Arsenic accumulation in native plants of West Bengal, India: prospects for phytoremediation but concerns with the use of medicinal plants

Arsenic (As) is a widespread environmental and food chain contaminant and class I, non-threshold carcinogen. Plants accumulate As due to ionic mimicry that is of importance as a measure of phytoremediation but of concern due to the use of plants in alternative medicine. The present study investigated As accumulation in native plants including some medicinal plants, from three districts [Chinsurah (Hoogly), Porbosthali (Bardhman), and Birnagar (Nadia)] of West Bengal, India, having a history of As pollution. A site-specific response was observed for Specific Arsenic Uptake (SAU; mg kg(-1) dw) in total number of 13 (8 aquatic and 5 terrestrial) collected plants. SAU was higher in aquatic plants (5-60 mg kg(-1) dw) than in terrestrial species (4-19 mg kg(-1) dw). The level of As was lower in medicinal plants (MPs) than in non-medicinal plants, however it was still beyond the WHO permissible limit (1 mg kg(-1) dw). The concentration of other elements (Cu, Zn, Se, and Pb) was found to be within prescribed limits in medicinal plants (MP). Among the aquatic plants, Marsilea showed the highest SAU (avg. 45 mg kg(-1) dw), however, transfer factor (TF) of As was the maximum in Centella asiatica (MP, avg. 1). Among the terrestrial plants, the maximum SAU and TF were demonstrated by Alternanthera ficoidea (avg. 15) and Phyllanthus amarus (MP, avg. 1.27), respectively. In conclusion, the direct use of MP or their by products for humans should not be practiced without proper regulation. In other way, one fern species (Marsilea) and some aquatic plants (Eichhornia crassipes and Cyperus difformis) might be suitable candidates for As phytoremediation of paddy fields.     

Prevalence of multidrug-resistant,coagulase-positive Staphylococcus aureus in nasal carriage,food, wastewater and paper currency in Jalandhar city (north-western), an Indian state of Punjab

Eighteen sites impacted by abandoned mine drainage (AMD) in Pennsylvania were sampled and measured for pH, acidity, alkalinity, metal ions, and sulfate. This study compared the accuracy of four acidity calculation methods with measured hot peroxide acidity and identified the most accurate calculation method for each site as a function of pH and sulfate concentration. Method E1 was the sum of proton and acidity based on total metal concentrations; method E2 added alkalinity; method E3 also accounted for aluminum speciation and temperature effects; and method E4 accounted for sulfate speciation. To evaluate errors between measured and predicted acidity, the Nash-Sutcliffe efficiency (NSE), the coefficient of determination (R ²), and the root mean square error to standard deviation ratio (RSR) methods were applied. The error evaluation results show that E1, E2, E3, and E4 sites were most accurate at 0, 9, 4, and 5 of the sites, respectively. Sites where E2 was most accurate had pH greater than 4.0 and less than 400 mg/L of sulfate. Sites where E3 was most accurate had pH greater than 4.0 and sulfate greater than 400 mg/L with two exceptions. Sites where E4 was most accurate had pH less than 4.0 and more than 400 mg/L sulfate with one exception. The results indicate that acidity in AMD-affected streams can be accurately predicted by using pH, alkalinity, sulfate, Fe(II), Mn(II), and Al(III) concentrations in one or more of the identified equations, and that the appropriate equation for prediction can be selected based on pH and sulfate concentration.     

Water Quality Modeling of Municipal Discharges from Sea Outfalls,Mumbai

The island city of Mumbai with a population of about 10 million generates about 2000 million liters per day (mld) of sewage from the seven service areas of the city sewerage network and discharges it into the adjoining west coast and the two creeks in the Arabian Sea. This has resulted in degradation of coastal water quality, contamination of the adjoining beaches and seafronts. The Municipal Corporation of Greater Mumbai has therefore, undertaken the task of delineating appropriate sewage disposal system to achieve cleaner marine ecosystem through marine outfalls at specific locations. This paper presents the results of the mathematical simulations on the impacts of discharge is-a-vis the length of the outfall and level of land treatment apriori. The results of the simulation indicate the level of bacterial pollution to be higher near the diffuser locations as compared to nearshore regions. 48 hsimulation result analysis shows that FC counts nearthe diffuser location will be in the range of 2000–8000 counts per 100 ml.     

Measurement of particulate phase polycyclic aromatic hydrocarbon (PAHs) around a petroleum refinery

A study on concentrations of ambient particulates viz. total suspended particulate matters (TSP), respirable suspended particulate matter (RSPM) and polycyclic aromatic hydrocarbons (PAH) were carried out at six sites around the Asia’s largest, 12 MMTPA, petroleum refinery in west coast of India. PAH concentrations are correlated with each other in these sites, suggesting that they have related sources and sinks. The present article discusses the monitoring aspects such as sample collection, pretreatment and analytical methods and compares the monitored levels for assessing the source receptor distribution pattern. The main sources of RSPM and PAHs in urban air are automobile exhaust (CPCB, Polycyclic aromatic hydrocarbons (PAHs) in air and their effects on human health. “”, 2003; Manuel et al., Environmental Science and Technology, 13: 227–231, 2004) and industrial emissions like petroleum refinery (Vo-Dinh, Chemical analysis of polycyclic aromatic hydrocarbons, Wiley: New York, 1989; Wagrowaski and Hites, Environmental Science and Technology, 31: 279–282, 1997). Polycyclic aromatic hydrocarbons (PAH) are ubiquitous constituents of urban airborne particulate mostly generated by anthropogenic activities (Li et al., Environmental Science and Technology, 37:1958–2965, 2003; Thorsen et al., Environmental Science and Technology, 38: 2029–2037, 2004; Ohura et al., Environmental Science and Technology, 32: 450–455, 2004) and some of them are of major health concern mainly due to their well-known carcinogenic and mutagenic properties (Soclo et al., Marine Pollution Bulletin, 40: 387–396, 2000; Chen et al., Environment International, 28: 659–668, 2003; Larsen and Baker, Environmental Science and Technology, 32: 450–455, 2003). Limited information is available on PAHs contributions from refineries to ambient air. Hence this study would not only create a database but also provide necessary inputs towards dose-response relationship for fixing standards. Also, since it acts as precursor to green house gas, the data would be useful for climate change assessments. The objective of this article is to find out the concentration of PAHs in particulate matter around petroleum refinery and compare with their concentrations in major Indian urban centers.     

