Dissipation and runoff transport of metazachlor herbicide in rapeseed cultivated and uncultivated plots in field conditions

The environmental fate of metazachlor herbicide was investigated under field conditions in rapeseed cultivated and uncultivated plots, over a period of 225 days. The cultivation was carried out in silty clay soil plots with two surface slopes, 1 and 5 %. The herbicide was detectable in soil up to 170 days after application (DAA), while the dissipation rate was best described by first-order kinetics and its half-life ranged between 10.92 and 12.68 days. The herbicide was detected in the soil layer of 10–20 cm from 5 to 48 DAA, and its vertical movement can be described by the continuous stirred tank reactor (CSTR) in series model. Relatively low amounts of metazachlor (less than 0.31 % of the initial applied active ingredient) were transferred by runoff water. More than 80 % of the total losses were transferred at the first runoff event (12 DAA), with herbicide concentrations in runoff water ranging between 70.14 and 79.67 μg L⁻¹. Minor amounts of the herbicide (less than 0.07 % of the initial applied active ingredient) were transferred by the sediment, with a maximum concentration of 0.57 μg g⁻¹ (12 DAA), in plots with 5 % inclination. Finally, in rapeseed plants, metazachlor was detected only in the first sampling (28 DAA) at concentrations slightly higher than the limit of quantification; when in seeds, no residues of the herbicide were detected.

     

Using Various Guidelines and Approaches for the Assessment of Marine Sediment Quality

The aim of the present study is to explore the implications of using different quality guidelines and approaches for marine sediment characterization. As a case study, the sediments of Souda Port, Crete, Greece, were examined in order to assess heavy metal contamination and to estimate anthropogenic contribution and potential adverse effects to aquatic environment, as well as to indicate feasible future management options. The concentration of six heavy metals (Co, Cr, Cu, Ni, Pb, and Zn) was determined and compared with different sediment quality guidelines (SQGs) and regional/national criteria established for dredged material characterization and management. In addition, the geo-accumulation index (I_geo) was calculated and the sediments toxicity and heavy metals bioavailability were determined. Based on the experimental data, it is deduced that Souda sediments are characterized as moderately polluted only in terms of Co, Ni, and Pb.     

Organic and elemental carbon associated to PM10 and PM2.5 at urban sites of northern Greece

Organic carbon (OC) and elemental carbon (EC) concentrations, associated to PM₁₀ and PM_2.5 particle fractions, were concurrently determined during the warm and the cold months of the year (July–September 2011 and February–April 2012, respectively) at two urban sites in the city of Thessaloniki, northern Greece, an urban-traffic site (UT) and an urban-background site (UB). Concentrations at the UT site (11.3?±?5.0 and 8.44?±?4.08 14 μg m^?3 for OC₁₀ and OC_2.5 vs. 6.56?±?2.14 and 5.29?±?1.54 μg m^?3 for EC₁₀ and EC_2.5) were among the highest values reported for urban sites in European cities. Significantly lower concentrations were found at the UB site for both carbonaceous species, particularly for EC (6.62?±?4.59 and 5.72?±?4.36 μg m^?3 for OC₁₀ and OC_2.5 vs. 0.93?±?0.61 and 0.69?±?0.39 μg m^?3 for EC₁₀ and EC_2.5). Despite that, a negative UT-UB increment was frequently evidenced for OC_2.5 and PM_2.5 in the cold months possibly indicative of emissions from residential wood burning at the urban-background site. At both sites, cconcentrations of OC fractions were significantly higher in the cold months; on the contrary, EC fractions at the UT site were prominent in the warm season suggesting some influence from maritime emissions in the nearby harbor area. Secondary organic carbon, being estimated using the EC tracer method and seasonally minimum OC/EC ratios, was found to be an appreciable component of particle mass particularly in the cold season. The calculated secondary contributions to OC ranged between 35 and 59 % in the PM₁₀ fraction, with relatively higher values in the PM_2.5 fraction (39–61 %). The source origin of carbonaceous species was investigated by means of air parcel back trajectories, satellite fire maps, and concentration roses. A local origin was mainly concluded for OC and EC with limited possibility for long range transport of biomass (agricultural waste) burning aerosol.     

