RESUMO
Seasonal and local characteristics of perfluorinated alkylated substances (PFASs) were examined using size-segregated particles including an ultrafine range. The examination included sampling and analysis of ambient particles collected at four sites located in different environments in three different countries, Japan (Kanazawa and Okinawa), Hong Kong and India. To minimize the evaporation artefacts derived from PFASs during the sampling, an air sampler that permitted particles smaller than 0.1 µm (PM0.1) to be separated at a moderate pressure drop (<5-15 kPa), was used for all of the air sampling procedures. In the case of Kanazawa, a local city in Japan, the concentration of PFASs was found to be dominated by carboxylates, especially PFOA, PFNA and PFDA regardless of the particle size and sampling period. Ultrafine particles were found to be the largest contributor to the mass fraction of PFCAs, while the maximum PFOS mass fractions were determined to be in the coarse-sized fractions. The seasonal difference in the total PFAS concentration can be largely attributed to precipitation. The results were basically similar for all sites that were examined. The type of land use may be a more influencing factor on the mass fraction of the PFASs than the country of origin. The dependency of PFAS mass fraction on the specific surface of the particle suggests that ultrafine PFAS particles are segregated, not only by gas deposition but could also be segregated by a mechanism involving compositional dependence or the primary source of the particles. Other possible sources of PFASs, other than from traffic are also possible.
Assuntos
Poluentes Atmosféricos/análise , Atmosfera/química , Hidrocarbonetos Fluorados/análise , Tamanho da Partícula , Material Particulado/análise , Cidades , Monitoramento Ambiental , Hong Kong , Índia , JapãoRESUMO
The concentrations of 10 PFCs (perfluorinated compounds: PFOS, PFHxS, PFOSA, N-EtFOSA, PFDoDA, PFUnDA, PFDA, PFNA, PFOA, and PFHpA) were measured in liver samples of Indo-Pacific humpback dolphins (Sousa chinensis) (n=10) and finless porpoises (Neophocaena phocaenoides) (n=10) stranded in Hong Kong between 2003 and 2007. PFOS was the dominant PFC in the tissues at concentrations ranging at 26-693 ng/g ww in dolphins and 51.3-262 ng/g ww in porpoises. A newly developed combustion ion chromatography for fluorine was applied to measure total fluorine (TF) and extractable organic fluorine (EOF) in these liver samples to understand PFC contamination using the concept of mass balance analysis. Comparisons between the amounts of known PFCs and EOF in the livers showed that a large proportion (approximately 70%) of the organic fluorine in both species is of unknown origin. These investigations are critical for a comprehensive assessment of the risks of these compounds to humans and other receptors.
Assuntos
Ácidos Alcanossulfônicos/análise , Golfinhos/metabolismo , Flúor/análise , Fluorocarbonos/análise , Fígado/química , Toninhas/metabolismo , Poluentes Químicos da Água/análise , Animais , China , Cromatografia por Troca Iônica/métodos , Monitoramento Ambiental/métodos , Compostos Orgânicos/análiseRESUMO
Perfluorochemicals (PFCs) are wide-spread contaminants on a global scale. There is an increasingly growing number of data on environmental occurrence, sources and risk of PFCs to humans and aquatic biota in highly industrialised countries but inadequate information exists for less industrialised regions. In the present study, concentrations and profiles of PFCs were examined in surface waters (rivers, lakes, streams, coastal region of the Baltic Sea) of Poland. PFOS was the dominant compound found in water at most of the sites surveyed and its concentration varied between < 0.5 and 150 ng/L and next was PFHxS with < 0.25 to 110 ng/L, while at much smaller concentration of < 0.5 to 18 ng/L occurred PFOA. The long-chain carboxylates (C11-C16) could be found only in water of a drainage ditch near to the Sarzyna site, i.e., PFUnDA occurred at 0.17 ng/L, PFTeDA of 0.06 ng/L, PFDoDA at 0.1 ng/L and PFHxDA at 0.12 ng/L. PFDA was found at several locations in the Gulf of Gdansk and its concentration varied between < 0.01 and 0.07 ng/L. The profile of PFCs in surface water at several sites of Poland with PFOS as a major compound, followed by PFOA is similar to that reported for other countries in Europe as well as for India, while this is different from that of Korea, Japan and the USA, where PFOA was the predominant contaminant.
