Composting of municipal solid waste by different methods improved the growth of vegetables and reduced the health risks of cadmium and lead

Environmental Science and Pollution Research - Reutilization of putrescible municipal solid wastes (MSW) in agriculture can provide valuable plant nutrients. However, it may pose serious...     

The role of endogenous nitric oxide in melatonin-improved tolerance to lead toxicity in maize plants

Melatonin (MT) and nitric oxide (NO) are known as scavengers of free radicals and an antioxidant against biotic and abiotic stresses in plant defense systems. However, whether NO interplays role in MT-induced antioxidant defense remains to be determined in the plants exposed to lead (Pb) toxicity. So, two experiments were designed to evaluate the role of NO in MT-mediated tolerance of maize plants to Pb stress. In the initial experiment, prior to starting different treatments, a solution of 0.05- or 0.10-mM MT was sprayed every other day for a period of 10 days to the leaves of maize plants exposed to Pb stress (0.1-mM PbCl₂). Pb toxicity significantly caused reduction in plant biomass (both fresh and dry), PSII maximum efficiency (F_v/F_m), total chlorophyll, leaf potassium (K), calcium (Ca), and leaf water potential, but it resulted in increased levels of proline, hydrogen peroxide (H₂O₂), malondialdehyde (MDA), electron leakage (EL), leaf Pb, and endogenous NO. An addition experiment was set up to further understand whether NO played role in mitigation of Pb toxicity in maize plants by MT using scavengers of NO and cPTIO combined with the MT treatments. MT-induced tolerance to Pb toxicity was totally eliminated by cPTIO by reversing endogenous NO. The present results clearly indicated that MT mediated the endogenous NO to improve tolerance of maize plants to Pb toxicity. This evidence was also supported by the increases of H₂O₂ and MDA and reduces some antioxidant enzyme activities tested as well as the plant growth inhibition and increased leaf Pb content by application of MT combined with cPTIO.

     

Processes affecting the movement of organochlorine pesticides (OCPs) between soil and air in an industrial site in Turkey

Soil and atmospheric concentrations, dry deposition and soil-air gas exchange of organochlorine pesticides (OCPs) were investigated at an industrial site in Aliaga, Izmir, Turkey. Current-use pesticides, endosulfan and chlorpyrifos, had the highest atmospheric levels in summer and winter. Summertime total (gas + particle) OCP concentrations in air were higher, probably due to increased volatilization at higher temperatures and seasonal local/regional applications of current-use pesticides. Particle deposition fluxes were generally higher in summer than in winter. Overall average dry particle deposition velocity for all the OCPs was 4.9 ± 4.1 cm s⁻¹ (average ± SD). ΣDDXs (sum of p,p′-DDT, p,p′-DDD, and p,p′-DDE) were the most abundant OCPs in Aliaga soils (n = 48), probably due to their heavy historical use and persistence. Calculated fugacity ratios and average net gas fluxes across the soil-air interface indicated volatilization for α-CHL, γ-CHL, heptachlorepoxide, cis-nonachlor, trans-nonachlor, and p,p′-DDT in summer, and for α-CHL, γ-CHL, trans-nonachlor, endosulfan sulfate, and p,p′-DDT in winter. For the remaining OCPs, soil acted as a sink during both seasons. Comparison of the determined fluxes showed that dry particle, gas-phase, and wet deposition are significant OCP input mechanisms to the soil in the study area.     

Potential concerns related to using octadecyltrichlorosilane (OTS) in rendering soils and porous ceramics hydrophobic

The treatment of hydrophilic porous ceramics to render them hydrophobic and wetting to non-aqueous phase liquids (NAPLs) is frequently needed in multiphase flow experiments to control the flow or to measure the pressure of the NAPL. In addition, research dealing with soil wettability implies a need for hydrophobic or NAPL-wet soils. The traditional procedure, which has been widely used in literature, to render hydrophilic porous ceramics and soils hydrophobic is achieved by placing the hydrophilic solid in a 5% (by volume) octadecyltrichlorosilane (OTS) solution in ethanol followed by rinsing in ethanol. This research assesses the use of this procedure as it was found that this treatment procedure resulted in excess OTS on the surface of treated hydrophobic solids which can dissolve in an organic phase and in turn alter the wettability condition of adjacent hydrophilic soils. A modified procedure, which results in hydrophobic solids free of excess OTS, is presented.     

