Effect of exogenous Ca on the physiology and growth indicators of pakchoi under foliar and root fluorine stress.

Fluorine (F) is not an essential element for vegetation and excessive F can be phytotoxic to plant growth, which can cause fluorosis to human beings by ingesting F-contaminated plant. Although there have been some studies focusing on the toxicity of F to plants and the retarding effect of Ca to F-stress plant, atmospheric F contamination to vegetation and the role of the application of foliar Ca are scantly reported. This study investigated several biochemical parameters to evaluate F toxicity under both F-exposure (root and leaf F-exposure) and the remedial effects of foliar Ca. The results showed that F concentration of pakchoi leaves was correlated with exogenous F level positively in both foliar and root F-exposure series, and F concentration of pakchoi roots was only changed under root F-exposure treatments. Ca supplement (0.5 g/L and 1 g/L) significantly decreased plant F concentration. Both F-exposure treatments caused lipid peroxidation in plants and exogenous Ca alleviated the toxicity of F to pakchoi. Meanwhile, chlorophyll-a concentration was decreased by foliar and root F, whereas chlorophyll-b concentration was only affected by foliar F, and chlorophyll-a concentration could be elevated by exogenous Ca but chlorophyll-b could not. It was concluded that both atmospheric and root F can impair pakchoi growth and disturb photosynthesis, and foliar Ca showed an ameliorative effect to F toxicity of pakchoi through alleviating chlorophyll decomposition, increasing protein content and alleviating oxidative damage.

A comprehensive review on endemic and experimental fluorosis in sheep: Its diverse effects and prevention.

Fluoride is a natural element widely distributed in the environment and plays an important role in the growth of humans and animals. However, in many species, high concentrations of fluoride induce several problems, such as dental, skeletal, and non-skeletal fluorosis. Sheep living in endemic areas are sensitive to the chronic toxicity of fluoride, and they have been found to suffer not only from teeth and bone problems but also from other organs. Studies indicating the chronic harmful effects of fluoride on teeth, bones, blood biochemical parameters, kidney, liver, heart, reproductive system and growth in sheep have been clearly summarized in this review. Besides, this work also includes updated progress in terms of prevention or reduction of fluoride toxicity in this species.

Coal utilization in China: environmental impacts and human health.

Coal is one of the major energy resources in China, accounting for approximately 70 % of primary energy consumption. Many environmental problems and human health risks arise during coal exploitation, utilization, and waste disposal, especially in the remote mountainous areas of western China (e.g., eastern Yunnan, western Guizhou and Hubei, and southern Shaanxi). In this paper, we report a thorough review of the environmental and human health impacts related to coal utilization in China. The abundance of the toxic trace elements such as F, As, Se, and Hg in Chinese coals is summarized. The environmental problems (i.e., water, soil, and air pollution) that are related to coal utilization are outlined. The provenance, distributions, typical symptoms, sources, and possible pathways of endemic fluorosis, arsenism, and selenosis due to improper coal usage (briquettes mixed with high-F clay, mineralized As-rich coal, and Se-rich stone coal) are discussed in detail. In 2010, 14.8, 1.9 million, and 16,000 Chinese people suffered from dental fluorosis, skeletal fluorosis, and arsenism, respectively. Finally, several suggestions are proposed for the prevention and treatment for endemic problems caused by coal utilization.

Health effects of arsenic, fluorine, and selenium from indoor burning of Chinese coal.

China's economy has developed rapidly in the last two decades, leading to an increase in energy consumption and consequently emissions from energy generation. Coal is a primary energy source in China because of its abundance and will continue to be used in the future. The dominance of coal in energy production is expected to result in increasing levels of exposure to environmental pollution in China. Toxic trace elements emitted during coal combustion are the main sources of indoor air pollution. They are released into the atmosphere mainly in the forms of fine ash and vapors and have the potential to adversely affect human health. Those trace elements, which volatilize during combustion, are hazardous air pollutants (HAPs) and are particularly rich in Chinese coals. Among the HAPs, arsenic (As), fluorine (F), and selenium (Se) have already been identified as pollutants that can induce severe health problems. In this review, the geochemical characteristics of As, F, and Se, including their concentration, distribution, and mode of occurrences in Chinese coal, are documented and discussed. Our investigations have confirmed the current As- and F-induced epidemics in Guizhou (Southwest China) and Se epidemic in Hubei (Northeast China). In this study, diagnostic symptoms of arseniasis, fluorosis, and selenosis are also illustrated.

[Effect of fluorine, selenium and cadmium on anti-oxidase and microelements in rat's body].