Assuntos
Monitoramento Ambiental/estatística & dados numéricos , Fluorocarbonos/análise , Água Doce/química , Poluentes Químicos da Água/análise , Cromatografia Líquida de Alta Pressão , Polônia , Espectrometria de Massas em TandemRESUMO
Concentrations of nine antibiotics [erythromycin-H(2)O (ERY-H(2)O); trimethoprim (TMP); tetracycline (TET); norfloxacin (NOR); penicillin G (PEN G); penicillin V (PEN V); cefalexin (CLX); cefotaxim (CTX); and cefazolin (CFZ)] were measured in influent and effluent samples from four sewage treatment plants (STPs) in Hong Kong as well as in influent samples from one STP in Shenzhen. Levels of PEN V and CFZ were below method detection limits in all of the samples analyzed. CLX concentrations were the highest in most of the Hong Kong samples, ranging from 670 to 2900 ng/L and 240 to 1800 ng/L in influent and effluent samples, respectively, but CLX was not detected in the samples from Shenzhen. Comparatively lower concentrations were observed for ERY-H(2)O (470-810 ng/L) and TET (96-1300 ng/L) in the influent samples from all STPs in Hong Kong. CTX was found to be the dominant antibiotic in the Shenzhen STP influents with a mean concentration of 1100 ng/L, but occurred at lower concentrations in Hong Kong sewage. These results likely reflect regional variations in the prescription and use patterns of antibiotics between Hong Kong and Shenzhen. Antibiotic removal efficiencies depended on their chemical properties and the wastewater treatment processes used. In general, relatively higher removal efficiencies were observed for NOR (5-78%) and TET (7-73%), which are readily adsorbed to particulate matter, while lower removal efficiencies were observed for ERY-H(2)O (9-19%), which is relatively persistent in the environment. Antibiotics were removed more efficiently at Hong Kong STPs employing secondary treatment processes compared with those using primary treatment only. Concentrations of NOR measured in effluents from STPs in Hong Kong were lower than the predicted no-effect concentration of 8000 ng/L determined in a previous study. Therefore, concentrations of antibiotics measured in this preliminary study would be unlikely to cause adverse effects on microorganisms used in wastewater treatment processes at the sampled STPs.
Assuntos
Antibacterianos/análise , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/análise , China , Monitoramento AmbientalRESUMO
Perfluorooctanesulfonate (PFOS) at 1.6-39 ng/g ww and 4.8-200 pg/mL, respectively, perfluorooctanoate (PFOA) at 0.06-0.28 ng/g ww and<0.05-1.8 pg/mL, and perfluorodecanoate (PFDA) at 0.13-0.57 ng/g ww and 0.05-1.8 pg/mL, were detected in all specimens of European Beaver's (Castor fiber) liver as well as in whole blood of Cod (Gadus morhua), Velvet Scoter (Melanitta fusca), Eider Duck (Sommateria mollisima), Long-tailed Duck (Clangula hyemalis), Razorbill (Alca torda), Red-throated Diver (Gavia stellata) sampled in Poland. At smaller concentrations and at less frequency was perfluorononanoate (PFNA) at 0.05-1.4 ng/g ww and<0.2-2 pg/mL, perfluorohexanoate (PFHxA) at 0.03-0.23 ng/g ww and<0.05-0.69 pg/mL, while perfluorohexanesulfonate (PFHxS) at 0.05-4.3 pg/mL and perfluorooctanesulfonamidoacetate (PFOSA) at 0.1-13 pg/mL were also found in Cod as well as in molluscivorous diving-ducks and fish-eating birds but not in Beaver, while perfluoroheptanoate (PFHpA) at<0.05-0.74 pg/mL was found only in Cod.
