Endocrine disruptors in boiled drinking water carried in plastic containers: a pilot study in Thrissur, Kerala, India

Boiled drinking water is carried by students to schools and colleges in plastic containers. However, the risk associated with drinking water stored in plastic containers is very real especially the question of leachates finding their way into the water stored in these containers. In this pilot study, we identified the most common plastic container used by students to carry water and the factors that govern their choice. Polyethylene terephthalate (PET) was identified as the most favored plastic used to carry water. PET bottles were then subject to treatments that mimic conditions representative of normal consumer usage. The water sample collected was tested for the presence of phthalates, antimony & titanium, and their content estimated by gas chromatography and atomic absorption spectra. Although phthalates and antimony leach into water from PET bottles their concentration was not high enough to pose a threat to human life. However, the trend of increasing antimony concentration with temperature and time is a cause of concern because of its role as endocrine disruptors. Prolonged and repeated use of PET bottles to carry water, especially warm water may lead to health problems in the community.

Transesterification of Degummed Jatropha curcas Oil Using Tri-potassium Phosphate as Base Catalyst

Jatropha curcas oil and methanol are transesterified using potassium triphosphate as base catalyst. The effects of methanol to oil molar ratio, reaction temperature, stirring speed, catalyst concentration, solubility and its reusability on the yield of biodiesel are investigated. The base catalyst tri-potassium phosphate (K3PO4) is found to be highly suitable for oils having less than 1.5% free fatty acids (FFA). Highest biodiesel yield (approximately 92%) is acquired under optimum conditions of 9:1 methanol to oil molar ratio, 2% catalyst at 70°C reaction temperature at a stirring speed of 650 rpm. The chemical activity of K3PO4 is found to be similar to that of base catalyst potassium hydroxide (KOH) and the catalyst solubility in biodiesel as determined by atomic absorption spectra is only 4.81 ppm. It has been found that K3PO4 is highly hygroscopic and its reusability drastically decreases upon further usage and it can be reused only in wetted condition for three continuous usages with drastic reduction in catalytic strength. The biodiesel samples prepared were tested for several physicochemical properties and compared with the values of European biodiesel standards. The fatty acid methyl esters (FAME), also referred to as jatropha methyl esters (JME) in this paper, have been analyzed by gas chromatography and thermogravimetric analysis.

The Polluted Characters of Cr, Toluene and Dimethylbenzene in Contaminated Soil of Dongsheng Chemical Plant in Suzhou

We sampled total of 74 polluted soil samples in the polluted field, and set up 5 surface water inspect spots by means of setting plane sample points and deep well sampling according to the original produce layout and pollution situation of Dongsheng chemical plant. At the same time, we set 4 soil sampling points outside the polluted field, 6 inspect positions of surface water, and 4 atmospheres inspect stations. The total quantity and the concentration of active form of heavy metals elements in the soil samples were analyzed by atomic absorption spectra; and the volatility organic matters in the soil are measured using gas chromatography-mass spectrograph jointed measurement. The results show that the polluted concentration of Cr in sub-surface layer of the field is highest, and the largest concentrations of the total quantity of Cr, Cr6+, toluene and dimethylbenzene are 13900, 4840, 258 and 33.6 mg•kg-1, respectively. The datum show that the soil in the field is heavily polluted by toluene, dimethylbenzene, total Cr, and Cr6+, and some soil is characteristic of strong acid or strong alkali, and surface water inner the field exists heavy Cr6+ pollution.

Atomic absorption background of Ba in EXAFS analysis of BaFe12O19nanoparticles

The approximate barium X-ray atomic absorption in the energy region ofL-edges is reconstructed from the absorption spectrum of an aqueous solution of BaCl2. The result is corroborated by comparison with pure atomic absorption spectra of neighbour elements Xe and Cs. The application of the atomic absorption signal as a proper EXAFS background is demonstrated and discussed in the analysis of Ba hexaferrite nanoparticles with a very weak structural signal. The essential gain is found in the decrease of uncertainty intervals of structural parameters and their correlations. A simple analytical model of the absorption background for the practical EXAFS analysis is demonstrated.