Non-linear relationship between tourism,economic growth,urbanization, and environmental degradation: evidence from smooth transition models

Environmental Science and Pollution Research - The study aims to analyze two objectives: first is to explore the non-linear relationship between tourism development, economic growth, urbanization,...     

Exploring a new perspective of sustainable development drive through environmental Phillips curve in the case of the BRICST countries

Environmental Science and Pollution Research - Considering that the rigor of economic activities has widely been linked with the turbulent nature of the increasing global atmospheric and...     

Evaluation of Pb, Cu, Zn, Cd, Ni and Fe levels in Rosmarinus officinalis labaiatae (Rosemary) medicinal plant and soils in selected zones in Jordan

The concentration of heavy metals including Pb, Cu, Zn, Cd, Ni and Fe in different parts of Rosmarinus officinalis medicinal plant grown in Jordan were evaluated. Medicinal plant samples and soil samples were collected from three different zones in Jordan (Irbid, Al-Mafraq and Ma’an). Samples were analyzed by atomic absorption spectrometry (AAS) after chemical treatments using acid digestion procedures. Heavy metal levels in washed and unwashed in each part of R. officinalis were analyzed and compared statistically. Results show that concentrations of investigated heavy metals were varied from plant part to another part of R. officinalis. For example, Pb, Zn, Cu and Cd in most parts of R. officinalis in the three zones were concentrated in the following order: flowers, leaves, stems, whereas Pb, Ni and Fe were concentrated in order as follows: leaves, flowers and stems. Heavy metal concentrations in soil samples was evaluated and correlated with their levels in R. officinalis. Two standard reference materials of plant (SRM 1790a; spinach leaves and CRM 281; rye grass) and one standard reference materials of soil (GBW 07406) were examined to validate the method used. Results show that high recoveries were obtained.     

A land use regression model for predicting ambient concentrations of nitrogen dioxide in Hamilton, Ontario, Canada

This paper reports on the development of a land use regression (LUR) model for predicting the intraurban variation of traffic-related air pollution in Hamilton, Ontario, Canada, an industrial city at the western end of Lake Ontario. Although land use regression has been increasingly used to characterize exposure gradients within cities, research to date has yet to test whether this method can produce reliable estimates in an industrialized location. Ambient concentrations of nitrogen dioxide (NO2) were measured for a 2-week period in October 2002 at > 100 locations across the city and subsequently at 30 of these locations in May 2004 to assess seasonal effects. Predictor variables were derived for land use types, transportation, demography, and physical geography using geographic information systems. The LUR model explained 76% of the variation in NO2. Traffic density, proximity to a highway, and industrial land use were all positively correlated with NO2 concentrations, whereas open land use and distance from the lake were negatively correlated with NO2. Locations downwind of a major highway resulted in higher NO2 levels. Cross-validation of the results confirmed model stability over different seasons. Our findings demonstrate that land use regression can effectively predict NO2 variation at the intraurban scale in an industrial setting. Models predicting exposure within smaller areas may lead to improved detection of health effects in epidemiologic studies.     

Assessing forest canopy closure in a geospatial medium to address management concerns for tropical islands—Southeast Asia

The present study outlines an approach to classify forest density and to estimate canopy closure of the forest of the Andaman and Nicobar archipelago. The vector layers generated for the study area using satellite data was validated with the field knowledge of the surveyed ground control points. The methodology adopted in this present analysis is three-tiered. First, the density stratification into five zones using visual interpretation for the complete archipelago. In the second step, we identified two island groups from the Andaman to investigate and compare the forest strata density. The third and final step involved more of a localised phytosociological module that focused on the North Andaman Islands. The results based on the analysis of the high-resolution satellite data show that more than 75% of the mangroves are under high- to very high-density canopy class. The framework developed would serve as a significant measure to forest health and evaluate management concerns whilst addressing issues such as gap identification, conservation prioritisation and disaster management—principally to the post-tsunami assessment and analysis.     

Residual effects of tobacco biochar along with different fixing agents on stabilization of trace elements in multi-metal contaminated soils

The residual effect of tobacco biochar(TB ≥ 500°C) mono and co-application with Cahydroxide(CH),Ca-bentonite(CB) and natural zeolite(NZ) on the bio-availability of trace elements TE(s) in alkaline soils has not been deeply studied yet.A pot study that had earlier been investigated TB mono and blended with CH,CB and NZ on the immobilization of Pb,Cu Cd,and Zn by Chinese cabbage.Maize crop in the rotation was selected as test plant to assess the residual impact of amendments on stabilization of Pb,Cu Cd,and Zn in mine polluted(M-P),smelter heavily and low polluted(S-HP and S-LP,respectively) soils.The obtained results showed that stabilization of Pb,Cd,Cu and Zn reached 63.84% with TB + CB,61.19% with TB + CH,83.31% with TB + CH and 35.27% with TB + CH for M-P soil,36.46% with TB + NZ,38.46% with TB + NZ,19.40% with TB + CH and 62.43% with TB + CH for S-LP soil,52.94% TB + NZ,57.65% with TB + NZ,52.94% with TB + NZ,and 28.44% with TB + CH for S-LP soil.Conversely,TB + CH and TB alone had mobilized Pb and Zn up to19.29% and 34.96% in M-P soil.The mobility of Zn reached 8.38% with TB + CB and 66.03%with TB for S-HP and S-LP soils.The uptake and accumulation of Pb,Cd,Cu and Zn in shoot and root were reduced in three polluted soils.Overall,the combination of TB along with CH,CB and NZ has been proven to be effective in Pb,Cd,Cu and Zn polluted mine/smelter soils restoration.     

