International Journal of Environmental Analytical Chemistry, Jan 25, 2007
This study is the first thorough method optimisation for accelerated solvent extraction (ASE) of ... more This study is the first thorough method optimisation for accelerated solvent extraction (ASE) of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) from chemically dried compost. For PCBs, optimised solvent composition, temperature, pressure, number of static cycles, duration, and flush volume were as follows: toluene/acetone 1 : 3 (v/v), 120°C, 2000 psi, 3 × 5 min, and 50%, respectively. Limits of quantification and method precision were between 0.16 and 2.46 µg kg−1 dw and 6–17% respectively for individual PCBs. Absolute recoveries of isotope-labelled extraction standards used for each of the analytes ranged from 65 to 105% and relative recoveries were between 85 and 99%. The method proofed to be robust and was successfully applied to different compost samples. The optimisation of PAHs extraction was performed and resulted in the following conditions: solvent: hexane/acetone 1/3 (v:v), temperature: 140°C, pressure: 1500 psi, extraction time: 3 × 5 min, and 50% flush volume. Limits of detection and method precision for individual PAHs were between 1.1 and 37.2 µg kg−1 dw and 12–34% respectively. Absolute and relative recoveries ranged from 24 to 68% and from 85 to 99%, respectively. Optimal extraction conditions for PAHs were more difficult to determine due to the inhomogeneous distribution of PAHs in samples. However, the method appeared to be feasible and suggestions for further improvements are presented.
Environmental Science: Processes & Impacts, 2015
Over the last 30 years, concentrations of medium to heavy PAH remained remarkably constant for Sw... more Over the last 30 years, concentrations of medium to heavy PAH remained remarkably constant for Swiss topsoils, whereas concentrations of light PAH decreased.
ABSTRACT Typical concentrations and quantitative mass flows of anthropogenic compounds (such as p... more ABSTRACT Typical concentrations and quantitative mass flows of anthropogenic compounds (such as personal care compounds, bactericides, flame retardants, plasticizers, detergents, complexing agents, as well as mycotoxins) in waste water are compared to typical per person loads in the influents and effluents of waste water treatment plants. They are evaluated to assess their significance for the contamination of the aquatic environment. Usually the number of persons serviced by a waste water treatment plant (WWTP) is well known, as the design parameters of the WWTP heavily rely on the per person usage of water and the per person emissions of nutrients as well as organic carbon. It is the intention to use these basic data together with concentrations from some waste water treatment plants to make assessments on emissions from WWTPs, for which only basic design parameters are available. These data can be used for predictions of waste water contamination concerning pollutant loads and concentrations for waste water treatment plants that have not undergone extensive monitoring. The relevance of the respective pollutants for surface waters as well as sludge is demonstrated. The focus of this chapter is on those compounds that are emitted continuously during dry weather. - No storm water issues will covered in this book chapter.
Suspensions or solutions with 1% of Chinese galls (Galla chinensis, GC) or 1% of tannic acid (TA)... more Suspensions or solutions with 1% of Chinese galls (Galla chinensis, GC) or 1% of tannic acid (TA), inhibited germination of conidia or mycelium growth of Fusarium graminearum (FG) by 98%-100% or by 75%-80%, respectively, whereas dried bark from buckthorn (Frangula alnus, FA) showed no effect at this concentration. In climate chamber experiments where the wheat variety "Apogee" was artificially inoculated with FG and F. crookwellense (FCr) and treated with 5% suspensions of TA, GC and FA, the deoxynivalenol (DON) content in grains was reduced by 81%, 67% and 33%, respectively. In field experiments with two commercial wheat varieties and artificial or semi-natural inoculations, mean DON reductions of 66% (TA) and 58% (FA), respectively, were obtained. Antifungal toxicity can explain the high efficacies of TA and GC but not those of FA. The Fusarium head blight (FHB) and mycotoxin reducing effect of FA is probably due to elicitation of resistance in wheat plants. With semi-natural inoculation, a single FA application in the first half of the flowering period performed best. However, we assume that applications of FA at the end of ear emergence and a treatment, triggered by an infection period, with TA or GC during flowering, might perform better than synthetic fungicides.
To prevent overloading of sewer systems and to ensure sufficient recharging of the groundwater un... more To prevent overloading of sewer systems and to ensure sufficient recharging of the groundwater underneath sealed urban areas, collection and artificial infiltration of roof runoff water has become very popular in many countries including Switzerland. However, there is still a considerable lack of knowledge concerning the quality of roof runoff, particularly with respect to the presence of pesticides. In this work, the occurrence and the temporal variations in concentration in rainwater and in roof runoff from different types of roofs (i.e., clay tile roofs, polyester roofs, flat gravel roofs) were determined for the most important members of three widely used classes of pesticides (i.e., triazines, acetamides, phenoxy acids). It is shown that in rain and roof runoff, maximum pesticide concentrations originating primarily from agricultural use occurred during and right after the application periods. Maximum average concentrations for single rain events and total loads per year were, for example, for atrazine, 903 ng/L and 13 900 ng/ (m 2 year); for alachlor, 191 ng/L and 5900 ng/(m 2 year); and for R-dichlorprop, 106 ng/L and 5100 ng/(m 2 year). Further, the study reveals that a major portion of the compounds washed out from the atmosphere may actually reach the groundwater, particularly if the roof runoff is infiltrated directly into highly permeable zones of the subsurface. Nevertheless, although in some cases European Union and Swiss drinking water standards (100 ng/L) were not always met in rain and roof runoff waters, for the three compound classes investigated, the groundwater contamination potential of the pesticides originating from the atmosphere can be considered of equal or even smaller importance as compared to their direct use in agriculture. The investigations also show that leaching of pesticides used as construction chemicals on roofs, that is, as roof protection agents in sealings used on flat gravel roofs, may be a much more significant source of organic pollutants present in roof runoff (see also our following paper in this issue).
