Jyoti Prakash Maity

Effects of inorganic nutrient levels on the biodegradation of benzene, toluene, and xylene (BTX) by Pseudomonas spp. in a laboratory porous media sand aquifer model

The effect of inorganic nutrients (sulfate, phosphate, and ammonium chloride) on the aerobic biodegradation of benzene, toluene, and xylene (BTX) by Pseudomonas spp. was studied in the laboratory using a glass sand tank. The increase of nutrient levels resulted in enhanced bacterial growth and BTX degradation. Sulfate and phosphate serve as key electron acceptors in the microbiological processes degrading BTX. The observed bacterial morphological changes during BTX degradation reveal that the filamentous bacteria were the dominant species at low temperatures about 20 degrees C. The spherical and rod-shaped cells became dominant at higher temperatures ranging from 25 degrees C to 28 degrees C. When the BTX mixture was allowed to be biodegraded for longer incubation periods of 21-42 h at high phosphate concentrations, large amounts of rod-shaped cells were clustered. The morphological adaptation appears to be controlled by the temperature and nutrient levels in the sandy medium where Pseudomonas spp. thrives.

Metallic components of traffic-induced urban aerosol, their spatial variation, and source apportionment

This study proposes a practical method to estimate elemental composition and distribution in order to attribute source and quantify impacts of aerosol particles at an urban region in Kolkata, India. Twelve-hour total particulates were collected in winter (2005–2006) and analyzed by energy-dispersive X-ray fluorescence technique to determine multi-elemental composition, especially trace metals. The aerosols consist of various elements including K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, and Pb which exhibit significant concentration at various sites (pu2009<u20090.05). The concentration of different metallic elements were found in the order of Zn u2009> u2009Pb u2009> u2009Ni u2009> u2009Cu u2009> u2009Cr u2009>u2009 Co. Statistical multivariate analysis and correlation matrix analyses were performed for factor identification and consequent source apportionment. Contour profiles demonstrate spatial variation of elemental compositions indicating possible source contribution along with meteorological influences. Spatial differences were clearly most significant for Zn, Ni, Pb, and Cu reflecting the importance of anthropogenic inputs, primarily from automobile sources.

Arsenic-induced health crisis in peri-urban Moyna and Ardebok villages, West Bengal, India: an exposure assessment study

Drinking of arsenic (As)-contaminated groundwater has adverse effects on health of millions of people worldwide. This study aimed to determine the degree of severity of As exposure from drinking water in peri-urban Moyna and Ardebok villages, West Bengal, India. Arsenic concentrations in hair, nail and urine samp les of the individuals were determined. Arsenical dermatosis, keratosis and melanosis were investigated through medical evaluation. We have evaluated the association between As exposure from drinking water, and keratosis and melanosis outcomes. The results showed that 82.7xa0% of the sampled tube wells contain As concentrations above 10xa0μg/L, while 57.7xa0% contain As concentrations above 50xa0μg/L. The hair, nail and urine As concentrations were positively correlated with As concentrations in drinking water. In our study population, we observed a strong association between As concentrations ranging 51–99xa0μg/L and keratosis and melanosis outcomes, although the probability decreases at higher concentration ranges perhaps due to switching away from the use of As-contaminated tube wells for drinking and cooking purposes. High As concentrations in hair, nail and urine were observed to be associated with the age of the study population. The level of As concentrations in hair, nail and urine samples of the study population indicated the degree of severity of As exposure in the study region.

Effects of gamma radiation on fungi infected rice (in vitro).

Abstract Purpose: This work focuses on the effect of gamma radiation on seed born fungi (in vitro) on Oryza sativa (Swarna, Initial Evaluation Trial-5656). Materials and methods: The responses of fungi to gamma radiation (0–4.2 kGy; 0.12 kGy/h) were studied in individual cultures of major seed-borne fungi including Alternaria alternata, Aspergillus flavus, Trichoderma viride and Curvularia geniculata. Results: The inactivation of individual fungal-viability was noted between 1.0–2.0 kGy for A. alternata and A. flavus and 0.5–1.0 kGy for T. viride and C. geniculata. Complete inhibition was observed at <2.5 kGy. Formations of multiple germ tubes were noted in A. alternata and A. flavus at 2 kGy and 2.5 kGy, respectively. A. flavus required a higher dose to reduce viability to 10% (D10) value in comparison to other selected fungi. Conclusions: Different fungi exhibited different radiosensitivity. The dose range of 2–2.5 kGy was effective in killing all selected fungi. The fungi showing a higher D10 value exhibited multiple germ tubes.