Feasibility of incorporating waste grass clippings (Lolium perenne L.) in particleboard composites

This study investigated some of the important physical (thickness swelling) and mechanical (modulus of rupture, modulus of elasticity and internal bond) properties of single-layer particleboard panels made from eucalyptus (Eucalyptus camaldulensis Dehn.), waste of grass clippings (Lolium perenne L.) and combinations of the two. The chemical properties (pH, holocelluse and alpha cellulose contents, and water, alcohol-benzene and 1% sodium hydroxide solubilities) of the raw materials were also determined. Panels with a 6:94 ratio of grass-to-eucalyptus particles had the required mechanical properties for interior fitments including furniture and general uses. Boards manufactured with 100% grass clippings exhibited the lowest quality. The overall panel properties improved with a lower percentage of grass clippings added. Based on initial results, it also appears that grass should compose no more than 13% to achieve acceptable panel properties for interior fitments and general uses.     

Determination of Au(III) and Pd(II) ions by flame atomic absorption spectrometry in some environmental samples after solid phase extraction

A simple and sensitive solid phase extraction method was developed for simultaneous separation and preconcentration of gold and palladium ions with N-(4-methylphenyl)-2-{[(4-phenyl-5-pyridine-4-yl-4H-1,2,4-triazol-3-yl)thio]acetyl}hydrazine carbo thioamide complex on Amberlite XAD-1180 resin before their determination by flame atomic absorption spectrometry. Some analytical parameters such as HNO₃ concentration of the sample solution, amount of complexing agent, sample volume, eluent type and volume, effects of foreign ions and adsorption capacity of the resin were investigated for quantitative recovery of gold and palladium ions. The effects of some anions and cations were also examined. Under optimum conditions, the detection limits for gold and palladium ions were found to be 0.29 and 0.19 μg L^?1, respectively. The preconcentration factor for gold and palladium was 250. After being validated by standard addition and analysis of standard reference material, the procedure was successfully applied to the analysis of sea and stream water, anodic slime, gold ore, soil and electronic waste.     

Application of life cycle assessment for hospital solid waste management: A case study

This study was meant to determine environmental aspects of hospital waste management scenarios using a life cycle analysis approach. The survey for this study was conducted at the largest hospital in a major city of Pakistan. The hospital was thoroughly analyzed from November 2014 to January 2015 to quantify its wastes by category. The functional unit of the study was selected as 1 tonne of disposable solid hospital waste. System boundaries included transportation of hospital solid waste and its treatment and disposal by landfilling, incineration, composting, and material recycling methods. These methods were evaluated based on their greenhouse gas emissions. Landfilling and incineration turned out to be the worst final disposal alternatives, whereas composting and material recovery displayed savings in emissions. An integrated system (composting, incineration, and material recycling) was found as the best solution among the evaluated scenarios. This study can be used by policymakers for the formulation of an integrated hospital waste management plan.

Implications: This study deals with environmental aspects of hospital waste management scenarios. It is an increasing area of concern in many developing and resource-constrained countries of the world. The life cycle analysis (LCA) approach is a useful tool for estimation of greenhouse gas emissions from different waste management activities. There is a shortage of information in existing literature regarding LCA of hospital wastes. To the best knowledge of the authors this work is the first attempt at quantifying the environmental footprint of hospital waste in Pakistan.     

