خيارات البحث
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Emission factors of unintentional HCB and PeCBz and their correlation with PCDD/PCDF
2017
Gong, Wenwen | Fiedler, H. (Heidelore) | Liu, Xiaotu | Wang, Bin | Yu, Gang
Hexachlorobenzene (HCB) and pentachlorobenzene (PeCBz) have been listed as unintentional POPs in the annex of the Stockholm Convention and thus, attracted attention by government and researchers. Since the intentional production and use has ceased in most countries, the unintentional releases to the environment have increased. This study gathered 206 and 78 emission factors (EFs) of unintentional HCB and PeCBz from scientific publications and governmental reports, respectively. Most of the EFs referred to the release vector “air” (EFAir) and to a less extent to “product” (EFProduct). EFs were proposed for different source categories/classes used in the Toolkit according to the technologies that released the HCB or PeCBz. Overall, lowest and highest EFAir for HCB were found in the metallurgical industry range from 1 μg/t in well controlled plants (coke, iron and steel) up to 40,000 μg/t (secondary zinc). EFs for PeCBz were in similar order of magnitude. Due to lack of data, EFs to water, land or residue cannot be proposed. Using linear regression and statistical analysis such as Pearson correlation, we found strongest correlation of EFAir between HCB and PeCBz (R2 = 0.79, P < 0.01) and weaker, but still significant, correlations for EFAir between PCDD/PCDFTEQ and HCB (R2 = 0.56; P < 0.01) or PeCBz (R2 = 0.31 P < 0.01) for various thermal processes.
اظهر المزيد [+] اقل [-]Can toxicants used against cotton mealybug Phenacoccus solenopsis be compatible with an encyrtid parasitoid Aenasius bambawalei under laboratory conditions?
2017
Badshah, Hayat | Ullah, Farman | Calatayud, Paul Andre | Ullah, Hidayat | Ahmad, Bashir
The cotton mealybug, Phenacoccus solenopsis Tinsley (Sternorrhyncha: Pseudococcidae) is a serious pest of various cultivated plants in Pakistan. Recent reports show that the parasitoid Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae) is a good biocontrol agent of the pest. Compatibleness is important in any IPM programme, and the insecticide used must have little or no effects on the biological control agent. This study investigated the compatibility of neem treatments and a commercial insecticide, imidacloprid on A. bambawalei. Bioassays were laid out in a completely randomized design (CRD) under laboratory conditions. Results showed that the adult stage of the parasitoid was more susceptible to the commercial insecticide imidacloprid than the concealed pupal stage. Moreover, on the basis of the International Organization for Biological Control (IOBC) toxicity categories of the commercial insecticide, imidacloprid was moderately toxic throughout the study period (Ex >80%) while neem was slightly toxic after 24 h of use (Ex <80%). Results also suggest that A. bambawalei release should be delayed for at least 1 week after neem treatments. Because imidacloprid destroys A. bambawalei, it might cause resurgence of P. solenopsis; thus, farmers should avoid integrating the insecticide in the control of P. solenopsis.
اظهر المزيد [+] اقل [-]Aquatic photolysis of β2-agonist salbutamol: kinetics and mechanism studies
2017
Zhou, Lei | Wang, Qi | Zhang, Ya | Ji, Yuefei | Yang, Xi
Salbutamol (SAL) has been widely used as medicine both in treating asthma and in animal primary production; an increasing number of reports have detected SAL in natural waters. The photolysis kinetic and pathway of SAL in aquatic system were studied, as well as the effect of several natural water constituents, such as nitrate, dissolved oxygen (DO) and ferric ions. According to our research, the direct photolysis of SAL followed pseudo-first-order reaction kinetics. Alkaline condition could promote the degradation of SAL; the increase of solution pH would simultaneously increase the fraction of the deprotonated forms of SAL (including the deprotonated and zwitterionic species), which were easier to be excited, and result in the bathochromic shift of the UV-Vis spectrum and, finally, accelerate the degradation rate of SAL. The presence of nitrate could enhance the removal rate of SAL via generation hydroxyl radical (·OH) under irradiation. In addition, the absence of oxygen in the reaction solution could decrease the photolysis. Moreover, Fe(III) was able to chelate with SAL to form an octahedral complex, which was photochemically reactive. The octahedral complex could generate ·OH to oxidize SAL itself in turn. The pathways of SAL photolysis were also investigated by means of the solid phase extraction (SPE)-LC-MS method. The major pathways of SAL photodegradation included oxidation and side-chain cleavage.
