Biological impacts of ocean acidification: a postgraduate perspective on research priorities

Research into the effects of ocean acidification (OA) on marine organisms has greatly increased during the past decade, as realization of the potential dramatic impacts has grown. Studies have revealed the multifarious responses of organisms to OA conditions, indicating a high level of intra- and interspecific variation in species’ ability to accommodate these alterations. If we are to provide policy makers with sound, scientific input regarding the expected consequences of OA, we need a broader understanding of these predicted changes. As a group of 20 multi-disciplinary postgraduate students from around the globe, with a study focus on OA, we are a strong representation of ‘next generation’ scientists in this field. In this unique cumulative paper, we review knowledge gaps in terms of assessing the biological impacts of OA, outlining directions for future research.     

Comparative studies of liver and brain glycogen content of male and female Clarias batrachus (L.) after exposure of different doses of arsenic

Different doses of arsenic (As) were used to investigate comparative toxicity on the liver and brain glycogen content on male and female Indian catfish Clarias batrachus (L.). As-induced effects were associated with gender, dose (5, 10, or 15?mg?L^?1), and varying time periods (48, 96, or 144?h). It was noted that As produced dose- and time-dependent liver glycogenolysis and late brain glycogenolysis. Liver glycogenolysis was significantly increased after 48?h at all three As doses. At the highest dose 15?mg?L^?1, liver glycogen were markedly diminished at in both male and female fish, but in females more reduction was observed than in males. However, with brain glycogen, the significant decrease was noted at 144?h with all three dose levels in both genders, with male being more susceptible. Thus, this study indicates that As produces glycogenolysis. The reduction in the liver glycogen content was more pronounced in female than in the male fish, whereas brain glycogen content decrease was more prominent in males.     

Prioritising development planning in the Indian semi-arid Deccan using sustainable livelihood security index approach

This paper presents the status of sustainable livelihood security index (SLSI) of Karnataka, the most drought prone state in the Southern part of India. Computation of ecological security index, economic efficiency index and social equity index, and finally SLSI were carried out at the district level for the entire state, using empirical data. The selected indicators were first normalised, and then using estimated weights, indices were computed. The results indicate that the state has a very low SLSI with only 27.6% of total geographical area (TGA) and 21.7% of population being placed in the ‘sustainable’ and ‘highly sustainable’ categories (covering 10 districts) while only 34% of the TGA covering six districts falls in the ‘moderately sustainable’ category. The remaining area, confined mostly to the northern parts of the state, comprising 14 districts (51.8% of the state’s TGA) is categorised as ‘less sustainable’ and ‘very less sustainable’ exposing 44.4% (27.14 million) of state’s population to the perils of uncertain rainfall, high soil erosion rates, high social inequality and poor resource use efficiency. There is an urgent need to reorient development programmes and prioritise development investments in these vulnerable districts so that they are provided resources and opportunities to improve their ecological (more forest cover and less soil erosion), economic (higher agricultural productivity) and social (improved health and education facilities and rural infrastructure) status and achieve sustainable levels of livelihood.     

Hematological and biochemical alterations in sprayers occupationally exposed to mixture of pesticides at a mango plantation in Lucknow,India

The aim of this study was to examine the hematological and cholinesterase (ChE) activity levels of pesticide sprayers employed in mango plantations at Lucknow. Fifty-two sprayers from mango plantations who regularly spray mixtures of pesticides including organochlorines (OC), organophosphates (OP), and carbamates were included as exposed group. Twenty residents living close to mango plantations, but not involved in pesticide spraying were taken as controls. Pesticide residues for OC were analyzed in blood by gas chromatography with electron capture detector. There was a significant decrease in acetylcholinesterase and butyrylcholinesterase activities in pesticide sprayers (n?=?52) relative to the control group (n?=?20). A significant difference in the frequency distribution of hematological variations in red blood cell, white blood cell, monocytes, neutrophils, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and platelet count was observed. Residues of OC pesticides including α-hexachlorocyclohexane (HCH) and total HCH were found to be significantly higher in the blood of sprayers compared to controls. Hematological variations were quantitatively more frequent among the sprayers with 5 years of pesticide exposure compared to the controls and to subjects with less than 5 years of exposure group. Hematological abnormalities in sprayers were correlated with pesticide exposure as evidenced by lower ChE activity as well as the presence of OC pesticides in blood. The poorly controlled use of pesticides in the plantation appeared to have produced sub-clinical intoxication in the sprayers and indicated the need for training and implementation of proper, safer hygiene practices.     