than rural material. Fifth, the highest concentrations of POPs were usually observed in summer sa... more than rural material. Fifth, the highest concentrations of POPs were usually observed in summer samples. Finally, median compost concen-Composting and the application of compost to the soil follow the trations of POPs were greater by up to one order of magnitude than principle of recycling and sustainability. Compost can also have a in arable soils, as the primary recipients of compost, but were well positive effect on physical, chemical, and biological soil parameters. within the range of many urban soils. In conclusion, this work provides However, little is known about the origin, concentration, and transfora basis for the further improvement of composting and for future risk mation of persistent organic pollutants (POPs) in compost. We thereassessments of compost application. fore compiled literature data on some priority POPs in compost and its main feedstock materials from more than 60 reports. Our data evaluation suggests the following findings. First, median concentrations of ⌺ 16 polycyclic aromatic hydrocarbons (PAHs), ⌺ 6 polychlo-M odern societies produce considerable amounts rinated biphenyls (PCBs), and ⌺ 17 polychlorinated dibenzo-p-dioxins of waste. Some 40 million Mg of municipal solid and-furans (PCDD/Fs) were higher in green waste (1803, 15.6 g/kg waste (MSW) are collected annually for recycling in the dry wt., and 2.5 ng international toxicity equivalent [I-TEQ]/kg dry 15 member states of the European Union (before 2004). wt.) than in organic household waste (635, 14.6 g/kg dry wt., and This corresponds to approximately 18% of the total mu-2.2 ng I-TEQ/kg dry wt.) and kitchen waste (not available [NA], nicipal waste produced (European Commission, 2003). 14.9 g/kg dry wt., 0.4 ng I-TEQ/kg dry wt.). The POP concentrations In Switzerland, the annual production of MSW is about in foliage were up to 12 times higher than in other feedstock materials. 660 kg per capita, of which 45% is recycled and 55% Second, in contrast, compost from organic household waste and green is incinerated or disposed of (Kettler, 2002). To save waste contained similar amounts of ⌺ 16 PAHs, ⌺ 6 PCBs, and ⌺ 17 incineration costs and landfill capacities, recycling of PCDD/Fs (1915, 39.8 g/kg dry wt., and 9.5 ng I-TEQ/kg dry wt., and 1715, 30.6 g/kg dry wt., and 8.5 ng I-TEQ/kg dry wt., respec-MSW is essential. Policies aiming at reducing volumes tively). Third, concentrations of three-ring PAHs were reduced during the composting process, whereas five-to six-ring PAHs and ⌺ 6 PCBs Abbreviations: ACY, acenapththylene; ANT, anthracene; ASE, accelincreased by roughly a factor of two due to mass reduction during erated solvent extraction; BaA, benzo[a]anthracene; BaP, benzo[a] composting. ⌺ 17 PCDD/Fs had accumulated by up to a factor of 14.
Compost and digestate are important recycling fertilizers and have beneficial effects on soil par... more Compost and digestate are important recycling fertilizers and have beneficial effects on soil parameters. However, they can contain significant amounts of organic pollutants. Here, the first comprehensive data set on dibenzo-p-dioxins and -furans (PCDD/F), dioxin-like polychlorinated biphenyls (DL-PCB), brominated flame retardants, perfluorinated alkyl substances (PFAS), pesticides, phthalates, nonylphenol and chlorinated paraffins (CP) in source-separated compost and digestate from Switzerland is presented (n = 3-18). The median summation 17PCDD/F and summation 12DL-PCB concentrations were at 3.2 ng I-TEQ kg(-1)dry weight (dw) and 3.0 ng WHO-TEQ kg(-1)dw, respectively. Brominated diphenyl ether 209 (BDE 209) accounted for 72% of the total polyBDE content (10 microg kg(-1)dw). Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) levels were at 100 and 0.51 microg kg(-1)dw, respectively. PFAS were identified for the first time in compost and digestate (median concentration 6.3 microg kg(-1)dw, summation 21compounds). Out of 269 pesticides analysed, 30 fungicides, 14 herbicides, eight insecticides and one acaricide were detected. Di-(2-ethylhexyl)phthalate (DEHP) median concentration accounted for 280 microg kg(-1)dw and nonylphenol was below the detection limit of 1 mg kg(-1)dw. The sum of short and medium chain CP was between 90 and 390 microg kg(-1)dw. The concentrations observed were at or above the levels found in background soils, which are the main recipient of compost and digestate. Where actually applied, compost can contribute considerably to the total input of organic pollutants to the soil. However, on a total Swiss agricultural area base, inputs seem to be limited.
Deoxynivalenol and zearalenone are among the most prevalent toxins produced by Fusarium spp. They... more Deoxynivalenol and zearalenone are among the most prevalent toxins produced by Fusarium spp. They have been investigated in food and feed products for decades but rarely in the environment. We therefore established solid-phase extraction and liquid chromatography-mass spectrometry (LC-MS) methods to quantify these mycotoxins at trace concentrations in aqueous natural samples. In a model emission study, we inoculated a winter wheat field with Fusarium graminearum and subsequently monitored deoxynivalenol and zearalenone in its drainage water. Before during and after harvest in June and July 2007, these toxins were emitted in concentrations from 23 ng/L to 4.9 µg/L for deoxynivalenol and from not detected to 35 ng/L for zearalenone. Simultaneously, in July and August 2007, deoxynivalenol was also detected in a number of Swiss rivers in concentrations up to 22 ng/L and zearalenone was present in several river samples below the method quantification limit. Other mycotoxins might be emitted from Fusarium-infected fields as well, because some of them are produced in similar amounts as deoxynivalenol and zearalenone and exhibit similar or even higher water solubility than deoxynivalenol. The ecotoxicological consequences of the presence of mycotoxins in surface waters remain to be elucidated.
Formation of highly condensed black carbon (BC) from vegetation fires and wood fuel combustion pr... more Formation of highly condensed black carbon (BC) from vegetation fires and wood fuel combustion presumably transfers otherwise rapidly cycling carbon from the atmosphere‐biosphere cycle into a much slower cycling geological form. Recently reported BC fractions of total organic carbon (TOC) in surficial marine sediments span a wide range (2‐90%), leaving it presently unclear whether this variation reflects natural processes or is largely due to method differences. In order to elucidate the importance of BC to carbon burial the specificity of applied methods needs to be constrained. Here the operating range and applicability of a commonly used chemothermal oxidation (CTO) method is evaluated using putative BC standards, potentially interfering substances, and natural matrix standards. Test results confirm the applicability of the method to marine sediments. Integrity tests with model substrates suggest applicability to low‐carbon soils but only with a lower specificity to seawater part...