Assuntos
Ácidos Alcanossulfônicos/sangue , Animais Selvagens , Caprilatos/sangue , Poluentes Ambientais/sangue , Fluorocarbonos/sangue , Animais , Polônia , Especificidade da EspécieRESUMO
A total of 14 perfluorinated compounds (PFCs) were quantified in river water samples collected from tributaries of the Pearl River (Guangzhou Province, south China) and the Yangtze River (central China). Among the PFCs analyzed, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were the two compounds with the highest concentrations. PFOS concentrations ranged from 0.90 to 99 ng/l and <0.01-14 ng/l in samples from the Pearl River and Yangtze River, respectively; whereas those for PFOA ranged from 0.85 to 13 ng/l and 2.0-260 ng/l. Lower concentrations were measured for perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctanesulfoamide (PFOSA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorononaoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA). Concentrations of several perfluorocarboxylic acids, including perfluorododecanoic acid (PFDoDA), perfluorotetradecanoic acid (PFTeDA), perfluorohexadecanoic acid (PFHxDA) and perfluorooctadecanoic acid (PFOcDA) were lower than the limits of quantification in all the samples analyzed. The highest concentrations of most PFCs were observed in water samples from the Yangtze River near Shanghai, the major industrial and financial centre in China. In addition, sampling locations in the lower reaches of the Yangtze River with a reduced flow rate might serve as a final sink for contaminants from the upstream river runoffs. Generally, PFOS was the dominant PFC found in samples from the Pearl River, while PFOA was the predominant PFC in water from the Yangtze River. Specifically, a considerable amount of PFBS (22.9-26.1% of total PFC analyzed) was measured in water collected near Nanjing, which indicates the presence of potential sources of PFBS in this part of China. Completely different PFC composition profiles were observed for samples from the Pearl River and the Yangtze River. This indicates the presence of dissimilar sources in these two regions.
Assuntos
Fluorocarbonos/química , Rios/química , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Poluição Química da ÁguaRESUMO
Perfluorooctanesulfonylfluoride (POSF)-based compounds have been manufactured and used in a variety of industrial applications. These compounds degrade to perfluorooctanesulfonate (PFOS) which is regarded as a persistent end-stage metabolite and is found to accumulate in tissues of humans and wildlife. PFOS, perfluorohexanesulfonate (PFHxS), perfluorooctanoate (PFOA), and perfluorooctanesulfonamide (PFOSA) have been found in human sera from the United States. In this study, concentrations of PFHxS, perfluorobutanesulfonate (PFBS), PFOS, perfluorohexanoic acid (PFHxA), PFOA, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), and PFOSA were measured in 85 samples of whole human blood collected from nine cities (eight provinces) in China, including Shenyang (Liaoning), Beijing (Hebei), Zhengzhou (Henan), Jintan (Jiangsu), Wuhan (Hubei), Zhoushan (Zhejiang), Guiyang (Guizhou), Xiamen (Fujian), and Fuzhou (Fujian). Among the 10 perfluorinated compounds (PFCs) measured, PFOS was the predominant compound. The mean concentration of PFOS was greatest in samples collected from Shenyang (79.2 ng/mL) and least in samples from Jintan (3.72 ng/mL). PFHxS was the next most abundant perfluorochemical in the samples. No age-related differences in the concentrations of PFOA, PFOS, PFOSA, and PFHxS were observed. Gender-related differences were found,with males higher for PFOS and PFHxS, and females higher in PFUnDA. Concentrations of PFHxS were positively correlated with those of PFOS, while concentrations of PFNA, PFDA, and PFUnDA were positively correlated with those of PFOA. There were differences in the concentration profiles (percentage composition) of various PFCs in the samples among the nine cities.
