Bottled water: how safe is it?

Sales of bottled water have increased dramatically in recent years, with worldwide sales of more than dollars 35 billion, largely because of the public perception of purity and safety and public concern about the quality of tap water. Presently, there are no Food and Drug Administration (Washington, D.C.) recommendations regarding temperature and duration of storage for bottled water once it is opened and used. The objectives of this study were to examine the effects of time and storage temperature on bacterial growth and characterize the types of microorganisms contaminating bottled water after drinking once from the bottle. Bottled and tap water were tested using standard microbiology culture techniques. The bacterial count in bottled water increased dramatically, from less than 1 colony per milliliter (col/mL) to 38,000 col/mL over 48 hours of storage at 37 degrees C. Bacterial growth was markedly reduced at cold temperatures (refrigeration) compared with room temperature, with 50% fewer bacterial colonies in 24 hours and 84% fewer colonies in 48 hours. Interestingly, tap water resulted in only minimal growth, especially at cold temperatures (< 100 col/mL at 48 hours). These findings may be useful to increase public awareness and development of guidelines on storage temperature and expiration time for bottled water once it is opened and used.     

Effect of agricultural antibiotics on the persistence and transformation of 17beta-estradiol in a Sequatchie loam

A laboratory incubation study was conducted to investigate the effect of agricultural antibiotics (sulfamethazine, tylosin, and chlortetracycline) on the persistence and transformation of 17beta-estradiol in Sequatchie loam. We measured concentrations of 17beta-estradiol and its primary metabolite (estrone) in soils spiked with antibiotics and 17beta-estradiol. Dehydrogenase activity (DHA) was also measured as an indicator of the total microbial activity of the soils. The presence of antibiotics significantly decreased transformation of 17beta-estradiol to estrone. There was a positive correlation between the DHA and the concentrations of estrone in soil spiked with 17beta-estradiol only, implying that the reaction is mainly catalyzed by dehydrogenases. However, the positive correlation was weakened in soil spiked with 17beta-estradiol and antibiotics together. We recommend that any study evaluating the fate and transport of estrogenic hormones in soil should include the effect of agricultural antibiotics because antibiotics and estrogenic hormones are commonly excreted together in environmental samples.     

Applications of smart grid technology in Nepal: status,challenges, and opportunities

Environmental Science and Pollution Research - Energy transformation and sustainability have become a challenge, especially for developing countries, which face broad energy-related issues such as...     

A Time-Dependent System for Evaluating Groundwater Contamination Hazard Rating of Municipal Solid Waste Dumps

In developing countries, several old municipal solid waste dumps (unlined landfills) exist adjacent to large cities, releasing contaminants to the underlying aquifer, thus posing the hazard of groundwater contamination. These uncontrolled waste dumps need to be prioritized in terms of the groundwater contamination hazard posed by them, so that necessary control and remedial measures can be undertaken in a phased manner. This paper presents a time-dependent system for evaluating groundwater contamination hazard rating of municipal solid waste dumps. The system is based on source–pathway–receptor relationships and evaluates the relative value of hazard posed by a site over its entire leaching life, on a scale of 0–1,000. The system parameters have been selected based on literature and expert opinions. The Delphi technique is used to derive the relative importance weights of the system parameters. The proposed system is compared with six selected existing hazard rating systems. The comparison, made by way of score range analysis, shows that the proposed system exhibits a much wider range of hazard scores for various scenarios of site conditions, and hence the proposed system is more sensitive to varied site conditions. The application of different systems to six municipal solid waste dumps located in four cities of India shows that, whereas the existing systems individually produce clustered scores and return the same rank to more than one site, the proposed system produces significantly varying scores and return different ranks to different sites. This demonstrates that the proposed system improves decision making and makes a better basis for prioritization of municipal solid waste dumps for adopting control and remedial measures.     

Ground water quality in the Kathmandu valley of Nepal

A study was undertaken to assess the quality of groundwaters in the Kathmandu Valley, Nepal. The groundwater samples were randomly collected from shallow well, tube well, and deep-tube wells located at different places of Kathmandu, Lalitpur, and Bhaktapur districts in the Kathmandu valley. Physical, chemical, and microbiological parameters of the samples were evaluated to estimate the groundwater quality for drinking water. It was found that the groundwater in the valley is vulnerable to drink due to presence of iron and coliform bacteria. Iron was estimated to be much higher then the acceptable limit of World Health Organization (WHO) drinking-water quality guidelines (1.9 mg/L). Total coliform bacteria enumerated in groundwaters significantly exceeded the drinking-water quality standard and observed maximum coliform (267 CFU/100 mL) in shallow wells. The electrical conductivity and turbidity were found to be 875 ??S/cm and 55 NTU, respectively, which are above the WHO recommendations for drinking water guidelines. However, pH value was measured within the acceptable limit. Arsenic, chloride, fluoride, and hardness concentrations were found to be in agreement with the recommendations of WHO drinking-water quality guidelines.     

Heavy Metal Accumulation in Lichens from the Hetauda Industrial Area Narayani Zone Makwanpur District, Nepal

Lichen samples collected in and around Hetauda Industrial area,(HIA) Narayani zone, Makwanpur district, Nepal, were analyzedfor Cr, Ni, Pb, Zn, Ca, Mn, Fe, Si, and Al. The samples fromthe location inside the industrial area have higher levels ofmetal than the outside areas. Pyxine meissnerina growinginside the industrial area accumulated higher levels of all themetals analyzed.     

