Monthly Archives: February 2013

Most Earth species are still unknown… much for declining biodiversity

As reported here, most of the species on the earth have still not been identified and/or are unknown. If this is indeed the case, then how can anyone make claims of declining biodiversity?

Noise pollution, illness attributed to wind turbines in Massachusetts

“Two wind turbines towering above the Cape Cod community of Falmouth, Mass., were intended to produce green energy and savings — but they’ve created angst and division, and may now be removed at a high cost as neighbors complain of noise and illness.”

Click here for the full news article.

Fluoridation of drinking water “spin” continues….

Typically, review articles in the dental journals continue to list addition of fluoride chemicals to drinking water among other measures using fluoride products in caries prevention. This implies that addition of fluoride to drinking water will have the same effect as other practices as fluoride varnish or fluoride treatment. This is simply false. Addition of fluoride to drinking water is not necessary….

Ten Cate JM. Contemporary perspective on the use of fluoride products in caries prevention. Br Dent J. 2013 Feb 22;214(4):161-7. doi: 10.1038/sj.bdj.2013.162.

Dental caries has declined in the 40 years since fluoridated toothpastes were introduced. Much has been learned about why fluoride is so effective and how this knowledge can be used to optimise programmes for caries prevention. Fluoride works through enhancing the remineralisation of early stages of caries and by inhibiting demineralisation, which would lead to dental caries. Remineralisation involves the deposition of calcium phosphates from saliva to rebuild partly dissolved enamel crystallites. When fluoride is incorporated the dissolution of these reinforced crystallites will be reduced during a subsequent sugar-induced and bacteria-mediated acid attack. Fluoride works primarily when it is present in the oral cavity. Based on our understanding of the fluoride mode of action the following advice can be given from clinicians to their patients: The fluoride concentration in oral products is related to efficacy but the concentration does not necessarily need to be high to be efficacious. Fluoride availability throughout the day is important; this can be achieved when fluoride products are used as part of the daily hygiene routine (F-brushing or rinsing). Alternatively, when fluoride is provided in the drinking water or through professionally applied F-varnishes or gels, the patient will benefit without requiring daily compliance to its use. The latter methods are particularly effective as additional treatments in high caries individuals.

No evidence drinking water nitrate associated with bladder cancer

Weiwei Wang 王玮玮, Yunzhou Fan 范允舟, Guanglian Xiong 熊光练, Jing Wu 吴 静. Nitrate in drinking water and bladder cancer: A meta-analysis. Journal of Huazhong University of Science and Technology [Medical Sciences] December 2012, Volume 32, Issue 6, pp 912-918.

This study examined whether exposure to nitrate in drinking water is associated with increased risk for bladder cancer by conducting a comprehensive literature research. A meta-analysis was performed with and without adjustment for confounding factors. Three groups (reference, intermediate and high groups) were established in terms of different nitrate concentrations in each included study. Separate relative risk measures were calculated for intermediate and high groups. Heterogeneity was assessed by using the Q statistics. Publication bias was evaluated by Egger’s and Begg’s test. Quality assessment for studies was performed by using the Newcastle-Ottawa scale. Two cohorts, two case-controls, and one ecological study were included in this study. The adjusted data showed that the combined risk ratios (RRs) were 1.13 (95% CI: 0.81 to 1.57) and 1.27 (95% CI: 0.75 to 2.15) for intermediate and high groups respectively. For unadjusted data, the corresponding RRs were 1.18 (95% CI: 0.89 to 1.57) and 1.29 (95% CI: 0.81 to 2.07). Sensitivity test indicated that results were significantly underestimated when Ward’s study was included. No significant publication bias was found. There was heterogeneity among studies. The results suggested that there was no sufficient evidence that nitrate in drinking water is associated with increased risks for bladder cancer.