Assuntos
Ácidos Alcanossulfônicos/sangue , Poluentes Ambientais/sangue , Fluorocarbonos/sangue , Adolescente , Adulto , Idoso , Criança , China , Feminino , Humanos , Indústrias , Masculino , Manufaturas , Pessoa de Meia-Idade , População UrbanaRESUMO
Perfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS), have been identified in the coastal waters of China and Japan. An alkaline digestion method, coupled with solid-phase extraction (SPE), and high-performance liquid chromatography interfaced with high-resolution electrospray tandem mass spectrometry was developed to determine PFCs in mussel and oyster samples from coastal waters of South China and Japan. These techniques produced adequate recoveries and reporting limits with small quantities of PFCs. Concentrations of individual PFCs in mussels and oysters from South China and Japan ranged from 113.6 to 586.0 pg/g, wet weight (ww) for PFOS, 63.1 to 511.6 pg/g, ww for perfluorohexane sulfonate, 9.3 to 30.1 pg/g, ww for perfluorobutane sulfonate and 37.8 to 2957.0 pg/g, ww for perfluorooctane sulfonamide. The quantification of perfluorinated carboxylates was compromised by interferences from carboxylates in the procedural blanks. Perfluoroundecanoate and perfluorononanoate had relatively great blank interferences, which resulted in relatively poor limits of quantification for these compounds. Some PFCs were only identified in a limited number of samples: perfluorododecanoate in samples from Tokyo Bay, Japan (195.9 pg/g, ww); and perfluorodecanoate in Fuzhou, China (131.7 pg/g, ww) and Tokyo Bay (118.6 pg/g, ww). The greatest concentrations of perfluorooctanoate, perfluoroheptanoate, and perfluorohexanoate were observed in samples from Tokyo Bay and Bei Hai, South China.
Assuntos
Crassostrea/química , Monitoramento Ambiental/métodos , Fluorocarbonos/análise , Perna (Organismo)/química , Poluentes Químicos da Água/análise , Animais , China , Hidróxidos/química , Japão , Lipídeos/química , Metanol/química , Nylons/química , Compostos de Potássio/química , Proteínas/químicaRESUMO
Chlorobiphenyl (CB) and by-side chlorodibenzofuran (CDF), chlorodibenzo-p-dioxin (CDD), and chloronaphthalene (CN) homologue group and congener composition, and concentrations have been examined in technical CBs mixture Clophen A60. 101 peaks representing 116 CB congeners were quantified in Clophen A60, and most contributing were CBs nos. 138, 153,134/144/149, and 180 with 15.4, 12.3,8.2, and 6.5%, respectively. Di-, tri-, tetra-, penta-, hexa-, hepta-, and octa-CBs constituted, respectively, 0.03, 0.03, 0.32, 9.9, 52.7, and 4.9% of chlorobiphenyls content of the Clophen A60, while mono-, nona-, and decaCB were not quantified. Tetra- to octaCDDs were absent in Clophen A60 at concentration above the method limit of quantification of <0.01 microg/g, while the total CDFs and CNs were found at 12 and 42 microg/g, respectively. Tetra-, penta-, hexa-, and hepta-CDF with 27, 46, 19, and 7% contribution, respectively, dominated in homologue group profile of CDFs, while octa-CDF was absent in Clophen A60. In compositional profile of CDF congeners the most abundant were 1,2,4,7,8-PeCDF, 2,3,4,7,8-PeCDF, and 1,2,3,4,7,8-HxCDF and each had >5% contribution. Amongst the CN homologue groups the profile in descending order followed by hepta-, hexa-, octa-, and penta-CNs with 56, 26, 16, and 2%, respectively. In compositional profile of CNs the most abundant were the congeners such as 1,2,3,4,5,6,7-HpCN (no. 73), 1,2,3,4,6,7-/1,2,3,5,6,7-HxCN (nos. 66/67), and 1,2,3,4,5,6,7,8-OcCN (no. 75) with 55, 21, and 16%, respectively. In terms of dioxin-like toxicity of Clophen A60 the contribution from planar non-ortho and mono-ortho CBs, CDFs, and CNs was 5280, 594.5, and 33.1 ng TCDD TEQ/g, respectively, and the total TEQ of planar analogues was 5908 ng/g.