Dioxin uptake by Indian plant species

Dioxins like various gaseous pollutants and aerosols can be scavenged by appropriate vegetative greenbelts. Based on their stomatal properties and the models for contaminant uptake, uptake of dioxin (2,3,7,8-TCDD) by three important Indian plant species, viz. Eugenia jambolana (Jamun), Azadirachta indica (Neem) and Ficus religiosa (Peepal), has been estimated. 2,3,7,8-TCDD is a contaminant with severe harmful ecological ramifications. Computations show that Ficus religiosa has highest uptake capacity. The present exercise has its utility in designing appropriate green-belts for mitigating adverse environmental and human health impacts due to dioxins. This can be an effective management option for mitigating the damages caused by dioxins.     

Suitability assessment of groundwater for drinking, irrigation and industrial use in some North Indian villages

The study comprised suitability assessment of groundwater for drinking, irrigation, and industrial use. A total of 34 groundwater samples were collected from Rewari town and its perimeter from the land chiefly used for agriculture. Physico-chemical characterization of the samples revealed that groundwater from most of the sources was not fit for drinking owing to a high concentration of calcium, magnesium, hardness and fluoride. Suitability for irrigation, too, was low since most of the sources had high value of sodium adsorption ratio (SAR), residual sodium carbonate (RSC), soluble sodium percentage (SSP) and magnesium hazard which can render salinity and alkali hazard to soils on long term use in irrigation. No source of water was found to be suitable for industrial application since it had high concentration of calcium carbonate which can precipitate very easily. It was observed that sodium, sulphate, and chloride were the chief ions present in water and based on the abundance of ions and their correlation type, most of the groundwater samples are of sodium sulphate and/or sodium chloride type. The high concentration of the chemical constituents is attributed to the lithologic composition of the area. It was observed that the water of deep meteoric percolation type was of sodium sulphate type and the shallow of sodium chloride type.     

Assessment of metal enrichments in tsunamigenic sediments of Pichavaram mangroves, southeast coast of India

The 26 December 2004-Tsunami has deposited sediments in the Pichavaram mangrove ecosystem, east coast of India. Ten surface and three core sediment samples were collected within thirty days of the event. High concentrations of Cd, Cu, Cr, Pb, and Ni were observed in the tsunamigenic sediments. With respect to Fe, Zn, and Mn, there was little variation as compared to pre-tsunami values. The geo-accumulation index was calculated in order to assess the contamination of heavy metals in the sediments. The sediments were extremely contaminated with respect to Cd and they showed moderate to strong contamination with respect to Cr, Pb and Ni. The study highlighted the future risk of enhanced metal pollution in near future in this mangrove ecosystem.     

Atmospheric deposition of heavy metals (Cu, Zn, Cd and Pb) in Varanasi City, India

Rapid growth in urbanization and industrialization in developing countries may significantly contribute in heavy metal contamination of vegetables through atmospheric depositions. In the present study, an assessment was made to investigate the spatial and seasonal variations in deposition rates of heavy metals and its contribution to contamination of palak (Beta vulgaris). Samples of bulk atmospheric deposits and Beta vulgaris for analysis of Cu, Zn, Cd and Pb were collected from different sampling locations differing in traffic density and land use patterns. The results showed that the sampling locations situated in industrial or commercial areas with heavy traffic load showed significantly elevated levels of Cu, Zn and Cd deposition rate as compared to those situated in residential areas with low traffic load. The deposition rates of Cu, Zn and Cd were significantly higher in summer and winter as compared to rainy season, however, Pb deposition rate was significantly higher in rainy and summer seasons as compared to winter season. Atmospheric depositions have significantly elevated the levels of heavy metals in B. vulgaris collected during evening as compared to those collected in morning hours. The study further showed that local population has maximum exposure to Cd contamination through consumption of B. vulgaris. The present study clearly points out the urban and industrial activities of a city have potential to elevate the levels of heavy metals in the atmospheric deposits, which may consequently contaminate the food chain and thus posing health risk to the local population.     

Emission of isoprene from common Indian plant species and its implications for regional air quality

Isoprene is most dominant volatile organic compounds (VOC) emitted by many plants. In this study 40 common Indian plant species were examined for isoprene emission using dynamic flow through enclosure chamber technique. Isoprene emission rates of plants species were found to vary from undetectable to 69.5 microg g(-1) h(-1) (Madhuca latifolia). Besides, an attempt has been made to evaluate suitability of 80 common Indian plant species for planting programmes. Out of 80 species, 29 species were moderate to high emitters (10 to < or =25 microg g(-1) h(-1)), 12 species were low emitter emitters (1 to < or =10 microg g(-1) h(-1)) and remaining 39 species were found to be negligible or non emitters (<1 microg g(-1) h(-1)) of isoprene. About 50% plant species selected for planting programmes in India were found to be moderate to high emitters of isoprene.