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A memory structure adapted simulated annealing algorithm for a green vehicle routing problem Full text
2015
Küçükoğlu, İlker | Ene, Seval | Aksoy, Aslı | Öztürk, Nursel
Currently, reduction of carbon dioxide (CO₂) emissions and fuel consumption has become a critical environmental problem and has attracted the attention of both academia and the industrial sector. Government regulations and customer demands are making environmental responsibility an increasingly important factor in overall supply chain operations. Within these operations, transportation has the most hazardous effects on the environment, i.e., CO₂emissions, fuel consumption, noise and toxic effects on the ecosystem. This study aims to construct vehicle routes with time windows that minimize the total fuel consumption and CO₂emissions. The green vehicle routing problem with time windows (G-VRPTW) is formulated using a mixed integer linear programming model. A memory structure adapted simulated annealing (MSA-SA) meta-heuristic algorithm is constructed due to the high complexity of the proposed problem and long solution times for practical applications. The proposed models are integrated with a fuel consumption and CO₂emissions calculation algorithm that considers the vehicle technical specifications, vehicle load, and transportation distance in a green supply chain environment. The proposed models are validated using well-known instances with different numbers of customers. The computational results indicate that the MSA-SA heuristic is capable of obtaining good G-VRPTW solutions within a reasonable amount of time by providing reductions in fuel consumption and CO₂emissions.
Show more [+] Less [-]Improvement in phytoremediation potential of Solanum nigrum under cadmium contamination through endophytic-assisted Serratia sp. RSC-14 inoculation Full text
2015
Khan, Abdur Rahim | Ullah, Ihsan | Khan, Abdul Latif | Park, Gun-Seok | Waqas, Muhammad | Hong, Sung-Jun | Jung, Byung Kwon | Kwak, Yunyoung | Lee, In-Jung | Shin, Jae-Ho
The growth of hyperaccumulator plants is often compromised by increased toxicity of metals like cadmium (Cd). However, extraction of such metals from the soil can be enhanced by endophytic microbial association. Present study was aimed to elucidate the potential of microbe-assisted Cd phytoextraction in hyperaccumulator Solanum nigrum plants and their interactions under varied Cd concentrations. An endophytic bacteria Serratia sp. RSC-14 was isolated from the roots of S. nigrum. In addition to Cd tolerance up to 4 mM, the RSC-14 exhibited phosphate solubilization and secreted plant growth-promoting phytohormones such as indole-3-acetic acid (54 μg/mL). S. nigrum plants were inoculated with RSC-14 and were grown in different concentrations of Cd (0, 10, and 30 mg Cd kg⁻¹ sand). Results revealed that Cd treatment caused significant cessation in plant growth, biomass, and chlorophyll content, whereas significantly higher malondialdehyde (MDA) and electrolyte production in leaves were observed in a dose-dependent manner. Conversely, RSC-14 inoculation relived the toxic effects of Cd-induced stress by significantly increasing root/shoot growth, biomass production, and chlorophyll content and decreasing MDA and electrolytes contents. Ameliorative effects on host growth were also observed by the regulation of metal-induced oxidative stress enzymes such as catalase, peroxidase, and polyphenol peroxidase. Activities of these enzymes were significantly reduced in RSC-14 inoculated plants as compared to control plants under Cd treatments. The lower activities of stress responsive enzymes suggest modulation of Cd stress by RSC-14. The current findings support the beneficial uses of Serratia sp. RSC-14 in improving the phytoextraction abilities of S. nigrum plants in Cd contamination.
Show more [+] Less [-]Effectiveness of chemical amendments for stabilisation of lead and antimony in risk-based land management of soils of shooting ranges Full text
2015
Sanderson, Peter | Naidu, R. | Bolan, Nanthi
This study aims to examine the effectiveness of amendments for risk-based land management of shooting range soils and to explore the effectiveness of amendments applied to sites with differing soil physiochemical parameters. A series of amendments with differing mechanisms for stabilisation were applied to four shooting range soils and aged for 1 year. Chemical stabilisation was monitored by pore water extraction, toxicity characteristic leaching procedure (TCLP) and the physiologically based extraction test (PBET) over 1 year. The performance of amendments when applied in conditions reflecting field application did not match the performance in the batch studies. Pore water-extractable metals were not greatly affected by amendment addition. TCLP-extractable Pb was reduced significantly by amendments, particularly lime and magnesium oxide. Antimony leaching was reduced by red mud but mobilised by some of the other amendments. Bioaccessible Pb measured by PBET shows that bioaccessible Pb increased with time after an initial decrease due to the presence of metallic fragments in the soil. Amendments were able to reduce bioaccessible Pb by up to 50 %. Bioaccessible Sb was not readily reduced by soil amendments. Soil amendments were not equally effective across the four soils.
