Differential effect of cadmium and mercury on growth and metabolism of Solanum melongena L. seedlings

The present investigation reports the results of the effect of cadmium and mercury individually on seed germination, seedling growth, number of lateral roots, fresh and dry weights and seedling metabolism in Solanum melongena. Effect of different concentrations of these two heavy metals (Cadmium--50, 100, 300, 500, 700, 1000, 3000, 5000, 7000 and 9000 ppm and Mercury--5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 ppm) and durations for 6, 12 and 24 h were employed for all seedling parameters of brinjal. Both Cd and Hg showed drastic effects at high concentrations and longer duration with regard to seedling growth and metabolism.     

Seasonal distribution and contamination levels of total PHCs, PAHs and heavy metals in coastal waters of the Alang-Sosiya ship scrapping yard, Gulf of Cambay, India

Alang-Sosiya situated on the Gulf of Cambay is one of the largest ship breaking yard in the world. The seasonal distribution and contamination levels of dissolved and/or dispersed total petroleum hydrocarbons (PHCs), total polycyclic aromatic hydrocarbons (PAHs) and heavy metals in seawater during high tide are investigated. The concentrations of petroleum hydrocarbons and heavy metals are higher in the winter than in the monsoon and summer. The concentrations of total PHCs and PAHs are about three times higher in the winter and two times in the monsoon or summer at Along-Sosiya and about twice in all seasons at two stations one on either side 5 km away from it as compared to the reference station at Mahuva, 60 km away towards the south. Further, the levels of PHCs are correlated with salinity and compared with those of other regions. The concentration of all metals is the highest in the winter season followed by the monsoon and summer. We carried out the quantitative analysis of the possible relationships among 13 variables such as Al, Fe, Pb, Mn, Cu, Zn, Cd, Cr, Co, pH, NO3-, NO2 and PO4(3-).     

Studies on urban drinking water quality in a tropical zone

Anthropogenic activities associated with industrialization, agriculture and urbanization have led to the deterioration in water quality due to various contaminants. To assess the status of urban drinking water quality, samples were collected from the piped supplies as well as groundwater sources from different localities of residential, commercial and industrial areas of Lucknow City in a tropical zone of India during pre-monsoon for estimation of coliform and faecal coliform bacteria, organochlorine pesticides (OCPs) and heavy metals. Bacterial contamination was found to be more in the samples from commercial areas than residential and industrial areas. OCPs like α,γ-hexachlorocyclohexane and 1,1 p,p-DDE {dichloro-2, 2-bis(p-chlorophenyl) ethene)} were found to be present in most of the samples from study area. The total organochlorine pesticide levels were found to be within the European Union limit (0.5 μg/L) in most of the samples. Most of the heavy metals estimated in the samples were also found to be within the permissible limits as prescribed by World Health Organization for drinking water. Thus, these observations show that contamination of drinking water in urban areas may be mainly due to municipal, industrial and agricultural activities along with improper disposal of solid waste. This is an alarm to safety of public health and aquatic environment in tropics.     

Intracellular biosynthesis of Au and Ag nanoparticles using ethanolic extract of Brassica oleracea L. and studies on their physicochemical and biological properties

In this present study, we reported broccoli(Brassica oleracea L.) as a potential candidate for the synthesis of gold and silver nanoparticles(NPs) in green chemistry method. The synthesized metal nanoparticles are evaluated their antimicrobial efficacy against different human pathogenic organisms. The physico-chemical properties of gold nanoparticles were analyzed using different analytical techniques such as a UV–Vis spectrophotometer, Field Emission Scanning Electron Microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and a Fourier Transform Infrared spectrophotometer. In addition, gold and silver NP antimicrobial efficacy was checked by disc diffusion assay. UV–Vis color intensity of the nanoparticles was shown at 540 and 450 nm for gold and silver nanoparticles respectively. Higher magnification of the Field Emission Scanning Electron Microscopy image shows the variable morphology of the gold nanoparticles such as spherical, rod and triangular shapes and silver nanoparticles were seen in spherical shapes. The average spherical size of the particles was observed in 24–38 nm for gold and 30–45 nm for silver NPs. X-ray diffraction pattern confirmed the presence of gold nanoparticles and silver nanoparticles which were crystalline in nature. Additionally,the functional metabolites were identified by the Fourier Transform Infrared spectroscopy. IR spectra revealed phenols, alcohols, aldehydes(sugar moieties), vitamins and proteins are present in the broccoli extract which are accountable to synthesize the nanoparticles. The synthesized gold and silver NPs inhibited the growth of the tested bacterial and fungal pathogens at the concentration of 50 μg/m L respectively. In addition, broccoli mediated gold and silver nanoparticles have shown potent antimicrobial activity against human pathogens.     

