Roland Haag

PCDDs and PCDFs in sewage sludge, river and lake sediments from south west Germany

Sewage sludges and sediments of rivers and lakes are sinks for “persistent” organic compounds entering the environment. These matrices are therefore useful in the assessment of local and global pollution with certain compounds or classes of compounds. In recent years we have analyzed sediments of the rivers Neckar, Rhine, and Danube, from Lake Constance, and samples of sewage sludge from municipal waste water treatment plants of south-west Germany for PAH, phthalates, organochlorine pesticides, and PCBs. 1 We have now analyzed a number of these samples for PCDDs and PCDFs. Isomer-specific analyses for 2,3,7,8-subsituted PCDDs/PCDFs were carried out in all cases. In all samples PCDDs could be detected, and in most cases PCDFs as well. 2,3,7,8-TCDD was never detected at a detection limit of 0.01 ppb. In sediments (14 samples) the total PCDDs ranged from 0.1 to 2.9 ppb and PCDFs from “not detectable” to 1.2 ppb. The highest concentration for a 2,3,7,8-substituted PCDD∗ was found for 1,2,3,6,7,8-hexaCDD with 0.06 ppb. In sewage sludges (15 samples) the total PCDDs ranged from 4 to 65 ppb and PCDFs from 1 to 7 ppb. The highest concentration for a 2,3,7,8-substituted PCDD∗ was found for 1,2,3,6,7,8-hexaCDD with 0.57 ppb. Comparison of PCDD/PCDF patterns of congeners and isomers for the sewage sludge and river sediment samples with those of stack gas emissions of waste incinerators and of pentachlorophenol allows the conclusion that the main source of PCDDs and PCDFs found in these samples is pentachlorophenol. Results of the Lake Constance sediment core indicate that here the atmospheric immission from waste incineration might be predominant.

Selective determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin in the presence of a large excess of other polychlorinated dibenzodioxins and polychlorinated dibenzofurans

ZusammenfassungEin Verfahren wird beschrieben, das die selektive Abtrennung von 2,3,7,8-TCDD aus einer Mischung von allen PCDDs und PCDFs erlaubt. Dies geschieht durch Fraktionierung an Alumina Woelm B Super I, wodurch eine getrennte Elution aller PCDDs und PCDFs von 2,3,7,8-TCDD erreicht werden kann. Dieses Verfahren erlaubt die quantitative Bestimmung von 2,3,7,8-TCDD mit höherer Nachweisempfindlichkeit in Proben, die andere TCDDs bzw. PCDDs und PCDFs in extremen Überschüssen im Vergleich zu 2,3,7,8-TCDD enthalten. Am Beispiel der Bestimmung von 2,3,7,8-TCDD in Pentachlorphenol und in einem Produktionsrückstand von 2,4-Dichlorphenol wird die praktische Anwendbarkeit nachgewiesen.SummaryA procedure is described for the selective separation of 2,3,7,8-TCDD from all other PCDDs and PCDFs. For this purpose the mixture of PCDDs and PCDFs is fractionated on Alumina Woelm B Super I in such a manner that all PCDDs and PCDFs are eluted prior to 2,3,7,8-TCDD. This procedure allows a more sensitive quantitative determination of 2,3,7,8-TCDD in samples which contain 2,3,7,8-TCDD only as a very minor fraction of the other TCDDs or PCDDs and PCDFs. Determination of 2,3,7,8-TCDD in pentachlorophenol and in a waste sample from 2,4-dichlorophenol production by this procedure is described.

Problems Associated With the Measurement of PCDD and PCDF Emissions From Waste Incineration Plants

Abstract Fly ash and stack gases from municipal waste and industrial incinerators in the F.R.G. have been analyzed for dioxins (PCDD and PCDF). Most of the currently used procedures of stack gas sampling for PCDD/PCDF have been compared and were found to be equally effective. Differences are found, however, in the recovery of surrogates added to the sampling train before sampling, which makes it difficult to validate the sampling procedure. The analysis for PCDD%PCDF in stack gas or fly ash samples from municipal waste incinerators can no longer be considered an analytical problem. Thirty samples of stack gas from a single (old) municipal waste incinerator showed wide variation in PCDD/PCDF emission, indicating that single measurements are not useful in characterizing a plant for average PCDD/PCDF emission. It will be extremely difficult to correlate plant operating conditions to PCDD/PCDF stack gas emissions or PCDD/PCDF fly ash concentrations, because the effects produced by changing conditions are obscured by the variations which occur in PCDD/PCDF concentrations during steady conditions. The variations found under steady conditions can be explained by the proposed mechanisms of PCDD/PCDF formation and decomposition at low temperatures catalyzed by fly ash. Incineration of hospital waste and pyrolytic reclamation of copper in cables and aluminium produced significant emission of PCDD/PCDF. A major noncombustion source of higher chlorinated PCDD/PCDF (tetra- to octa-isomers) is pentachlorophenol, a widespread preservative which contributes to the PCDD/PCDF concentrations found, for example, in sewage sludge, river sediments and house dust.

PROBLEMS ASSOCIATED WITH THE MEASUREMENT OF PCDD AND PCDF EMISSIONS FROM WASTE INCINERATION PLANTS

Fly ash and stack gases from municipal waste and industrial incinerators in the F.R.G. have been analyzed for dioxins (PCDD and PCDF). Most of the currently used procedures of stack gas sampling for PCDD/PCDF have been compared and were found to be equally effective. Differences are found, however, in the recovery of surrogates added to the sampling train before sampling, which makes it difficult to validate the sampling procedure. The analysis for PCDD/PCDF in stack gas or fly ash samples from municipal waste incinerators can no longer be considered an analytical problem. Thirty samples of stack gas from a single (old) municipal waste incinerator showed wide variation in PCDD/PCDF emission, indicating that single measurements are not useful in characterizing a plant for average PCDD/PCDF emission. It will be extremely difficult to correlate plant operating conditions to PCDD/PCDF stack gas emissions or PCDD/PCDF fly ash concentrations, because the effects produced by changing conditions are obscured by the variations which occur in PCDD/PCDF concentrations during steady conditions. The variations found under steady conditions can be explained by the proposed mechanisms of PCDD/PCDF formation and decomposition at low temperatures catalyzed by fly ash. Incineration of hospital waste and pyrolytic reclamation of copper in cables and aluminium produced significant emission of PCDD/PCDF. A major non-combustion source of higher chlorinated PCDD/PCDF (tetra- to octa-isomers) is pentachlorophenol, a widespread preservative which contributes to the PCDD/PCDF concentrations found, for example, in sewage sludge, river sediments and house dust.