Tag Archives: toxicity

Toxicity evaluation of organic extracts from drinking water, Guangdong Province

Guan Y, Wang X, Wong M, Sun G, An T, Guo J, Zhang G. Evaluation of Genotoxic and Mutagenic Activity of Organic Extracts from Drinking Water Sources. PloS one. 2017 Jan 26;12(1):e0170454. doi: 10.1371/journal.pone.0170454.

An increasing number of industrial, agricultural and commercial chemicals in the aquatic environment lead to various deleterious effects on organisms, which is becoming a serious global health concern. In this study, the Ames test and SOS/umu test were conducted to investigate the potential genotoxicity and mutagenicity caused by organic extracts from drinking water sources. Organic content of source water was extracted with XAD-2 resin column and organic solvents. Four doses of the extract equivalent to 0.25, 0.5, 1 and 2L of source water were tested for toxicity. All the water samples were collected from six different locations in Guangdong province. The results of the Ames test and SOS/umu test showed that all the organic extracts from the water samples could induce different levels of DNA damage and mutagenic potentials at the dose of 2 L in the absence of S9 mix, which demonstrated the existence of genotoxicity and mutagenicity. Additionally, we found that Salmonella typhimurium strain TA98 was more sensitive for the mutagen. Correlation analysis between genotoxicity, Organochlorine Pesticides (OCPs) and Polycyclic Aromatic Hydrocarbons (PAHs) showed that most individual OCPs were frame shift toxicants in drinking water sources, and there was no correlation with total OCPs and PAHs.

Monitoring of Genotoxins in Drinking Water

Ames testing and use of other toxicity tests on drinking water has been proposed before. In general it is not possible to distinguish which compounds in drinking water are responsible for the toxicity. We’ve certainly known for many years that the majority of toxicity potential in drinking water can be attributed to a single compound that goes by the name of MX. General toxicity testing such as this has been debated in the past.

Ceretti E, Moretti M, Zerbini I, Villarini M, Zani C, Monarca S, Feretti D. Occurrence and Control of Genotoxins in Drinking Water: A Monitoring Proposal. Journal of public health research. 2016 Dec 21;5(3):769. doi: 10.4081/jphr.2016.769.

Many studies have shown the presence of numerous organic genotoxins and carcinogens in drinking water. These toxic substances derive not only from pollution, but also from the disinfection treatments, particularly when water is obtained from surface sources and then chlorinated. Most of the chlorinated compounds in drinking water are nonvolatile and are difficult to characterize. Thus, it has been proposed to study such complex mixtures using short-term genotoxicity tests predictive of carcinogenic activity. Mutagenicity of water before and after disinfection has mainly been studied by the Salmonella/microsome (Ames test); in vitro genotoxicity tests have also been performed in yeasts and mammalian cells; in situ monitoring of genotoxins has also been performed using complete organisms such as aquatic animals or plants (in vivo). The combination of bioassay data together with results of chemical analyses would give us a more firm basis for the assessment of human health risks related to the consumption of drinking water. Tests with different genetic end-points complement each other with regard to sensitivity toward environmental genotoxins and are useful in detecting low genotoxicity levels which are expected in drinking water samples.

Fluoride Toxicity – A Harsh Reality

Bandlapalli Pavani, Mandava Ragini, David Banji, Otilia J F Banji, N Gouri Pratusha. Fluoride Toxicity – A Harsh Reality. International Research Journal of Pharmacy, Vol 2, Iss 4, Pp 79-85 (2011).

There are many incidents of fluoride toxicity whether it is acute or chronic. Fluoride toxicity is an environmental hazard which arises from the upper layers of geological crust and is dissolved in water. Prolonged drinking of such water causes chronic fluoride toxicity. Use of fluoride containing compounds for various purposes such as dental products, metal, glass, refrigerator and chemical industries act as a source of fluoride poisoning and increase the risk of toxicity. This review reflects the deleterious effects of fluorides on various organs in the physiological system.

Fluoride Toxicity and Cognitive Impairment; China

Spittle B. Development of Fluoride Toxicity Including Cognitive Impairment with Reduced IQ: Pathophysiology, Interactions With Other Elements, and Predisposing and Protective Factors. Fluoride. Jul-Sep2016, Vol. 49 Issue 3, Part 1, p189-193.

The development of toxicity to the fluoride ion (F) may be complex and multifactorial with a number of pathophysiological path ways being possible, with the potential for interactions between toxins involving additivity, synergism, and antagonism, and with a number of other factors having predisposing and protective effects. In addition to cognitive impairment with a reduced intelligence quotient (IQ) in children developing through other mechanisms such as disturbed thyroid hormone metabolism and sonic hedgehog signalling, other pathophysiological factors such as reduced brain glucose uptake following a fluoride-induced reduction in insulin secretion may contribute. Environmental contamination with cadmium in a coal combustion fluorosis-affected rural area within China’s Three Gorges region may contribute to the dental and skeletal health problems in the population and the possibility of interactions between Cd and F affecting cognitive functioning requires further investigation. The propensity for the development of toxicity to F may involve interactions with a number of other factors as well as the levels of F exposure.