This paper investigates the ability of the traditional organic matter partitioning (OMP) model to... more This paper investigates the ability of the traditional organic matter partitioning (OMP) model to predict the solid-water distribution, and hence the dissolved exposures, of hydrophobic organic compounds (HOCs) in real field situations. Observed organic-carbon-normalized partitioning coefficients ((K oc) obs) of polychlorinated biphenyls, polychlorinated benzenes, polychlorinated dibenzo-dioxins and-furans, and p,pЈ-dichlorodiphenyltrichlorethane (DDT) with metabolites were selected from the literature and compared with their respective OMP model estimates. For all compound classes and in a majority of the investigated cases, (K oc) obs values were significantly larger than predicted. This translated into factors of overestimated dissolved exposures ranging from 1 to 1,000. Various reasons are discussed for the discrepancies between predictions and actual observations, such as the effect of the diagenetic state and other properties of the particulate organic matter. The greater enhancement in (K oc) obs of planar over nonplanar compounds suggests in certain cases that efficient interactions with aromatic soot phases may be significant. For an improved predictability of (K oc) obs and dissolved exposures of HOCs in the real environment, the inclusion of soot and possibly other distinct subfractions of bulk organic carbon into an extended solid-water partitioning model may be considered.
Although natural toxins, such as mycotoxins or phytoestrogens are widely studied and were recentl... more Although natural toxins, such as mycotoxins or phytoestrogens are widely studied and were recently identified as micropollutants in the environment, many of their environmentally relevant physicochemical properties have not yet been determined. Here, the sorption affinity to Pahokee peat, a model sorbent for soil organic matter, was investigated for 29 mycotoxins and two phytoestrogens. Sorption coefficients (K oc) were determined with a dynamic HPLC-based column method using a fully aqueous mobile phase with 5 mM CaCl 2 at pH 4.5. Sorption coefficients varied from less than 10 0.7 L/kg oc (e.g., all type B trichothecenes) to 10 4.0 L/kg oc (positively charged ergot alkaloids). For the neutral compounds the experimental sorption data set was compared with predicted sorption coefficients using various models, based on molecular fragment approaches (EPISuite's KOCWIN or SPARC), poly parameter linear free energy relationship (pp-LFER) in combination with predicted descriptors, and quantum-chemical based software (COSMOtherm)). None of the available models was able to adequately predict absolute K oc numbers and relative differences in sorption affinity for the whole set of neutral toxins, largely because mycotoxins exhibit highly complex structures. Hence, at present, for such compounds fast and consistent experimental techniques for determining sorption coefficients, as the one used in this study, are required.
There is an increasing recognition of the necessity to consider the heterogeneity of geosorbents,... more There is an increasing recognition of the necessity to consider the heterogeneity of geosorbents, and in particular the condensed carbon facies fraction, to improve prediction of hydrophobic pollutant phase speciation. Field observations of much elevated organic-...
Colloidal organic particles constitute the dominant portion of particulate organic matter in surf... more Colloidal organic particles constitute the dominant portion of particulate organic matter in surface seawater, but their influence on the phase speciation and bioavailability of hydrophobic organic compounds (HOCs) is sparsely evaluated. Studies on colloid-water partitioning have been focused on other regimes and have largely been performed on chemically defined subportions of total colloids such as the humic fraction. Available estimates of colloid-water partition coeffficients (K coc) are highly variable and not easily explained by regularly applied K ow-K oc relationships. Here, pyrene was partitioned to bulk natural colloids isolated using cross-flow ultrafiltration techniques from the surface water of a coastal bay. A key objective was to elucidate biogeochemical controls on the changing colloidsorbent qualities over the course of the dynamic allochtonous-autochtonous transition of a well-constrained boreal coastal spring bloom. The pyrene K coc was found to decrease from 12.9 (0.9 × 10 3 L w /kg oc in the terrestrial runoff dominated regime to values around 2.9 (0.7 × 10 3 L w /kg oc , once phytoplankton production became the governing source of organic matter to the surface waters. The changing K coc was well correlated with the molar extinction coefficient at 280 nm of the colloidal organic carbon. This study supports other reports of an improved prediction of HOC phase speciation through this simple molecular proxy of the "quality" of organic sorbents. While being poor sorbents on a carbon atom basis, relative to soils and sediments, coastal marine colloids, by their shear abundance, may significantly attenuate the truly dissolved exposures of HOCs with log K ow above 5.
The particle associations of polychlorinated dibenzo-pdioxins and polychlorinated dibenzofurans (... more The particle associations of polychlorinated dibenzo-pdioxins and polychlorinated dibenzofurans (PCDD/Fs) were studied in both the water column and the surface sediments of a marine fjord system and were found to poorly obey expectations from the organic matter partitioning (OMP) paradigm. The field observations were instead consistent with the presence of a stronger sorbent subdomain such as pyrogenic soot-carbon (SC) playing an important role in affecting the environmental distribution and fate of PCDD/Fs. Solid-water distribution coefficients (K d) of PCDD/ Fs actually observed in the water column were several orders of magnitude above predictions from a commonly used OMP model. Even when these elevated K d values were normalized to the particulate organic carbon (POC) content (i.e., K OC), the variability in K OC for individual PCDD/ Fs at different fjord locations and seasons of factors 100-1000 suggested that bulk organic matter was not the governing sorbent domain of the suspended particles. Further, POC-normalized particle concentrations of PCDD/ Fs (C OC) in a vertical profile (surface water-bottom watersurface sediment) revealed a strong increasing trend with depth. Factors of about 100 higher C OC for all PCDD/Fs in the sediment than in the surface water could not be explained by higher fugacity in the surrounding deep water nor with C:N or δ 13 C indexes of selective aging of the bulk organic matter. Instead this was hypothesized to reflect selective preservation of a more recalcitrant and highly sorbing, but minor, subdomain such as soot. The extent of enhanced PCDD/F sorption, above the OMP predictions, was positively correlated with the SC:POC ratio of the suspended particles in surface and deep waters. Finally, the geographical distribution of sedimentary PCDD/F concentrations were better explained by the SC content than by the bulk OC content of the sediment. Altogether, these field-based findings add to recent laboratory-based sorption studies to suggest that we need to consider both amorphous OC partitioning domains and SC particles as carriers of planar aromatic contaminants if we are to explain the environmental distribution and fate of pollutants such as PCDD/Fs.