Show more [+] Less [-]Pesticide pollution of multiple drinking water sources in the Mekong Delta, Vietnam: evidence from two provinces Full text
2015
Chau, N. D. G. | Sebesvari, Z. | Amelung, W. | Renaud, F. G.
Pollution of drinking water sources with agrochemicals is often a major threat to human and ecosystem health in some river deltas, where agricultural production must meet the requirements of national food security or export aspirations. This study was performed to survey the use of different drinking water sources and their pollution with pesticides in order to inform on potential exposure sources to pesticides in rural areas of the Mekong River delta, Vietnam. The field work comprised both household surveys and monitoring of 15 frequently used pesticide active ingredients in different water sources used for drinking (surface water, groundwater, water at public pumping stations, surface water chemically treated at household level, harvested rainwater, and bottled water). Our research also considered the surrounding land use systems as well as the cropping seasons. Improper pesticide storage and waste disposal as well as inadequate personal protection during pesticide handling and application were widespread amongst the interviewed households, with little overall risk awareness for human and environmental health. The results show that despite the local differences in the amount and frequency of pesticides applied, pesticide pollution was ubiquitous. Isoprothiolane (max. concentration 8.49 μg L⁻¹), fenobucarb (max. 2.32 μg L⁻¹), and fipronil (max. 0.41 μg L⁻¹) were detected in almost all analyzed water samples (98 % of all surface samples contained isoprothiolane, for instance). Other pesticides quantified comprised butachlor, pretilachlor, propiconazole, hexaconazole, difenoconazole, cypermethrin, fenoxapro-p-ethyl, tebuconazole, trifloxystrobin, azoxystrobin, quinalphos, and thiamethoxam. Among the studied water sources, concentrations were highest in canal waters. Pesticide concentrations varied with cropping season but did not diminish through the year. Even in harvested rainwater or purchased bottled water, up to 12 different pesticides were detected at concentrations exceeding the European Commission’s parametric guideline values for individual or total pesticides in drinking water (0.1 and 0.5 μg L⁻¹; respectively). The highest total pesticide concentration quantified in bottled water samples was 1.38 μg L⁻¹. Overall, we failed to identify a clean water source in the Mekong Delta with respect to pesticide pollution. It is therefore urgent to understand further and address drinking water-related health risk issues in the region.
Show more [+] Less [-]Do concentrations of pharmaceuticals in sewage reflect prescription figures? Full text
2015
van Nuijs, Alexander L. N. | Covaci, Adrian | Beyers, Herman | Bervoets, Lieven | Blust, Ronny | Verpooten, Gert | Neels, Hugo | Jorens, Philippe G.
In recent years, it has been demonstrated that sewage-based epidemiology can deliver interesting information on trends in illicit drug consumption. However, until now, no real evidence exists that the measured concentrations of drugs in sewage can be exactly correlated with the amounts of drugs used by a specific population. This study aimed therefore at correlating detailed monthly prescription figures of 11 pharmaceuticals (atenolol, bisoprolol, citalopram, fluoxetine, venlafaxine, losartan, telmisartan, valsartan, carbamazepine, metformin, and tramadol) with measured concentrations of these compounds in influent sewage from five sewage treatment plants in Belgium. For 7 out of the 11 substances, a ratio between loads calculated from the prescription figures and loads calculated from measured concentrations in the range of 0.30–3.00 was observed. For four pharmaceuticals (atenolol, bisoprolol, telmisartan, and venlafaxine), the observed relationship was less pronounced. The manuscript gives an overview of the possible uncertainties that are related with the calculated correlations. This study highlights the need for gathering all the necessary information regarding sewage sampling, stability of substances in sewage, pharmacokinetics, and analytical method performance when sewage-based epidemiology studies are performed.