Source Type Evaluation of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Sediments from the Muar River and Pulau Merambong,Peninsular Malaysia

This article is the most recent report of polycyclic aromatic hydrocarbons (PAHs) in the Muar River and Pulau Merambong, Peninsular Malaysia. A total of 16 priority pollutant PAHs in addition to methylphenanthrene among alkylated PAHs were analyzed in surface sediments during May 2013. Total PAHs ranged from 212 to 440 and 151 to 412 ng g^?1 dw in sediments from the Muar River and the Pulau Merambong, respectively. The Muar River showed an increasing trend of PAH concentrations, while no previous data exist for the Pulau Merambong. Generally, mixed petrogenic and pyrogenic sources of PAHs with predominance of the latter were detected in the study area. Effective management of oil pollution has caused a drastic decrease in petrogenic sources of PAHs.     

The comparison of heavy metal accumulation ratios of some fish species in Enne Dame Lake (Kütahya/Turkey)

The metal accumulation levels for muscle, skin, gill, liver and intestine tissues of some Cyprinidae species (Carassius carassius, Condrostoma nasus, Leuciscus cephalus and Alburnus alburnus) in Enne Dame Lake (Kütahya/Turkey), which is mostly fed by hot spring waters, were investigated. Analyses were performed for copper (Cu), zinc (Zn), manganese (Mn), iron (Fe), cobalt (Co), magnesium (Mg), nickel (Ni), chrome (Cr) and boron (B) using inductively coupled plasma-optic emission spectroscopy (ICP-OES), and cadmium (Cd) using atomic absorption spectrophotometer (AAS) utilizing microwave digestion techniques. The concentrations of the heavy metals found in the fish varied in the follow ing ranges: Cu: < DL-7.04, Zn: 6.96-357.25, Mn: < DL-20.70, Ni: < DL-6.21, Fe: 9.62-2500.33, Cr: < DL-1.74, Co: < DL-0.54, Cd: 0.01-0.27 and Mg: 197.44-904.90 mg/kg wet weight. While B had the second highest concentration in the water of the lake, it was not encountered in any tissue of the investigated species. In all tissues and the species, While the bioaccumulation factors (BAFs) of Mn, Zn, Fe and Cu were remarkably high, the BAFs of Mg, Cr, Co, and B were also fairly low or none. Although the heavy metal accumulation levels for the muscle were generally lower than other tissues, there were some exceptions. Cd level in the muscle of C. carassius was higher than the permissible limit stated by Turkish legislation, FAO and WHO. The mean metal amounts for all the investigated tissues and species are statistically compared and discussed in this study.     

Assessment of trace metal concentrations in muscle tissue of certain commercially available fish species from Kayseri,Turkey

Regular consumption of fish has been widely recommended by health authorities. However, it is known that some species accumulate high levels of contaminants including heavy metals (e.g., Hg, Cd, Pb, and As). In this study, Cu, Pb, Co, Ni, Cr, Mn, Cd, and Fe were determined in the muscle tissue of 11 commercially available fish species (Sparus auratus, Dicentrarchus labrax, Mullus barbatus, Belone belone, Psetta maxima, Epinephelus aeneus, Salmothymus, Soleidae, Pomatomus saltatrix, Engraulis encrasicolus, and Sarda sarda) supplied from retailers in Kayseri, Turkey. Determinations were carried out by flame atomic absorption spectrometry after the wet digestion method. The average metal concentrations of the 11 species were determined in the range of 0.54–1.79, 0.82–1.40, 2.38–4.54, 1.23–3.67, 5.01–5.97, 0.77–3.59, 0.48–1.06, and 5.05–122.8 μg/g wet weight for Cu, Pb, Co, Ni, Cr, Mn, Cd, and Fe, respectively. The permissible tolerable daily intake (PTDI) and calculated daily intake (CDI) values were compared, and the calculated daily intake values of the samples were found to be below the established values. Correlations between the metal contents in samples were investigated by performing correlation tests with SPSS 13.0 for windows.