Effects of β-cyclodextrin on adsorption and desorption of carbofuran in soils of divergent texture

Laboratory studies were conducted to determine the adsorption/desorption equilibrium of carbofuran between four divergently textured soils and distilled water and an aqueous solution of 0.01?mol?L^?1 β-cyclodextrin using a batch equilibrium technique. The determined adsorption isotherms for silt loam soils were of L-shaped, for sandy loam soil S-shaped, in agreement with a Freundlich isotherm. In the presence of β-cyclodextrin, the adsorption of carbofuran to the four soils was lower than with distilled water. Positive hysteresis was observed in all soils with distilled water, negative hysteresis when using a solution of β-cyclodextrin as desorbent. The results indicate the potential use of β-cyclodextrin for remediation of pesticide-contaminated soils.     

Ecological determinism increases with organism size

After much debate, there is an emerging consensus that the composition of many ecological communities is determined both by species traits, as proposed by niche theory, as well as by chance events. A critical question for ecology is, therefore, which attributes of species predict the dominance of deterministic or stochastic processes. We outline two hypotheses by which organism size could determine which processes structure ecological communities, and we test these hypotheses by comparing the community structure in bromeliad phytotelmata of three groups of organisms (bacteria, zooplankton, and macroinvertebrates) that encompass a 10 000-fold gradient in body size, but live in the same habitat. Bacteria had no habitat associations, as would be expected from trait-neutral stochastic processes, but still showed exclusion among species pairs, as would be expected from niche-based processes. Macroinvertebrates had strong habitat and species associations, indicating niche-based processes. Zooplankton, with body size between bacteria and macroinvertebrates, showed intermediate habitat associations. We concluded that a key niche process, habitat filtering, strengthened with organism size, possibly because larger organisms are both less plastic in their fundamental niches and more able to be selective in dispersal. These results suggest that the relative importance of deterministic and stochastic processes may be predictable from organism size.     

Use of industrial byproducts to filter phosphorus and pesticides in golf green drainage water

Golf courses are vulnerable to phosphate (PO) and pesticide loss by infiltration of the sandy, porous grass rooting media used and through subsurface tile drainage. In this study, an effort was made to remove PO, chlorothalonil, mefenoxam, and propiconazole in a golf green's drainage water with a filter blend comprised of industrial byproducts, including granulated blast furnace slag, cement kiln dust, silica sand, coconut shell-activated carbon, and zeolite. To test this filter media, two 6-h storm events were simulated by repeat irrigation of the golf green after PO and pesticide application. Drainage flows ranged from 0.0034 to 0.6433 L s throughout the course of the simulations. A significant decrease in the chlorothalonil load for the experimental run (with filter media) was observed compared with the control (without filter media) ( < 0.05). In general, percent reductions in chlorothalonil were very high (>80%) near peak flows. In contrast, filter media was not effective in removing PO, mefenoxam, or propiconazole ( > 0.05). Instead, it appears that the filter blend added PO to the effluent above flow rates of 0.037 L s. Overall, flow rate, the amount of filter media used, and contaminant properties may have influenced the filter media's ability to remove contaminants. More research is needed to determine the optimal blend and configuration for the filter media to remove significant amounts of all contaminants investigated.     

Ionically Crosslinked Chitosan/Tragacanth Gum Based Polyelectrolyte Complexes for Antimicrobial Biopackaging Applications

Journal of Polymers and the Environment - The novel polyelectrolyte complexes (PEC) were prepared by mixing different Wt% of Tragacanth gum (TG) to Chitosan (CS) and systematic evaluation of...     

Exploration of Multifunctional Properties of Piper betel Leaves Extract Incorporated Polyvinyl Alcohol-Oxidized Maize Starch Blend Films for Active Packaging Applications

Journal of Polymers and the Environment - This study explains the development of eco-friendly polyvinyl alcohol (PVA)/oxidized maize starch (OMS)/Betel leaves extract (BLE) blend films by employing...     

Integrated process approach for degradation of p-cresol pollutant under photocatalytic reactor using activated carbon/TiO2 nanocomposite: application in wastewater treatment

Environmental Science and Pollution Research - Over the years, biodegradation has been an effective technique for waste water treatment; however, it has its own limitations. In order to achieve a...     

Changes in nutritive value of fish, Channa punctatus after chronic exposure to zinc

The present investigation was undertaken to assess the effects of sublethal concentrations of zinc (0.1 and 0.2 mgl(-1)) on the nutritional value of fish Channa punctatus after exposure for 135 days. The parameters studied were, levels of total proteins, glycogen, total lipids, cholesterol and vitamins (A and D) in the muscle. Total proteins, glycogen, total lipids and vitamin D show highly significant decline from day 90 to 135, while cholesterol and vitamin A, show no significant changes upto 105 days. This study signifies a drastic reduction in the nutritive value of fish, which is compounded by the fact that under natural conditions fish are exposed to these levels of zinc for prolonged periods.     

Effects of estradiol-17beta and 17alpha, 20beta-dihydroxy-4-pregnen-3-one on different phospholipids metabolism and histological changes in ovary during reproductive growth in the catfish, Heteropneustes fossilis (Bloch)

Effect of cumulative doses of estradiol -17beta (E2-7, 14 and 28 mg/kg body weight) and 17alpha, 20beta-dihydroxy-4-pregnen-3-one (17alpha,20betaP-7, 14 and 28 mg/kg body weight) on total phospholipids (TP) and various phospholipids- phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol (PI) and phosphatidylethanolamine (PE) on liver plasma and ovary were investigated during the reproductively active preparatory and prespawning phases of the annual reproductive cycle in the freshwater female catfish, H. fossilis. The effect of E2 on TP was generally stimulatory and has pronounced effect than 17alpha,20betaP during both the phases. The levels of PC was promoted high during prespawning phase by E2 comparatively very less than by 17alpha, 20betaP in studied tissues during both the phases. The levels of PS after E2 treatments was maximum in all tissues during prespawning phase whereas 17alpha,20betaP was effective only in liver during this phase. The PI was elevated in liver during preparatory phase but its elevation was in all studied tissues during prespawning phase after E2 treatments. The levels of PI was most effective in ovary during preparatory phase in response to 17alpha,20betaP. The levels of PE was declined in liver but elevated in ovary after E2 treatments during both the phases. Treatments of E2 during preparatory phase showed greater number of vitellogenic oocytes as compared to 17alpha,20betaP treatments. The present finding has demonstrated that estradiol-17beta has more pronounced effects than the 17alpha,20beta P in regulation of different phospholipids and ovarian recrudescence during reproductively active phases and among the phospholipids the PC is the main phospholipids of vitellogenin/ovarian lipids in H. fossilis.     

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.