Degradation Kinetics of an Aged Hydrocarbon-Contaminated Soil   总被引：1，自引：0，他引：1  

Snežana Maletić  Božo Dalmacija  Srđan Rončević  Jasmina Agbaba  Olgica Petrović 《Water, air, and soil pollution》2009,201(1-4):149-159

PM2.5 and PM10 samples were collected in the urban atmosphere of Elche (southeastern Spain) between December 2004 and November 2005. The samples were analyzed for mass and water-soluble inorganic ions (Na⁺, ${\text{NH}}^{{\text{ + }}}_{{\text{4}}}$ , K⁺, Ca²⁺, Mg²⁺, Cl^?, ${\text{NO}}^{{\text{ - }}}_{{\text{3}}}$ and ${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$ ) with the aim of investigating the influence of the climatic and geographic features of a coastal semiarid area on the contribution of these species to PM levels. Secondary inorganic ions ( ${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$ , ${\text{NO}}^{{\text{ - }}}_{{\text{3}}}$ , ${\text{NH}}^{{\text{ + }}}_{{\text{4}}}$ ) were the major components in the fine fraction (PM2.5), accounting for 40% of the total mass. The relationship between non-marine ${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$ and ${\text{NH}}^{{\text{ + }}}_{{\text{4}}}$ indicated that fine sulfate particles were completely neutralized by ammonium. In the coarse fraction (PM10–2.5), nitrate (as NaNO₃ and Ca(NO₃)₂), together with crustal (CaCO₃) and marine species (NaCl) accounted for almost 50% of the total mass. Fine sulfate and coarse nitrate showed summer maximums. In contrast, the concentrations of fine ${\text{NO}}^{{\text{ - }}}_{{\text{3}}}$ were lowest in the warm period. Ammonium presented both winter and summer maximums. The levels of marine ions, except for coarse Cl^?, were highest in summer when the dominant wind flow is from the sea. No significant seasonal variations were observed for coarse Ca²⁺ and ${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$ . The concentrations of all inorganic ions increased during Saharan dust events, in particular, fine ${\text{NH}}^{{\text{ + }}}_{{\text{4}}}$ and ${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$ and coarse $NO_3^ - $ . Coarse calcium was proved not to be a good tracer for this type of episode in our region since the average levels of this cation are elevated and the relative increase in its concentrations during African events was not as high as expected.  相似文献   

Evaluating the necessity for thermal treatment in clay-based metal immobilization techniques as an environmentally acceptable sediment remediation process     

Dejan Krcmar  Milena Dalmacija  Bozo Dalmacija  Miljana Prica  Jelena Trickovic  Elvira Karlovic 《Journal of Soils and Sediments》2013,13(7):1318-1326

Purpose

The objective of this research was to apply the same immobilization (stabilization/solidification) clay-based treatments to sediment contaminated with different metals (Pb, Cd, Ni, Zn, Cu, Cr) with different distributions and availabilities in sediment. We also examined the possibility of using clay as an immobilization agent without the application of thermal treatment, in order to reduce the economic cost of this expensive remediation procedure.

Materials and methods

Clay from a canal in Vojvodina, Republic of Serbia, was used as the immobilization agent in a stabilization/solidification treatment to remediate metal-contaminated sediment. Semi-dynamic and toxicity characteristic leaching tests were conducted to assess the effectiveness of the nonthermal and thermal immobilization treatments with clay, and the long-term leaching behavior of these metals was determined using the following parameters: cumulative percentage of metals leached; diffusion coefficients; leachability indices; and toxicity characteristic leaching test concentration.

Results and discussion

Based on these parameters, both clay-based treatments were effective in immobilizing metals in the contaminated sediment. Results suggest that both heating temperature and clay proportion in the sediment–clay mixture impact the degree of metal immobilization.

Conclusions

Clay-based products are potentially good immobilization materials for metal-contaminated sediments, with the distribution of metals in the original sediment not influencing the efficacy of the treatments. Even without the thermal treatment, the metals were effectively immobilized. The leaching of metals was largely inside the regulatory limits and the treated samples can be regarded as nonhazardous materials. This justifies the choice of not applying the more expensive thermal treatment during remediation, especially when treating sediments containing a mixture of pollutants.  相似文献   

Sorption Behaviour of Trichlorobenzenes and Polycyclic Aromatic Hydrocarbons in the Absence or Presence of Carbon Nanotubes in the Aquatic Environment     

Jelena Tričković  Marijana Kragulj Isakovski  Malcolm Watson  Snežana Maletić  Srđan Rončević  Božo Dalmacija  Zoltán Kónya  Ákos Kukovecz 《Water, air, and soil pollution》2016,227(10):374

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Photocatalytic Degradation of Herbicide Quinmerac in Various Types of Natural Water     

Vesna N. Despotovi?  Biljana F. Abramovi?  Daniela V. ?oji?  Sanja J. Kler  Milena B. Dalmacija  Luka J. Bjelica  Dejan Z. Or?i? 《Water, air, and soil pollution》2012,223(6):3009-3020