Photocatalytic degradation of Reactive Red 195 using anatase/brookite TiO2 mesoporous nanoparticles: Optimization using response surface methodology (RSM) and kinetics studies

In the present study, the photocatalytic degradation of Reactive Red 195 (RR195) from aqueous samples under UV-A irradiation by using anatase/brookite TiO₂ (A/B TiO₂) mesoporous nanoparticles has been investigated. Batch experiments were conducted to study the effects of the main parameters affecting the photocatalytic process. The effects and interactions of most influenced parameters, such as substrate concentration and catalyst load, were evaluated and optimized by using a central composite design model and a response surface methodology. The results indicated that the dye degradation efficiency in the experimental domain investigated was mainly affected by the tested variables, as well as their interaction effects. Analysis of variance showed a high coefficient of determination value (R ²?=?0.9947), thus ensuring a satisfactory adjustment of the first-order regression model (2FI model) with the experimental data. The obtained results also indicate that catalyst loading plays an important role in determining the removal efficiency of RR195 attributable to both photodegradation and adsorption process. Under optimal conditions (initial dye concentration (50 mg/L) and catalyst loading (2,000 mg/L), A/B TiO₂ showed similar removal efficiency compared to that of commercial titania (Degussa P25). Also, at these conditions, complete degradation of RR195 can be achieved by both catalysts within 15 min under UV-A irradiation. The experiments demonstrated that dye removal on the prepared A/B TiO₂ was facilitated by the synergistic effects between adsorption and photocatalysis. Photocatalytic mineralization of RR195 was monitored by total organic carbon. The recycling experiments confirmed the stability of the catalyst.     

Heavy metal accumulation and metallothionein concentration in the frog Rana ridibunda after exposure to chromium or a mixture of chromium and cadmium

The accumulation of two heavy metals (chromium (Cr) and cadmium (Cd)) in the liver, kidney and gut of Rana ridibunda exposed to Cr or to a mixture of Cr and Cd was investigated. The concentration of metallothioneins (MTs) in the same tissues was also studied. Both metals accumulated mainly in the kidney. Cr accumulation in the liver and gut was not affected by the presence of Cd. Furthermore, Cr concentration in the kidney was doubled when Cd was present. MT concentration did not increase after Cr treatment but it increased two- to six-fold over control values in mixture-exposed frogs, the highest value being observed in the gut. MTs in the gut could act as a barrier preventing ingested heavy metals from entering the blood stream. MT concentration correlated positively with Cd concentrations in both the liver and the gut of mixture-exposed animals.     

Endocrine disrupting compounds in municipal and industrial wastewater treatment plants in Northern Greece

The occurrence and fate of endocrine disrupting compounds (EDCs) in a sewage treatment plant and two industrial wastewater treatment plants from textile and tannery factories were investigated. EDCs of interest are 4-nonylphenol, 4-octylphenol, their ethoxylate oligomers (mono- and di-ethoxylates of nonylphenol and octylphenol), bisphenol A, triclosan and steroid estrogens. Target compounds were determined in dissolved fraction, total suspended solids and sludge by employing solid phase extraction and ultrasonication followed by gas chromatography–mass spectrometry.Nonylphenols and oligomers with one or two ethoxy groups were the most abundant compounds in raw wastewater as well as in effluents from all the treatment stages of sewage treatment plant, followed by triclosan and bisphenol A. Steroids were found at very low concentrations. Almost all phenolic EDCs compounds were predominantly associated to suspended solids in influents whereas the dissolved fraction dominated the treated effluents. High removal rates, ranging from 86% to 99%, were observed throughout the whole treatment process. Biodegradation was the main removal pathway of EDCs. Tannery wastewaters exhibited high concentrations of nonylphenolic compounds. This type of wastewaters could pose a significant risk to the aquatic and terrestrial environment.     

Benzotriazoles, Alkylphenols and Bisphenol A in Municipal Wastewaters and in the Glatt River, Switzerland