OBJECTIVE: To study the effect of fluorine, selenium and cadmium on lipid peroxide(LPO), the activity of glutathione peroxidase (GSH-Px) and microelements such as cadmium, selenium and zinc in rats. METHODS: Measurement of the contents of LPO, GSH-Px and microelements such as cadmium, selenium and zinc in SD rats after killing that have drunk water containing fluorine, selenium and cadmium eight-week ago. RESULTS: The contents of GSH-Px in the serum, liver and kidney of rats that were contaminated with fluorine, selenium and cadmium respectively remarkably reduced and the content of LPO noticeably increased in comparison with those of rats without being contaminated. The contents of GSH-Px noticeably increased and LPO remarkably reduced in those contaminated with the combination of any two of the three elements when compared with those in the rats contaminated with any one element of them, while the contents of GSH-Px in those contaminated with the combination of the three elements increased even more. Excessive selenium or cadmium led to the increase of selenium content in kidney and cadmium content in liver by several times. Excessive fluorine or cadmium gave rise to the lack of selenium and zinc. Selenium brought out universal increase of zinc in liver and kidney. The combination of fluorine and selenium or the combination of cadmium and selenium or that of fluorine, selenium and cadmium produced remarkable decrease of the accumulation of selenium in kidney and cadmium in liver. They also lowed the loss of zinc caused by fluorine or cadmium. CONCLUSION: Excessive fluorine, selenium or cadmium could inhabit the activity of GSH-Px in rats, which could diminish the antioxidation ability of the body. But when two or three of the chemical elements coexisted, they reduced the inhabitation of each of them on the activity of GSH-Px and in the meantime decreased the accumulation of cadmium and selenium and diminished the loss of zinc caused by fluorine and cadmium.

[The late sequelae of body exposure to phosphorus, fluorine and their derivatives (a review of the literature)]. / Otdalennye posledstviia vozdeistviia fosfora, ftora i ikh proizvodnykh na organizm (obzor literatury).

Presents data on mutagenic, gonadotoxic, embryotoxic and teratogenic activities of phosphorus, fluorine and their derivatives. The investigations have revealed the mechanisms of these chemical substances toxic action on the genetic apparatus, reproductive organs, progeny. The problem is interesting and needs further investigations.

[Harmful elements versus iron, zinc and copper: their interactions in animals and humans. I. Mercury, tin, nickel, selenium, fluorine and aluminum]. / Pier wiastki szkodliwe a zelazo, czynk i miedz: interakcje w organizmie zwierzat i ludzi. Cz. I. Rtec, cyna, nikiel, selen, fluor, glin.

A literature survey was made of the interactions--in the organism--between some food contaminating elements (mercury, tin, nickel, selenium, fluorine, aluminium) and iron, zinc and copper. The harmful elements may disturb the mineral metabolism already at the stage of intestinal absorption. Moreover, they bring about changes in microelement distribution in the tissues and cells. On account of their approximately similar chemical structure, they compete for the sites of binding to some proteins, including enzymic ones. In this respect a special role is played by ++metallothionein, a protein with the ability of regulating free metal contents in the tissues and thus possibly displaying some detoxifying properties. Many mechanisms and relationships determining the interactions between the surveyed food contaminants and iron, zinc and copper remain, however, not elucidated.

[Modifying effect of nutrition on the mutagenic activity of phosphorus and fluorine compounds]. / Modifitsiruiushchee vliianie pitaniia na mutagennyi éffekt soedinenii fosfora i ftora.

The test animals were fed with low-grade food during 2-5 months under conditions of acute and chronic action of hydrogen phosphide and hydrogen fluoride induced by inhalation, that resulted in the pronounced impairment of the chromosomal apparatus of the bone marrow cells in the rats. A principal possibility has been established of modification of the hydrogen phosphide and hydrogen fluoride cytogenetic effect by the alimentary action. In particular, it has been found that the effect is significantly higher when the rats are fed with a low-grade ration than under conditions of balanced nutrition.

[Effect of several microelements contained in drinking water on the development of atherosclerosis]. / Prouchvane vliianieto na niakoi mikroelementi, sudurzhashti se v piteinite vodi, vurkhu razvitieto na aterosklerozata.

During his whole life man drinks water - about 2 litres in 24 hours for an adult in the countries with moderate climate. Usually, drinking water contains many microelements. Their type and concentration depend mainly on the geochemical characteristic of the earth layers. The pollution of waters by industrial enterprises has, very likely, an effect on the content of microelements. According to literature data, in epidemiological studies information was collected, providing grounds to admit that some microelements have an effect ion atherosclerosis advancement. The results obtained are not convincing enough to judge if a casual relationship exists between the microelements in the drinking water and atherosclerosis advancement. In order to supplement the existing studies, the authors carried out investigations to elucidate the role of some microelement in the progress of experimental atherosclerosis. The results obtained provided grounds to claim that the microelements chromium, zinc, lead, cadmium, vanadium stimulate or restrict the advancement of experimental atherosclerosis.

High fluorine water to wether sheep maintained in pens. Aluminum chloride as a possible alleviator of fluorosis.

The experiment reported here, gave the following answers to the questions asked (see introduction): a. Water with 30 ppm F gave deleterious effects on wethers. A considerable difference was observed as compared to animals given about 1 ppm F in their water, see Table IV. b. The toxicity was slightly less from bore hole water containing 30 ppm F, as compared to Nairobi tap water with added fluorine to 30 ppm F. The difference in toxicity may be due to the very high content of minerals in the bore hole water, see Table I. c. More fluorine was excreted in faeces when aluminum chloride was added to the diet, as compared to animals which did not receive aluminum chloride. Aluminum chloride had no alleviating effect on fluorosis, but apparently decreased gut absorption of fluorine and also reduced fluorine retention in the bones, se Table VII. Under the conditions of this experiment, toxic levels of fluorine were considerable lower than the quoted safe levels in the literature.