اظهر المزيد [+] اقل [-]Agroforestry: a sustainable environmental practice for carbon sequestration under the climate change scenarios—a review
2017
Abbas, Farhat | Hammad, Hafiz Mohkum | Shah, Fahad | Cerdà, Artemio | Rizwan, Muhammad | Farhad, Wajid | Ehsan, Sana | Bakhat, Hafiz Faiq
Agroforestry is a sustainable land use system with a promising potential to sequester atmospheric carbon into soil. This system of land use distinguishes itself from the other systems, such as sole crop cultivation and afforestation on croplands only through its potential to sequester higher amounts of carbon (in the above- and belowground tree biomass) than the aforementioned two systems. According to Kyoto protocol, agroforestry is recognized as an afforestation activity that, in addition to sequestering carbon dioxide (CO₂) to soil, conserves biodiversity, protects cropland, works as a windbreak, and provides food and feed to human and livestock, pollen for honey bees, wood for fuel, and timber for shelters construction. Agroforestry is more attractive as a land use practice for the farming community worldwide instead of cropland and forestland management systems. This practice is a win–win situation for the farming community and for the environmental sustainability. This review presents agroforestry potential to counter the increasing concentration of atmospheric CO₂ by sequestering it in above- and belowground biomass. The role of agroforestry in climate change mitigation worldwide might be recognized to its full potential by overcoming various financial, technical, and institutional barriers. Carbon sequestration in soil by various agricultural systems can be simulated by various models but literature lacks reports on validated models to quantify the agroforestry potential for carbon sequestration.
اظهر المزيد [+] اقل [-]Characterization and valorization of biomass ashes
2016
Trivedi, Nikhilesh S. | Mandavgane, Sachin A. | Mehetre, Sayaji | Kulkarni, B. D.
In India, farming is the primary source of income for many families. Following each harvest, a huge amount of biomass is generated. These are generally discarded as “agrowaste,” but recent reports have indicated several beneficial uses for these biomasses and their ashes. However, before the utilization of biomass ashes (BMAs), their chemical and physical properties need to be investigated (characterized) so as to utilize their potential benefit to the fullest. In this paper, eight different biomass ashes (soybean plant ash, mustard plant ash, maize ash, groundnut plant ash, cotton plant ash, wheat plant ash, pigeon peas ash, and groundnut shell ash) were characterized, and their chemical properties are discussed. Surface chemical composition analysis, proximate analysis, and ultimate analysis were performed on all BMA samples, and properties such as porosity, particle density, bulk density, point of zero charge, BET surface area, water-absorption capacity, and bulk parameters such as surface pH and surface charges were determined. BMAs were characterized by SEM and FTIR. The surface areas of biomass ashes vary from 1.9 to 46 m²/g, and point of zero charge for all BMAs exceed 9.8, which confirmed the alkaline nature of these samples. Based on the chemical composition, BMAs are categorized into four types (S, C, K, and CK), and their utilization is proposed based on the type. BMAs find applications in agriculture and construction industries; glass, rubber, and zeolite manufacturing; and in adsorption (as a source of silica/zeolites). The paper also discusses the research challenges and opportunities in utilization of BMAs.
اظهر المزيد [+] اقل [-]Occurrence and diversity of tetracycline resistance genes in the agricultural soils of South Korea
2016
Kim, Song Yeob | Kuppusamy, Saranya | Kim, Jang-hwan | Yoon, Young-Eun | Kim, Kwon-Rae | Lee, Yong Bok
Reports on the occurrence and diversity of antibiotic-resistant bacteria and genes, which are considered to be emerging pollutants worldwide, have, to date, not been published on South Korean agricultural soils. This is the first study to investigate the persistence of tetracycline (oxytetracycline, tetracycline, and chlortetracycline)-resistant bacterial community and genes in natural and long-term fertilized (NPK, pig, and cattle manure composts) agricultural soils in South Korea. The results showed that oxytetracycline and chlortetracycline could be the dominant residues in animal manures; regular fertilization of manures, particularly pig manures, may be the prime cause for the spread and abundance of tetracycline resistance in South Korean agricultural soils. Both the country’s natural and agricultural soils are reservoirs of antibiotic-resistant species. Of the 113 tetracycline-resistant isolates identified (19 typical bacterial genera and 36 distinct species), approximately 40 to 99 % belonged to Gram-positive bacteria and Bacillus constituted the predominant genera. Of the 24 tet genes targeted, tetG, tetH, tetK, tetY, tetO, tetS, tetW, and tetQ were detected in all soil samples, highlighting their predominance and robust adaptability in soils. Meanwhile, it is suggested that tetC, tetE, tetZ, tetM, tetT, and tetP(B) are the common residues in pig manures, and furthermore, the treatment of soils with pig manures may wield a different impact on the tet gene resistome in agricultural soils. This study thus highlights the necessity for regulating the usage of tetracyclines in South Korean animal farming. This must be followed by proper monitoring of the subsequent usage of animal manures especially that derived from pig farms located in agricultural soils.
