Concentrations and sources of an emerging pollutant, decabromodiphenylethane (DBDPE), in sewage sludge for land application.

The presence of an emerging brominated flame retardant, decabromodiphenylethane (DBDPE), has been confirmed in Spanish sewage sludge. Thirty one samples from different urban wastewater treatment plants (WWTPs) were analyzed for this brominated flame retardant. DBDPE was positively identified and quantified in all samples at lower concentrations (47.0 +/- 29.7 ng/g dry weight (dw); mean +/- SD) than those obtained for decabromodiphenyl ether (BDE-209) (290 +/- 236 ng/g dw; mean +/- SD) in a previous study. Influence of the WWTP characteristics in the pollutant levels was evaluated. No significant correlations were obtained between DBDPE concentrations and the population or sewage sludge production rate associated with the plants, neither wastewater treatment method. Sources of DBDPE in the sludge were also evaluated. Data indicate a common origin for DBDPE and BDE-209, which may be related to leaching processes during the use and disposal of consumer products containing these chemicals. Nevertheless, DBDPE contents are not influenced by industrial activities, which suggests that the infusion of DBDPE commercial mixture is not a source of this chemical into the environment, and indicates that the use of DBDPE in the Spanish industry is still low compared to deca-BDE.

Sources and behaviour of polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in Spanish sewage sludge.

Presence, sources and behaviour of polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were evaluated in Spanish sewage sludge. A total of 120 samples were seasonally collected from October 2005 to September 2006 at 31 urban wastewater treatment plants (WWTPs). Concentrations of PBDEs (ranging between 57.5 and 2606 ng/g dry weight) were two to three orders of magnitude higher than those obtained for PCDDs (0.17-5.03 ng/g d.w.) and PCDFs (0.05-3.07 ng/g d.w.). All the samples presented International Toxicity Equivalents (I-TEQ) levels (ranging between 2.06 and 44.4 ng/kg d.w.) below the limit values proposed by European Union for land application. Congener patterns evaluation revealed that the use of Deca-BDE commercial mixture seems to be the major source of PBDEs in the sludge. Nevertheless, origin of PCDD/Fs should be related to atmospheric deposition, faeces and presence of PCDD/Fs precursors such as pentachlorophenol in the sludge. No correlations (p>0.05) were found between pollutant concentrations (PBDEs and PCDD/Fs) and wastewater treatment plant (WWTP) characteristics (capacity nor sludge rate). Lower levels of PBDEs and PCDFs were found in WWTPs using biological nitrogen and phosphorous elimination, suggesting that these compounds are susceptible of microbial elimination. According to our knowledge, this is the first work comparing together both PBDEs and PCDD/Fs sludge patterns.

Feasibility of high-performance immunochromatography as an isolation method for PCBs and other dioxin-like compounds.

A high performance immunochromatographic procedure to isolate polychlorinated biphenyls (PCBs) and other dioxin-like compounds from a sample is shown. Development of the procedure includes (i) synthesis of the hapten, binding it to the spacer arm and to the carrier protein to make the immunizing molecule; (ii) raising and purification of anti-PCB antibodies; (iii) building of the immunocolumn; (iv) selection of the binding, rinsing, and elution conditions adequate for these highly lipophilic compounds; (v) study of the influence of the concentration and volume of sample on recovery; and (vi) study of the selectivity of the immunosystem for dioxins, furans, PCBs, and several insecticides of different toxicity. Evaluation of the method is carried out by analyzing the fractions retained and nonretained in the immunocolumn by GC/MS. The immunochromatographic system that is developed shows itself to be feasible as cleanup and isolation steps carried out prior to GC/MS analyses. When compared to classical cleanup and isolation methods traditionally used for analysis of PCBs in water, the immunochromatographic method is > 20x faster and uses 100x less organic solvents, and its selectivity is enormously enhanced. Good recoveries are obtained with both kinds of methods. The immunochromatographic procedure fulfils the acceptance criteria indicated by the EPA, even for sub-parts-per-billion concentrations.