The concentration and distribution of 2,3,7,8-dibenzo-p-dioxins/-furans in chickens

The concentrations of the 2,3,7,8-Cl substituted dibenzo-p-dioxins/-furans (PCDDs/PCDFs) were determined in the edible tissues of whole chicken fryers and compared with the values found in their abdominal fat. The values are presented both on a whole weight basis and on a lipid adjusted basis for each tissue. While there is a marked difference in the concentration of the 2,3,7,8-dibenzo-p-dioxins in the edible tissues expressed on a whole weight basis, the lipid-adjusted concentrations of the individual dioxins were not statistically different in the various tissues. This validates the use of lipid adjusted concentrations of 2,3,7,8-PCDDs/PCDFs in abdominal fat for the determination of the presence of these compounds in different tissues.     

In-field measurements of PCDD/F emissions from domestic heating appliances for solid fuels

Within this project the emissions into the atmosphere of polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) of 30 domestic heating appliances in Austrian households were tested. The appliances were single stoves (kitchen stove, continuous burning stove and tiled stove) and central heating boilers for solid fuels up to a nominal heat input of 50 kW. A main objective of this survey was to determine the PCDD/F emissions of domestic heating units under routine conditions. Therefore, the habitual combustion conditions used by the operators were not influenced. The original fuels and lightning supports were used and the operation of the units was carried out by the householders according to their usual practice. The data obtained were used to calculate in-field PCDD/F-emission factors. Most of the appliances have shown PCDD/F emissions within a concentration range of 0.01-0.3 ng TEQ/MJ. Modern fan-assisted wood heating boilers with afterburning and units for continuously burning of wood chips and wood pellets had the lowest emissions. High emissions were caused by unsuitable heating habits such as combustion of wastes and inappropriate operation of the appliances. There were only small differences between single stoves and central heating boilers or between wood and coal-fired appliances. The emission factors calculated are higher than those cited in literature, which are mainly derived from trials on test stands under laboratory conditions.     

Contaminant trends in soils and crops

The evidence for long-term changes in the contaminant content of soils and crops is reviewed. Heavy metals, acidification and trace organic contaminants are each considered separately, with the emphasis placed on changes brought about by inputs from long-term atmospheric deposition. It is argued that effectively all soils in industrialised countries have become contaminated with selected trace substances (notably Pb, Cd, polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and -furans) above their true (historical) background level by aerial inputs. In the case of Pb, for example, cumulative deposition inputs over several centuries have probably roughly doubled the Pb burden of contemporary UK surface soils. Despite this, there is little evidence for a concomitant rise in the contaminant content of UK crops through the twentieth century. In fact, the burden of many contaminants in vegetation may well be somewhat lower than in earlier decades of this century because (1) crop composition is strongly influenced by direct deposition onto the above-ground portion of the plant, (2) root uptake and translocation of soil-borne heavy metals and recalcitrant organic contaminants are inefficient processes, and (3) UK air quality has generally improved over the last 10-20 years. Acidification of soils is of considerable regional significance. The evidence for changes in soil pH over this century is reviewed, and it is concluded that atmospheric inputs have enhanced the rate of soil acidification over large areas of Scandinavia and elsewhere.     

Application of GC-MS/MS for the analysis of PCDD/Fs in sewage effluents

The application of high resolution gas chromatography in combination with tandem mass spectrometry in an ion trap was tested to substitute the expensive high resolution mass spectrometry in analysing polychlorinated dibenzo-p-dioxins and furans in sewage effluents. In tandem mass spectrometry, a set of parameters has to be optimised in order to attain the required sensitivity. To the best of our knowledge, this is the first time a method development for analysing PCDD/Fs with GC-MS/MS in an ion trap is described in this detail. Nine parameters are varied, including isolation window, collision induced dissociation (CID) amplitude, CID time, acquisition mass range, broadband amplitude, CID bandwidth, modulation range, filament current and ion trap temperature. This technique can be adapted to other analytes. By this optimisation, limits of detection of 0.01-0.05 ng/l are obtained. With its selectivity and sensitivity, tandem mass spectrometry is a powerful tool for the determination of PCDD/Fs in water samples. 55 sewage effluent samples from Germany were analysed.     

