Hexachlorocyclohexane (HCH) as new Stockholm Convention POPs��a global perspective on the management of Lindane and its waste isomers

Purpose

Hexachlorocyclohexane (HCH) isomers (??-, ??- and ??- (Lindane)) were recently included as new persistent organic pollutants (POPs) in the Stockholm Convention, and therefore, the legacy of HCH and Lindane production became a contemporary topic of global relevance. This article wants to briefly summarise the outcomes of the Stockholm Convention process and make an estimation of the amount of HCH waste generated and dumped in the former Lindane/HCH-producing countries.

Results

In a preliminary assessment, the countries and the respective amount of HCH residues stored and deposited from Lindane production are estimated. Between 4 and 7 million tonnes of wastes of toxic, persistent and bioaccumulative residues (largely consisting of alpha- (approx. 80%) and beta-HCH) are estimated to have been produced and discarded around the globe during 60 years of Lindane production. For approximately 1.9 million tonnes, information is available regarding deposition. Countries are: Austria, Brazil, China, Czech Republic, France, Germany, Hungary, India, Italy, Japan, Macedonia, Nigeria, Poland, Romania, Slovakia, South Africa, Spain, Switzerland, Turkey, The Netherlands, UK, USA, and former USSR. The paper highlights the environmental relevance of deposited HCH wastes and the related POPs?? contaminated sites and provides suggestions for further steps to address the challenge of the legacy of HCH/Lindane production.

Conclusion

It can be expected that most locations where HCH waste was discarded/stockpiled are not secured and that critical environmental impacts are resulting from leaching and volatilisation. As parties to the Stockholm Convention are legally required to take action to stop further POPs pollution, identification and evaluation of such sites are necessary.     

Prediction of the solubility of zinc, copper, nickel, cadmium, and lead in metal-contaminated soils

Risk assessment of metal-contaminated soil depends on how precisely one can predict the solubility of metals in soils. Responses of plants and soil organisms to metal toxicity are explained by the variation in free metal ion activity in soil pore water. This study was undertaken to predict the free ion activity of Zn, Cu, Ni, Cd, and Pb in metal-contaminated soil as a function of pH, soil organic carbon, and extractable metal content. For this purpose, 21 surface soil samples (0–15 cm) were collected from agricultural lands of various locations receiving sewage sludge and industrial effluents for a long period. One soil sample was also collected from agricultural land which has been under intensive cropping and receiving irrigation through tube well water. Soil samples were varied widely in respect of physicochemical properties including metal content. Total Zn, Cu, Ni, Cd, and Pb in experimental soils were 2,015?±?3,373, 236?±?286, 103?±?192, 29.8?±?6.04, and 141?±?270 mg kg^?1, respectively. Free metal ion activity, viz., pZn²⁺, pCu²⁺, pNi²⁺, pCd²⁺, and pPb²⁺, as estimated by the Baker soil test was 9.37?±?1.89, 13.1?±?1.96, 12.8?±?1.89, 11.9?±?2.00, and 11.6?±?1.52, respectively. Free metal ion activity was predicted by pH-dependent Freundlich equation (solubility model) as a function of pH, organic carbon, and extractable metal. Results indicate that solubility model as a function of pH, Walkley–Black carbon (WBC), and ethylenediaminetetraacetic acid (EDTA)-extractable metals could explain the variation in pZn²⁺, pCu²⁺, pNi²⁺, pCd²⁺, and pPb²⁺ to the extent of 59, 56, 46, 52, and 51 %, respectively. Predictability of the solubility model based on pH, KMnO₄-oxidizable carbon, and diethylenetriaminepentaacetic acid-extractable or CaCl₂-extractable metal was inferior compared to that based on EDTA-extractable metals and WBC.     

A preliminary process design and economic assessment of a catalyst rejuvenation process for waste disposal of refinery spent catalysts

Spent hydroprocessing catalysts from refineries have been classified as hazardous solid waste by the United States Environmental Protection Agency (USEPA), refiners must find a viable but economical solution to solve this serious environmental issue. Catalyst rejuvenation is an attractive option for minimizing the environmental problems associated with spent catalysts. In this study, a preliminary design for such a process and the corresponding economic analysis are performed to assess the proposed catalyst rejuvenation process for metal-fouled spent catalysts generated in residue hydroprocessing units. The scenarios used in the economic assessment are based on three options of process synthesis and two operator modes. It is found that the option of rejuvenating medium and lightly fouled spent catalyst produced by the refinery will be the best solution for refiners, both environmentally and economically.     