A simple and robust method for determination of neem (Azadirachta indica A. Juss) oil in neem oil coated urea

The production of neem oil coated urea (NOCU), a technology developed by the Indian Agricultural Research Institute, has been grown to over 2.0 million tons per year. The estimation of neem oil content in NOCU is important due to its significance in ensuring agronomic efficiency. Therefore, this study was taken up to develop a simple method for the determination of neem oil in NOCU. The procedure involves extraction of neem oil from NOCU; saponification of extracted oil; oxidation of released glycerol to formaldehyde, and subsequent conversion of formaldehyde to a dihydrolutidine derivative. Its concentration was determined spectrophotometrically. The recoveries of neem oil from NOCU with oil load of 500 and 1000?ppm were 87.6?±?3.0% and 90.0?±?4.8% respectively with direct method; and improved to 92.6?±?4.0% and 96.7?±?3.8% after including the in situ purification. A simple method based on the Hantzsch reaction was developed for the determination of neem oil in NOCU. This method is superior to earlier methods in terms of sensitivity, simplicity, and time required.     

Microbial pullulan for food,biomedicine, cosmetic,and water treatment: a review

Environmental Chemistry Letters - Most fossil fuel-derived polymers used for food packaging are non-biodegradable and induce pollution by microplastic, calling for safer material. Here we review...     

Invasive plants as biosorbents for environmental remediation: a review

Environmental Chemistry Letters - Water contamination is an environmental burden for the next generations, calling for advanced methods such as adsorption to remove pollutants. For instance,...     

Spectrophotometric method for the determination of chromium (VI) in water samples

A simple and sensitive spectrophotometric method for the determination of chromium has been developed. The method is based on the diazotization of Dapsone in hydroxylamine hydrochloride medium and coupling with N-(1-Napthyl) Ethylene Diamine Dihydrochloride by electrophilic substitution to produce an intense pink azo-dye, which has absorption maximum at 540 nm. The Beer's law is obeyed from 0.02-1.0 microg mL(-1) and the molar absorptivity is 3.4854 L mol(-1) cm(-1). The Limits of quantification and Limit of detection of the proposed method are 0.0012 microg mL(-1) and 0.0039 microg mL(-1) respectively. The method has been successfully applied for the determination of chromium in water samples and the results were statistically evaluated with that of the reference method.     

Reduction of pollutants in pulp paper mill effluent treated by PCP-degrading bacterial strains

Two PCP-degrading bacterial strains, Bacillus cereus (ITRC-S6) and Serratia marcescens (ITRC-S7) were used for the treatment of pulp and paper mill effluent at conditions; 1.0% glucose and 0.5% peptone at 30 +/- 1 degrees C at 120 rpm for 168 h of incubation. These two bacterial strains effectively reduced colour (45-52%), lignin (30-42%), BOD (40-70%), COD (50-60%), total phenol (32-40%) and PCP (85-90%) within 168 h of incubation. However, the highest reduction in colour (62%), lignin (54%), BOD (70%), COD (90%), total phenol (90%) and PCP (100%) was recorded by mixed culture treatment. The bacterial mechanism for the degradation of pulp and paper mill effluent may be explained by an increase in the cells biomass using added co-substrates resulting liberation of significant amount of chloride due to bacterial dechlorination of chlorolignins and chlorophenols this showed reduction in colour, lignin and toxicity in the effluent. Further, GC-MS analysis of ethyl acetate-extractable compounds from treated pulp paper mill effluent reinforces the bacterium capability for the degradation of lignin and pentachlorophenol, as many aromatic compounds such as 2-chlorophenol, 2, 4, 6-trichlorophenol and tetrachlorohydroquinone, 6-chlorohydroxyquinol and tetrachlorohydroquinone detected which were not present in the untreated effluent.     

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.