The mycotoxin zearalenone (ZON) is a very potent natural endocrine disrupting chemical, produced ... more The mycotoxin zearalenone (ZON) is a very potent natural endocrine disrupting chemical, produced by Fusarium graminearum fungi growing on crops such as wheat and maize. Although it is well-investigated in food and feed, very little is known about its environmental fate and behavior. Here, we report the occurrence of ZON on F. graminearum infected wheat and maize fields in crop organs and soil and its emission via drainage water. ZON amounts in the investigated crops and topsoil were between 6.1 and 25.0 and up to 5.6 g/ha, respectively. ZON concentrations in drainage water were in the low nanogram per liter range with a maximum of 35 ng/ L. Cumulated ZON amounts emitted via drainage water ranged from 0.1 to 4.3 mg/ha, depending on the crop cultivated in the respective period. This corresponds to fractions between 0.001 and 0.070% of the initially present ZON amount in the plants. Because of the low concentrations emitted via drainage water, it can be assumed that ZON contributes little if at all to the overall estrogenicity of major surface water bodies. However, in small creeks, mainly fed by agricultural runoff, ZON might be present in environmentally critical concentrations at times of F. graminearum infections.
During a field study on the occurrence and behavior of pesticides during artificial infiltration ... more During a field study on the occurrence and behavior of pesticides during artificial infiltration of roof runoff, the herbicide R-mecoprop and its S-enantiomer were detected in roof runoff in much higher concentrations (up to 500 µg/L) than in the corresponding rainwater. We hypothesized in the foregoing paper in this issue that the root protection agent Preventol B 2 in the bituminous sheets, which is a bi-ester of (R,S)-mecoprop (see Figure 1), was the source of these compounds. In this work, the occurrence and variations of (R,S)-mecoprop in the runoff from different flat roofs were investigated. It is shown that concentrations of a few micrograms per liter at an R to S enantiomeric ratio (ER) of 0.8-1.4 can permanently be expected in roof runoff from flat roofs which have Preventol B 2 containing sealing membranes incorporated. The major factors that govern the release of (R,S)mecoprop are the type of bituminous sheet, the biological activity, and the intensity of the applied rooftop greening. A field study in the Greifensee catchment area revealed that wastewater treatment plants (WWTPs) are a major source of (R,S)-mecoprop which most probably originates from construction materials equipped with Preventol B 2. A comparison of the (R,S)-mecoprop loads from flat roofs and from agricultural applications into surface waters revealed that these loads were in the same order of magnitude.
Environmental Science and Pollution Research, 2012
The insecticide dichlorodiphenyltrichloroethane (DDT) was mainly used in Pakistan as pest control... more The insecticide dichlorodiphenyltrichloroethane (DDT) was mainly used in Pakistan as pest control in agriculture and for the eradication of malaria. For the DDT production, a factory was established in 1963 in Amangarh, near Nowshera district, Khyber Pakhtunkhwa, Pakistan. In 2001, the Pakistan government banned the usage of DDT, and subsequently, the Amangarh DDT factory also stopped its production. The present study was designed to investigate the occurrence of DDT residues after its closure. Total ∑DDT from soil samples at each depth was extracted by using a standard solvent extraction method. For the characterization of soil physical properties, three-to-five composite soil samples were collected from the site for soil particle size distribution, while soil pH and electrical conductivity were determined in a 1:5 ratio (soil water solution). The mean concentrations of ∑DDT in surface (0-15 cm), subsurface (15-30 cm) and deep horizon (30-45 cm) soil were 125.5, 143.6 and 148.9 mg kg −1 , respectively. The concentrations of ∑DDT in 89% of the samples were higher than the probable effects level and threshold effects level. The contamination of ∑DDT was considerably higher than the standard limit (17 mg kg −1). The highest concentration of ∑DDT in the subsurface and deep horizon indicated that the ∑DDT percolated deep into the soil and may also have contaminated the groundwater.
Isolation of carbon nanotubes from complex environmental matrices is possible using the chemother... more Isolation of carbon nanotubes from complex environmental matrices is possible using the chemothermal oxidation method.
Critical Reviews in Environmental Science and Technology, 1995
Page 1. Critical Reviews in Environmental Science and Technology, 25(3):201-268 (1995) Induction ... more Page 1. Critical Reviews in Environmental Science and Technology, 25(3):201-268 (1995) Induction of Cytochrome P450 as a Biomarker for Environmental Contamination in Aquatic Ecosystems Thomas D. Bucheli and Karl ...
Zearalenone (ZON) is known as a very potent, naturally occurring estrogenic mycotoxin. It is one ... more Zearalenone (ZON) is known as a very potent, naturally occurring estrogenic mycotoxin. It is one of the most prevalent mycotoxin produced as a secondary metabolite by Fusarium species growing on cereals such as wheat and corn. It has been studied extensively in food and feed products for decades but only rarely and somewhat by chance in the environment. We therefore elucidated its agro-environmental fate and behavior by conducting a series of field studies and monitoring campaigns. Specifically, ZON was investigated in plants, soils and drainage waters from wheat and corn fields artificially infected with Fusarium graminearum. In addition, manure, sewage sludge and surface waters were analyzed for ZON. Three main input pathways of ZON onto soil could be identified: i) wash-off from Fusarium-infected plants (in the order of 100 mg/ha), ii) plant debris remaining on the soil after harvest (up to few g/ha), and iii) manure application (in the order of 100 mg/ha). Our results show that ...