اظهر المزيد [+] اقل [-]Integrated modeling of agricultural scenarios (IMAS) to support pesticide action plans: the case of the Coulonge drinking water catchment area (SW France)
2017
Vernier, Françoise | Leccia-Phelpin, Odile | Lescot, Jean-Marie | Minette, Sébastien | Miralles, André | Barberis, Delphine | Scordia, Charlotte | Kuentz-Simonet, Vanessa | Tonneau, Jean-Philippe
Non-point source pollution is a cause of major concern within the European Union. This is reflected in increasing public and political focus on a more sustainable use of pesticides, as well as a reduction in diffuse pollution. Climate change will likely to lead to an even more intensive use of pesticides in the future, affecting agriculture in many ways. At the same time, the Water Framework Directive (WFD) and associated EU policies called for a “good” ecological and chemical status to be achieved for water bodies by the end of 2015, currently delayed to 2021–2027 due to a lack of efficiency in policies and timescale of resilience for hydrosystems, especially groundwater systems. Water managers need appropriate and user-friendly tools to design agro-environmental policies. These tools should help them to evaluate the potential impacts of mitigation measures on water resources, more clearly define protected areas, and more efficiently distribute financial incentives to farmers who agree to implement alternative practices. At present, a number of reports point out that water managers do not use appropriate information from monitoring or models to make decisions and set environmental action plans. In this paper, we propose an integrated and collaborative approach to analyzing changes in land use, farming systems, and practices and to assess their effects on agricultural pressure and pesticide transfers to waters. The integrated modeling of agricultural scenario (IMAS) framework draws on a range of data and expert knowledge available within areas where a pesticide action plan can be defined to restore the water quality, French “Grenelle law” catchment areas, French Water Development and Management Plan areas, etc. A so-called “reference scenario” represents the actual soil occupation and pesticide-spraying practices used in both conventional and organic farming. A number of alternative scenarios are then defined in cooperation with stakeholders, including socio-economic conditions for developing alternative agricultural systems or targeting mitigation measures. Our integrated assessment of these scenarios combines the calculation of spatialized environmental indicators with integrated bio-economic modeling. The latter is achieved by a combined use of Soil and Water Assessment Tool (SWAT) modeling with our own purpose-built land use generator module (Generator of Land Use version 2 (GenLU2)) and an economic model developed using General Algebraic Modeling System (GAMS) for cost-effectiveness assessment. This integrated approach is applied to two embedded catchment areas (total area of 360,000 ha) within the Charente river basin (SW France). Our results show that it is possible to differentiate scenarios based on their effectiveness, represented by either evolution of pressure (agro-environmental indicators) or transport into waters (pesticide concentrations). By analyzing the implementation costs borne by farmers, it is possible to identify the most cost-effective scenarios at sub-basin and other aggregated levels (WFD hydrological entities, sensitive areas). Relevant results and indicators are fed into a specifically designed database. Data warehousing is used to provide analyses and outputs at all thematic, temporal, or spatial aggregated levels, defined by the stakeholders (type of crops, herbicides, WFD areas, years), using Spatial On-Line Analytical Processing (SOLAP) tools. The aim of this approach is to allow public policy makers to make more informed and reasoned decisions when managing sensitive areas and/or implementing mitigation measures.