Nanocarriers for drug delivery applications

Environmental Chemistry Letters - Nanobiotechnology research has recently provided numerous basic and applied advances in the health sector. Nanocarriers have been developed for efficient drug...     

Biomass and carbon budgeting of sustainable agroforestry systems as ecosystem service in Indian Himalayas

Adoption of agroforestry is paramount as a climate change mitigation and adaptation strategy. The assessment of plant biomass is crucial for understanding the vulnerability of biological systems to climate change. In the present study, agroforestry systems viz., agrisilviculture (AS), agrihorticulture (AH), agrihortisilviculture (AHS) and agrisilvihorticulture (ASH) were investigated for biomass production and carbon stock in vegetation as well as in soil in the Indian central Himalaya along the elevation i.e. E₁ (<1100 m), E₂ (1100–1400 m), E₃ (1400–1700 m), E₄ (1700–2000 m) and E₅ (>2000 m). Mean aboveground and belowground biomass were 73.9% and 26.1%, respectively, of total biomass (64.4 t ha^?1) in agroforestry systems. Fodder and/or timber trees accounted for 31% (in AHS) to 74% (in AS) of total biomass, while fruit trees accounted for 18% (in ASH) to 73% (in AH) of total biomass. The contribution of agriculture crops to total biomass fluctuated between 19% (in ASH) and 26% (in AH). Total vegetation biomass, soil carbon and total carbon density in agroforestry systems increased significantly along the elevation, with maximum biomass at elevation E₅ (32.0 t ha^?1, 64.7 t C ha^?1 and 96.7 t C ha^?1). Total biomass of vegetation among agroforestry systems differed significantly. Soil carbon stock was highest in AHS (59.5 t C ha^?1) and total carbon density (vegetation + soil) was highest in ASH (93.0 t C ha^?1). Thus, in Indian Himalayas, vegetation biomass, carbon stock, soil and total carbon (vegetation + soil) stock increased along the elevation.

Abbrviations: AG: aboveground; BG: belowground; WD: wood density; VOB: volume over bark; BEF: biomass expansion factor; AS: agrisilviculture; AH: agrihorticulture; ASH: agrisilvihorticulture; AHS: agrihortisilviculture; E: elevation; C: carbon; CO₂: carbon-di-oxide; IPCC: Intergovernmental Panel on Climate Change; DBH: diameter at breast height; AGBD: aboveground biomass density; BGBD: belowground biomass density; GSVD: growing stock volume density     

High-resolution modeling and evaluation of ozone air quality of Osaka using an MM5-CMAQ system

High-resolution modeling approach is increasingly being considered as a necessary step for improving the monitoring and predictions of regional air quality.This is especially true for highly urbanized region with complex terrain and land-use.This study uses Community Multiscale Air Quality (CMAQ) model coupled with MM5 mesoscale model for a comprehensive analysis to assess the suitability of such high-resolution modeling system in predicting ozone air quality in the complex terrains of Osaka,Japan.The 1-km and 3-km grid domains were nested inside a 9-km domain and the domain with 1-km grid covered the Osaka region.High-resolution Grid Point Value-Mesoscale Model μgPV-MSM) data were used after suitable validation.The simulated ozone concentrations were validated and evaluated using statistical metrics using performance criteria set for ozone.Daily maxima of ozone were found better simulated by the 1-km grid domain than the coarser 9-km and 3-km domains,with the maximum improvement in the mean absolute gross error about 3 ppbv.In addition,1-km grid results fared better than other grids at most of the observation stations that showed noticeable differences in gross error as well as correlation.These results amply justify the use of the integrated high-resolution MM5-CMAQ modeling system in the highly urbanized region,such as the Osaka region,which has complex terrain and land-use.     

