Tag Archives: Mexico

Mexico City food and beverages contain fluoride

Cantoral A, Luna-Villa LC, Mantilla-Rodriguez AA, Mercado A, Lippert F, Liu Y, Peterson KE, Hu H, Téllez-Rojo MM, Martinez-Mier EA. Fluoride Content in Foods and Beverages From Mexico City Markets and Supermarkets. Food and nutrition bulletin. 2019 Jul 25. doi: 10.1177/0379572119858486.

BACKGROUND: Sources of fluoride exposure for Mexicans include foods, beverages, fluoridated salt, and naturally fluoridated water. There are no available data describing fluoride content of foods and beverages consumed in Mexico.

OBJECTIVE: To measure the content of fluoride in foods and beverages typically consumed and to compare their content to that of those from the United States and the United Kingdom.

METHODS: Foods and beverages reported as part of the Mexican Health and Nutrition Survey (n = 182) were purchased in the largest supermarket chains and local markets in Mexico City. Samples were analyzed for fluoride, at least in duplicate, using a modification of the hexamethyldisiloxane microdiffusion method. Value contents were compared to those from the US Department of Agriculture and UK fluoride content tables.

RESULTS: The food groups with the lowest and highest fluoride content were eggs (2.32 µg/100 g) and seafood (371 µg/100 g), respectively. When estimating the amount of fluoride per portion size, the lowest content corresponded to eggs and the highest to fast foods. Meats and sausages, cereals, fast food, sweets and cakes, fruits, dairy products, legumes, and seafood from Mexico presented higher fluoride contents than similar foods from the United States or the United Kingdom. Drinks and eggs from the United States exhibited the highest contents, while this was the case for pasta, soups, and vegetables from the United Kingdom.

CONCLUSION: The majority of items analyzed contained higher fluoride contents than their US and UK counterparts. Data generated provide the first and largest table on fluoride content, which will be useful for future comparisons and estimations.

Bacterial contamination of drinking water, Guadalajara, Mexico

Rubino F, Corona Y, Pérez JGJ, Smith C. Bacterial Contamination of Drinking Water in Guadalajara, Mexico. International journal of environmental research and public health.  2018 Dec 27;16(1). pii: E67. doi: 10.3390/ijerph16010067.

In many regions where drinking water supply is intermittent and unreliable, households adapt by storing water in cisterns or rooftop tanks. Both intermittent supply and stored water can be vulnerable to contamination by microorganisms with deleterious health effects. The Metropolitan Zone of Guadalajara is a rapidly growing urban center with over five million residents where household storage is nearly ubiquitous. This pilot study was conducted in July 2018 to examine the microbiological quality of drinking water in Guadalajara. Samples were tested for free available chlorine residual, total coliform bacteria, and Escherichia coli. A survey on access to water and public perspectives was also conducted. Water exiting rooftop tanks exceeded regulatory limits for total coliform levels in half of the homes studied. Piped water arriving at two homes had total coliform levels that far exceeded regulatory limits. No E. coli were detected in any of the samples. Only 35% of homes had a chlorine residual between the recommended 0.2 and 1.5 mg/L. Many homes reported unpleasant odors and colors. Only 7% of residents drank the piped water. Future studies are needed, especially during April and May when many homes reported a higher disruption to water service.

Drinking Water Quality in Rural Oaxaca, Mexico

Rowles LS 3rd, Alcalde R, Bogolasky F, Kum S, Diaz-Arriaga FA, Ayres C, Mikelonis AM, Toledo-Flores LJ, Alonso-Gutiérrez MG, Pérez-Flores ME, Lawler DF, Ward PM, Lopez-Cruz JY, Saleh NB. Perceived versus actual water quality: Community studies in rural Oaxaca, Mexico. Sci Total Environ. 2017 Dec 6;622-623:626-634. doi: 10.1016/j.scitotenv.2017.11.309.

Compromised water quality risks public health, which becomes particularly acute in economically marginalized communities. Although the majority of the clean-water-deprived population resides in Sub-Saharan Africa and Asia, a significant portion (32 million) lives in Meso- and Latin-America. Oaxaca is one of the marginalized southern states of Mexico, which has experienced high morbidity from infectious diseases and also has suffered from a high rate of infant mortality. However, there has been a paucity of reports on the status of water quality of culturally diverse rural Oaxaca. This study follows community-based participatory research methods to address the data gap by reporting on water quality (chemical and microbiological) and by exploring social realities and water use practices within and among communities. Surveys and water quality analyses were conducted on 73 households in three rural communities, which were selected based on the choice of water sources (i.e., river water, groundwater, and spring water). Statistically significant variations among communities were observed including the sanitation infrastructure (p-value 0.001), public perception on water quality (p-value 0.007), and actual microbiological quality of water (p-value 0.001). Results indicate a high prevalence of diarrheal diseases, a desire to improve water quality and reduce the cost of water, and a need for education on water quality and health in all the surveyed communities. The complexities among the three studied communities highlight the need for undertaking appropriate policies and water treatment solutions.

Prenatal Fluoride Exposure Associated with Lower Cognitive Function, Mexico

Bashash M, Thomas D, Hu H, Angeles Martinez-Mier E, Sanchez BN, Basu N, Peterson KE, Ettinger AS, Wright R, Zhang Z, Liu Y, Schnaas L, Mercado-García A, María Téllez-Rojo M, Hernández-Avila M. Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6-12 Years of Age in Mexico. Environmental health perspectives. 2017 Sep 19;125(9):097017. doi: 10.1289/EHP655.