Using fiber optics to detect moisture intrusion into a landfill cap consisting of a vegetative soil barrier

The intrusion of moisture into landfills can pose a health hazard because of the possibility that the moisture will carry harmful substances into the groundwater. Early detection of moisture anywhere within these landfills is essential if corrective action is to be taken well before an occurrence of this kind. This paper presents the results of a field-scale simulation test of the use of fiber optics to detect the presence of moisture within landfill covers, using a detection method based on the thermal response of soils as a function of their moisture content. By sending electrical current through an embedded stainless-steel tube, soils of varying moisture content were heated and time-dependent temperature measurements were obtained with a fiber-optic distributed temperature sensor system. The optical fiber itself lay within the tube, but its temperature was a function of how rapidly heat was conducted into the surrounding medium. The results of this experiment, which are in agreement with those obtained using more traditional "point" sampling and laboratory analysis, are presented along with the strengths and limitations of the thermal-response method of detecting moisture.     

Using Fiber Optics to Detect Moisture Intrusion into a Landfill Cap Consisting of a Vegetative Soil Barrier

Abstract

The intrusion of moisture into landfills can pose a health hazard because of the possibility that the moisture will carry harmful substances into the groundwater. Early detection of moisture anywhere within these landfills is essential if corrective action is to be taken well before an occurrence of this kind. This paper presents the results of a field-scale simulation test of the use of fiber optics to detect the presence of moisture within landfill covers, using a detection method based on the thermal response of soils as a function of their moisture content. By sending electrical current through an embedded stainless-steel tube, soils of varying moisture content were heated and time-dependent temperature measurements were obtained with a fiber-optic distributed temperature sensor system. The optical fiber itself lay within the tube, but its temperature was a function of how rapidly heat was conducted into the surrounding medium. The results of this experiment, which are in agreement with those obtained using more traditional “point” sampling and laboratory analysis, are presented along with the strengths and limitations of the thermal-response method of detecting moisture.     

Recycling of flame retardants containing printed circuits: A study of the possible formation of polyhalogenated dibenzodioxins/-furans

The generation of halogenated dibenzo-p-dioxins/-furans could be expected during recycling of printed circuits containing flame retardants. The presence of precursor substances (e.g. flame retardants like tetrabromobis-phenol A or PCB), partly elevated temperatures, and catalytical effects of copper seem to represent typical formation conditions for “dioxins”. To control the possible contamination of granulated material and thus of work places, in a pilot plant a test run was carried out with a hammer mill and an impact grinder. The air samples examined did not contain PXDD/F residues and the shredded material was contaminated only with PBDD/F at very low concentrations (0.03 – 1.13 ng/g). A test with printed circuits under thermal stress up to 300 °C in an oven generated low amounts of PBDD/F (0.74 – 4.51 ng/g). These tests provide proof that printed circuits can be recycled.     

Gas-particle partitioning of PCDD/Fs in Nagoya urban air, Japan

Polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) in the atmosphere were sampled by a high-volume filter/sorbent air sampler at an urban (Nagoya, Japan) site from May 2000 to January 2001 under the average ambient temperatures ranging from 1 degrees C to 33 degrees C. The gas and particle phase concentrations of PCDD/Fs were measured and then the field gas-particle partitioning data were used to assess the Junge-Pankow adsorption model and the K(OA) absorption model. For both PCDDs and PCDFs, passable agreement was obtained between the measured and predicted particulate-band fraction (phi) values by the Junge-Pankow model, but the model tends to overpredict phi for all individual Cl4-8DD/F congeners, especially for the lower chlorinated congeners. On the other hand, good agreement was obtained between the measured and predicted log K(p) values by the K(OA) model for both PCDDs and PCDFs. However, the K(OA) absorption model did not fit the field data at low ambient temperature below 5 degrees C. The disagreement at low ambient temperatures was estimated to arise from the gas adsorption artifacts during the sampling. From the validation by the field measurement data in Nagoya urban air, it is found that the K(OA) absorption model is capable of predicting more accurately gas-particle partitioning of PCDD/Fs than the Junge-Pankow adsorption model.     

