A new probability model with application to heavy-tailed hydrological data

Environmental and Ecological Statistics - Because of the dramatic changes that are being observed in the climatic conditions of the world, such as excess of rains, drought and huge floods, we...     

Ecotoxicological assessment of oil-based paint using three-dimensional multi-species bio-testing model: pre- and post-bioremediation analysis

The present study validates the oil-based paint bioremediation potential of Bacillus subtilis NAP1 for ecotoxicological assessment using a three-dimensional multi-species bio-testing model. The model included bioassays to determine phytotoxic effect, cytotoxic effect, and antimicrobial effect of oil-based paint. Additionally, the antioxidant activity of pre- and post-bioremediation samples was also detected to confirm its detoxification. Although, the pre-bioremediation samples of oil-based paint displayed significant toxicity against all the life forms. However, post-bioremediation, the cytotoxic effect against Artemia salina revealed substantial detoxification of oil-based paint with LD₅₀ of 121 μl ml^?1 (without glucose) and >?400 μl ml^?1 (with glucose). Similarly, the reduction in toxicity against Raphanus raphanistrum seeds germination (%FG?=?98 to 100%) was also evident of successful detoxification under experimental conditions. Moreover, the toxicity against test bacterial strains and fungal strains was completely removed after bioremediation. In addition, the post-bioremediation samples showed reduced antioxidant activities (% scavenging?=?23.5?±?0.35 and 28.9?±?2.7) without and with glucose, respectively. Convincingly, the present multi-species bio-testing model in addition to antioxidant studies could be suggested as a validation tool for bioremediation experiments, especially for middle and low-income countries.

?

     

Monitoring and assessment of toxic metals in Gulf War oil spill contaminated soil using laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) was applied for the detection of toxic metals in oil spill contaminated soil (OSCS). The OSCS samples were collected from Khursania Saudi Arabia along the coast of Persian Gulf exposed to oil spills in 1991 Gulf war. Environmentally important elements like Aluminum Magnesium, Calcium, Chromium, Titanium, Strontium, Iron, Barium, Sodium, potassium, Zirconium and Vanadium from the contaminated soil have been detected. Optimal experimental conditions for analysis were investigated. The LIBS system was calibrated using standard samples containing these trace elements. The results obtained using Laser-Induced Breakdown Spectroscopy (LIBS) were compared with the results obtained using Inductively Coupled Plasma Emission Spectroscopy (ICP). The concentrations of some elements (Ba and Cr) were found higher than permissible safe limits. Health risks associated with exposure to such toxic elements are also discussed.     

Impact of storm water on groundwater quality below retention/detention basins

Groundwater from 33 monitoring of peripheral wells of Karachi, Pakistan were evaluated in terms of pre- and post-monsoon seasons to find out the impact of storm water infiltration, as storm water infiltration by retention basin receives urban runoff water from the nearby areas. This may increase the risk of groundwater contamination for heavy metals, where the soil is sandy and water table is shallow. Concentration of dissolved oxygen is significantly low in groundwater beneath detention basin during pre-monsoon season, which effected the concentration of zinc and iron. The models of trace metals shown in basin groundwater reflect the land use served by the basins, while it differed from background concentration as storm water releases high concentration of certain trace metals such as copper and cadmium. Recharge by storm water infiltration decreases the concentration and detection frequency of iron, lead, and zinc in background groundwater; however, the study does not point a considerable risk for groundwater contamination due to storm water infiltration.     

Abundance pattern of wedge clam Donax cuneatus (L.) in different spatial scale in the vicinity of a coastal nuclear power plant

Impact of thermal discharge from a coastal power station (Madras Atomic Power Station, southeast coast of India) on the spatial variability of Donax cuneatus abundance was assessed to determine the impact boundary. Totally, 20 sites were selected both on south and north side in increasing spatial scale from mixing zone, 12 locations were selected toward south side at a distance from 0 (near mixing point) to 2,000 m and eight location were selected toward north from the effluent mixing zone. Mean water temperature along the coast ranged from 29.1 ±0.15°C to 31.2 ± 0.15°C. Total organic carbon content in the sediment ranged from 0.27% to 0.70%. D. cuneatus population on the swash zone was ranged between 1.3 ± 1.5 and 88.3 ± 9.6 m^???2. Meager population of wedge clam was observed up to 100 m (S100) south from mixing point and abundance gradually increased in different spatial scale. Comparatively high abundance was observed from S400 and reached maximum at S1000 (64.0 ± 3.6 m^???2). Similar pattern was observed on north side too but less abundance was observed only up to 80 m (N80). Maximum abundance was observed at control location C3-N500 (88.3 ± 9.6 m^???2). Forty meters on either side of discharge point was highly impacted, 80 to 100 m toward plume flow (south) was moderately impacted, and 80 m north of mixing point also witnessed moderate impact. After 100 m (N100), north was not affected by effluents, whereas between 100 and 400 m, south was influenced slightly. Multivariate clustering pattern on the environmental variables of all sampling locations and population trend of D. cuneatus at those stations showed similarity. Present investigation unambiguously showed that the abundance pattern of D. cuneatus on the sandy beach of east coast of Kalpakkam is not governed by single major factor but due to the result of multiple interacting factors. The population size of the wedge clam with reference to the effect of power plant effluents and other features of habitats of the beach ecosystem are also discussed.     

