Surfactant enhanced pyrene degradation in the rhizosphere of tall fescue (Festuca arundinacea)

Environmental Science and Pollution Research - The present study was conducted to evaluate the effect of two non ionic surfactants (Tween 80 and Triton X-100), a biosurfactant (Lecithin), and...     

Optimisation of rainwater tank design from large roofs: A case study in Melbourne, Australia

Rainwater tanks for larger roof areas need optimisation of tank size, which is often not carried out before installation of these tanks. This paper presents a case study of rainwater tank evaluation and design for large roof areas, located in Melbourne, Australia, based on observed daily rainfall data representing three different climatic regimes (i.e. dry average, and wet years). With the aim of developing a comprehensive Decision Support Tool for the performance analysis and design of rainwater tanks, a simple spreadsheet based daily water balance model is developed using daily rainfall data, contributing roof area, rainfall loss factor, available storage volume, tank overflow and irrigation water demand. In this case study, two (185 m³ and 110 m³) underground rainwater tanks are considered. Using the developed model, effectiveness of each tank under different climatic scenarios are assessed. The analysis shows that both the tanks are quite effective in wet and average years, however less effective in dry years. A payback period analysis of the tanks is preformed which reveals that the total construction cost of the tanks can be recovered within 15-21 years time depending on tank size, climatic conditions and future water price increase rates. For the tanks, a relationship between water price increase rates and payback periods is developed. The study highlights the need for detailed optimisation and financial analysis for large rainwater tanks to maximise the benefits.     

The environmental Kuznets curve hypothesis for Bangladesh: the importance of natural gas,liquefied petroleum gas,and hydropower consumption

Environmental Science and Pollution Research - Mitigating environmental pollution has become a global agenda keeping the sustainability of socioeconomic and environmental development into...     

The diagnostic accuracy of intraoperative frozen section biopsy for diagnosis of sentinel lymph node metastasis in breast cancer patients: a meta-analysis

Environmental Science and Pollution Research - Sentinel lymph node (SLN) sampling is important for evaluating the nodal stage of breast cancer when the axillary nodes are clinically free of...     

Risk assessment and chemical decontamination of an oxime carbamate insecticide (methomyl) from eggplant, Solanum melongena L.

Methomyl, S-methyl (EZ)-N-(methylcarbamoyloxy)thioacetimidate, is a systemic insecticide chosen for the management of shoot and fruit borer, Leucinodes orbonalis G. Codex Alimentarious Commission has proposed a maximum residue limit (MRL) of 0.2 mg kg^???1 of methomyl, and there is a need to validate this value on eggplant. First + first-order model can explain the nonlinear dissipation pattern of methomyl conveniently in comparison to first-order kinetics. The preharvest intervals (PHI) of 27.3 and 35.3 days as obtained from first + first-order model for single and double doses would bring down the methomyl residue below MRL in actual practice. The respective half-lives were 6.6 and 7.8 days. On the other hand, first-order model suggests methomyl dissipated with a half-life value around 5 days and proposed PHIs of 6.57 and 8.57 days for single and double doses, which was far from reality. Hence, five different decontamination agents were chosen for the decontamination of methomyl from eggplant. Safety factors such as theoretical maximum daily intake and maximum permissible intake were used to evaluate risk assessment to human health. A 3-day waiting period for the both doses, following conventional agricultural practice and processing factor could not ensure sufficient margin of safety. Subjecting the data to a processing factor of 60% could not bring the residues below the proposed MRL by Codex. Methomyl is not found appropriate and effective for application in eggplant. Either the proposed MRL needs to be revised or good agricultural practice involving methomyl for plant protection in eggplant cultivation is questioned.     

Development of Anticorrosive Poly(Ether-Urethane) Amide Coatings from Linseed Oil: A Sustainable Resource

Polyetheramide(PEtA) resin was synthesized by the condensation polymerization of N,N-bis(2-hydroxy ethyl) linseed oil fatty amide diol (HELA) with resorcinol. It was further treated with different percentage of toluylene 2-4-diisocyanate (TDI) to obtain the urethane modified polyetheramide resins (UPEtA). The structural elucidation of PEtA and urethane modified polyetheramide(UPEtA) were carried out by FT-IR, ¹H-NMR and ¹³C-NMR spectroscopic techniques. These analyses confirm the formation of PEtA and UPEtA. Physico-chemical and physico-mechanical analysis were performed by standard laboratory methods. The resin composition UPEtA-24 showed best physico-mechanical properties with scratch hardness 2.0 kg, impact resistance 150 lb/in. and good bending ability. The thermal stability and curing behavior of polymers were respectively studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Thermal analysis shows that these coatings can be used safely upto 190 °C. The coatings of UPEtA resins were prepared on mild steel strips. The anticorrosive behavior of UPEtA coatings were investigated in acid, alkali, water and xylene. All the coatings exhibit good chemical resistance performance in acid, alkali, saline and organic solvents, while the resin UPEtA-24 shows the best performance.     