Determination of Pb and Cd in road dusts over the period in which Pb was removed from petrol in the UK

It is commonly agreed that automobile exhaust has been the most important source of Pb pollution in urban areas, and that Cd may come from wear and tear of tyres. This study evaluates the fall in Pb concentrations in road dusts in Manchester as a consequence of the removal of Pb from petrol in January 2000. In the work presented here a slurry graphite furnace atomic absorption methodology for the determination of Pb and Cd in road dusts has been developed and is compared with an acid digestion method in terms of efficiency. The reproducibility and accuracy of the results obtained by acid digestion and the slurry method have been studied and a certified reference material CRM 038 was analysed to confirm the reliability of the proposed methods. Different factors were evaluated throughout this work including: (i) the effect of traffic density on Pb and Cd levels in road dust samples collected weekly during the period of May 1999 until September 2000; (ii) comparison between the Pb and Cd levels in a busy road and a residential street; (iii) the effect of distance from the source on Pb and Cd levels; The results of these experiments show a reduction in Pb levels over the sampling period. The relationship between road dust particle size and Pb and Cd concentration was also investigated in the 4-250 microns size range using the slurry method, showing that there is a relationship between metal concentration and particle size; the highest concentrations being for the smallest particle size.     

Evaluation of some organic-based biopolymers as green inhibitors for calcium sulfate scales

This study focused on using scale inhibitors for calcium sulfate that are not only highly effective, but also comply with present restrictive environmental control legislations. In this respect, some biodegradable compounds-based biopolymers, such as carboxymethyl starch (CMS), carboxymethyl cellulose (CMC), and chitosan (Ch), were evaluated at temperatures 90–95 and 130°C. The results obtained were compared with the performance of polyaspartic acid (PAA), which is well known in this application, as well as other chelating synthetic polymers (polyacrylamide and amphoteric polyacrylamide). The role of the degree of substitution (DS) of carboxymethylated biopolymer and the charge density of polyacrylamide (AmPAM-30 and AmPAM-50) on inhibition performance of scale were also examined. The synergistic effect of PAA with investigated inhibitors was studied for economic and environmental purposes. The results revealed that both the degree of substitution of carboxymethylated biopolymers and charge density of polyacrylamide have a profound effect on improving the performance of the investigated scale inhibitors. The efficiency values were correlated to the thermal degradation behavior (TGA) of biopolymers. PAA had the highest synergistic effect of all investigated inhibitors, where the inhibition efficiency was found to range from 98% to 100%, at a temperature of 130°C, with low doses of both PAA (2 ppm) together with biopolymers. This efficiency is observed using 20–40 ppm of PAA. The synergistic effect of PAA (2 ppm) also showed enhancement of the performance of low doses of polyacrylamides (5 ppm) in maintaining soluble Ca²⁺ in solutions, increasing the efficiency from ∼57% to ∼100%, as well as its ecotoxicological property.     

Genotypic Variation in the Phytoremediation Potential of Indian Mustard for Chromium

The term “phytoremediation” is used to describe the cleanup of heavy metals from contaminated sites by plants. This study demonstrates phytoremediation potential of Indian mustard (Brasicca juncea (L.) Czern. & Coss.) genotypes for chromium (Cr). Seedlings of 10 genotypes were grown hydroponically in artificially contaminated water over a range of environmentally relevant concentrations of Cr (VI), and the responses of genotypes in the presence of Cr, with reference to Cr accumulation, its phytotoxity and anti-oxidative system were investigated. The Cr accumulation potential varied largely among Indian mustard genotypes. At 100 μM Cr treatment, Pusa Jai Kisan accumulated the maximum amount of Cr (1680 μg Cr g⁻¹ DW) whereas Vardhan accumulated the minimum (107 μg Cr g⁻¹ DW). As the tolerance of metals is a key plant characteristic required for phytoremediation purpose, effects of various levels of Cr on biomass were evaluated as the gross effect. The extent of oxidative stress caused by Cr stress was measured as rate of lipid peroxidation. The level of thiobarbituric acid reactive substances (TBARS) was enhanced at all Cr treatments when compared to the control. Inductions of enzymatic and nonenzymatic antioxidants were monitored as metal-detoxifying responses. All the genotypes responded to Cr-induced oxidative stress by modulating nonenzymatic antioxidants [glutathione (GSH) and ascorbate (Asc)] and enzymatic antioxidants [superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR)]. The level of induction, however, differed among the genotypes, being at its maximum in Pusa Jai Kisan and its minimum in Vardhan. Pusa Jai Kisan was grown under natural field conditions with various Cr treatments, and Cr-accumulation capacity was studied. The results confirmed that Pusa Jai Kisan is a hyperaccumulator of Cr and hypertolerant to Cr-induced stress, which makes this genotype a viable candidate for use in the development of phytoremediation technology of Cr-contaminated sites.