Under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a key comparison, CCQM K55.b, was coordinated by the Bureau International des Poids et Mesures (BIPM) in 2010/2011. Nineteen national measurement institutes and the BIPM participated. Participants were required to assign the mass fraction of aldrin present as the main component in the comparison sample for CCQM-K55.b which consisted of technical grade aldrin obtained from the National Measurement Institute Australia that had been subject to serial recrystallization and drying prior to sub-division into the units supplied for the comparison.Aldrin was selected to be representative of the performance of a laboratory's measurement capability for the purity assignment of organic compounds of medium structural complexity [molar mass range 300 Da to 500 Da] and low polarity (pKOW < −2) for which related structure impurities can be quantified by capillary gas phase chromatography (GC).The key comparison reference value (KCRV) for the aldrin content of the material was 950.8 mg/g with a combined standard uncertainty of 0.85 mg/g. The KCRV was assigned by combination of KCRVs assigned by consensus from participant results for each orthogonal impurity class. The relative expanded uncertainties reported by laboratories having results consistent with the KCRV ranged from 0.3% to 0.6% using a mass balance approach and 0.5% to 1% using a qNMR method.The major analytical challenge posed by the material proved to be the detection and quantification of a significant amount of oligomeric organic material within the sample and most participants relying on a mass balance approach displayed a positive bias relative to the KCRV (overestimation of aldrin content) in excess of 10 mg/g due to not having adequate procedures in place to detect and quantify the non-volatile content—specifically the non-volatile organics content—of the comparison sample.There was in general excellent agreement between participants in the identification and the quantification of the total and individual related structure impurities, water content and the residual solvent content of the sample.The comparison demonstrated the utility of 1H NMR as an independent method for quantitative analysis of high purity compounds. In discussion of the participant results it was noted that while several had access to qNMR estimates for the aldrin content that were inconsistent with their mass balance determination they decided to accept the mass balance result and assumed a hidden bias in their NMR data. By contrast, laboratories that placed greater confidence in their qNMR result were able to resolve the discrepancy through additional studies that provided evidence of the presence of non-volatile organic impurity at the requisite level to bring their mass balance and qNMR estimates into agreement.Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison ...

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Polycyclic aromatic hydrocarbons (PAHs) were studied in street dust (SD) samples collected in the center of Niterói, a tropical city located in the State of Rio de Janeiro, Brazil, at the margins of Guanabara Bay. Sampling was carried out monthly during the year of 2002 in order to evaluate seasonal variation of PAH concentrations. Samples were extracted by ultrasonic treatment with dichloromethane, cleaned up by solid phase extraction and analyzed by gas chromatographymass spectrometry. The concentrations of the twenty one analyzed PAHs ranged from 3.2 to 132 ng/g. Of all PAHs, pyrene, fluoranthene and naphthalene showed the highest geometric means. Total PAH concentration ( PAH) ranged from 434 to 1247 ng/g with levels of carcinogenic PAHs ( CARC) representing 29 to 45% of PAHs. The highest value of PAH occurred in July 2002, when the lowest temperatures were measured in the Central Area of Niterói City. PAH and CARC showed significant correlations with daily mean and minimum temperature, as well as with temperature during sampling, indicating that both are influenced by these parameters. The obtained results suggest that a seasonal variation of total PAH levels in SD may occur in the studied area.

Proper solid waste disposal is important to avoid human and environmental contamination. The NBR 10,004 Waste Classification lists several polycyclic aromatic hydrocarbons (PAHs) and indicates that the presence of at least one PAH in a waste sample is enough to classify it as hazardous. The aim of this study was a preliminary evaluation of PAHs in solid waste samples from selected industries to obtain a preliminary overview of their potential for contamination in case of improper disposal. One or more PAHs listed in NBR 10,004 (benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, indene[1,2,3-c,d]pyrene, chrysene, or fluoranthene) were found in all samples, thus leading to their classification as hazardous waste. Our results showed that toxicologically relevant PAHs were found in all the samples, indicating that their final disposal must be performed in appropriate areas in order to minimize human health risks and environmental contamination from waste disposal areas.

PAHs and BTEX were studied in groundwater from monitoring wells of gasoline stations of Rio de Janeiro City, Brazil during 2003 and 2004. Total PAH concentration ranged from 0.05 to 84.9 microg/L. Total BTEX concentration varied between not-detected to 3.6 x 10(3) microg/L. Some samples exceeded the maximum concentration limit of Brazilian regulations for benzene in fresh or drinking water. Carcinogenic PAHs were found in few samples but only one sample in each year exceeded the regulated concentrations for benzo[a]pyrene. The concentrations of PAHs and BTEX indicate that some places may be contaminated by gasoline leakage.