Subsurface nutrient modelling using finite element model under Boro rice cropping system

Boro rice, an emerging low-risk crop variety of rice, cultivated using residual or stored water after Kharif season. To enhance the quality and production of rice, potassium (K) and phosphorus (P) are the common constituents of agricultural fertilizers. However, excess application of fertilizers causes leaching of nutrients and contaminates the groundwater system. Therefore, assessment and optimization of fertilizer dose are needed for better management of fertilizers. Towards this, the present study determines the path, persistence, and mobility of K and P under the Boro rice cropping system. The experimental site consisted of four plots having Boro rice with four different fertilizer doses of nitrogen (N), P, K viz. 100%, 75%, 50%, and 25% of the recommended dose. Disturbed soil samples were analysed for K and P from pre-sown land to tillering stage at 0–5, 5–10, 10–15, 15–30, 30–45, and 45–60 cm depths. Simultaneously, K and available P were also simulated in the subsurface soil layers through the HYDRUS-1D model. The statistical comparisons were made with RMSER, E, and PBIAS between the modelled values and laboratory-measured values. Although, the results showed that all the treatments considered had agreeable simulations for both K and P, the K simulations were found to be better as compared to P simulations except for 25% where P simulations outperformed K. The simulated concentration at all doses was found most appropriate when measured for the subsurface layers (up to 45 cm), while showed an underestimation in the bottom layers (45–60 cm) of soil.

     

Selective separation of cobalt versus nickel by split-phosphinate complexation using a phosphonium-based ionic liquid

Environmental Chemistry Letters - The rising demand of metals for batteries is calling for advanced methods to separate metallic mixtures in mineral ores and electronic waste. In particular, the...     

Use of water quality index and multivariate statistical techniques for the assessment of spatial variations in water quality of a small river

Rapid urban development has led to a critical negative impact on water bodies flowing in and around urban areas. In the present study, 25 physiochemical and biological parameters have been studied on water samples collected from the entire section of a small river originating and ending within an urban area. This study envisaged to assess the water quality status of river body and explore probable sources of pollution in the river. Weighted arithmetic water quality index (WQI) was employed to evaluate the water quality status of the river. Multivariate statistical techniques namely cluster analysis (CA) and principal component analysis (PCA) were applied to differentiate the sources of variation in water quality and to determine the cause of pollution in the river. WQI values indicated high pollution levels in the studied water body, rendering it unsuitable for any practical purpose. Cluster analysis results showed that the river samples can be divided into four groups. Use of PCA identified four important factors describing the types of pollution in the river, namely (1) mineral and nutrient pollution, (2) heavy metal pollution, (3) organic pollution, and (4) fecal contamination. The deteriorating water quality of the river was demonstrated to originate from wide sources of anthropogenic activities, especially municipal sewage discharge from unplanned housing areas, wastewater discharge from small industrial units, livestock activities, and indiscriminate dumping of solid wastes in the river. Thus, the present study effectively demonstrates the use of WQI and multivariate statistical techniques for gaining simpler and meaningful information about the water quality of a lotic water body as well as to identify of the pollution sources.     

Chemical characterization and health risk assessment of soil and airborne particulates metals and metalloids in populated semiarid region,Agra, India

Rapid industrialization and urbanization have contaminated air and soil by heavy metals and metalloids from biogenic, geogenic and anthropogenic sources in many areas of the world, either directly or indirectly. A case study was conducted in three different microenvironments, i.e., residential sites, official sites and official sites; for each sites, we choose two different locations to examine the elemental concentration in fine particulate matter and soil and health risk assessment. The concentration values of heavy metals and metalloid in the air and soil in the Agra region were measured using inductively coupled plasma-atomic emission spectrophotometry. The exposure factor and health risk assessment for carcinogenic and non-carcinogenic effects due to heavy metals and metalloid contaminants have been calculated for both children and adults by following the methodology prescribed by USEPA. For the elements As, Cr, Cd, Ni and Pb selected for the carcinogenic health risk assessment, the calculated results lie above the threshold ranges. We observed the lifetime exposure to heavy metals through mainly three pathways, ingestion, inhalation and dermal contact of soil and air from that particular area. Therefore, the overall hazard quotient (HQ) values for children are more than that of adults. The assessment of health risk signifies that there were mainly three exposure pathways for people: ingested, dermal contact and inhalation. The major exposure pathway of heavy metals to both children and adults is ingestion. The values of HQ are higher than the safe level (=1), indicating a high risk exists in present condition. Meanwhile, HQs value for children is higher than that for adults, indicating that children have higher potential health risk than adults in this region.

