Emission reduction of PCDD/Fs by flue gas recirculation and activated carbon in the iron ore sintering

Impact of a Nanoscale Iron-Chlorobenzene Mixture on Pulmonary Injury in Rat Pups: Extending Exposure Knowledge Using Network Technology

Particulate matter coexists with persistent organic pollutants (POPs) in the atmosphere, which can enter the human body by accompanying inhalable particles in the respiratory tract. Photochemical conversion further alters the chemical composition of the precursor particles and secondary products. This study investigated the effects of nanoscale iron-chlorobenzene mixtures and their photochemical conversion products on early lung development in rat pups. Using network toxicology and animal experiments, we constructed a compound toxicity-target network and developed air exposure models. This study revealed that both pollutants, before and after photochemical conversion, bound to the aryl hydrocarbon receptor (AhR), increased oxidative stress, altered lung tissue morphology, and reduce inflammatory factor expression. Rat pups were highly sensitive to pollutants during critical stages of lung development. However, no significant differences in oxidative stress or inflammation were observed between the pollutants, likely because of immature lung tissues. Once tissue damage reached a threshold, the response to increasing pollutant concentrations diminished. This study provides insights into atmospheric pollutant toxicity and scientific evidence for the risk assessment of dioxin-like nanoscale mixtures.

A novel approach to the extraction and analysis of dioxins and furans sampled onto Amberlite XAD-2 sorbent

Despite the efficacy of strong emission control plans that have been implemented the last few decades, polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) may still be released from anthropogenic sources such as sinter plants, and municipal and hazardous waste incinerators. Monitoring for PCDDs and PCDFs in gaseous emissions from such facilities is important due to the acute toxicity of these compounds even at trace levels. Currently, most of these samples from the African continent are being analysed abroad at high cost, with the direct consequence that the number of measurements are kept to a minimum. In this context, we developed a more affordable analytical approach for the measurement of PCDD/Fs sampled onto Amberlite XAD-2 sorbent, which relies on a novel extraction, clean-up, and analysis method with the aim of reducing both the cost and the complexity of standard methods while maintaining high quality results. A simple, sequential, 3 hour end-over-end tumbling extraction procedure was developed employing acetone : n-hexane (1 : 9) as extraction solvent. This was combined with a dimethyl sulfoxide (DMSO) clean-up to remove aliphatic interferences, prior to direct analysis by gas chromatography triple quadrupole mass spectrometry. The Unites States Environmental Protection Agency Method 23, in contrast, requires a 16 hour Soxhlet extraction with toluene and multiple column chromatography steps. The end-over-end tumbling extraction yielded an average recovery of 79% for PCDD/Fs usually monitored in gaseous samples, whilst an average recovery of 89% was achieved for the DMSO clean-up procedure. In addition, an overall average recovery of 78% and a Z-score of -1.1 was obtained using the developed method for the proficiency testing of a solid reference material, proving the method is fit for purpose. It was then successfully applied to the analysis of air emissions from a medical waste incinerator, which further showed that the alternative approach may deliver quality, fast, and cost-effective analysis of gaseous PCDD/Fs sampled onto Amberlite XAD-2 sorbent in a developing country context.

Health assessment of emerging persistent organic pollutants (POPs) in PM2.5 in northern and central Taiwan

Over the last two decades, Taiwan has effectively diminished atmospheric concentrations of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) through the adept utilization of advanced technologies and the implementation of air pollution control devices. Despite this success, there exists a dearth of data regarding the levels of other PM2.5-bound organic pollutants and their associated health risks. To address this gap, our study comprehensively investigates the spatial and seasonal variations, potential sources, and health risks of PCDD/Fs, Polychlorinated biphenyls (PCBs), and Polychlorinated naphthalene (PCNs) in Northern and Central Taiwan. Sampling collections were conducted at three specific locations, including six municipal waste incinerators in Northern Taiwan, as well as a traffic and an industrial site in Central Taiwan. As a result, the highest mean values of PM2.5 (20.3-39.6 μg/m3) were observed at traffic sites, followed by industrial sites (14.4-39.3 μg/m3), and the vicinity of the municipal waste incinerator (12.4-29.4 μg/m3). Additionally, PCDD/Fs and PCBs exhibited discernible seasonal fluctuations, displaying higher concentrations in winter (7.53-11.9 and 0.09-0.12 fg I-TEQWHO/m3) and spring (7.02-13.7 and 0.11-0.16 fg I-TEQWHO/m3) compared to summer and autumn. Conversely, PCNs displayed no significant seasonal variations, with peak values observed in winter (0.05-0.10 fg I-TEQWHO/m3) and spring (0.03-0.08 fg I-TEQWHO/m3). Utilizing a Positive Matrix Factorization (PMF) model, sintering plants emerged as the predominant contributors to PCDD/Fs, constituting 77.9% of emissions. Woodchip boilers (68.3%) and municipal waste incinerators (21.0%) were identified as primary contributors to PCBs, while municipal waste incinerators (64.6%) along with a secondary copper and a copper sludge smelter (22.1%) were the principal sources of PCNs. Moreover, the study specified that individuals aged 19-70 in Northern Taiwan and those under the age of 12 years in Central Taiwan were found to have a significantly higher cancer risk, with values ranging from 9.26 x 10-9-1.12 x 10-7 and from 2.50 x 10-8-2.08 x 10-7respectively.