Geochemical characteristics of the mud volcano fluids in southwestern Taiwan and their possible linkage to elevated arsenic concentration in Chianan plain groundwater

Fluid and mud samples were collected from Wushanting (WST), Hsiaokunshui (HKS), Yenshuikeng (YSK), Kuantzeling (KZL), and Kunshuiping (KSP) mud volcanoes of southwestern Taiwan. Concentrations of major ions and trace elements in mud volcanic fluids were analyzed to find the possible linkage to elevated arsenic (As) concentrations in the Chianan plain groundwater. The elevated Na+, K+, and Cl− concentrations indicated possible marine origin of the fluids. The trace element concentrations in the mud volcanic fluids were generally low, but the As concentrations were up to 0.12xa0mg/L. High contents of As, Fe, and Mn were observed in the mud samples. Saturation index calculations indicated that both carbonate and oxide minerals acted as potential sinks for As in the mud volcanic fluids. Arsenic in the dewatering fluids and muds may be transported by the subsurface flow and surface streams as suspended solids and eventually deposited in the Chianan plain aquifers. Under reducing conditions, As may be released from the host minerals (such as Fe- and Mn-oxides/hydroxides), thereby causing widespread groundwater As pollution.

Diversity of epiphytic lichens and their role in sequestration of atmospheric metals

Diversity and abundance of five species of epiphytic lichens were assessed in Kolkata, India. Significant correlation between abundance of lichen species and volume of vehicular traffic suggests atmospheric pollution load in urban region. Parmelia caperata (L.) Ach. and Graphis scripta (L.) Ach. exhibited higher abundance among the five species studied indicating their higher level of tolerance to air pollution. Significant correlations (pxa0<xa00.05) between levels of heavy traffic and both diversity and abundance of all lichen species were also observed. These findings indicate a potential threat to the survival of the lichen communities in Kolkata. Study further deals with quantifying the effectiveness of lichen species in accumulating metallic elements like Pb, Zn, and Cu. This was achieved by analyzing the most abundant lichen species (Parmelia caperata) collected from nine different sites in winter, summer, and monsoon seasons. Metal content in lichen thalli, as analyzed by AAS, shows their elevated levels with the order Pbxa0>xa0Znxa0>xa0Cu. Relationship between metal content and volume of vehicular traffic suggests that co-associated, metallic elements are emitted as vehicle-derived pollutants as well as diffuse industrial emissions. Accumulation of these metals is higher in winter which is proportionate with the higher degree of metabolism due to higher humidity in this season. Study also demonstrates the dynamics of metal uptake by the lichen at different sites influenced with different degree of vehicular traffic. Overall results confirm suitability of lichen with their potential role in sequestration of atmospheric metal contamination.

Groundwater contamination by arsenic in of 24-Parganas district of West Bengal, India: A health risk

Arsenic poisoning due to contaminated groundwater in West Bengal, India, has been thought to be limited to the Lower Ganga Plain (LGP). Skin lesions in villagers led us to evaluate arsenic exposure in the Moyna and Adrebok villages of 24 Porgana (s) West Bengal, India in the LGP where tube wells water was used for drinking water. Results of this investigation are indicated that the groundwater of Moyna and Adrebok villages have been severely affected by As (arsenic). Most of the tubewells exceeded Arsenic (As) concentration upper limit of Indian standard (50µg/L). Few people were affected by chronic bronchitis and whole body infection. The concentration of total arsenic in urine, hair, and nails has been proposed as an indicator of environmental exposure to arsenic. The positive associations between arsenic contents measured in the urine, hair, and nails indicate the degree of severity of arsenic exposure. The arsenic concentrations were found very high in nails with respect to hair and urine. However, arsenic concentrations in hair and urine were found very high. The correlation statistics indicate that the As concentrations in nails, hair and urine are highly correlated with the concentrations of ground water. The arsenic concentrations in urine, hair and nail were increased with the increase of age upto 42 year. The arsenic concentrations in hair and nail were increased more in compare to urine sample. Interestingly the arsenic concentration in urine, hair and nail were decreased from 43 year. As arsenic shows strong reactivity and therefore affinity towards thiol compounds, it preferentially accumulates in peripheral keratin-rich tissues such as skin, nail, and hair. The cases showed significantly higher arsenic accumulation in nail and hair. This load, coupled with the genetic idiosyncrasies of the arsenic-metabolizing genes, determines whether a particular individual will be susceptible to arsenic toxicity.