اظهر المزيد [+] اقل [-]Revaluation of stockpile amount of PFOS-containing aqueous film-forming foam in Japan: gaps and pitfalls in the stockpile survey
2017
Zushi, Yasuyuki | Yamamoto, Atsushi | Tsunemi, Kiyotaka | Masunaga, Shigeki
Stockpiles of perfluoro-octane sulfonic acid (PFOS) containing aqueous film-forming foam (AFFF) have the potential to be emitted by leaching, spills, and during use in fire response and other processes. Several studies have discussed the high levels of stockpiled PFOS-containing AFFF and the risk they pose to the environment; however, there are large gaps in the amounts in Japan compared with other countries. For example, 300 tons are stockpiled in Canada, 2200–2600 tons in Switzerland, 1400 tons in Norway, and 19,000 tons in Japan from their reports for publication. The gap is considered to be a result of lack of surveys of several important sources. In this study, we revaluated the stockpile of AFFF in Japan to verify the reported value and identify the source of this gap based on information available in peer-reviewed papers, governmental reports, and business reports. The major reason for the gap between Japan and other countries was considered to be the survey of stockpiles in car-parking facilities, which accounted for 46.7% of the total amounts in Japan, but were not considered in other countries. These stockpiles indicate a high potential for accidental leaching or spilling of the AFFF by careless storage. Therefore, it is recommended that continual surveys of the AFFF stockpile in car-parking facilities be conducted in the rest of the world.
اظهر المزيد [+] اقل [-]Occurrence of cardiovascular drugs in the sewage-impacted Vistula River and in tap water in the Warsaw region (Poland)
2016
Giebułtowicz, Joanna | Stankiewicz, Albert | Wroczyński, Piotr | Nałęcz-Jawecki, Grzegorz
In recent years, cardiovascular diseases were the second most common cause of death worldwide. Therefore, the consumption of drugs used to treat cardiovascular diseases is high. So far, there were no such comprehensive reports regarding the presence of cardiovascular drugs in surface and tap waters, particularly in Central and Eastern Europe. The aim of our study was to determine the presence of 30 pharmaceutically active compounds and some of their metabolites, at specific points of the Vistula River and in tap water samples in the Warsaw region. The analysis was performed using the liquid chromatography–electrospray ionization–tandem mass spectrometry method, coupled to solid-phase extraction. To the best of the authors’ knowledge, this is the first time where the presence of ciprofibrate in the environment was investigated. Cardiovascular drugs found at the highest concentrations (reaching 1 μg/L or higher) in surface water were beta-blockers, sartans and diuretics. In tap water samples, trace amounts of pharmaceuticals were detected, for almost all target compounds. This highlights their inadequate elimination by the treatment facility used in the Warsaw region. The presence of cardiovascular compounds in the aquatic environment could have a long-term effect even at a low exposure level, since synergy effects amongst pharmaceuticals may occur.
اظهر المزيد [+] اقل [-]Benchmark dose for cadmium exposure and elevated N-acetyl-β-D-glucosaminidase: a meta-analysis
2016
Liu, CuiXia | Li, YuBiao | Zhu, ChunShui | Dong, ZhaoMin | Zhang, Kun | Zhao, Yanbin | Xu, YiLu
Cadmium (Cd) is a well-known nephrotoxic contaminant, and N-acetyl-β-D-glucosaminidase (NAG) is considered to be an early and sensitive marker of tubular dysfunction. The link between Cd exposure and NAG level enables us to derive the benchmark dose (BMD) of Cd. Although several reports have already documented urinary Cd (UCd)-NAG relationships and BMD estimations, high heterogeneities arise due to the sub-populations (age, gender, and ethnicity) and BMD methodologies being employed. To clarify the influences that these variables exert, firstly, a random effect meta-analysis was performed in this study to correlate the UCd and NAG based on 92 datasets collected from 30 publications. Later, this established correlation (Ln(NAG) = 0.51 × Ln(UCd) + 0.83) was applied to derive the UCd BMD₅ of 1.76 μg/g creatinine and 95 % lower confidence limit of BMD₅ (BMDL₅) of 1.67 μg/g creatinine. While the regressions for different age groups and genders differed slightly, it is age and not gender that significantly affects BMD estimations. Ethnic differences may require further investigation given that limited data is currently available. Based on a comprehensive and systematic literature review, this study is a new attempt to quantify the UCd-NAG link and estimate BMD.
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