UK tea contains significant fluoride levels…

Laura Chana, Aradhana Mehraa, Sohel Saikatb, Paul Lyncha. Human exposure assessment of fluoride from tea (Camellia sinensis L.): A UK based issue? Food Research International. Volume 51, Issue 2, May 2013, Pages 564–570

Fluoride concentrations in UK tea, including the leading supermarket economy labelled products, were determined. Fluoride ranged from 93 to 820 mg/kg in the products and 0.43 to 8.85 mg/L in the infusions. The UK supermarket economy teas contained elevated fluoride, ranging from 3.60 to 7.96 mg/L in a 2 minute brewing infusion, comparable to Chinese brick tea, indicating the use of mature leaves in their manufacture. Considering the dietary reference intake (DRI) of 4 mg/day of fluoride for an adult consuming 1 L of tea, prepared from an economy tea, containing 6.0 mg/L fluoride, 75–120% of the DRI fluoride is available for absorption by the human system in the presence of food, increasing to 150% when fasting. Excess fluoride in the diet can lead to detrimental health effects such as fluorosis of the teeth and skeletal fluorosis and consuming economy branded tea will lead to exposure.

Click here for full paper (fee).

Dust, paint, drinking water lead exposure to Montreal children

Patrick Levallois, Julie St-Laurent, Denis Gauvin, Marilène Courteau, Michèle Prévost, Céline Campagna, France Lemieux, Shokoufeh Nour, Monique D’Amour and Pat E Rasmussen. The impact of drinking water, indoor dust and paint on blood lead levels of children aged 1–5 years in Montréal (Québec, Canada). Journal of Exposure Science and Environmental Epidemiology. doi: 10.1038/jes.2012.129

Lead is neurotoxic at very low dose and there is a need to better characterize the impact of domestic sources of lead on the biological exposure of young children. A cross-sectional survey evaluated the contribution of drinking water, house dust and paint to blood lead levels (BLLs) of young children living in old boroughs of Montréal (Canada). Three hundred and six children aged 1 to 5 years and currently drinking tap water participated in the study. For each participant, residential lead was measured in kitchen tap water, floor dust, windowsill dust and house paint and a venous blood sample was analyzed. Multivariate logistic regression was used to evaluate the association between elevated BLL in the children (≥ 75th percentile) and indoor lead contamination by means of odds ratios (OR) using 95% confidence intervals (CI). There was an association between BLL ≥75th percentile (1.78 μg/dL) and water lead when the mean water concentration was >3.3 μg/L: adjusted OR=4.7 (95% CI: 2.1–10.2). Windowsill dust loading >14.1 μg/ft2 was also associated with BLL ≥1.78 μg/dL: adjusted OR=3.2 (95% CI: 1.3–7.8). Despite relatively low BLLs, tap water and house dust lead contribute to an increase of BLLs in exposed young children.

Click here for full paper (Open Source).

Drinking water arsenic and liver cancer in Taiwan….a threshold effect.

This study suggests a threshold effect for drinking water arsenic in villages along the southwest coast area of Taiwan.

Hung-Jung Lina, Tzu-I Sunge, Chi-Yi Cheng, How-Ran Guoe. Arsenic levels in drinking water and mortality of liver cancer in Taiwan. Journal of Hazardous Materials. (2013)

The carcinogenic effect of arsenic is well documented, but epidemiologic data on liver cancer were limited. To evaluate the dose–response relationship between arsenic in drinking water and mortality of liver cancer, we conducted a study in 138 villages in the southwest coast area of Taiwan. We assessed arsenic levels in drinking water using data from a survey conducted by the government and reviewed death certificates from 1971 to 1990 to identify liver cancer cases. Using village as the unit, we conducted multivariate regression analyses and then performed post hoc analyses to validate the findings. During the 20-year period, 802 male and 301 female mortality cases of liver cancer were identified. After adjusting for age, arsenic levels above 0.64 mg/L were associated with an increase in the liver cancer mortality in both genders, but no significant effect was observed for lower exposure categories. Post hoc analyses and a review of literature supported these findings. We concluded that exposures to high arsenic levels in drinking water are associated with the occurrence of liver cancer, but such an effect is not prominent at exposure levels lower than 0.64 mg/L.

Click here for full paper (fee).