Insights to false positive total cyanide measurements in wastewater plant effluents.

Many publicly owned treatment works in North America are exceeding permitted limits for total cyanide in their wastewater treatment effluents. A recently introduced rapid, segmented, flow-injection analysis procedure using UV digestion and amperometric detection of the membrane-separated cyanide was used to investigate the various scenarios by which elevated cyanide levels might be present in wastewater treatment plant effluent. A number of significant interferences can produce false positive bias during sample analysis with the traditional acid distillation technique, but are minimized or absent with the new analytical method. However, increased levels of cyanide were found in some chlorinated wastewaters compared to the levels before chlorination, suggesting a fast reaction mechanism associated with the disinfectant and some precursor in the wastewater. In particular, the contact of chlorine with nitrite in the presence of a carbon precursor appears to contribute to cyanide formation during wastewater treatment and sample handling. This paper explores the scenarios under which cyanide can form during wastewater treatment as well as those in which a false bias for total cyanide can be obtained during sample processing and provides guidance for appropriate sample handling, screening, and processing to ensure valid analytical results.     

Decomposition of organohalogen compounds in municipal solid waste incineration plants. Part I: Chlorofluorocarbons

Disposal of chlorofluorocarbons in a municipal solid waste incinerator has been studied. Destruction of CFC-11 (trichloromonofluoromethane) and CFC-113 (trichlorotrifluoroethane) was found to be better than 99.9%. Neither emission limits for hydrogen chloride or hydrogen fluoride specified in the 17^th BImSchV are exceeded during CFC incineration nor could formation of toxic halogenated organic compounds like dibenzo-p-dioxins or dibenzofurans be observed.     

Estimating biotransformation rate constants of organic chemicals from modeled and measured elimination rates.

In this study, biotransformation rate constants are estimated for a large set of organic compounds. Biotransformation (km) is considered part of the total elimination, further consisting of physico-chemical elimination to water (kw), depuration by feces (kf) and growth dilution (gamma). Existing models are used to estimate kw and kf, and gamma. The difference between measured elimination rate constants and the sum of predicted elimination rate constants for water, feces and growth indicates the ration of biotransformation in the total elimination. In all examined animal classes, polycyclic aromatic hydrocarbons seem to be metabolized at an intermediate rate. Because of the relative low hydrophobicity of some of the studied compounds, their physico-chemical elimination rate constant is relatively high, and the relative contribution of metabolism to total elimination of these compounds is therefore relatively low. Fish seem to be capable of metabolizing chlorodibenzo-p-dioxins and -furans, DDT, chloroanilines and phenol.     

Increase of the PCDD/F-contamination of milk, butter and meat samples by use of contaminated citrus pulp

In Germany from 1993 to 1997, the polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) contamination of food decreased slowly but constantly. However, for milk and butter, this trend was gradually reversed beginning in September 1997: From summer 1997 to February 1998 the average PCDD/F contamination of dairy products increased from a low level of about 0.6 pg I-TEQ/g fat in summer 1997. The dioxin content, of a limited number of randomly collected samples, rose on average to 1.41 pg I-TEQ/g fat (median 1.06 pg I-TEQ/g fat) in different regions of Germany in February 1998. A butter sample from the Netherlands with 1.96 pg I-TEQ/g fat hinted at the same source. The congener pattern in all contaminated milk and butter samples had elevated amounts of 2,3,7,8-TCDD and 1,2,3,7,8-PeCDD. Also, meat samples (beef, cow's meat and veal) with the same dioxin pattern were found to contain between 1.72 and 4.26 pg I-TEQ/g fat (background contamination of 0.53 pg I-TEQ/g fat). Large number of samples were analyzed to find a key for the cause. With a farmer producing milk with about 4.9 pg I-TEQ/g fat, a new source of PCDD/F for food contamination was discovered: the use of PCDD/F contaminated citrus pulp from Brazil as feed material for ruminants on a very large scale. Containing about 5-10 ng I-TEQ/kg, this component was about 20-100 times more highly contaminated than average feed with background contamination. Very complex pieces of circumstantial evidence were gathered to prove the correlation between this component of feed and the increase of dioxin contamination in milk. With respect to the huge trade of this feed ingredient on the global market, many other countries were involved. As an immediate response on these findings, the European Community fixed a preliminary maximum permitted level of 500 pg I-TEQ/kg citrus pulp, valid since August 1998.     