Assuntos
Benzofuranos/análise , Dioxinas/análise , Hidrocarbonetos Clorados/análise , Naftalenos/análise , Bifenilos Policlorados/análise , Bifenilos Policlorados/química , Cromatografia Líquida de Alta Pressão , Dibenzofuranos Policlorados , Cromatografia Gasosa-Espectrometria de Massas , Dibenzodioxinas Policloradas/análise , Dibenzodioxinas Policloradas/toxicidadeRESUMO
Non- and mono-ortho CBs as well as also highly toxic by-side impurities such as chlorodibenzofurans, chlorodibenzo-p-dioxins, and chloronaphthalenes after a subsequent 2D-HPLC and HRGC-HRMS separation, detection, and identification were quantified in technical chlorobiphenyl Chlorofen formulation. Chlorofen is highly chlorinated CB mixture and its compositional profile of mono-ortho CBs is occupied by 2,3,3',4,4',5'-HxCB (no. 157) with 96.6% and followed by 2,3,3',4,4',5-HxCB (no. 156) with 3.3% and 2,3',4,4',5,5'-HxCB (no. 167) with <0.1%, while nos. 105, 114, 118, 123, and 189 remained undetected (<10 microg/g). Amongst non-ortho CBs only a trace of 3,3',4,4'-TeCB (no. 77) was found at 15 microg/g, while CBs nos. 81, 126, and 169 were absent. TCDD TEQ for mono- and non-ortho CBs in Chlorofen was 2320 and 1.5 ng/g, respectively, while for CDFs and CNs were 45 and 731 ng/g, respectively, and for both types of contaminants most contributing were OcCDF and OcCN. No tetra- to OcCDD was found in Chlorofen.
Assuntos
Poluentes Ambientais/análise , Bifenilos Policlorados/análise , Dibenzodioxinas Policloradas/análogos & derivados , Dibenzodioxinas Policloradas/análise , Poluentes do Solo/análise , Indústria Química , Cromatografia Líquida de Alta Pressão , Monitoramento Ambiental , Cromatografia Gasosa-Espectrometria de Massas , Substâncias Perigosas , Polônia , Bifenilos Policlorados/química , Dibenzodioxinas Policloradas/químicaRESUMO
Perfluorinated compounds (PFCs), such as perfluorooctanesulfonate (PFOS) and related compounds, have recently been identified in the environment. PFOS, the terminal degradation product of many of the PFCs, has been found globally in many wildlife species, as well as open ocean waters, even in remote regions far from sources. In this study, a solid-phase extraction procedure coupled with high-performance liquid chromatography interfaced to high-resolution mass spectrometry was used to isolate, identify, and quantify small concentrations of PFCs in seawater. These techniques were applied to investigate the local sources of PFCs in several industrialized areas of Asia and provide information on how the PFCs are circulated by coastal currents. Ranges of concentrations of PFOS in coastal seawaters of Hong Kong, the Pearl River Delta, including the South China Sea, and Korea were 0.09-3.1, 0.02-12, and 0.04-730 pg/mL, respectively, while those of perfluorooctanoic acid (PFOA) were 0.73-5.5, 0.24-16, and 0.24-320 pg/mL, respectively. Potential sources of PFCs include major industrialized areas along the Pearl River Delta of southern China and major cities of Korea, which are several of the fastest growing industrial and economic regions in the world. Detectable concentrations of PFOS and PFOA in waters of southern China were similar to those in the coastal marine environment of Japan and certain regions in Korea. Concentrations of PFCs in several locations in Korean waters were 10-100-fold greater than those in the other locations on which we report here. The spatial and seasonal variations in PFC concentrations in surface seawaters in the Pearl River Delta and South China Sea indicate the strong influence of the Pearl River discharge on the magnitude and extent of PFC contamination in southern China. All of the concentrations of PFOS were less than those that would be expected to cause adverse effects to aquatic organisms or their predators except for one location in Korea adjacent to an industrialized area. Hazard quotients were from <0.001 to 0.002 for aquatic animals and ranged from <0.001 to 17 for predatory birds.