Soil biogeochemical characteristics influenced by alum application in a municipal wastewater treatment wetland

Constructed treatment wetlands are a relatively low-cost alternative used for tertiary treatment of wastewater. Phosphorus (P) removal capacity of these wetlands may decline, however, as P is released from the accrued organic soils. Little research has been done on methods to restore the treatment capacity of aging constructed wetlands. One possibility is the seasonal addition of alum during periods of low productivity and nutrient removal. Our 3-mo mesocosm study investigated the effectiveness of alum in immobilizing P during periods of reduced treatment efficiency, as well as the effects on soil biogeochemistry. Eighteen mesocosms were established, triplicate experimental and control units for Typha sp., Schoenoplectus californicus, and submerged aquatic vegetation (SAV) (Najas guadalupensis dominated). Alum was slowly dripped to the water column of the experimental units at a rate of 0.91 g Al m(-2) d(-1) and water quality parameters were monitored. Soil cores were collected at experiment initiation and completion and sectioned into 0- to 5- and 5- to 10-cm intervals for characterization. The alum floc remained in the 0- to 5-cm surface soil, however, soil pH and microbial parameters were impacted throughout the upper 10 cm with the lowest pH found in the Typha treatment. Plant type did not impact most biogeochemical parameters; however, data were more variable in the SAV mesocosms. Amorphous Al was greater in the surface soil of alum-treated mesocosms, inversely correlated with soil pH and microbial biomass P in both soil layers. Microbial activity was also suppressed in the surface soil of alum-treated mesocosms. This research suggests alum may significantly affect the biogeochemistry of treatment wetlands and needs further investigation.     

Development of chitosan-alginate based biosorbent for the removal of p-chlorophenol from aqueous medium

Removal of p-chlorophenol (pCP) from synthetic aqueous solutions was studied through adsorption on a biosorbent developed from chitosan (CS) and sodium alginate (SA), the natural cationic and anionic polysaccharides, respectively. Chitosan-coated sodium alginate beads were prepared and treated with calcium chloride solution in order to improve the stability as well as hydrophobic character. The resulting beads (CS/CA) were characterized using FTIR spectra, scanning electron microscopy (SEM), and BET surface analysis. The efficiency of this biosorbent in removing pCP from aqueous medium was studied under batch equilibrium and dynamic column flow experimental conditions. The binding capacity of the biosorbent was studied as a function of initial pH, contact time, initial concentration of adsorbate and amount of biomass. The data were fitted to pseudo-first-order, pseudo-second-order, and Weber–Morris models and found that the adsorption process followed pseudo-first-order kinetics. Further, the equilibrium data were fitted to Freundlich, Langmiur, and Dubinin–Radushkevich (D–R) adsorption isotherms and the isotherm constants were evaluated for adsorption of pCP. The maximum monolayer adsorption capacity of CS/CA beads was found to be 127 mg g^?1. Column flow results were used to generate breakthrough curves. The experimental results suggested that the chitosan–calcium alginate blended biosorbent was effective for the removal of pCP from aqueous medium.     