International Journal of Environmental Analytical Chemistry, Jan 25, 2007
This study is the first thorough method optimisation for accelerated solvent extraction (ASE) of ... more This study is the first thorough method optimisation for accelerated solvent extraction (ASE) of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) from chemically dried compost. For PCBs, optimised solvent composition, temperature, pressure, number of static cycles, duration, and flush volume were as follows: toluene/acetone 1 : 3 (v/v), 120°C, 2000 psi, 3 × 5 min, and 50%, respectively. Limits of quantification and method precision were between 0.16 and 2.46 µg kg−1 dw and 6–17% respectively for individual PCBs. Absolute recoveries of isotope-labelled extraction standards used for each of the analytes ranged from 65 to 105% and relative recoveries were between 85 and 99%. The method proofed to be robust and was successfully applied to different compost samples. The optimisation of PAHs extraction was performed and resulted in the following conditions: solvent: hexane/acetone 1/3 (v:v), temperature: 140°C, pressure: 1500 psi, extraction time: 3 × 5 min, and 50% flush volume. Limits of detection and method precision for individual PAHs were between 1.1 and 37.2 µg kg−1 dw and 12–34% respectively. Absolute and relative recoveries ranged from 24 to 68% and from 85 to 99%, respectively. Optimal extraction conditions for PAHs were more difficult to determine due to the inhomogeneous distribution of PAHs in samples. However, the method appeared to be feasible and suggestions for further improvements are presented.
Environmental Science: Processes & Impacts, 2015
Over the last 30 years, concentrations of medium to heavy PAH remained remarkably constant for Sw... more Over the last 30 years, concentrations of medium to heavy PAH remained remarkably constant for Swiss topsoils, whereas concentrations of light PAH decreased.
ABSTRACT Typical concentrations and quantitative mass flows of anthropogenic compounds (such as p... more ABSTRACT Typical concentrations and quantitative mass flows of anthropogenic compounds (such as personal care compounds, bactericides, flame retardants, plasticizers, detergents, complexing agents, as well as mycotoxins) in waste water are compared to typical per person loads in the influents and effluents of waste water treatment plants. They are evaluated to assess their significance for the contamination of the aquatic environment. Usually the number of persons serviced by a waste water treatment plant (WWTP) is well known, as the design parameters of the WWTP heavily rely on the per person usage of water and the per person emissions of nutrients as well as organic carbon. It is the intention to use these basic data together with concentrations from some waste water treatment plants to make assessments on emissions from WWTPs, for which only basic design parameters are available. These data can be used for predictions of waste water contamination concerning pollutant loads and concentrations for waste water treatment plants that have not undergone extensive monitoring. The relevance of the respective pollutants for surface waters as well as sludge is demonstrated. The focus of this chapter is on those compounds that are emitted continuously during dry weather. - No storm water issues will covered in this book chapter.
Suspensions or solutions with 1% of Chinese galls (Galla chinensis, GC) or 1% of tannic acid (TA)... more Suspensions or solutions with 1% of Chinese galls (Galla chinensis, GC) or 1% of tannic acid (TA), inhibited germination of conidia or mycelium growth of Fusarium graminearum (FG) by 98%-100% or by 75%-80%, respectively, whereas dried bark from buckthorn (Frangula alnus, FA) showed no effect at this concentration. In climate chamber experiments where the wheat variety "Apogee" was artificially inoculated with FG and F. crookwellense (FCr) and treated with 5% suspensions of TA, GC and FA, the deoxynivalenol (DON) content in grains was reduced by 81%, 67% and 33%, respectively. In field experiments with two commercial wheat varieties and artificial or semi-natural inoculations, mean DON reductions of 66% (TA) and 58% (FA), respectively, were obtained. Antifungal toxicity can explain the high efficacies of TA and GC but not those of FA. The Fusarium head blight (FHB) and mycotoxin reducing effect of FA is probably due to elicitation of resistance in wheat plants. With semi-natural inoculation, a single FA application in the first half of the flowering period performed best. However, we assume that applications of FA at the end of ear emergence and a treatment, triggered by an infection period, with TA or GC during flowering, might perform better than synthetic fungicides.
To prevent overloading of sewer systems and to ensure sufficient recharging of the groundwater un... more To prevent overloading of sewer systems and to ensure sufficient recharging of the groundwater underneath sealed urban areas, collection and artificial infiltration of roof runoff water has become very popular in many countries including Switzerland. However, there is still a considerable lack of knowledge concerning the quality of roof runoff, particularly with respect to the presence of pesticides. In this work, the occurrence and the temporal variations in concentration in rainwater and in roof runoff from different types of roofs (i.e., clay tile roofs, polyester roofs, flat gravel roofs) were determined for the most important members of three widely used classes of pesticides (i.e., triazines, acetamides, phenoxy acids). It is shown that in rain and roof runoff, maximum pesticide concentrations originating primarily from agricultural use occurred during and right after the application periods. Maximum average concentrations for single rain events and total loads per year were, for example, for atrazine, 903 ng/L and 13 900 ng/ (m 2 year); for alachlor, 191 ng/L and 5900 ng/(m 2 year); and for R-dichlorprop, 106 ng/L and 5100 ng/(m 2 year). Further, the study reveals that a major portion of the compounds washed out from the atmosphere may actually reach the groundwater, particularly if the roof runoff is infiltrated directly into highly permeable zones of the subsurface. Nevertheless, although in some cases European Union and Swiss drinking water standards (100 ng/L) were not always met in rain and roof runoff waters, for the three compound classes investigated, the groundwater contamination potential of the pesticides originating from the atmosphere can be considered of equal or even smaller importance as compared to their direct use in agriculture. The investigations also show that leaching of pesticides used as construction chemicals on roofs, that is, as roof protection agents in sealings used on flat gravel roofs, may be a much more significant source of organic pollutants present in roof runoff (see also our following paper in this issue).