Trace level determination of selected organophosphorus pesticides and their degradation products in environmental air samples by liquid chromatography-positive ion electrospray tandem mass spectrometry

This paper describes a new analytical method for determination of organophosphorus pesticides (OPs) along with their degradation products involving liquid chromatography (LC) positive ion electrospray (ESI+) tandem mass spectrometry (MS-MS) with selective reaction monitoring (SRM). Chromatography was performed on a Gemini C6-Phenyl (150 mmx2.0 mm, 3 microm) with a gradient elution using water-methanol with 0.1% formic acid, 2 mM ammonium acetate mobile phase at a flow rate of 0.2 mL min(-1). The LC separation and MS/MS operating conditions were optimized with a total analysis time less than 40 minutes. Method detection limits of 0.1-5 microg L(-1) for selected organophosphorus pesticides (OP), OP oxon degradation products, and other degradation products: 3,5,6-trichloro-2-pyridinol (TCP); 2-isopropyl-6-methyl-4-pyrimidol (IMP); and diethyl phosphate (DEP). Some OPs such as fenchlorphos are less sensitive (MDL 30 microg L(-1)). Calibration curves were linear with coefficients of correlation better than 0.995. A three-point identification approach was adopted with area from first selective reaction monitoring (SRM) transition used for quantitative analysis, while a second SRM transition along with the ratio of areas obtained from the first to second transition are used for confirmation with sample tolerance established by the relative standard deviation of the ratio obtained from standards. This new method permitted the first known detection of OP oxon degradation products including chlorpyrifos oxon at Bratt's Lake, SK and diazinon oxon and malathion oxon at Abbotsford, BC in atmospheric samples. Atmospheric detection limits typically ranged from 0.2-10 pg m(-3).     

Status of the PCDD and PCDF contamination of commercial milk caused by milk cartons

Within the scope of this study, possible migration of polychlorinated dibenzodioxins and -furans (PCDDs/PCDFs) from cartons (produced using bleached cardboard) into cow's milk was investigated. Three different types of carton were examined. The milk samples were taken at different times of storage and analysed for PCDDs/PCDFs. In contrast to a similar study carried out in 1990, the I-TEQ-results of all cartons analysed may be considered very low. No significant migration of toxic (2,3,7,8-chlorine-substituted) PCDDs/PCDFs could be observed. This is due to the very low PCDD/PCDF concentrations in modern cardboards as a result of the elemental chlorine-free (ECF) bleaching processes used. As far as the milk samples are concerned, no influence of the cardboards (according to the I-TEQ data) could be ascertained. I-TEQ concentrations in milk did not noticeably change during storage times of three, six and eight days. The I-TEQ-data obtained for all milk samples was found to be in the range typical of background concentrations in cow's milk in Germany. Although 1,2,7,8-TCDF is not included in the calculation of the TEQ (no 2,3,7,8-chlorine-substitution), analysis of this congener in cardboard samples was also carried out as a matter of general interest for cardboard investigations and an indicator of pulp bleaching with free chlorine.     

