ofasthmatic attacks ofthese patients. Questionnaires were also used to determine if the indoor sources contributed to the attack. Diary cards were used to collect information on the frequency of asthmatic attacks. Each patient's progress was followed through every week during the study period and the attacks were recorded. The data on air quality on the PM10, sulphur dioxide, nitrogen dioxide, carbon monoxide and ozone were collected hourly using the microcomputer system of air monitoring unit from the Universiti Pertanian Malaysia air quality monitoring station located at the City Hall, Kuala Lumpur. The meteorological parameters such as temperature, relative humidity and rain-fall levels were also monitored daily. The asthmatic attack percentage was obtained by dividing the number of attacks in a day with the total number of sample and multiplying by a hundred. Statistical tests indicated that there was a significant correlation between asthmatic attacks and the PM10 concentrations (r=0.73), nitrogen dioxide (r=0.57) and.carbon monoxide (r=0.53) throughout the study period. During the haze episode, more significant correlations between asthmatic attacks, PM10 concentra-tions (0.86), carbon monoxide (0.79) and nitrogen oxide (0.53) were found. Multiple regression statistical test showed that PM10 had the greatest influence on the asthmatic attack rate. The minute respirable particulate which entered the respiratory system of the asthmatics triggered attacks on these patients.
Background: Prolonged exposure of heavy metals in the respirable particulate matter (PM10) from municipal solid waste (MSW) landfills may affect children health. Objective: To investigate the association of reported respiratory symptom with heavy metals in PM10, with heavy metals in fingernails among children residing close to MSW landfills. Methods: Two groups of children age 7 to 12 years old were involved in this cross-sectional study. Those residing within 3 km radius from a landfill were the exposed group and those residing more than 3 km radius as the unexposed group. Questionnaires adapted from American Thoracic Society were applied in the survey. Fingernails were used as biomarker. Ten heavy metals elements in PM and fingernail samples were analysed using inductively coupled plasma mass spectrometry (ICP-MS). Results: The cadmium, chromium, copper, manganese, nickel and lead concentrations in PM around the MSW landfills and residential areas exceeded the Canada and USEPA standard permissible limit. Heavy metals in fingernails (p
Pesticides application is essential in protecting crops and increases their productivity. However, this causes the pesticide residues to contaminate the crops and their surrounding environment that will eventually lead to exposure to human being. There is very little understanding on the human health effects of pesticides, thus many studies are being carried out for this purpose. In conjunction to this, there are various analytical methods on multi-residue pesticides analysis that have been developed over the years in various samples. This review provides an overview of the reported concentration of pesticides, the extraction and determination techniques of pesticides in environmental samples and the potential health effects they imposed on human in Malaysia from 2007 to 2017.
Introduction: Tanjung Karang is a paddy growing town in Selangor, Malaysia. The paddy farmers in Tanjung Karang were using pesticides to control pests from invading the crops during agricultural activities with limited knowledge of its deleterious effects on their health. Objective: This study aims to (i) determine the respiratory health symptoms of paddy farmers due to occupational exposure of commonly used pesticides through inhalation and (ii) assess correlations between climatological conditions and the concentrations of pesticides in personal air samples among paddy farmers in Tanjung Karang, Malaysia. Methods: A cross-sectional study was carried out to assess the occupational exposures to pesticides among 83 paddy farmers in Kampung Sawah Sempadan. The data were collected with face-to-face interviews with the farmers based on a set of questionnaire. Results: The self-reported respiratory health symptoms of paddy farmers were as follows: breathing difficulty (16.9%), chest pain (15.7%), cough (41.0%), phlegm (39.8%), and wheezing (18.1%). Simple logistic regressions analysis indicated that exposure to azoxystrobin, buprofezin, chlorantraniliprole, fipronil, isoprothiolane, pretilachlor, propiconazole, tricyclazole and trifloxystrobin were contributing factors that affect self-reported respiratory health symptoms in this study. Spearman’s correlation coefficient test stated that the concentrations of chlorantraniliprole, fipronil and pymetrozine were affected by wind speed and temperature. Conclusion: The information obtained in this study is useful to understand the exposure of pesticides among paddy farmers and useful for risk management in the agricultural community.
This is a study of the incidence of dental fluorosis and the urine fluoride concentration among school children. About 84 Malay students with the age range of 16 to 17 years from a National Secondary School in the district of Kuala Lipis, Pahang was selected as respondents. The selection was based on the exposure to fluoride in drinking water supply systems. Fifty two respondents were selected from the fluoridated water supply area while 32 others were selected from the non-fluoridated area (comparative group). The objectives of this study were to determine the relationship between urine fluoride concentrations with the incidence of dental fluorosis and to compare the difference in these two variables between the 2 groups of respondents. The urine fluoride concentration was determined using a fluoride-ion specific electrode. Dental fluorosis was examined through a physical examination using the Tooth Surface Index of Fluorosis (TSIF). There was no significant difference in the mean urine fluoride concentration (mg/L) (t=0.186, p=0.853), mean urine fluoride concentration (mg/g creatinine) (t=0.069, p=0.945) and dental fluorisis (TSIF mean score) (t=0.288, p=0.774) between the two groups. There was a significant direct correlation between the urine fluoride concentrations (mg/L) (r= 0.425, p<0.00l) and the urine fluoride concentraÂtions (mg/g creatinine) (r=0.252, p=0.021) with dental fluorisis (TSIF mean score). Multiple regression statistics, indicated that dental fluorosis was significantly related to urine fluoride concentrations (b=0.0.61, p=0.028) and the number of glass of their favourite drink consumed daily (b=0.071, p=0.003). In conclusion, the urine fluoride concentrations, which represent the degree of exposure to fluoride, were found to be related to dental fluorosis, which is the biological indicator for excessive exposure to fluoride. There is no difference on the degree and the effects of exposure to fluoride between the two groups of respondents although they consumed water from two different water supply systems. Thus, the exposure to fluoride is not only through the drinking water supply, but also by other sources such as the intake of carbonated drinks and fruit juice.