Assessment of heavy metals (Cd and Pb) and micronutrients (Cu, Mn, and Zn) of paddy (Oryza sativa L.) field surface soil and water in a predominantly paddy-cultivated area at Puducherry (Pondicherry, India), and effects of the agricultural runoff on the elemental concentrations of a receiving rivulet

The concentrations of toxic heavy metals—Cd and Pb and micronutrients—Cu, Mn, and Zn were assessed in the surface soil and water of three different stages of paddy (Oryza sativa L.) fields, the stage I—the first stage in the field soon after transplantation of the paddy seedlings, holding adequate amount of water on soil surface, stage II—the middle stage with paddy plants of stem of about 40 cm length, with sufficient amount of water on the soil surface, and stage III—the final stage with fully grown rice plants and very little amount of water in the field at Bahour, a predominantly paddy cultivating area in Puducherry located on the southeast Coast of India. Comparison of the heavy metal and micronutrient concentrations of the soil and water across the three stages of paddy field showed their concentrations were significantly higher in soil compared with that of water (p?<?0.05) of the fields probably because of accumulation and adsorption in soil. The elemental concentrations in paddy soil as well as water was in the ranking order of Cd?>?Mn?>?Zn?>?Cu?>?Pb indicating concentration of Cd was maximum and Pb was minimum. The elemental concentrations in both soil and water across the three stages showed a ranking order of stage II?>?stage III?>?stage I. The runoff from the paddy fields has affected the elemental concentrations of the water and sediment of an adjacent receiving rivulet.     

Biodegradable Microspheres for Controlled Release of an Antibiotic Ciprofloxacin

Ciprofloxacin (CF) loaded biodegradable microspheres of Poly(lactide-co-caprolactone)-PF127 (a poloxamer block copolymer of Ethylene Oxide/Propylene Oxide) were prepared by using solvent evaporation technique. The microspheres were characterized by differential scanning calorimetry (DSC) and X-ray diffractometry (X-RD) technique to confirm the polymorphism of ciproflaxacin (CF) drug. The X-RD and DSC techniques indicated molecular level dispersion of CF in the microspheres. Scanning electron micrographic images (SEM) of the microspheres indicated smooth surfaces of the spherical microspheres. Cumulative release characteristics of the matrices for CF, the antibiotic drug, were investigated in pH 7.4 media. It was possible to release CF in controlled manner up to 72 h. The developed ciprofloxacin loaded Poly(lactide-co-caprolactone)-PF127 microspheres were evaluated for preliminary antibacterial applications.     

Modeling Air Flow Dynamics in Radon Mitigation Systems: A Simplified Approach

Subslab air flow dynamics provide important diagnostic information for designing optimal radon mitigation systems based on the subslab depressurization technique. In this paper, it is suggested that subslab air flow induced by a central suction point be treated as radial air flow through a porous bed contained between two impermeable disks. Next, we show that subslab air flow is most likely to be turbulent under actual field situations in houses with subslab gravel beds, while remaining laminar when soil is present under the slab. The physical significance of this model is discussed and simplified closedform equations are derived to predict pressure and flows at various distances from a single central depressurization point. A laboratory apparatus was built in order to verify our model and experimentally determine the model coefficients of the pressure drop versus flow for commonly encountered subslab gravel materials. These pressure drop coefficients can be used in conjunction with our simplified model as a rational means of assessing subslab connectivity in actual houses, which is an important aspect of the pre-mitigation diagnostic phase. Preliminary field verification results in a house with gravel under the basement slab are presented and discussed.     

Modeling the energy content of combustible ship-scrapping waste at Alang-Sosiya, India, using multiple regression analysis

Alang-Sosiya is the largest ship-scrapping yard in the world, established in 1982. Every year an average of 171 ships having a mean weight of 2.10 x 10(6)(+/-7.82 x 10(5)) of light dead weight tonnage (LDT) being scrapped. Apart from scrapped metals, this yard generates a massive amount of combustible solid waste in the form of waste wood, plastic, insulation material, paper, glass wool, thermocol pieces (polyurethane foam material), sponge, oiled rope, cotton waste, rubber, etc. In this study multiple regression analysis was used to develop predictive models for energy content of combustible ship-scrapping solid wastes. The scope of work comprised qualitative and quantitative estimation of solid waste samples and performing a sequential selection procedure for isolating variables. Three regression models were developed to correlate the energy content (net calorific values (LHV)) with variables derived from material composition, proximate and ultimate analyses. The performance of these models for this particular waste complies well with the equations developed by other researchers (Dulong, Steuer, Scheurer-Kestner and Bento's) for estimating energy content of municipal solid waste.