Application of the new C18 speedisks to the analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans in water and effluent samples

A recently introduced disk for solid-phase extraction of pollutants from water (C18 Speedisk) has been tested for the analysis of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF). The complete procedure of analysis has been validated with spiked deionized water. The accuracy, expressed as recovery for the sum of 2,3,7,8-substituted congeners. is 92% and the precision, expressed as the RSD of reproducibility, is 5.8%. The limit of detection (LOD), using 2 l of water, is 4.2 pg/l (0.6 pg ITEQ/l) for the sum of 2,3,7,8-substituted congeners. Actually, the C18 Speedisks have substituted the use of other C18 membrane disks in our laboratory because they allow the fast and efficient analysis of samples with high content of suspended material and reduce the time of elution of free-particulate samples. These disks have been successfully applied to the analysis of water from different sources and with very different physical and chemical characteristics: seawater, rain water, an industrial effluent, a landfill leachate and the inlet and chlorinated and non-chlorinated outlet water from a wastewater treatment plant.     

Positive vs. false detection: A comparison of analytical methods and performance for analysis of cyclic volatile methylsiloxanes (cVMS) in environmental samples from remote regions

Contamination and analytical variation can significantly hinder trace analysis of cyclic methyl volatile siloxanes (cVMS); potentially resulting in the report of false positives at concentrations approaching detection limits. To assess detection and variation associated with trace cVMS analysis in environmental matrices, a co-operative laboratory comparison for the analysis of octametylcyclotetrasiloxane (D4), decamethylcylcopentasiloxane (D5), and dodecametylcyclohexasiloxane (D6) in sediment and biota from the Svalbard Archipelago was conducted. Two definitions of detection limits were evaluated in this study; method detection limits (MDL, matrix defined) and limits of detection (LOD, solvent defined). D5 was the only cVMS detected above both LOD (0.08–0.81 ng g⁻¹ ww) and MDL (0.47–2.36 ng g⁻¹ ww) within sediment by all laboratories where concentrations ranged from 0.55 to 3.91 ng g⁻¹ ww. The percentage of positive detects for D5 decreased by 80% when MDL was defined as the detection limit. D5 was also detected at the highest frequency among all laboratories in fish liver with concentrations ranging from 0.72 to 345 ng g⁻¹ ww. Similar to sediment, percentage of positive detects for D5 decreased by 60% across all laboratories for fish livers when using MDL (0.68–3.49 ng g⁻¹ ww). Similar observations were seen with both D4 and D6, indicating that sample matrix significantly contributes to analytical response variation. Despite differences in analytical methods used between laboratories, good agreement was obtained when using MDL to define detection limits. This study shows the importance of incorporating variation introduced by sample matrices into detection limit calculations to insure data accuracy of cVMS at low concentrations.     

Optimisation and use of tandem-in-time mass spectrometry in comparison with immunoassay and HRGC/HRMS for PCDD/F screening

Rapid screening of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans using quadrupole ion storage tandem-in-time mass spectrometry (QISTMS) conjointly with polyclonal antibody immunoassay has been considered. The optimisation of the fragmentation of the parent ion in the trap has been completed. The analysis of fly ashes from a municipal waste incinerator contaminated at different levels has then been realised. Results obtained using QISTMS, HRMS and immunoassay are compared.     

Linking molecular interactions to consequent effects of persistent organic pollutants (POPs) upon populations

There is great concern about the potential adverse effects of persistent organic pollutants (POPs) on wildlife. Threats come from toxic chemicals with long half lives in the environment that were released worldwide on a large scale in the past, at a time when little was known of their potential effects on the environment. Although the Stockholm Convention (2001) initially targeted 12 POP chemicals--organochlorinated compounds--for the reduction/elimination of releases, the problem can be extended to persistent toxic substances more generally. Therefore, identifying early biomarkers for possible toxic effects to populations in the long term is a challenge for ecotoxicologists. Regional decline in fish, bird and/or invertebrate populations resulting from exposure to POPs, such as DDT (dichlorodiphenyltrichloroethane), PCBs (polychlorinated biphenyls), PCDD (polychlorinated dibenzo-p-dioxins), and TBT (tributyltin) could be related to some biochemical, endocrine and physiological effects in individuals. Examples of known mechanisms of POP ecotoxicity will be illustrated in the first part. The next parts will be devoted to (i) data gaps and limitations to extrapolation from lower to higher levels of biological organization, (ii) confusing factors in field studies and the combined effects of persistent toxic pollutants and (iii) recommendations for the design and interpretation of experimental studies.