Arsenic in drinking water: sources,occurrence and health effects (a review)

Because dramatic cases of arsenic contamination of water resources, soils, vegetables, humans and animals increase, this review has focussed on the fate and behaviour of this element and what kind of health impacts are related with its release in surface or ground waters. In a first part, we point out how the primary minerals can lead to As mobilization and exportation by surface waters and suspended matter. We also emphasize the particular key role for As retention through both adsorption onto natural Fe(III) (hydr)oxides, Mn oxides and/or precipitation as Fe(III) arsenates. Nowadays, numerous and efficient systems for arsenic removal from any natural resources are available to produce good quality drinking water (with <10 μg/l As); however it is not within the scope of the present review. In a second part we focus on recent knowledge about the human toxicity of the various arsenic species. Chronic exposure to As in drinking water lead to many health diseases and, although the mechanisms of toxification/detoxification are not well identified, the role of methylated species is discussed. Some epidemiologic studies are cited, but the exact relationship between past chronic As exposure and present health diseases has been questioned.     

Mineral element composition of natural vegetation and its relation to soil of Pugavalley,Ladakh, India

Summary Uranium and boron contents in plant samples along with the representative soil samples collected from the Puga Valley have been estimated by the particle etch technique. The uranium content in soil samples varies from 1.9 to 12.8 ppm with an average of 6.8 ppm and in plant samples from 0.20 to 17 ppm with an average of 3.3 ppm. The boron concentration in soil samples varies from 8.2 to 40.6 ppm with an average of 24.2 ppm and in plants from 17.7 to 42.8 ppm with an average of 27.5 ppm.At higher altitudes (around 4600 meters above the sea level), the typical plant assemblage have a relatively high capacity to absorb uranium and boron from soil. This interrelation and distribution is recorded in the present study.     

The isotopic composition of anthropogenic boron and its potential impact on the environment

The present study investigates the isotopic composition of anthropogenic boron (B) and its potential affects on the environment. The isotopic ratios of B in synthetic products from the main ores in the world have been measured by negative thermal ionization mass spectrometry. The data show that the isotopic compositions of Na-borate products and washing powders overlap with those of natural Na-borate minerals. In contrast, the¹¹B/¹⁰B ratios of synthetic Ca-borate and Na/Ca borate products are significantly lower (by 15 permil) and overlap with those of the natural Ca-borate minerals. Consequently, the original isotopic signature of natural borate minerals is not modified during the manufacturing process of synthetic products. The B isotopic composition of domestic wastewater from Israel and Riverside, California suggests that B in sewage is derived from Na-borate components used in detergents. Since B, like other inorganic ions, is not removed during conventional sewage treatment, it accumulates in domestic wastewater. Although the B concentration in pristine groundwaters is generally low (<0.05 mg/L), contaminant sources (e.g., wastewater) are relatively enriched in B (0.5–1 mg/L). The isotopically distinguished signature of borate compounds is used to trace groundwater contamination.     

Sorghum phytochemicals and their potential impact on human health

Sorghum is a rich source of various phytochemicals including tannins, phenolic acids, anthocyanins, phytosterols and policosanols. These phytochemicals have potential to significantly impact human health. Sorghum fractions possess high antioxidant activity in vitro relative to other cereals or fruits. These fractions may offer similar health benefits commonly associated with fruits. Available epidemiological evidence suggests that sorghum consumption reduces the risk of certain types of cancer in humans compared to other cereals. The high concentration of phytochemicals in sorghum may be partly responsible. Sorghums containing tannins are widely reported to reduce caloric availability and hence weight gain in animals. This property is potentially useful in helping reduce obesity in humans. Sorghum phytochemicals also promote cardiovascular health in animals. Such properties have not been reported in humans and require investigation, since cardiovascular disease is currently the leading killer in the developed world. This paper reviews available information on sorghum phytochemicals, how the information relates to current phytonutrient research and how it has potential to combat common nutrition-related diseases including cancer, cardiovascular disease and obesity.     

Biogeochemistry of selenium and its impact on food chain quality and human health

In areas where soils are low in bioavailable selenium (Se), potential Se deficiencies cause health risks for humans. Though higher plants have been considered not to require this element, the experience with low-Se soils in Finland has provided evidence that the supplementation of commercial fertilizers with sodium selenate affects positively not only the nutritive value of the whole food chain from soil to plants, animals and humans but also the quantity of plant yields. The level of Se addition has been optimal, and no abnormally high concentrations in plants or in foods of animal origin have been observed. Se levels in serum and human milk indicate that the average daily intake has been within limits considered to be safe and adequate. In fact, plants act as effective buffers, because their growth is reduced at high Se levels. They also tend to synthesize volatile compounds in order to reduce excess Se. On the other hand, when added at low concentrations, Se exerts a beneficial effect on plant growth via several mechanisms. As in humans and animals, Se strengthens the capacity of plants to counteract oxidative stress caused by oxygen radicals produced by internal metabolic or external factors. At proper levels it also delays some of the effects of senescence and may improve the utilization of short-wavelength light by plants. High additions are toxic and may trigger pro-oxidative reactions. Thus, the present supplementation of fertilizers with Se can be considered a very effective and readily controlled way to increase the average daily Se intake nationwide.     

Plant calcium oxalate crystal formation, function, and its impact on human health

Crystals of calcium oxalate have been observed among members from most taxonomic groups of photosynthetic organisms ranging from the smallest algae to the largest trees.The biological roles for calcium...