than rural material. Fifth, the highest concentrations of POPs were usually observed in summer sa... more than rural material. Fifth, the highest concentrations of POPs were usually observed in summer samples. Finally, median compost concen-Composting and the application of compost to the soil follow the trations of POPs were greater by up to one order of magnitude than principle of recycling and sustainability. Compost can also have a in arable soils, as the primary recipients of compost, but were well positive effect on physical, chemical, and biological soil parameters. within the range of many urban soils. In conclusion, this work provides However, little is known about the origin, concentration, and transfora basis for the further improvement of composting and for future risk mation of persistent organic pollutants (POPs) in compost. We thereassessments of compost application. fore compiled literature data on some priority POPs in compost and its main feedstock materials from more than 60 reports. Our data evaluation suggests the following findings. First, median concentrations of ⌺ 16 polycyclic aromatic hydrocarbons (PAHs), ⌺ 6 polychlo-M odern societies produce considerable amounts rinated biphenyls (PCBs), and ⌺ 17 polychlorinated dibenzo-p-dioxins of waste. Some 40 million Mg of municipal solid and-furans (PCDD/Fs) were higher in green waste (1803, 15.6 g/kg waste (MSW) are collected annually for recycling in the dry wt., and 2.5 ng international toxicity equivalent [I-TEQ]/kg dry 15 member states of the European Union (before 2004). wt.) than in organic household waste (635, 14.6 g/kg dry wt., and This corresponds to approximately 18% of the total mu-2.2 ng I-TEQ/kg dry wt.) and kitchen waste (not available [NA], nicipal waste produced (European Commission, 2003). 14.9 g/kg dry wt., 0.4 ng I-TEQ/kg dry wt.). The POP concentrations In Switzerland, the annual production of MSW is about in foliage were up to 12 times higher than in other feedstock materials. 660 kg per capita, of which 45% is recycled and 55% Second, in contrast, compost from organic household waste and green is incinerated or disposed of (Kettler, 2002). To save waste contained similar amounts of ⌺ 16 PAHs, ⌺ 6 PCBs, and ⌺ 17 incineration costs and landfill capacities, recycling of PCDD/Fs (1915, 39.8 g/kg dry wt., and 9.5 ng I-TEQ/kg dry wt., and 1715, 30.6 g/kg dry wt., and 8.5 ng I-TEQ/kg dry wt., respec-MSW is essential. Policies aiming at reducing volumes tively). Third, concentrations of three-ring PAHs were reduced during the composting process, whereas five-to six-ring PAHs and ⌺ 6 PCBs Abbreviations: ACY, acenapththylene; ANT, anthracene; ASE, accelincreased by roughly a factor of two due to mass reduction during erated solvent extraction; BaA, benzo[a]anthracene; BaP, benzo[a] composting. ⌺ 17 PCDD/Fs had accumulated by up to a factor of 14.
Compost and digestate are important recycling fertilizers and have beneficial effects on soil par... more Compost and digestate are important recycling fertilizers and have beneficial effects on soil parameters. However, they can contain significant amounts of organic pollutants. Here, the first comprehensive data set on dibenzo-p-dioxins and -furans (PCDD/F), dioxin-like polychlorinated biphenyls (DL-PCB), brominated flame retardants, perfluorinated alkyl substances (PFAS), pesticides, phthalates, nonylphenol and chlorinated paraffins (CP) in source-separated compost and digestate from Switzerland is presented (n = 3-18). The median summation 17PCDD/F and summation 12DL-PCB concentrations were at 3.2 ng I-TEQ kg(-1)dry weight (dw) and 3.0 ng WHO-TEQ kg(-1)dw, respectively. Brominated diphenyl ether 209 (BDE 209) accounted for 72% of the total polyBDE content (10 microg kg(-1)dw). Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) levels were at 100 and 0.51 microg kg(-1)dw, respectively. PFAS were identified for the first time in compost and digestate (median concentration 6.3 microg kg(-1)dw, summation 21compounds). Out of 269 pesticides analysed, 30 fungicides, 14 herbicides, eight insecticides and one acaricide were detected. Di-(2-ethylhexyl)phthalate (DEHP) median concentration accounted for 280 microg kg(-1)dw and nonylphenol was below the detection limit of 1 mg kg(-1)dw. The sum of short and medium chain CP was between 90 and 390 microg kg(-1)dw. The concentrations observed were at or above the levels found in background soils, which are the main recipient of compost and digestate. Where actually applied, compost can contribute considerably to the total input of organic pollutants to the soil. However, on a total Swiss agricultural area base, inputs seem to be limited.
Deoxynivalenol and zearalenone are among the most prevalent toxins produced by Fusarium spp. They... more Deoxynivalenol and zearalenone are among the most prevalent toxins produced by Fusarium spp. They have been investigated in food and feed products for decades but rarely in the environment. We therefore established solid-phase extraction and liquid chromatography-mass spectrometry (LC-MS) methods to quantify these mycotoxins at trace concentrations in aqueous natural samples. In a model emission study, we inoculated a winter wheat field with Fusarium graminearum and subsequently monitored deoxynivalenol and zearalenone in its drainage water. Before during and after harvest in June and July 2007, these toxins were emitted in concentrations from 23 ng/L to 4.9 µg/L for deoxynivalenol and from not detected to 35 ng/L for zearalenone. Simultaneously, in July and August 2007, deoxynivalenol was also detected in a number of Swiss rivers in concentrations up to 22 ng/L and zearalenone was present in several river samples below the method quantification limit. Other mycotoxins might be emitted from Fusarium-infected fields as well, because some of them are produced in similar amounts as deoxynivalenol and zearalenone and exhibit similar or even higher water solubility than deoxynivalenol. The ecotoxicological consequences of the presence of mycotoxins in surface waters remain to be elucidated.
Formation of highly condensed black carbon (BC) from vegetation fires and wood fuel combustion pr... more Formation of highly condensed black carbon (BC) from vegetation fires and wood fuel combustion presumably transfers otherwise rapidly cycling carbon from the atmosphere‐biosphere cycle into a much slower cycling geological form. Recently reported BC fractions of total organic carbon (TOC) in surficial marine sediments span a wide range (2‐90%), leaving it presently unclear whether this variation reflects natural processes or is largely due to method differences. In order to elucidate the importance of BC to carbon burial the specificity of applied methods needs to be constrained. Here the operating range and applicability of a commonly used chemothermal oxidation (CTO) method is evaluated using putative BC standards, potentially interfering substances, and natural matrix standards. Test results confirm the applicability of the method to marine sediments. Integrity tests with model substrates suggest applicability to low‐carbon soils but only with a lower specificity to seawater part...