The efficiency of the photocatalytic degradation of the herbicide quinmerac in aqueous TiO₂ suspensions was examined as a function of the type of light source, TiO₂ loading, pH, temperature, electron acceptors, and hydroxyl radical (^?OH) scavenger. The optimum loading of catalyst was found to be 0.25?mg?mL^?1 under UV light at pH?7.2, with the apparent activation energy of the reaction being 13.7?kJ?mol^?1. In the first stage of the reaction, the photocatalytic degradation of quinmerac (50???M) followed approximately a pseudo-first order kinetics. The most efficient electron acceptor appeared to be H₂O₂ along with molecular oxygen. By studying the effect of ethanol as an ^?OH scavenger, it was shown that the heterogeneous catalysis takes place mainly via ^?OH. The results also showed that the disappearance of quinmerac led to the formation of a number of organic intermediates and ionic byproducts, whereas its complete mineralization occurred in about 120?min. The reaction intermediates (7-chloro-3-methylquinoline-5,8-dione, three isomeric phenols hydroxy-7-chloro-3-methylquinoline-8-carboxylic acids, and 7-chloro-3-(hydroxymethyl)quinoline-8-carboxylic acid) were identified and the kinetics of their appearance/disappearance was followed by LC?CESI?CMS/MS. Tentative photodegradation pathways were proposed and discussed. The study also encompassed the effect of quality of natural water on the rate of removal of quinmerac.  相似文献   

Characterisation, Availability, and Risk Assessment of the Metals in Sediment after Aging     

Milica B. Velimirovi?  Miljana Dj. Prica  Bo?o D. Dalmacija  Sr?an D. Ron?evi?  Milena B. Dalmacija  Milena Dj. Be?eli?  Jelena S. Tri?kovi? 《Water, air, and soil pollution》2011,214(1-4):219-229

The behavior of metals in sediments after their disposal to land has important implications for the environmental management. The sediment from the Carska Bara (Serbia) was polluted with adequate metal salts in order to reach severe contamination based on the pseudo-total metal content of Pb, Cd, Ni, Zn, Cu, and Cr according to the corresponding Dutch standards and Canadian guidelines. The toxicity and fate of the metal in sediment depend on its chemical form, and therefore, quantification of the different forms of a metal is more meaningful than the estimation of its total concentration. In this study, fractionation of metals in sediment has been investigated to determine its speciation and ecotoxic potential, as well as evaluation of metal potential toxicity based on the simultaneously extracted metals (SEMs) and acid volatile sulfides (AVSs) analysis at the beginning of the experiment and after 5?weeks of sediment aging. The investigations suggest that Cd, Pb, and Zn have a tendency to associate with labile fraction, the most mobile and most dangerous fraction for the environment. Risk assessment code revealed their high risk. Copper and chromium showed low to medium risk to the aquatic environment. Nickel showed no risk to the aquatic environment. This was the case at the beginning and after 5?weeks of aging. Aging yielded an increased mobility of all metals based on the increased proportion in mobile fractions. The ??[SEM _i ]/[AVS] ratio was found to be >1 both at the beginning and after 5?weeks of aging, with the ratio showing an increase with time. This ratio indicates the potential availability/toxicity and, according to the US EPA criteria, the samples belong to the group with probable negative effect. If particular metals are considered, only the ??[SEM _i ]/[AVS] ratio for zinc was >1 at the beginning. After 5?weeks, the ratio was >1 for zinc, lead, and copper. Comparison of the results of sequential extraction and the results of SEM and AVS analysis showed good agreement for lead and zinc.  相似文献   

Geochemical monitoring of organic and inorganic pollutants in the sediment of the Eastern Posavina (Serbia)     

Nenad Grba  Dejan Krčmar  Franz Neubauer  Srđan Rončević  Marijana Kragulj Isakovski  Jelena Molnar Jazic  Božo Dalmacija 《Journal of Soils and Sediments》2017,17(11):2610-2619

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Measuring the technical efficiency and exploring the inefficiency determinants of vegetable farms in Samsun province,Turkey     

Mehmet Bozoğlu  Vedat Ceyhan 《Agricultural Systems》2007

The purposes of this research were to measure the technical efficiency of sample vegetable farms and subsequently to explore determinants of technical inefficiency in the Samsun province of Turkey. Stochastic Frontier Analysis was used to measure technical efficiency. Farm managers from 75 randomly selected farms were interviewed for farm level data in the 2002–2003 production periods. Research results revealed that the average output of vegetable farms in Samsun could increase by 18% under prevailing technology. The technical efficiency of the sample vegetable farms ranged from 0.56 to 0.95 (0.82 average). The variables of schooling, experience, credit use, participation by women and information score negatively affected technical inefficiency. However, age, family size, off-farm income and farm size showed a positive relationship with inefficiency. Therefore, this study proposes strategies such as providing better extension services and farmer training programs, integrating women into the training and extension programs, raising the educational level of farmers, and providing farmers with greater access to credit, to enhance technical efficiency.  相似文献