BACKGROUND: Some evidence suggests that fluoride may be neurotoxic to children. Few of the epidemiologic studies have been longitudinal, had individual measures of fluoride exposure, addressed the impact of prenatal exposures or involved more than 100 participants.

OBJECTIVE: Our aim was to estimate the association of prenatal exposure to fluoride with offspring neurocognitive development.

METHODS: We studied participants from the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) project. An ion-selective electrode technique was used to measure fluoride in archived urine samples taken from mothers during pregnancy and from their children when 6-12 y old, adjusted for urinary creatinine and specific gravity, respectively. Child intelligence was measured by the General Cognitive Index (GCI) of the McCarthy Scales of Children’s Abilities at age 4 and full scale intelligence quotient (IQ) from the Wechsler Abbreviated Scale of Intelligence (WASI) at age 6-12.

RESULTS: We had complete data on 299 mother-child pairs, of whom 287 and 211 had data for the GCI and IQ analyses, respectively. Mean (SD) values for urinary fluoride in all of the mothers (n=299) and children with available urine samples (n=211) were 0.90 (0.35) mg/L and 0.82 (0.38) mg/L, respectively. In multivariate models we found that an increase in maternal urine fluoride of 0.5mg/L (approximately the IQR) predicted 3.15 (95% CI: -5.42, -0.87) and 2.50 (95% CI -4.12, -0.59) lower offspring GCI and IQ scores, respectively.

CONCLUSIONS: In this study, higher prenatal fluoride exposure, in the general range of exposures reported for other general population samples of pregnant women and nonpregnant adults, was associated with lower scores on tests of cognitive function in the offspring at age 4 and 6-12 y. https://doi.org/10.1289/EHP655.

Antimony Leaching from Drinking Water Bottling Material

C.A. Chapa-Martínez, L. Hinojosa-Reyes, A. Hernández-Ramírez, E. Ruiz-Ruiz, L. Maya-Treviño, J.L. Guzmán-Mar. An evaluation of the migration of antimony from polyethylene terephthalate (PET) plastic used for bottled drinking water. Science of The Total Environment, Volume 565, 15 September 2016, Pages 511-518.

The leaching of antimony (Sb) from polyethylene terephthalate (PET) bottling material was assessed in twelve brands of bottled water purchased in Mexican supermarkets by atomic fluorescence spectrometry with a hydride generation system (HG-AFS). Dowex® 1X8-100 ion-exchange resin was used to preconcentrate trace amounts of Sb in water samples. Migration experiments from the PET bottle material were performed in water according to the following storage conditions: 1) temperature (25 and 75 °C), 2) pH (3 and 7) and 3) exposure time (5 and 15 days), using ultrapure water as a simulant for liquid foods. The test conditions were studied by a 23 factorial experimental design. The Sb concentration measured in the PET packaging materials varied between 73.0 and 111.3 mg/kg. The Sb concentration (0.28–2.30 μg/L) in all of the PET bottled drinking water samples examined at the initial stage of the study was below the maximum contaminant level of 5 μg/L prescribed by European Union (EU) regulations. The parameters studied (pH, temperature, and storage time) significantly affected the release of Sb, with temperature having the highest positive significant effect within the studied experimental domain. The highest Sb concentration leached from PET containers was in water samples at pH 7 stored at 75 °C for a period of 5 days. The extent of Sb leaching from the PET ingredients for different brands of drinking water can differ by as much as one order of magnitude in experiments conducted under the worst-case conditions. The chronic daily intake (CDI) caused by the release of Sb in one brand exceeded the Environmental Protection Agency (USEPA) regulated CDI value of 400 ng/kg/day, with values of 514.3 and 566.2 ng/kg/day for adults and children. Thus, the appropriate selection of the polymer used for the production of PET bottles seems to ensure low Sb levels in water samples.

How do Climate Models Account for Volcano Eruptions?

“Popocatépetl volcano came to life on Sunday morning, sending a column of gas and ash 2,000 metres (6,500ft) into the sky in central Mexico. A 12km (7.5-mile) security ring around the volcano has been mandated, preventing passage close to the crater. Popocatépetl’s last major eruption was in 2000, when more than 40,000 people had to be evacuated.” click here

Association of Urine Fluoride with Dental Fluorosis; Mexico

Jarquín-Yañez L, de Jesús Mejía-Saavedra J, Molina-Frechero N, Gaona E, Rocha-Amador DO, López-Guzmán OD, Bologna-Molina R. Association between urine fluoride and dental fluorosis as a toxicity factor in a rural community in the state of San Luis Potosi. TheScientificWorldJournal. 2015;2015:647184. doi: 10.1155/2015/647184.

OBJECTIVE: The aim of this study is to investigate urine fluoride concentration as a toxicity factor in a rural community in the state of San Luis Potosi, Mexico.

MATERIALS AND METHODS: A sample of 111 children exposed to high concentrations of fluoride in drinking water (4.13 mg/L) was evaluated. Fluoride exposure was determined by measuring urine fluoride concentration using the potentiometric method with an ion selective electrode. The diagnosis of dental fluorosis was performed by clinical examination, and the severity of damage was determined using Dean’s index and the Thylstrup-Fejerskov (TF) index.

RESULTS: The range of exposure in the study population, evaluated through the fluoride content in urine, was 1.1 to 5.9 mg/L, with a mean of 3.14±1.09 mg/L. Dental fluorosis was present in all subjects, of which 95% had severe cases. Higher urine fluoride levels and greater degrees of severity occurred in older children.

CONCLUSIONS: The results show that dental fluorosis was determined by the presence of fluoride exposure finding a high positive correlation between the severity of fluorosis and urine fluoride concentration and the years of exposure suggested a cumulative effect.