Fluoride contamination in drinking water in rural habitations of Central Rajasthan, India

Fluoride concentration in groundwater sources used as major drinking water source in rural area of block Nawa (Nagaur District), Rajasthan was examined and the toxic effects by intake of excess fluoride on rural habitants were studied. In block 13, habitations (30%) were found to have fluoride concentration more than 1.5 mg/l (viz. maximum desirable limit of Indian drinking water standards IS 10500, 1999). In five habitations (11%), fluoride concentration in groundwater is at toxic level (viz. above 3.0 mg/l). The maximum fluoride concentration in the block is 5.91 mg/l from Sirsi village. As per the desirable and maximum permissible limit for fluoride in drinking water, determined by World Health Organization or by Bureau of Indian Standards, the groundwater of about 13 habitations of the studied sites is unfit for drinking purposes. Due to the higher fluoride level in drinking water, several cases of dental and skeletal fluorosis have appeared at alarming rate in this region. There is an instant need to take ameliorative steps in this region to prevent the population from fluorosis. Groundwater sources of block Nawa can be used for drinking after an effective treatment in absence of other safe source. The evaluation of various defluoridation methods on the basis of social and economical structure of India reveals that the clay pot chip, activated alumina adsorption, and Nalgonda techniques are the most promising.     

Microelectrophoretic study of environmentally induced DNA damage in fish and its use for early toxicity screening of freshwater bodies

This study investigates the potential of the comet and micronucleus assays of fish DNA as a means of screening the toxicity of aquatic environments. Catla catla and Cirrhinus mrigala collected from the River Chenab in Pakistan were used as a case study for the application of comet and micronucleus techniques. Comet and micronucleus assays were used to compare DNA damage in C. catla and C. mrigala collected from polluted areas of the River Chenab and farmed fish. Atomic absorption spectrophotometry showed an acute level of toxicity from Cd, Cu, Mn, Zn, Pb, Cr, Sn, and Hg in river water. Comet assay showed significant (p < 0.05) DNA damage in C. catla representing 17.33 ± 2.42, 11.53 ± 2.14, and 14.17% DNA in the comet tail, averaged from three sites of the polluted area of the river. Tail moment was observed as 10.06 ± 2.71, 3.11 ± 0.74, and 14.70 ± 1.89, while olive moment was 8.85 ± 1.84, 3.83 ± 0.76, and 7.11 ± 0.73, respectively. Highly significant (p < 0.01) damage was reported in C. mrigala as 37.29 ± 2.51, 34.96 ± 2.53, and 38.80 ± 2.42% DNA in comet tail, tail moment was 23.48 ± 3.90, 19.78 ± 4.26, and 14.30 ± 1.82, and olive moment was 16.22 ± 2.04, 13.83 ± 1.96, and10.99 ± 0.90. Significant (p < 0.05) differences were observed in genotoxicity between farmed and polluted area fish. Micronucleus assay showed a similar picture of significant difference in respect to single and double micronucleus induction: i.e., 23.20 ± 4.19 and 2.80 ± 1.07‰ in C. catla and 44.80 ± 3.73 and 06.20 ± 0.97‰, respectively, in C. mrigala. Nuclear abnormalities were found as 6.00 ± 0.84 and 09.60 ± 1.72/thousand cells, respectively, in both species. The results of this study suggest that these novel fish DNA damage assays can be used as an expedient toxicity screening for aquatic environments.     

Accumulation of mercury and its effect on antioxidant enzymes in brain, liver, and kidneys of mice.

The effect of mercuric chloride (HgCl2) on the activities of catalase, superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and its effect on glutathione (GSH) content were evaluated in different organs (liver, kidneys, and brain) of mice after administration at 0, 0.25, 0.5 and 1.0 mg/kg/day for 14 days. The uptake of mercury shows that the kidneys accumulated the highest levels of mercury compare to brain and liver. The enzyme levels varied in mercury treated organs compare to control. A dose dependent increase of antioxidant enzymes occurred in the liver and kidneys. The increase in enzyme activities correlated with highest mercury accumulation in the kidneys and liver. Mercury is known to generate reactive oxygen species (ROS) in vivo and in vitro, therefore, it is likely that enzyme activities increased to scavenge ROS levels produced as a result of mercury accumulation. Glutathione content increased in liver and kidneys of mercury treated mice compare to control. The results showed that the highest oral dose of mercury significantly increased antioxidant enzymes in kidneys and liver. The increased antioxidant enzymes enhance the antioxidant potential of the organs to reduce oxidative stress.     

Spectroscopic Analysis of Ultraviolet Lamps for Disinfection of Air in Hospitals

In order to have feasibility study of ultraviolet lamps for air disinfection in hospitals, a number of lamps were studied spectroscopically. It was required to understand if these lamps really emitted 253.7 nm. Was the radiation intense enough to disinfect the surrounding air in the hospital? And to know about the percent transmission of the UV rays through the glass of the lamps. The intensity and UV dose were calculated at various distances in air from the lamps. While putting 1-min exposure time in the reciprocity law, the intensity/distance and dose/distance graphs were drawn for various lamps. From the trend line of the graph the distance at which the lamp emitted 10 μW/cm² was calculated. In this study the 1-min exposure time was considered, using the Riley’s designed upper room air disinfection data for 90% kill rate. In the light of the results these lamps were considered fit to be installed either in the air ducts or in the upper room at certain distances for air disinfection, and suggestions were given for the improvement of the system proposed.