This paper investigates the ability of the traditional organic matter partitioning (OMP) model to... more This paper investigates the ability of the traditional organic matter partitioning (OMP) model to predict the solid-water distribution, and hence the dissolved exposures, of hydrophobic organic compounds (HOCs) in real field situations. Observed organic-carbon-normalized partitioning coefficients ((K oc) obs) of polychlorinated biphenyls, polychlorinated benzenes, polychlorinated dibenzo-dioxins and-furans, and p,pЈ-dichlorodiphenyltrichlorethane (DDT) with metabolites were selected from the literature and compared with their respective OMP model estimates. For all compound classes and in a majority of the investigated cases, (K oc) obs values were significantly larger than predicted. This translated into factors of overestimated dissolved exposures ranging from 1 to 1,000. Various reasons are discussed for the discrepancies between predictions and actual observations, such as the effect of the diagenetic state and other properties of the particulate organic matter. The greater enhancement in (K oc) obs of planar over nonplanar compounds suggests in certain cases that efficient interactions with aromatic soot phases may be significant. For an improved predictability of (K oc) obs and dissolved exposures of HOCs in the real environment, the inclusion of soot and possibly other distinct subfractions of bulk organic carbon into an extended solid-water partitioning model may be considered.
Although natural toxins, such as mycotoxins or phytoestrogens are widely studied and were recentl... more Although natural toxins, such as mycotoxins or phytoestrogens are widely studied and were recently identified as micropollutants in the environment, many of their environmentally relevant physicochemical properties have not yet been determined. Here, the sorption affinity to Pahokee peat, a model sorbent for soil organic matter, was investigated for 29 mycotoxins and two phytoestrogens. Sorption coefficients (K oc) were determined with a dynamic HPLC-based column method using a fully aqueous mobile phase with 5 mM CaCl 2 at pH 4.5. Sorption coefficients varied from less than 10 0.7 L/kg oc (e.g., all type B trichothecenes) to 10 4.0 L/kg oc (positively charged ergot alkaloids). For the neutral compounds the experimental sorption data set was compared with predicted sorption coefficients using various models, based on molecular fragment approaches (EPISuite's KOCWIN or SPARC), poly parameter linear free energy relationship (pp-LFER) in combination with predicted descriptors, and quantum-chemical based software (COSMOtherm)). None of the available models was able to adequately predict absolute K oc numbers and relative differences in sorption affinity for the whole set of neutral toxins, largely because mycotoxins exhibit highly complex structures. Hence, at present, for such compounds fast and consistent experimental techniques for determining sorption coefficients, as the one used in this study, are required.
There is an increasing recognition of the necessity to consider the heterogeneity of geosorbents,... more There is an increasing recognition of the necessity to consider the heterogeneity of geosorbents, and in particular the condensed carbon facies fraction, to improve prediction of hydrophobic pollutant phase speciation. Field observations of much elevated organic-...
Colloidal organic particles constitute the dominant portion of particulate organic matter in surf... more Colloidal organic particles constitute the dominant portion of particulate organic matter in surface seawater, but their influence on the phase speciation and bioavailability of hydrophobic organic compounds (HOCs) is sparsely evaluated. Studies on colloid-water partitioning have been focused on other regimes and have largely been performed on chemically defined subportions of total colloids such as the humic fraction. Available estimates of colloid-water partition coeffficients (K coc) are highly variable and not easily explained by regularly applied K ow-K oc relationships. Here, pyrene was partitioned to bulk natural colloids isolated using cross-flow ultrafiltration techniques from the surface water of a coastal bay. A key objective was to elucidate biogeochemical controls on the changing colloidsorbent qualities over the course of the dynamic allochtonous-autochtonous transition of a well-constrained boreal coastal spring bloom. The pyrene K coc was found to decrease from 12.9 (0.9 × 10 3 L w /kg oc in the terrestrial runoff dominated regime to values around 2.9 (0.7 × 10 3 L w /kg oc , once phytoplankton production became the governing source of organic matter to the surface waters. The changing K coc was well correlated with the molar extinction coefficient at 280 nm of the colloidal organic carbon. This study supports other reports of an improved prediction of HOC phase speciation through this simple molecular proxy of the "quality" of organic sorbents. While being poor sorbents on a carbon atom basis, relative to soils and sediments, coastal marine colloids, by their shear abundance, may significantly attenuate the truly dissolved exposures of HOCs with log K ow above 5.
The particle associations of polychlorinated dibenzo-pdioxins and polychlorinated dibenzofurans (... more The particle associations of polychlorinated dibenzo-pdioxins and polychlorinated dibenzofurans (PCDD/Fs) were studied in both the water column and the surface sediments of a marine fjord system and were found to poorly obey expectations from the organic matter partitioning (OMP) paradigm. The field observations were instead consistent with the presence of a stronger sorbent subdomain such as pyrogenic soot-carbon (SC) playing an important role in affecting the environmental distribution and fate of PCDD/Fs. Solid-water distribution coefficients (K d) of PCDD/ Fs actually observed in the water column were several orders of magnitude above predictions from a commonly used OMP model. Even when these elevated K d values were normalized to the particulate organic carbon (POC) content (i.e., K OC), the variability in K OC for individual PCDD/ Fs at different fjord locations and seasons of factors 100-1000 suggested that bulk organic matter was not the governing sorbent domain of the suspended particles. Further, POC-normalized particle concentrations of PCDD/ Fs (C OC) in a vertical profile (surface water-bottom watersurface sediment) revealed a strong increasing trend with depth. Factors of about 100 higher C OC for all PCDD/Fs in the sediment than in the surface water could not be explained by higher fugacity in the surrounding deep water nor with C:N or δ 13 C indexes of selective aging of the bulk organic matter. Instead this was hypothesized to reflect selective preservation of a more recalcitrant and highly sorbing, but minor, subdomain such as soot. The extent of enhanced PCDD/F sorption, above the OMP predictions, was positively correlated with the SC:POC ratio of the suspended particles in surface and deep waters. Finally, the geographical distribution of sedimentary PCDD/F concentrations were better explained by the SC content than by the bulk OC content of the sediment. Altogether, these field-based findings add to recent laboratory-based sorption studies to suggest that we need to consider both amorphous OC partitioning domains and SC particles as carriers of planar aromatic contaminants if we are to explain the environmental distribution and fate of pollutants such as PCDD/Fs.
