Degradation of PCDD, PCDF, PAH, PCB and chlorinated phenols during the destruction-treatment of landfill seepage water in laboratory model reactor (UV, Ozone, and UV/Ozone)

Seepage water of toxic waste landfills is polluted with high concentrations of toxic organic compounds. The concentrations in the seepage water we applied for chlorinated phenols are between 2 μg/1 and 1 mg/l, for PCB between 800 pg/l and 250 ng/l, for PAH between 200 ng/l and 12 μg/l and for PCDD and PCDF between 20 pg/l and 1 ng/l. Usual purification methods produce highly contaminated residues, which have to be treated by pyrolysis or are deposited again at a landfill. A better way is to destruct these contaminants by UV/ozone treatment. The treatment of seepage water by UV-irradiation, ozone and UV/ozone is compared. Results show no significant effect during all treatments for PCB and PCDD/PCDF. The chlorinated phenols and PAH were mostly destroyed by UV/ozone treatment more than 90 %. The pH value has no influence on the UV/ozone treatment of seepage water.     

Nachhaltige Entwicklung von Managementstrategien

In order to support evaluation and decision processes with respect to sustainability of management strategies, different mathematical methods can be applied. In this paper, the fundamentals of these so-called multi-criteria evaluation and decision-support instruments are presented. Moreover, advantages and disadvantages are worked out using an example data set of strategies of sustainable water management. It is shown that particularly transparency, objectivity and the degree of participation of stakeholders are the main characteristics: Whereas the Hasse diagram technique is directed to the scientifically given data matrix, and therefore yields an objective and transparent evaluation and data analysis, concordance analysis, utility function theory, PROMETHEE and AHP (analytical hierarchy process) have their preferences as participants or stakeholders in the decision process.     

In vivo measurements of the internal pH of Hediste (Nereis) diversicolor (Annelida, Polychaeta) exposed to ambient sulphidic conditions using pH microelectrodes

 The effect of different ambient sulphide concentrations on the internal pH regime of Hediste (Nereis) diversicolor was studied under in vivo conditions using liquid membrane pH microelectrodes, a method which is new to marine sciences. As a case study, the hypothesis was tested whether organisms exposed to ambient sulphidic conditions are able to lower their internal pH which, in effect, would reduce sulphide influx into the animals and thus could represent an effective detoxification mechanism. It was shown that a significant lowering of the internal pH occurred within only 20 min after adding sulphide. This pH lowering appeared to be dependent on the external sulphide concentration of the ambient medium and showed a saturation beyond a threshold level of about 130 μM. It is discussed whether this sulphide-induced pH drop is an active regulatory mechanism and acts as an effective protection mechanism against sulphide during short-term exposures. Received: 1 June 1999 / Accepted in revised form: 3 May 2000     

Transfer von PCDD/F und anderen organischen Umweltchemikalien im System Boden-Pflanze-Luft I. Modellierung des Transferverhaltens

Die Massenbilanz von PCDD/F—insbesondere von 2,3,7,8-TCDD—im System Boden-Pflanze-Luft wird mit einem einfachen konzeptuellen Modell berechnet. Die wichtigsten Ergebnisse sind:

Diurnal variations of abiotic parameters in a stream,recipient for drainage water in Ranstad,southwest Sweden

During 24 h, water samples were taken for determination of a number of key parameters in a water system containing high concentrations of FeII at circumneutral pH. None of the major constituents (Ca, Mg, Na, K and sulfate) showed diurnal variations, while dissolved oxygen and pH increased during the night. This increase could entirely be explained by the decrease in water temperature. However, the concentration of FeII slightly increased at constant concentration of total Fe during the night, opposite to earlier observations in other systems where the presence of FeII was shown to be controlled by photoreduction. Nocturnal peaks of FeII have also been observed in other systems with high iron concentrations, however, at acidic pH, but without obvious explanation. The mechanisms for this process therefore need further investigation.     

Polybrominated diphenyl ethers (PBDEs) in freshwater mussels and fish from Flanders, Belgium

The levels and distribution of PBDEs in zebra mussels and several freshwater fish species (eel, carp and gibel carp) were investigated for different sites in Flanders, Belgium. In parallel, other organohalogenated contaminants, such as polychlorinated biphenyls (PCBs), p,p[prime or minute]-DDE and hexachlorobenzene (HCB) were also measured and their relationship with PBDEs was investigated. At most sites, individual PBDE congeners were present at detectable levels in mussel tissue, with the mean [summation operator]PBDE concentration ranging from 0.15 to 1.8 ng g(-1) wet weight (ww). The PCB concentrations in mussels ranged from 6.2 to 102 ng g(-1) ww. HCB and p,p[prime or minute]-DDE could be measured in mussels from most sites, mean values ranging from below the limit of quantification (LOQ) to 0.58 ng g(-1) ww and from 0.66 to 6.5 ng g(-1) ww, respectively. Except for one site (Blokkersdijk, Antwerp) where PBDEs were below the LOQ in carp muscle, all fish samples from other sites contained detectable PBDE levels, with the highest concentrations (14 +/- 14 ng g(-1) ww) being measured in eel liver from Watersportbaan (Ghent). The sampled sites covered a broad concentration range of organohalogenated pollutants with the highest values being consistently measured in eel liver. With few exceptions, all correlations between PBDEs and organochlorine pollutants for each species were low (r < 0.50) and most were statistically not significant (p > 0.05). This suggests that the exposure to contaminants arises from local sources possessing different signatures of PBDEs and organochlorine pollutants.     

PBDEs in marine and freshwater sediments from Belgium: levels, profiles and relations with biota

Sediments from the Belgian North Sea (BNS), the Western Scheldt Estuary (SE) and freshwater watercourses from the Scheldt basin were analysed for eight PBDE congeners, namely BDEs 28, 47, 99, 100, 153, 154, 183 and 209. Previously analysed biological samples from the same locations in the BNS and the SE have been shown to contain large amounts of PBDEs. Surprisingly, PBDE concentrations in the sediments were below the LOQ for samples from the BNS (except BDE 209), while in those from the SE the sum of PBDEs (not including BDE 209) were higher and ranged from 0.20 to 0.41 ng g(-1) dw. BDE 209 could be detected in 83% of the samples from the BNS and in all the samples from the SE. Concentrations up to 1200 ng g(-1) were hereby measured in the SE. Compared to the marine and estuarine locations, the sediments from the freshwater watercourses were relatively more polluted with the lower brominated PBDEs (<0.20-19 ng g(-1) dw). BDE 209 concentrations up to 320 ng g(-1) dw were measured in those sediments. However, the contribution of BDE 209 to the total amount of PBDEs varied much more at the freshwater locations than in the SE, which suggests a different input of pollutants. PBDE profiles observed in biological samples do not match the profiles of the sediments. BDE 183 and 209 could not be quantified in biota, although these congeners were undoubtedly present in the sediments. This raises questions about the bioavailability of these congeners in the environment.