Environmental fate of hazardous chemicals and their alternatives in flame-retarded products

学位の種別: 課程博士審査委員会委員 : （主査）東京大学客員教授 鑢迫 典久, 東京大学教授 福田 健二, 東京大学教授 須貝 俊彦, 東京大学准教授 鈴木 牧, 東京大学准教授 吉永 淳University of Tokyo(東京大学

Emerging halogenated flame retardants and hexabromocyclododecanes in food samples from an e-waste processing area in Vietnam

Emerging halogenated flame retardants (HFRs) and hexabromocyclododecanes (HBCDs) accumulate in human foodstuffs in a Vietnamese e-waste handling area.</p

Congener-Specific Partition Properties of Chlorinated Paraffins Evaluated with COSMOtherm and Gas Chromatographic Retention Indices

Chlorinated Paraffins (CPs) are high volume production chemicals and have been found in various organisms including humans and in environmental samples from remote regions. It is thus of great importance to understand the physical-chemical properties of CPs. In this study, gas chromatographic (GC) retention indexes (RIs) of 26 CP congeners were measured on various polar and nonpolar columns to investigate the relationships between the molecular structure and the partition properties. Retention measurements show that analytical standards of individual CPs often contain several stereoisomers. RI values show that chlorination pattern have a large influence on the polarity of CPs. Single Cl substitutions (-CHCl-, -CH2Cl) generally increase polarity of CPs. However, many consecutive -CHCl- units (e.g., 1,2,3,4,5,6-C11Cl6) increase polarity less than expected from the total number of -CHCl- units. Polyparameter linear free energy relationship descriptors show that polarity difference between CP congeners can be explained by the H-bond donating properties of CPs. RI values of CP congeners were predicted using the quantum chemically based prediction tool COSMOthermX. Predicted RI values correlate well with the experimental data (R2, 0.975–0.995), indicating that COSMOthermX can be used to accurately predict the retention of CP congeners on GC columns. </p

Direct Measurements of Vapor Pressures of Chlorinated Paraffin Congeners from Technical Mixtures

Chlorinated Paraffins (CPs) are a complex group of manmade chemicals detected widely in the environment. To predict their environmental fate and effects, it is important to understand their physical-chemical properties including vapor pressure. In this study, the first direct measurements of the vapor pressure for CP congener groups (C10–16Cl4–11) are presented. Vapor pressure was measured above three industrial CP mixtures with different congener distributions between 20 and 50°C using a gas saturation method. The measured saturated vapor pressure (P*) decreased with increasing carbon chain length and Cl content. ΔHvap ranged between 73 and 122 kJ mol-1, consistent with data from the literature and model prediction. The experimental log P* at 25°C agreed well with predictions from an empirical regression model in the literature (R2 = 0.97; RSME = 0.25) and with those predicted from the COSMO-RS-trained fragment contribution model (R2 = 0.95; RSME = 0.35). A new empirical model was calibrated with the P* data for 35 congener groups measured in this study. Predicted log P* values correlate well with field-measured gas/particle partition coefficients and may therefore be used for estimating the environmental fate and pathways of a broad range of CPs in the environment. </p

Compositional Analysis of Commercial Oligomeric Organophosphorus Flame Retardants Used as Alternatives for PBDEs: Concentrations and Potential Environmental Emissions of Oligomers and Impurities

Four commercial oligomeric organophosphorus flame retardants (o-PFRs) were characterized using a refractive index detector and atmospheric pressure photoionization (APPI)-quadrupole time-of-flight mass spectrometry (QTOF-MS) compatible with gel permeation chromatography (GPC). Commercial o-PFRs consisted of approximately 90% or more oligomers and several impurities. Triphenyl phosphate (TPHP), tris­(dimethylphenyl) phosphate (TDMPP), tris­(2-chloroisopropyl) phosphate (TCIPP), and some new impurities were identified as byproducts of some manufacturing process of commercial o-PFRs for the first time. The concentrations of TPHP, TDMPP, and TCIPP were more than 1 weight %, whereas those of new impurities might be approximately 1 weight % by comparison among their abundances acquired through GPC-APPI-QTOF-MS analysis. Based on their vapor pressure and water solubility estimations, the potential environmental emissions of low molecular weight impurities were expected to be higher than those of oligomers. The presence and environmental emissions of low molecular weight impurities might be regarded as risk factors along with commercial o-PFRs

Short- and Medium-Chain Chlorinated Paraffins in Polyvinylchloride and Rubber Consumer Products and Toys Purchased on the Belgian Market

This study investigates the presence of Stockholm Convention listed short-chain chlorinated paraffins (SCCPs) and their replacement medium-chain chlorinated paraffins (MCCPs) counterparts in polyvinyl chloride and rubber consumer products and toys purchased on the Belgian market in 2019. SCCPs were detected in 27/28 samples at concentrations ranging from &lt;LOQ&ndash;130,000 &micro;g/g with a median level of 2.5 &micro;g/g, while MCCPs were detected in only five samples ranging &lt;LOQ&ndash;3500 &micro;g/g. Levels of SCCPs in all but one of the samples were below the European Union&rsquo;s guideline limit of 0.15%, by weight, and concentrations of both SCCPs and MCCPs in the majority of products suggested unintentional incorporation to the polymeric materials. The homologue distribution of SCCPs was generally dissimilar to known commercial formulations and appeared to be indicative of contamination during manufacture or via recycling of previously treated goods. MCCP patterns, conversely, were broadly representative of those reported for industrial mixtures and may have been inadvertently incorporated via the application of mixed carbon-chain length CP formulations or recycled goods. This research suggests that overall SCCP presence has decreased in goods on the European market compared with previous reports and that both SCCPs and MCCPs may still enter EU marketplaces from unintentional sources

Analysis of monomeric and oligomeric organophosphorus flame retardants in fish muscle tissues using liquid chromatography–electrospray ionization tandem mass spectrometry: Application to Nile tilapia (Oreochromis niloticus) from an e-waste processing area in northern Vietnam

Using electrospray ionization tandem mass spectrometry combined with liquid chromatography (LC), a novel analytical method was developed to quantify eight monomeric organophosphorus flame retardants (m-PFRs) and three oligomeric organophosphorus flame retardants (o-PFRs) in fish muscle samples. The optimization and validation experiments indicate that the developed method can determine accurately the concentrations of analytes in fish muscle samples. The recoveries of analytes in fish muscle samples were in the range of 74–105%. The coefficients of variation of the concentrations of analytes in fish muscle samples were 0.6–8.9%. The concentrations of analytes in procedural blanks were below the limit of quantification (LOQ) values. Furthermore, the developed method was applied to the analysis of m-PFRs and o-PFRs in the muscle samples of tilapias collected from an electronic waste (e-waste) processing area in northern Vietnam. The concentrations of m-PFRs such as tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP), and triphenyl phosphate (TPHP) were dominant among the investigated m-PFRs. The respective concentrations of TCEP, TCIPP, and TPHP were up to 160, 300, and 230 ng g−1 lipid weight, respectively, whereas those of o-PFRs were up to 10 ng g−1 lipid weight. The results of this study indicate lower accumulation potential of o-PFRs compared with m-PFRs for the first time