High-resolution modeling and evaluation of ozone air quality of Osaka using MM5-CMAQ system

High-resolution modeling approach is increasingly being considered as a necessary step for improving the monitoring and predictions of regional air quality. This is especially true for highly urbanized region with complex terrain and land-use. This study uses Community Multiscale Air Quality (CMAQ) model coupled with MM5 mesoscale model for a comprehensive analysis to assess the suitability of such high-resolution modeling system in predicting ozone air quality in the complex terrains of Osaka, Japan. The 1-km and 3-km grid domains were nested inside a 9-km domain and the domain with 1-km grid covered the Osaka region. High-resolution Grid Point Value-Mesoscale Model (GPV-MSM) data were used after suitable validation. The simulated ozone concentrations were validated and evaluated using statistical metrics using performance criteria set for ozone. Daily maxima of ozone were found better simulated by the 1-km grid domain than the coarser 9-km and 3-km domains, with the maximum improvement in the mean absolute gross error about 3 ppbv. In addition, 1-km grid results fared better than other grids at most of the observation stations that showed noticeable di erences in gross error as well as correlation. These results amply justify the use of the integrated high-resolution MM5-CMAQ modeling system in the highly urbanized region, such as the Osaka region, which has complex terrain and land-use.     

Effects of molecular weight and concentration of carboxymethyl cellulose on morphology of hydroxyapatite nanoparticles as prepared with one-step wet chemical method

Nano-sized apatite particles (nAP) synthesized with carboxymethyl cellulose (CMC) have shown great application potentials in in situ heavy metal remediation. However, differences in CMC’s properties effects on the size of nAP produced are not well understood. In this paper, two types of CMC, with respective molecular weights (MW) of ～120000 and ～240000 Dalton or respective polymerization degrees of 500 (CMC-500) and 1050 (CMC-1050), were studied in a concentration range of 0.05%–0.5% (w/w) for nAP synthesis. Morphology of the particles was characterized with transmission electron microscopy (TEM). Results showed that 0.05% CMC-500 solution gave an average particle size of 148.7±134.9 nm, 0.25% CMC-500 solution produced particles of 21.8±20.4 nm, and, 0.5% CMC-500 solution contained particles of 15.8±7.7 nm. In comparison, 0.05% CMC-1050 solution produced nanoparticles of 6.8±3.2 nm, 0.25% CMC-1050 produced smaller nAP of 4.3±3.2 nm, and 0.5% CMC-1050 synthesized the smallest nanoparticles in this study, with an average diameter of 3.0±2.1 nm. Chemical composition of the products was identified with X-ray diffraction (XRD) as pure hydroxyapatite. Interactions between nAP and CMC were discussed with help of attenuated total reflection Fourier transform infrared (ATRFTIR) spectroscopic data. This study showed that CMC at higher concentration as well as higher MW facilitated to produce finer nanoparticles, showing that nAP size could be manipulated by selecting appropriate CMC MW and/or applying appropriate CMC concentration.     

Oxidative stress mediated cytotoxicity of TiO2 nano anatase in liver and kidney of Wistar rat

This study examined the adverse effects of TiO₂ nanoparticle (nano-TiO₂) on the kidney and liver of Wistar rats. Changes of serum biochemical parameters and pathological lesions indicated that liver and kidney were significantly affected in animals treated with 50?mg?kg^?1 of nano-TiO₂. The inverse relationship between the level of reactive oxygen species and the activities of superoxide dismutase, catalase, and glutathione peroxidase indicates that nano-TiO₂ induces oxidative stress. A significant increase in the apoptosis of liver and kidney in a dose-dependent manner was also observed. The ultrastructural observations confirmed the internalization of nano-TiO₂ and their direct involvement in the mitochondria-mediated cytotoxicity. Data indicated that nano-TiO₂ induce oxidative stress which produces genotoxicity such as oxidative DNA damage, micronuclei (MN) induction, and cell apoptosis in liver and kidney.     

Concentrations of Hchs and Ddts in the Tissues of River Dolphins,Platanista Gangetica,From the River Ganges,India

Abstract

Concentrations of HCH and DDT organochlorine insecticide residues were measured in blubber, muscle and oil samples from three specimens of river dolphins, Platanista gangetica, from the River Ganges, India. Concentrations of HCH and DDT ranged from 94 to 289 ng g^?1 and from 1324 to 9388 ng g^?1 on wet wt. basis respectively. Comparisons are made with other aquatic mammals and other studies on river dolphins. P. gangetica appears to exhibit similar patterns of accumulation with age and with ß-HCH and p-p′-DDE being accumulated to higher levels than other HCH isomers and parent DDT and its other metabolites, respectively. These organochlorines may pose a health risk to river dolphin populations that are already showing evidence of environmental stress. Further studies are recommended.