Show more [+] Less [-]Amelioration of an Ultisol profile acidity using crop straws combined with alkaline slag Full text
2015
Li, Jiu-yu | Masud, M. M. | Li, Zhong-yi | Xu, Ren-kou
The acidity of Ultisols (pH <5) is detrimental to crop production. Technologies should be explored to promote base saturation and liming effect for amelioration of Ultisol pH. Column leaching experiments were conducted to investigate the amelioration effects of canola straw (CS) and peanut straw (PS) in single treatment and in combination whether with alkaline slag (AS) or with lime on Ultisol profile acidity. The treatment without liming materials was set as control, and the AS and lime in single treatment are set for comparison. Results indicated that all the liming materials increase soil profile pH and soil exchangeable base cations at the 0–40-cm depth, except that the lime had amelioration effect just on 0 to 15-cm profile. The amelioration effect of the liming materials on surface soil acidity was mainly dependent on the ash alkalinity in organic materials or acid neutralization capacity of inorganic materials. Specific adsorption of sulfate (SO₄ ²⁻) or organic anions, decarboxylation of organic acids/anions, and the association of H⁺ with organic anions induced a “liming effect” of crop residues and AS on subsoil acidity. Moreover, SO₄ ²⁻ and chloride (Cl⁻) in PS, CS, and AS primarily induced base cations to move downward to subsoil and exchange with exchangeable aluminum (Al³⁺) and protons (H⁺). These anions also promoted the exchangeable Al to leach out of the soil profile. The CS was more effective than PS in decreasing soil acidity in the subsoil, which mainly resulted from higher sulfur (S) and Cl content in CS compared to PS. The CS combined with AS was the better amendment choice in practical agricultural systems.
Show more [+] Less [-]Response of the microbial community to seasonal groundwater level fluctuations in petroleum hydrocarbon-contaminated groundwater Full text
2015
Zhou, Ai-xia | Zhang, Yu-ling | Dong, Tian-zi | Lin, Xue-yu | Su, Xiao-si
The effects of seasonal groundwater level fluctuations on the contamination characteristics of total petroleum hydrocarbons (TPH) in soils, groundwater, and the microbial community were investigated at a typical petrochemical site in northern China. The measurements of groundwater and soil at different depths showed that significant TPH residue was present in the soil in this study area, especially in the vicinity of the pollution source, where TPH concentrations were up to 2600 mg kg⁻¹. The TPH concentration in the groundwater fluctuated seasonally, and the maximum variation was 0.8 mg L⁻¹. The highest TPH concentrations were detected in the silty clay layer and lied in the groundwater level fluctuation zones. The groundwater could reach previously contaminated areas in the soil, leading to higher groundwater TPH concentrations as TPH leaches into the groundwater. The coincident variation of the electron acceptors and TPH concentration with groundwater-table fluctuations affected the microbial communities in groundwater. The microbial community structure was significantly different between the wet and dry seasons. The canonical correspondence analysis (CCA) results showed that in the wet season, TPH, NO₃ ⁻, Fe²⁺, TMn, S²⁻, and HCO₃ ⁻ were the major factors correlating the microbial community. A significant increase in abundance of operational taxonomic unit J1 (97 % similar to Dechloromonas aromatica sp.) was also observed in wet season conditions, indicating an intense denitrifying activity in the wet season environment. In the dry season, due to weak groundwater level fluctuations and low temperature of groundwater, the microbial activity was weak. But iron and sulfate-reducing were also detected in dry season at this site. As a whole, groundwater-table fluctuations would affect the distribution, transport, and biodegradation of the contaminants. These results may be valuable for the control and remediation of soil and groundwater pollution at this site and in other petrochemical-contaminated areas. Furthermore, they are probably helpful for reducing health risks to the general public from contaminated groundwater.