     

Characterization of carbonaceous aerosols over Delhi in Ganga basin: seasonal variability and possible sources

The mass concentration of carbonaceous species, organic carbon (OC), and elemental carbon (EC) using a semicontinuous thermo-optical EC-OC analyzer, and black carbon (BC) using an Aethalometer were measured simultaneously at an urban mega city Delhi in Ganga basin from January 2011 to May 2012. The concentrations of OC, EC, and BC exhibit seasonal variability, and their concentrations were ～2 times higher during winter (OC 38.1?±?17.9 μg m^?3, EC 15.8?±?7.3 μg m^?3, and BC 10.1?±?5.3 μg m^?3) compared to those in summer (OC 14.1?±?4.3 μg m^?3, EC 7.5?±?1.5 μg m^?3, and BC 4.9?±?1.5 μg m^?3). A significant correlation between OC and EC (R?=?0.95, n?=?232) indicate their common emission sources with relatively lower OC/EC ratio (range 1.0–3.6, mean 2.2?±?0.5) suggests fossil fuel emission as a major source of carbonaceous aerosols over the station. On average, mass concentration of EC was found to be ～38 % higher than BC during the study period. The measured absorption coefficient (b_abs) was significantly correlated with EC, suggesting EC as a major absorbing species in ambient aerosols at Delhi. Furthermore, the estimated mass absorption efficiency (σ_abs) values are similar during winter (5.0?±?1.5 m² g^?1) and summer (4.8?±?2.8 m² g^?1). Significantly high aerosol loading of carbonaceous species emphasize an urgent need to focus on air quality management and proper impact assessment on health perspective in these regions.     

Hazard assessment of metals in invasive fish species of the Yamuna River,India in relation to bioaccumulation factor and exposure concentration for human health implications

Monitoring of heavy metals was conducted in the Yamuna River considering bioaccumulation factor, exposure concentration, and human health implications which showed contamination levels of copper (Cu), lead (Pb), nickel (Ni), and chromium (Cr) and their dispersion patterns along the river. Largest concentration of Pb in river water was 392 μg L^?1; Cu was 392 μg L^?1 at the extreme downstream, Allahabad and Ni was 146 μg L^?1 at midstream, Agra. Largest concentration of Cu was 617 μg kg^?1, Ni 1,621 μg kg^?1 at midstream while Pb was 1,214 μg kg^?1 at Allahabad in surface sediment. The bioconcentration of Cu, Pb, Ni, and Cr was observed where the largest accumulation of Pb was 2.29 μg kg^?1 in Oreochromis niloticus and 1.55 μg kg^?1 in Cyprinus carpio invaded at Allahabad while largest concentration of Ni was 174 μg kg^?1 in O. niloticus and 124 μg kg^?1 in C. carpio in the midstream of the river. The calculated values of hazard index (HI) for Pb was found more than one which indicated human health concern. Carcinogenic risk value for Ni was again high i.e., 17.02?×?10^?4 which was larger than all other metals studied. The results of this study indicated bioconcentration in fish due to their exposures to heavy metals from different routes which had human health risk implications. Thus, regular environmental monitoring of heavy metal contamination in fish is advocated for assessing food safety since health risk may be associated with the consumption of fish contaminated through exposure to a degraded environment.     

Molasses-based growth and lipid production by Chlorella pyrenoidosa: A potential feedstock for biodiesel

Biodiesel provides a feasible solution to the twin crisis of energy security and environmental concerns prevalent today, and it can be extracted from conventional oil crops as well as microalgae. However, lipid productivity in case of microalgae is much higher and has several advantages as compared with crop plants, so it is a better feedstock for biodiesel. In case of Chlorella pyrenoidosa, the heterotrophic cultured cells were found to be better in terms of lipid production, and ultimately biodiesel production, but the bottleneck is that in this mode glucose is used to feed the cells, which amounts to almost 80% of the total cost of biodiesel production. The purpose of this study is to evaluate and highlight the feasibility of using the industrially cheap cane molasses as a carbon source in place of glucose for a large-scale, low-cost lipid production of Chlorella pyrenoidosa. When treated molasses was used as a carbon source instead of glucose, the biomass sharply increases from 0.89 to 1.22 g L^–1. On the other hand, the total lipid content increases from 0.27 to 0.66 g g^–1. The specific growth rate and yield was higher in treated molasses as compared with that in glucose-supplemented. A mathematical model was also developed based on logistic, Luedeking–Piret, and Luedeking-Piret-like equations. Model predictions were in satisfactory agreement with the measured data, and the mode of lipid production was growth-associated.     

Ganga River sediments of India predominate with aerobic and chemo-heterotrophic bacteria majorly engaged in the degradation of xenobiotic compounds

Environmental Science and Pollution Research - Sediment provides a stagnant habitat to microbes that accumulate organic matter and other industrial pollutants from the upper layer of the water. The...     

Wood Polypropylene (PP) Composites Manufactured by Mango Wood Waste with Virgin or Recycled PP: Mechanical,Morphology, Melt Flow Index and Crystalline Behaviour

Compositions of wood-polypropylene composites (WPCs) are prepared through melt compounding followed by injection moulding. WPCs are formulated for eight compositions with a different weight ratio of wood, virgin or recycled polypropylene and coupling agent. WPCs compositions are compared in terms of Melt Flow Index, Tensile, FESEM images, Flexural and crystallinity index for same operating variable conditions. From the results, recycled polypropylene based WPCs are superior in comparison to virgin polypropylene based WPCs. With the addition of 5 % coupling agent in recycled polypropylene-based composites for 45:50 composition, tensile and flexural values of WPCs are higher in comparison to all composition and neat virgin or recycled polypropylene. This work stands for the utilization of waste wood with recycled plastic for replacement of wood and virgin plastic.