Combined Toxicity of Fluoride and Cadmium

Olszowski T, Sikora M, Chlubek D. Combined Toxicity of Fluoride and Cadmium. Fluoride. Jul-Sep2016, Vol. 49 Issue 3, Part 1, p194-203.

Fluoride (F – ) and cadmium (Cd) are toxicants found ubiquitously in the human environment. The aim of this review was to identify and characterize studies that attempted to determine the combined toxicity of F – and Cd. The effects of F – and Cd on liver and kidney (with a special focus on chronic kidney disease of unknown etiology), bone, tooth enamel, dental caries, and brain were taken into consideration. Based on the results of the studies described in this review, various types of combined toxicity of F – and Cd might occur: additive, synergistic, or antagonistic, with the latter two being true interactions. However, the type of combined action occurring seems to depend on many factors, such as which toxic effect is considered, the dose levels of F – and Cd and their dose ratio, exposure duration, presence of other elements, etc. Moreover , when analyzing the combined toxic effects of F – and Cd, the possible interactions of these toxicants with other elements (e.g., fluoride with aluminum and arsenic; cadmium with lead, arsenic, zinc, selenium, and calcium) should also be taken into consideration. We also may not exclude the independent action of F – and Cd on some selected functions/health outcomes. Due to the huge gaps in knowledge, additional studies are required to address this important public health issue, i.e., the combined effects of exposure to these common environmental toxicants , especially among people with high exposure to these elements.

Arsenic and Fluoride Toxicity to Human Umbilical Vein Cells

Ma Y, Ma Z, Yin S, Yan X, Wang J. Arsenic and fluoride induce apoptosis, inflammation and oxidative stress in cultured human umbilical vein endothelial cells. Chemosphere. 2016 Oct 14;167:454-461. doi: 10.1016/j.chemosphere.2016.10.025.

Excessive amount of inorganic arsenic (iAs) and fluoride (F) coexist in drinking water in many regions, which is associated with high risk of vascular diseases. However, the underlying mechanisms are not well studied. The present study was to evaluate the effects of iAs and F individual or combined exposure on endothelial activation and apoptosis in vitro. Primary human umbilical vein endothelial cells (HUVECs) were exposed to 5 μM As2O3 and/or 1 mM NaF. Changes in endothelial cell apoptosis, inflammation, oxidative stress and nitric oxide (NO) production were analyzed. The results showed that iAs and/or F induced significant increase in endothelial cell apoptosis and inflammation as indicated by the increase of mRNA and protein expression of vascular cell adhesion molecule-1, intercellular adhesion molecule-1, and pentraxin 3. Furthermore, iAs and/or F exposure induced intracellular reactive oxygen species and malondialdehyde generation. Results showed iAs and/or F exposure increased the activity of NADPH oxidase (NOX) and up-regulated the mRNA expression of NOX subunits p22phox. The results indicated that activation of NOX was related to oxidative stress induced by iAs and/or F. Also, iAs and/or F reduced NO production in HUVECs. The up-regulation of inflammation genes expression and oxidative stress in iAs and F co-exposed ECs were less pronounced as compared to single F-exposed cells, which showed an antagonistic effect between iAs and F. In conclusion, endothelial activation and apoptosis induced by iAs and/or F are potential mechanisms in their vascular toxicity. Oxidative stress and impaired NO production are involved in their pro-inflammatory and pro-apoptotic effects.

Sodium Fluoride and Male Reproduction

Zhang J, Li Z, Qie M, Zheng R, Shetty J, Wang J. Sodium fluoride and sulfur dioxide affected male reproduction by disturbing blood-testis barrier in mice. Food Chem Toxicol. 2016 Aug;94:103-11. doi: 10.1016/j.fct.2016.05.017.

Fluoride and sulfur dioxide (SO2), two well-known environmental toxicants, have been implicated to have adverse effects on male reproductive health in humans and animals. The objective of this study to investigate if the BTB is one of the pathways that lead to reproductive toxicity of sodium fluoride and sulfur dioxide alone or in combination, in view of the key role of blood testis barrier (BTB) in testis. The results showed that a marked decrease in sperm quality, and altered morphology and ultrastructure of BTB in testis of mice exposure to fluoride (100 mg NaF/L in drinking water) or/and sulfur dioxide (28 mg SO2/m(3), 3 h/day). Meanwhile, the mRNA expression levels of some vital BTB-associated proteins, including occluding, claudin-11, ZO-1, Ncadherin, α-catenin, and connexin-43 were all strikingly reduced after NaF exposure, although only the reduction of DSG-2 was statistically significant in all treatment groups. Moreover, the proteins expressions also decreased significantly in claudin-11, N-cadherin, α-catenin, connexin-43 and desmoglein-2 in mice treated with fluoride and/or SO2. These changes in BTB structure and constitutive proteins may therefore be connected with the low sperm quality in these mice. The role of fluoride should deserves more attention in this process.