Show more [+] Less [-]Potential risk assessment of polybrominated diphenyl ethers (PBDEs) by consuming animal-derived foods collected from interior areas of China Full text
2015
Gong, Yan | Wen, Sheng | Zheng, Chuangmu | Peng, Xitian | Li, Yonggang | Hu, Dingjin | Pang, Laikwan
Polybrominated diphenyl ethers (PBDEs) are one class of brominated flame retardants (BFRs). Although studies have reported the occurrence of PBDEs in freshwater fish species from several locations, to our best knowledge, there was no comprehensive data on PBDEs in foods of animal origin, such as pork, egg, and milk samples from interior areas of China, where pork and eggs are the major constituents of diet. The levels of PBDEs (BDE-28, 47, 99, 100, 153, 154, and 183) were determined in samples of animal-derived foods widely consumed by the population of Hubei in east-central China and the middle reaches of the Yangtze River. Two hundred six samples of animal-derived foods were randomly acquired in 17 sites of Hubei in 2010. The highest medium concentration of ∑₇PBDEs was found in chicken eggs (0.191 ng/g wet weight (ww)), followed by duck eggs (0.176 ng/g ww), pork (0.050 ng/g ww), carps (0.047 ng/g ww), and cow milk (0.013 ng/g ww). The estimated dietary intake of Σ₇PBDEs for a standard adult of 60 kg body weight based on medium and 95th percentile concentrations with consumption of animal-derived foods in Hubei province were 157.5 and 1960.3 pg/kg body weight/day, respectively. Chicken eggs (65.9 %) and pork (23.4 %) were the largest contributors to dietary intake of ∑₇PBDEs through animal-derived foods. The same PBDE sources were exposed in Hubei province via principal component analysis (PCA), and the particular congener profile in samples of animal-derived foods revealed the possible exposure history of octa-BDEs and penta-BDEs in the local region. The large margins of exposure (MOE) calculated following the European Food Safety Authority (EFSA) approach for three important congeners, BDE-47, BDE-99, and BDE-153, indicated that the estimated dietary exposures were unlikely to be a significant health concern to in Hubei.
Show more [+] Less [-]Human food safety and environmental hazards associated with the use of methyltestosterone and other steroids in production of all-male tilapia Full text
2015
Mlalila, Nichrous | Mahika, Charles | Kalombo, Lonji | Swai, Hulda | Hilonga, Askwar
In recent years, all-male cultures of Nile tilapia (Oreochromis niloticus) have been the most preferred mode of production in aquaculture industry. All-male individuals achieve higher somatic growth rate and shut high energy losses associated with gonadal development and reproduction. The economic advantages of culturing all-male tilapia have led to the development of procedures for producing unisex cultures, using 17α-methyltestosterone (MT). Despite widespread use of the MT in tilapia farming, the implications of hormone treatment in relation to human health and the environment have raised a number of concerns in the scientific community. In this review, the hormonal application processes, economic and ecological significance of MT, food safety and residual MT, comparative uses of steroids in aquaculture, animal husbandry, and medicine have been briefly reviewed for regulatory guidelines, and finally, future research perspectives have been addressed. The review can be used as policy-making guidelines in aquaculture framework development as can be emphasized in African continent, among others. The most important conclusion to draw is that the quantity of MT used in conventional practice is large compared to the actual dose required for sex reversal, fish produced are safe for human consumptions, and the environmental hazards should be further emphasized.
Show more [+] Less [-]Occurrence and human exposure of parabens and their chlorinated derivatives in swimming pools Full text
2015
Li, Wenhui | Shi, Yali | Gao, Lihong | Liu, Jiemin | Cai, Yaqi
As an emerging group of endocrine-disrupting chemicals, parabens have attracted growing attention due to their potential effects on human health. In the present study, the occurrence and distribution of eight parabens, four chlorinated parabens, and their common hydrolysis product, p-hydroxybenzoic acid (PHBA), were investigated in 39 swimming pools in Beijing, China. Methyl paraben and propyl paraben were the predominant compounds in swimming pools, accounting for 91.2 % of the total parabens. It is noteworthy that octyl paraben, a paraben with longer chain, was firstly detected in this study. There were several factors affecting the levels of parabens among the 39 swimming pools. The concentrations of parabens and chlorinated derivatives detected in indoor pools (144 ng L⁻¹) were roughly 20-fold higher than those in outdoor pools (6.78 ng L⁻¹). Hotel pools appear to present higher level of target compounds (361 ng L⁻¹) than that in health club (228 ng L⁻¹), municipal (130 ng L⁻¹), school (75.6 ng L⁻¹), and community pools (63.0 ng L⁻¹). Moreover, the level of these compounds in pools during weekends (174 ng L⁻¹) was much higher than that during weekdays (52.3 ng L⁻¹). The dynamics of target compounds were also investigated to provide a general trend of the level of parabens in a school indoor swimming pool during a 14-week period. Human exposure assessment was conducted to estimate the potential risk of exposure to parabens and their chlorinated derivatives in swimming pools. Considering the total exposure dose of multiple parabens, human exposure to parabens from the water of swimming pools is negligible. However, the threat of these parabens to children in swimming pool should be concerned.
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