ABSTRACT
2,4,6-Trinitrotoluene (TNT) and its by-products dinitrotoluene (DNT) pose a significant threat to human health and other living organisms.However, the conventional analytical methods involved in bulky and expensive instruments are complicated and time-consuming, impeding quick and on-line determination.In this work, a facile yet effective strategy of utilizing UV-vis spectroscopy coupled with partial least squares (PLS) was proposed, through which TNT and two isomers of DNT (2,4-DNT and 2,6-DNT) in nature water could be rapidly and simultaneously determined without any pre-separation.Variable combination population analysis (VCPA) was utilized to select important feather variables and significantly improved the predictive performance of the PLS model.The calibration set contained 25 samples constructed by orthogonal array design (OAD).The predictive ability of the models was validated by an independent prediction set including 15 samples, achieving up to 0.99 of the determination coefficients (R2) for each of the analytes.The optimized models were successfully applied to determine the 3 ingredients in 8 environmental samples involving in tap, lake and two kinds of river water with the recovery values of great than 97%.Finally, the proposed method was further validated by high performance liquid chromatography method.UV-vis spectroscopy coupled with chemometrics may be used as simple and effective strategy with high potential in environmental monitoring.
ABSTRACT
A spring is a result of karsts topography where surface water has infiltrated the earth's surface recharge area, becoming part of groundwater and emerges from below to become natural spring water. From few observations, local people tend to consume this water directly for many health reasons. The objective of the study was to determine the concentration of lead (Pb) and cadmium (Cd) in natural water resources and bottled drinking water sources, and compared with the existing standard. This field assessment was carried out in 2014 as part of the educational module for public health master student. About 13 water samples were collected directly from the tubing into the pre-washed sample bottle and rinse with the sampling water in the field. Sample preservation was achieved by acidifying to pH less 4.0 with nitric acid (HNO3). Samples were stored in a cooler with temperature between 0 to 4oC. Heavy metals were analysed by standard method for graphite furnace atomic absorption spectrophotometer (GFAAS) with Zeeman’s correction. Pb and Cd content were analysed from 13 samples which consists of eight natural spring water and five flavoured bottled drinking water. The result showed that Pb content in spring water ranges between 1.8 and 37.3ppb, while the Cd content in spring water ranges between 3.0 and 23.0ppb. In the commercialised drinking water, the amount of Pb ranges between 0.4 and 2.6 ppb, while the content of Cd ranges between 0.8 and 7.0 ppb. This study indicates that there are high content of Pb and Cd in most of the natural spring water points and some bottled drinking water that are available within Klang Valley. In the absence of any specific point sources, the possibility of urban area and high traffic source leading to run off as well as rock types may result in variations observed. Hence, very worrying, especially that these sources of water were consumed directly as drinking water or eye drops without knowing its content. Further tests, coupled with supportive soil and conductivity studies, are required to test all possible similar natural sources to safeguard the health of people.
ABSTRACT
The objective of the study was to conduct bacteriological analysis of water with special reference to Salmonella spp from natural sources of rural habitations of East Sikkim. A total of 28 Salmonella serovars isolated were biotyped, phage typed and tested for their anti-microbial susceptibility. All the isolates of Salmonella enterica serovar Typhi belonged to Biotype I. Four isolates of S. typhi belonged to phage type A. All S. paratyphi A isolates belong to phage 2. All the isolates were sensitive to chloramphenicol, cefi xime and amikacin. Untreated natural water sources are unsafe for human consumption.
ABSTRACT
Gas chromatography with mass spectrum detector ( GC-MSD) coupled with purge-and-trap system was set up to analyze the concentration of isoprene in natural waters. The best experimental conditions were established, including purge gas flow rate ( 50 mL/min ) , purge time ( 15 min ) , the optimum capillary column ( Rt-Alumina BOND/KCl) and the appropriate condition of temperature programming. When analyzing isoprene in natural waters, the precision was <4% (n=6), the detection limit was 0. 5 pmol/L and the recovery was 91%-102%. The preservative experiment showed that there was no obvious variation in sample concentrations of isoprene within 60 days. The concentrations of isoprene measured with the method ranged from 60 . 8 to 278 . 7 pmol/L in the Jiaozhou Bay and its adjacent river estuaries and from 44 . 7 to 77 . 2 pmol/L in Yellow River estuary, which was in good accord with those results reported in literatures in other coastal waters. In conclusion, the analytical method could meet the requirements of the analysis of concentration of isoprene in natural waters.
ABSTRACT
There are various toxic elements present in our surroundings out of that the toxic heavy metals Pb, Cd, As, Se, Cr and Cu can cause several harms to human these metals enter in humans by water. The all kind of waste materials are thrown into natural water bodies in each city, this makes the all ground and natural water sources contaminated. The all six metals have determined by Atomic absorption spectrophotometer(AAS) in selected water samples from Sagar Lake and dug wells, hand pumps, tube wells etc. during Jan.2009 to June 2010 in every month the all most all sample have higher metal concentrations than their prescribed permissible limits by WHO.
ABSTRACT
Minerals play an important role in the body as essential nutrients. However, it is not easy to meet DRIs because food sources of minerals are limited. Recently, consumption of bottled natural water has been increasing in Korea due to water pollution and distrust of tap water. The present study was conducted to investigate mineral contents in bottled natural water and their intakes among Korean adults. We analyzed eight minerals in seven kinds of bottled natural water by ICP-spectrometry and conducted a survey on the intake status of water and bottled natural water with 400 Korean young adults. The mean contents of Ca, Mg, Fe, Zn, Cu, Mn, Se, and Mo in bottled natural water were 22.45+/-22.48 mg/L, 10.59+/-9.97 mg/L, 0.27+/-0.18 microgram/L, 2.06+/-1.48 microgram/L, 5.47+/-0.70 microgram/L, 1.43+/-0.37 microgram/L, 1.90+/-0.96 microgram/L, and 3.34+/-0.79 microgram/L, respectively. The mean age, height, weight, and BMI were 22.76 years, 174.94 cm, 68.64 kg, and 22.41 kg/m2 for males (n=150) and 21.25 years, 162.04 cm, 51.05 kg, and 19.46 kg/m2 for females (n=250), respectively. The respective daily intakes of total water and bottled natural water as water itself were 670.30 ml and 212.20 ml for males and 488.04 ml and 132.72 ml for females. The daily intakes of Ca, Mg, Fe, Zn, Cu, Mn, Se, and Mo from bottled natural water were 4.76 mg, 2.25 mg, 0.06 microgram, 0.44 microgram, 1.16 microgram, 0.30 microgram, 0.40 microgram, and 0.71 microgram for males and 2.98 microgram, 1.41 mg, 0.04 microgram, 0.27 microgram, 0.73 microgram, 0.19 microgram, 0.25 microgram, and 0.44 microgram for females, respectively. Overall, the contents of Ca, Mg, and Se in bottled natural water were relatively high and the daily intakes of these minerals were 0.4~1.0% of the DRIs.
Subject(s)
Adult , Female , Humans , Male , Young Adult , Drinking , Korea , Minerals , Water , Water PollutionABSTRACT
Foram feitos estudos comparativos entre 4 métodos para determinação de nitrato em amostras de águas naturais, colhidas em 10 poços na cidade de Aso Paulo. Procurou-se destacar os problemas operacionais e os possíveis interferentes para cada método. Com base nos resultados obtidos, foi sugerido o método do ácido fenoldissufônico como o mais apropriado para o uso em análises de rotina de amostras de água (AU).