210-Polonium studies in some environmental and biological matrices of Domiasiat uranium deposit area, West Khasi Hills, Meghalaya, India

The study was performed using a silicon surface barrier alpha spectrometer at Bhabha Atomic Research Centre, Mumbai, India. Through the study, the observed ²¹⁰Po activity in water sample from different locations in the Domiasiat area ranges from 0.04 to 0.69 Bq/l. The daily and annual intake of ²¹⁰Po through water was also estimated and the mean value of 0.72 and 263.61 Bq, respectively, were observed. It is observed that the effective doses through water were higher than the World Health Organization recommended dose of 0.05 mSv/year. The total annual effective doses through terrestrial ingestion for all the locations was studied and the mean annual effective dose was observed to be 0.315 mSv, which, when compared to the worldwide and the Indian values, was observed to be slightly higher. The mean activity in soil is found to be 124.8 ±5.7 Bq/kg and in meat the activity is 0.43 ±0.05 Bq/kg. In fishes, an activity of 0.48 ±0.07 Bq/kg in Garra lamta, 0.29 ±0.02 Bq/kg in Neolissocheilus hexaganolepis, and 3.3 ±0.1 Bq/kg in Macrobrachium sp. is observed. Activity concentration in plant samples was analyzed and the activity ranges from 0.020 ±0.002 to 9.69 ±0.35 Bq/kg. Committed effective dose by the adult population of the Domiasiat area through intake of ²¹⁰Po through these food items was also determined and compared with the Indian average value and the worldwide average value.     

Soil adsorption studies of a rice herbicide,cyhalofop-butyl,in two texturally different soils of India

The ability of herbicides to be adsorbed by the soil and sediment and their tendency to be desorbed are some of the most important factors affecting soil and water contamination. Therefore, a sorption study was conducted to evaluate the adsorption of cyhalofop-butyl, butyl (2R)-2-[4-(4-cyano-2-fluorophenoxy) phenoxy] propanoate, in the sandy clay loam and clayey soils using a batch equilibrium method. The adsorption of cyhalofop-butyl was found positively related with the clay and organic carbon content. Freundlich constants (K _f) of cyhalofop-butyl in the clayey and sandy clay loam were found to be 13.39 and 2.21, respectively. Sorption coefficients (K _oc) and distribution coefficients (K _d) were found to be 265.38 and 2,092.79, and 1.38 and 11.48, for sandy clay loam and clayey soils, respectively. The adsorption isotherm suggested a relatively higher affinity of cyhalofop-butyl to the adsorption sites at low equilibrium concentrations. The low value of the soil organic carbon partition coefficient (K _oc) of cyhalofop-butyl in the sandy loam soil suggested its weaker adsorption in soil and thus increased its risk of mobility into water sources; hence, it should be used judiciously to prevent groundwater contamination     

Changing lichen diversity in and around urban settlements of Garhwal Himalayas due to increasing anthropogenic activities

Decrease in lichen diversity is an important biometric tool to assess the prevailing environmental condition in an area. An attempt has been made to explore the utility of lichen diversity in the monitoring of air pollution in the city of Pauri and Srinagar, Garhwal Himalayas, Uttaranchal. Eighty five lichen species were recorded from Pauri and Srinagar (Garhwal) in June 2005. It was observed that polluted sites had very low lichen diversity, mostly dominated by members of lichen family Physciaceae. Kiyonkaleshwar area is the site with maximum lichen diversity (46 lichen taxa) located in a more or less pollution-free area of Pauri city. Two-dimensional principal components analysis plot revealed significant positive contribution of natural (unaltered) sites towards lichen biodiversity, thus affirming the utility of lichen diversity in biomonitoring studies in a wide geographical area.     

Monitoring changes in soil organic carbon pools, nitrogen, phosphorus, and sulfur under different agricultural management practices in the tropics

Soil organic matter not only affects sustainability of agricultural ecosystems, but also extremely important in maintaining overall quality of environment as soil contains a significant part of global carbon stock. Hence, we attempted to assess the influence of different tillage and nutrient management practices on various stabilized and active soil organic carbon pools, and their contribution to the extractable nitrogen phosphorus and sulfur. Our study confined to the assessment of impact of agricultural management practices on the soil organic carbon pools and extractable nutrients under three important cropping systems, viz. soybean–wheat, maize–wheat, and rice–wheat. Results indicated that there was marginal improvement in Walkley and Black content in soil under integrated and organic nutrient management treatments in soybean–wheat, maize–wheat, and rice–wheat after completion of four cropping cycles. Improvement in stabilized pools of soil organic carbon (SOC) was not proportional to the applied amount of organic manures. While, labile pools of SOC were increased with the increase in amount of added manures. Apparently, green manure (Sesbania) was more effective in enhancing the lability of SOC as compared to farmyard manure and crop residues. The KMnO₄-oxidizable SOC proved to be more sensitive and consistent as an index of labile pool of SOC compared to microbial biomass carbon. Under different cropping sequences, labile fractions of soil organic carbon exerted consistent positive effect on the extractable nitrogen, phosphorus, and sulfur in soil.