- DOI: http://dx.doi.org/10.1065/espr2006.01.295 Background Many organic micropollutants occur at trace concentrations in municipal wastewater effluents and in the aquatic environment. Some of these xenobiotic chemicals can be considered as 'emerging' contaminants and some are suspect to have endocrine disrupting effects. Among the latter are nonylphenol (NP), octylphenol (OP) and bisphenol A (BPA), which deserve special attention due to their ubiquitous occurrence in the aquatic environment. The complexing agents benzotriazole (BT) and tolyltriazole (TT) are applied as anticorrosive agents (e.g. in cooling and hydraulic fluids, in antifreezing fluids, in aircraft deicing fluids, in dish washing liquids for silver protection), as antifogging agents and as intermediates for the synthesis of various chemicals. The environmental occurrence of NP and OP is caused by the fact that they are intermediate products (metabolites) in the biodegradation of alkylphenol polyethoxylate surfactants. BPA is globally used for the production of polycarbonate and epoxy resins. Methods BT, TT, NP, OP and BPA were quantitatively determined in municipal wastewater effluents in Switzerland and in the Glatt River. The analytes were enriched by solid-phase enrichment. BT and TT were determined underivatized by electrospray LC/tandem MS. Reversed-phase LC was performed on octylsilica columns with isocratic water/methanol elution. Multiple reaction monitoring of the positive ions provided selective and sensitive detection for reliable quantifications. NP, OP and BPA were determined by GC/MS after derivatization with N-methyl-N-(trimethylsilyl)-trifluoroacetamide. Results and Discussion BT and TT concentrations in primary and secondary effluents of municipal wastewater treatment plants varied from below 10 to 100 μg/L. The ranges of the concentrations in the Glatt River in ng/L were 636–3,690 for BT, 122–628 for TT, 68–326 for NP, 6–22 for OP and 9–76 for BPA. The corresponding mass flows in g/d were 93–1,870 for BT, 18–360 for TT, 24–183 for NP, 1–16 for OP and 2–72 for BPA. The concentrations and mass flows of NP in the River Glatt were drastically lower than the analogous values found 15 years ago. Thus, a substantially decreased environmental exposure can be observed due to the reduction of the use of alkyphenol polyethoxylate surfactants in Switzerland. The current concentrations of NP, OP and BPA are within the ranges reported for weakly impacted surface waters. Conclusion The investigated contaminants occur at quantitatively measurable but varying concentrations in municipal wastewaters and in the Glatt River reflecting their ubiquitous input into wastewaters and their different behaviour during biological wastewater treatment.     

Uncertainty in optimal pollution levels: modelling and evaluating the benefit area

This paper identifies the optimal pollution level under the assumptions of linear, quadratic and exponential damage and abatement cost functions and investigates analytically the certain restrictions that the existence of this optimal level requires. The evaluation of the benefit area is discussed and the mathematical formulation provides the appropriate methods for that to be calculated. The positive, at least from a theoretical point of view, is that both the quadratic and the exponential case obey the same form for evaluating the benefit area. These benefit area estimations can be used as indexes between different rival policies, and depending on the environmental problem, the policy that produces the maximum area will be the beneficial policy.     

Chemical composition and mass closure of ambient coarse particles at traffic and urban-background sites in Thessaloniki,Greece

Concentrations and chemical composition of the coarse particle fraction (PM_c) were investigated at two urban sites in the city of Thessaloniki, Greece, through concurrent sampling of PM₁₀ and PM_2.5 during the warm and the cold months of the year. PM_c levels at the urban-traffic site (UT) were among the highest found in literature worldwide exhibiting higher values in the cold period. PM_c levels at the urban-background site (UB) were significantly lower exhibiting a reverse seasonal trend. Concentration levels of minerals and most trace metals were also higher at the UT site suggesting a stronger impact from traffic-related sources (road dust resuspension, brake and tire abrasion, road wear). According to the chemical mass closure obtained, minerals (oxides of Si, Al, Ca, Mg, Fe, Ti, and K) dominated the PM_c profile, regardless of the site and the period, with organic matter and secondary inorganic aerosols (mainly nitrate) also contributing considerably to the PM_c mass, particularly in the warm period. The influence of wind speed to dilution and/or resuspension of coarse particles was investigated. The source of origin of coarse particles was also investigated using surface wind data and atmospheric back-trajectory modeling. Finally, the contribution of resuspension to PM_c levels was estimated for air quality management perspectives.     

Assessment of Human and Ecosystem Risk Due to Agricultural Waste Compost Application on Soils: A Review

Agricultural wastes (AW) are often characterized by varying pH and substantial contamination potential, which are mainly related to their high organic load, thus affecting—when improperly disposed of—soils, living organisms, and water bodies. Composting of AW is the most commonly used management option and results in the production of soil improver that enhances crop growth and contributes to agricultural sustainability. This study aims to present the framework for assessing human and ecosystem risk when compost produced from AW is applied on soil. In order to develop this framework, issues such as origin, composition and pre-treatment of AW, application rates on soils, bioavailability and mobility of contaminants present in compost, exposure routes and rates as well as determination of the fate of contaminants in soil, air, and water, should be taken into consideration.