Synergistic Effects of Multiple Metal Contaminants on Electrokinetic Remediation of Soils

This article presents a bench‐scale study performed to investigate the removal of heavy metals when they exist individually and in combination in soils. Electrokinetic experiments were conducted using two types of clayey soils, kaolin and glacial till. These soils were contaminated with Cr(VI) only, with Ni(II) only, and with Cr(VI), Ni(II), and Cd(II) combined. It was found that in kaolin, a significant pH variation occurred due to electric potential application, affecting the adsorption‐desorption and dissolution‐precipitation, as well as the extent of migration of the contaminants. In glacial till, however, pH changes were not affected significantly. In both kaolin and glacial till, the migration of Cr(VI) and Ni(II) was higher when they were present individually compared to when they existed together with Cd(II). Cr(VI) migration as single or combined contaminant was lower in kaolin as compared to that in glacial till. This result was due to the low pH conditions created near the anode region in kaolin that led to high Cr(VI) adsorption to the clay surfaces. In glacial till, however, nickel precipitated with or without the presence of co‐contaminants due to high pH conditions in the soil. Overall, this study demonstrates that adsorption, precipitation, and reduction are the significant hindering mechanisms for the removal of heavy metals using electrokinetic remediation. The direction of the contaminant migration and overall removal efficiency depend on the polarity of the contaminant, the presence of co‐contaminants, and the type of soil. © 2001 John Wiley & Sons.     

Feasibility of the hydrogen sulfide test for the assessment of drinking water quality in post-earthquake Haiti

In 2010, a magnitude 7.0 earthquake struck Haiti, severely damaging the drinking and wastewater infrastructure and leaving millions homeless. Compounding this problem, the introduction of Vibrio cholerae resulted in a massive cholera outbreak that infected over 700,000 people and threatened the safety of Haiti’s drinking water. To mitigate this public health crisis, non-government organizations installed thousands of wells to provide communities with safe drinking water. However, despite increased access, Haiti currently lacks the monitoring capacity to assure the microbial safety of any of its water resources. For these reasons, this study was designed to assess the feasibility of using a simple, low-cost method to detect indicators of fecal contamination of drinking water that could be implemented at the community level. Water samples from 358 sources of drinking water in the Léogâne flood basin were screened with a commercially available hydrogen sulfide test and a standard membrane method for the enumeration of thermotolerant coliforms. When compared with the gold standard method, the hydrogen sulfide test had a sensitivity of 65 % and a specificity of 93 %. While the sensitivity of the assay increased at higher fecal coliform concentrations, it never exceeded 88 %, even with fecal coliform concentrations greater than 100 colony-forming units per 100 ml. While its simplicity makes the hydrogen sulfide test attractive for assessing water quality in low-resource settings, the low sensitivity raises concerns about its use as the sole indicator of the presence or absence of fecal coliforms in individual or community water sources.     

Geochemical assessment of metal transport in glacial till during electrokinetic remediation

This paper presents the chemical speciation and retention behavior of chromium (Cr), nickel (Ni), and cadmium (Cd) prior to and after the electrokinetic remediation in glacial till soil. The speciation of the metals was predicted using the chemical speciation program MINEQL⁺. The simulations were performed for single-contaminant with only Cr(VI) or Ni, and multi-contaminants consisting of: (1) Cr(VI), Ni, and Cd; (2) Cr(III), Ni and Cd; (3) Cr(VI), Cr(III), Ni and Cd; (4) Cr(VI), Ni, and Cd with reducing agents; and (5) Cr(III), Ni, and Cd with oxidizing agent (Mn). The results showed that the speciation and distribution of cationic metals [Ni, Cd, and Cr(III)] in glacial till soil remain unaffected or slightly affected during electrokinetics. This is attributed to the high pH buffering capacity of the glacial till, leading the metals to precipitate in the soil prior to and after electrokinetics. This study showed that during electrokinetics, Cr(VI) existed as anionic complex and migrated towards the anode and the migration is maximum in case of a single-contaminant system. The study also showed that near the anode in the absence of any reducing and oxidizing agent, Cr(VI) mostly adsorbed, and some of Cr(VI) reduced to Cr(III) and migrated towards the cathode and finally precipitated due to high pH conditions. Ni and Cd remain adsorbed or precipitated due to the high pH conditions throughout the soil. Among the reducing agents, the sulfide had significant effect on the migration of metals compared to ferrous ions. While in the presence of oxidizing agent (Mn), no noticeable Cr(VI) was found in the soil sample indicating the reduction of Cr(VI) to Cr(III) and the predominance of reducing conditions due to the presence of naturally occurring iron in the glacial till soil. Overall, this study provides a reasonable explanation of the speciation and distribution of chromium, nickel and cadmium during the electrokinetic remediation of glacial till soil.