Interlaboratory comparison of the determination of chlorinated dibenzo-p-dioxins and dibenzofurans according to regulatory methods EN 1948 and EPA 1613b.

Four laboratories participated in a collaborative study to determine differences in analytical results generated according to two different compliance methods, US EPA Method 1613b and European Union Method EN 1948 for the determination of chlorinated dibenzo-p-dioxins and dibenzofurans (CDD/CDFs). Various sample matrices containing the analytes at levels ranging from parts-per-quadrillion (ppq) to parts-per-billion (ppb) were used to illustrate differences and similarities between the two analytical methods. The choice of the sample matrices analyzed in this study was made to mirror many of the real-world samples that are of interest to Dow and also to test the laboratories on many different, complex matrices. For this reason, commercially available performance evaluation samples were not used. The study results indicate that the 1613b requirement for confirmation of analyte identity and concentration on a second, polar gas chromatographic column for 2378-tetrachlorodibenzofuran (TCDF) only may lead to quantitative results which are biased high compared to EN 1948 which additionally requires confirmation for all 2378-substituted tetra--through hexachlorodibenzo-p-dioxins and dibenzofurans.

Export of toxic chemicals - a review of the case of uncontrolled electronic-waste recycling.

This paper reviews the concentrations of persistent organic pollutants such as flame retardants (PBDEs), dioxins/furans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and heavy metals/metalloid concentrations of different environmental media at Guiyu, a traditional rice-growing village located in southeastern Guangdong Province (PR China), which has turned into an intensive electronic-waste (e-waste) recycling site. Incomplete combustion of e-waste in open air and dumping of processed materials are the major sources of various toxic chemicals. By comparing with existing data available in other areas and also guidelines adopted in different countries, it is obvious that the environment is highly contaminated by these toxic chemicals derived from the recycling processes. For example, the monthly concentration of the sum of 22 PBDE congeners contained in PM(2.5) (16.8ngm(-3)) of air samples at Guiyu was 100 times higher than published data. In order to safeguard the environment and human health, detailed investigations are urgently needed, especially on tracking the exposure pathways of different toxic chemicals which may affect the workers and local residents especially mothers, infants and children.