Studied the Methyl and Ethylmercury Artifacts in Biological Samples Using Sodium Tetra(n-Propyl)Borate as a Derivatizing Agent

Sodium tetra (n-propyl) borate was used as derivatizing agent to measure methyl and ethylmercury compounds. This study investigated the artifact formation of methyl and ethylmercury compounds during derivatization using NaBPr4, simultaneously with the influence of this artifact on methylmercury analysis in biological samples (chlor alkali hair samples). The artifact methylmercury and ethylmercury compounds during derivatization using NaBPr4 were evident and depended strongly on the amount of inorganic mercury (Hg2+) present in the sample solution for derivatization and depended on the purity of sodium tetra (n-propyl) borate reagent. The high formation rate of artifact Et-Hg (0.76–0.81% of high-level Hg2+ present) interferes strongly with the ethylmercury analysis. The rate of artifact formation of Me-Hg is small and constant at the different concentration ranges of In-Hg (0.012% of In-Hg present) and does not affect on Me-Hg analysis and it can be subtracted from this Me-Hg artifact ratio from the measured value of Me-Hg in the biological samples. However, the mathematical correction for Me-Hg measurement can be done only when the Et-Hg peak is already appearing in the chromatogram samples

Global sourcing of low-inorganic arsenic rice grain

Arsenic in rice grain is dominated by two species: the carcinogen inorganic arsenic (the sum of arsenate and arsenite) and dimethylarsinic acid (DMA). Rice is the dominant source of inorganic arsenic into the human diet. As such, there is a need to identify sources of low-inorganic arsenic rice globally. Here we surveyed polished (white) rice across representative regions of rice production globally for arsenic speciation. In total 1180 samples were analysed from 29 distinct sampling zones, across 6 continents. For inorganic arsenic the global x ~ x~ was 66 μg/kg, and for DMA this figure was 21 μg/kg. DMA was more variable, ranging from < 2 to 690 μg/kg, while inorganic arsenic ranged from < 2 to 399 μg/kg. It was found that inorganic arsenic dominated when grain sum of species was < 100 μg/kg, with DMA dominating at higher concentrations. There was considerable regional variance in grain arsenic speciation, particularly in DMA where temperate production regions had higher concentrations. Inorganic arsenic concentrations were relatively consistent across temperate, subtropical and northern hemisphere tropical regions. It was only in southern hemisphere tropical regions, in the eastern hemisphere that low-grain inorganic arsenic is found, namely East Africa (x ~ x~  < 10 μg/kg) and the Southern Indonesian islands (x ~ x~  < 20 μg/kg). Southern hemisphere South American rice was universally high in inorganic arsenic, the reason for which needs further exploration

Rice grain cadmium concentrations in the global supply-chain

One of cadmium’s major exposure routes to humans is through rice consumption. The concentrations of cadmium in the global polished (white), market rice supply-chain were assessed in 2270 samples, purchased from retailers across 32 countries, encompassing 6 continents. It was found on a global basis that East Africa had the lowest cadmium with a median for both Malawi and Tanzania at 4.9 μg/kg, an order of magnitude lower than the highest country, China with a median at 69.3 μg/kg. The Americas were typically low in cadmium, but the Indian sub-continent was universally elevated. In particular certain regions of Bangladesh had high cadmium, that when combined with the high daily consumption rate of rice of that country, leads to high cadmium exposures. Concentrations of cadmium were compared to the European Standard for polished rice of 200 μg/kg and 5% of the global supply-chain exceeded this threshold. For the stricter standard of 40 μg/kg for processed infant foods, for which rice can comprise up to 100% by composition (such as rice porridges, puffed rice cereal and cakes), 25% of rice would not be suitable for making pure rice baby foods. Given that rice is also elevated in inorganic arsenic, the only region of the world where both inorganic arsenic and cadmium were low in grain was East Africa

Trace element levels in Mediterranean grains

This is the first study to compare total arsenic (As) and other trace elements in the agricultural soils and grain of Eastern, Western and Southern Libya, North Africa and the Middle East (NA &amp; MIDEA). Soil pot experiments and field experiments were conducted to determine the levels of As within wheat grains in Libya. In the soil pot experiments, wheat genotypes were planted in similar soils and yet differences in grain As concentration were found among the cultivars. The highest As accumulation was found in T. durum; however, in the field data the highest levels were found in T. aestrivum. The levels of As and other trace elements found in agricultural soils from the Eastern Western and Southern regions of Libya are examined. Mean As concentrations in the clay mineral agricultural soils of the Eastern Region were nearly 4.8 and 4.1 times higher than in the southern and western regions, respectively. It is possible that the parent material of that region contains elevated levels of As, which are then exhibited in the overlying soil. Differences in the levels of As and other trace elements found in the irrigated agricultural soil of Southern Libya were compared with non-irrigated soil from the same region.  Concentrations of P, Zn and As in soil were higher in irrigated compared to non-irrigated soils, while the concentration of Cd is nearly the same in all soil samples. A market basket investigation was conducted to determine the total levels of As and Se in rice purchased from supermarkets. The average level of As in rice from NA &amp; MIDEA is 0.22 mg/kg, comparable with average levels in Australia.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

KEYWORDS Drinking water Coliforms bacteria Feacal coliform bacteria MPN technique Plate count technique DETECTION AND ENUMERATION OF COLIFORM BACTERIA IN DRINKING WATER AT HOSPITAL OF BENGHAZI/LIBYA

ABSTRACT The aim of present study was to detect the presence or absence of coliform and faecal coliform bacteria from tap water of Benghazi Hospital, Libya at three different seasons. Samples were collected every month from two points viz surgery department (tapwater) and kidneys department (dialysis water) and examined by MPN and plate count methods. Presence of faecal coliform bacteria was not reported from both sources. However, the presence of coliform bacteria was reported from both source and it was slightly higher than the recommended one from both sources. Chemical analysis of water indicates the presence of organic matter like NO3 but the level was lower than the recommended by both world health organization (WHO) and environmental protection agency (EPA)