The mycotoxin zearalenone (ZON) is a very potent natural endocrine disrupting chemical, produced ... more The mycotoxin zearalenone (ZON) is a very potent natural endocrine disrupting chemical, produced by Fusarium graminearum fungi growing on crops such as wheat and maize. Although it is well-investigated in food and feed, very little is known about its environmental fate and behavior. Here, we report the occurrence of ZON on F. graminearum infected wheat and maize fields in crop organs and soil and its emission via drainage water. ZON amounts in the investigated crops and topsoil were between 6.1 and 25.0 and up to 5.6 g/ha, respectively. ZON concentrations in drainage water were in the low nanogram per liter range with a maximum of 35 ng/ L. Cumulated ZON amounts emitted via drainage water ranged from 0.1 to 4.3 mg/ha, depending on the crop cultivated in the respective period. This corresponds to fractions between 0.001 and 0.070% of the initially present ZON amount in the plants. Because of the low concentrations emitted via drainage water, it can be assumed that ZON contributes little if at all to the overall estrogenicity of major surface water bodies. However, in small creeks, mainly fed by agricultural runoff, ZON might be present in environmentally critical concentrations at times of F. graminearum infections.
During a field study on the occurrence and behavior of pesticides during artificial infiltration ... more During a field study on the occurrence and behavior of pesticides during artificial infiltration of roof runoff, the herbicide R-mecoprop and its S-enantiomer were detected in roof runoff in much higher concentrations (up to 500 µg/L) than in the corresponding rainwater. We hypothesized in the foregoing paper in this issue that the root protection agent Preventol B 2 in the bituminous sheets, which is a bi-ester of (R,S)-mecoprop (see Figure 1), was the source of these compounds. In this work, the occurrence and variations of (R,S)-mecoprop in the runoff from different flat roofs were investigated. It is shown that concentrations of a few micrograms per liter at an R to S enantiomeric ratio (ER) of 0.8-1.4 can permanently be expected in roof runoff from flat roofs which have Preventol B 2 containing sealing membranes incorporated. The major factors that govern the release of (R,S)mecoprop are the type of bituminous sheet, the biological activity, and the intensity of the applied rooftop greening. A field study in the Greifensee catchment area revealed that wastewater treatment plants (WWTPs) are a major source of (R,S)-mecoprop which most probably originates from construction materials equipped with Preventol B 2. A comparison of the (R,S)-mecoprop loads from flat roofs and from agricultural applications into surface waters revealed that these loads were in the same order of magnitude.
Environmental Science and Pollution Research, 2012
The insecticide dichlorodiphenyltrichloroethane (DDT) was mainly used in Pakistan as pest control... more The insecticide dichlorodiphenyltrichloroethane (DDT) was mainly used in Pakistan as pest control in agriculture and for the eradication of malaria. For the DDT production, a factory was established in 1963 in Amangarh, near Nowshera district, Khyber Pakhtunkhwa, Pakistan. In 2001, the Pakistan government banned the usage of DDT, and subsequently, the Amangarh DDT factory also stopped its production. The present study was designed to investigate the occurrence of DDT residues after its closure. Total ∑DDT from soil samples at each depth was extracted by using a standard solvent extraction method. For the characterization of soil physical properties, three-to-five composite soil samples were collected from the site for soil particle size distribution, while soil pH and electrical conductivity were determined in a 1:5 ratio (soil water solution). The mean concentrations of ∑DDT in surface (0-15 cm), subsurface (15-30 cm) and deep horizon (30-45 cm) soil were 125.5, 143.6 and 148.9 mg kg −1 , respectively. The concentrations of ∑DDT in 89% of the samples were higher than the probable effects level and threshold effects level. The contamination of ∑DDT was considerably higher than the standard limit (17 mg kg −1). The highest concentration of ∑DDT in the subsurface and deep horizon indicated that the ∑DDT percolated deep into the soil and may also have contaminated the groundwater.
Isolation of carbon nanotubes from complex environmental matrices is possible using the chemother... more Isolation of carbon nanotubes from complex environmental matrices is possible using the chemothermal oxidation method.
Critical Reviews in Environmental Science and Technology, 1995
Page 1. Critical Reviews in Environmental Science and Technology, 25(3):201-268 (1995) Induction ... more Page 1. Critical Reviews in Environmental Science and Technology, 25(3):201-268 (1995) Induction of Cytochrome P450 as a Biomarker for Environmental Contamination in Aquatic Ecosystems Thomas D. Bucheli and Karl ...
Zearalenone (ZON) is known as a very potent, naturally occurring estrogenic mycotoxin. It is one ... more Zearalenone (ZON) is known as a very potent, naturally occurring estrogenic mycotoxin. It is one of the most prevalent mycotoxin produced as a secondary metabolite by Fusarium species growing on cereals such as wheat and corn. It has been studied extensively in food and feed products for decades but only rarely and somewhat by chance in the environment. We therefore elucidated its agro-environmental fate and behavior by conducting a series of field studies and monitoring campaigns. Specifically, ZON was investigated in plants, soils and drainage waters from wheat and corn fields artificially infected with Fusarium graminearum. In addition, manure, sewage sludge and surface waters were analyzed for ZON. Three main input pathways of ZON onto soil could be identified: i) wash-off from Fusarium-infected plants (in the order of 100 mg/ha), ii) plant debris remaining on the soil after harvest (up to few g/ha), and iii) manure application (in the order of 100 mg/ha). Our results show that ...
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