Assuntos
Ácidos Alcanossulfônicos/análise , Fluorocarbonos/análise , Água do Mar/análise , Poluentes Químicos da Água/análise , Ácidos Alcanossulfônicos/normas , Caprilatos/análise , Caprilatos/normas , China , Ecologia/normas , Monitoramento Ambiental , Fluorocarbonos/normas , Hong Kong , Coreia (Geográfico) , Biologia Marinha/normas , Padrões de Referência , Medição de Risco , Estações do Ano , Poluentes Químicos da Água/normasRESUMO
Invasion of zebra mussels, Dreissena polymorpha, and round gobies, Neogobius melanostomus, into the Great Lakes has altered the food web structure and thereby the pathways of toxic contaminants such as polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs). In this study, concentrations of PCNs and PCBs were measured in organisms of a Great Lakes benthic food chain encompassing zebra mussels. PCNs were found in all of the benthic organisms, including phytoplankton, algae, amphipods, zebra mussels, round goby, and smallmouth bass, Micropterus dolomieui. Concentrations of PCNs were greater in samples collected from the Raisin River than in samples from the St. Clair River. Biomagnification factors (BMF) for tetra- through octa-CN congeners in going from algae to zebra mussels from the St. Clair River ranged from 3 to 10. No major biomagnification of PCNs was found in round gobies, when concentrations were related to those in their prey species, zebra mussels. The biomagnification potential of PCNs appears to be similar to that of PCBs in the benthic food chain investigated in this study, despite the fact that PCNs may be metabolized by organisms higher in the food chain. Among several congeners, the BMFs of PCN congeners 35, 42, 43/45, 52/60, 58, and 66/67 were highest in round gobies. PCNs accounted for 1-22% of the total TEQs (toxic equivalents) of PCBs and PCNs in benthic organisms analyzed in this study. PCB congener 126 was the major contributor to TEQs, accounting for 72-99% of the PCB-TEQs in the food chain organisms analyzed.
Assuntos
Cadeia Alimentar , Naftalenos/análise , Naftalenos/farmacocinética , Bifenilos Policlorados/análise , Bifenilos Policlorados/farmacocinética , Poluentes Químicos da Água/farmacocinética , Anfípodes , Animais , Bivalves , Monitoramento Ambiental , Eucariotos , Peixes , Great Lakes Region , Fitoplâncton , Distribuição Tecidual , Poluentes Químicos da Água/análiseRESUMO
The concentrations of 63 congeners of chloronaphthalene (CN; polychlorinated naphthalenes, PCNs) in dated on approximately 500 B.C. to 2000 sediment core from the Lake Kitaura in Japan have been quantified by HRGC/HRMS after double column HPLC fractionation. Sediment from the Lake Kitaura showed a time-dependent pattern in distribution of CNs since the approximately 500 B.C. Starting from the 1910s the total CNs content increased accelerating from the 1960s, and, in parallel, the pattern of CN congeners has changed with a substantial increase in contribution from the penta, hexa, hepta, and octaCN. The total CNs content normalized to dry weight of sediment peaked out in the layer dated on 1984-1985, and next nearly two-fold decreased with further gradually decreasing concentration in 1987-2000. An occurrence of tri and tetraCNs in deep sediment layers corresponded to preindustrial synthesis and use of CNs seems to be connected to relatively greater water solubility and mobility in the pore water of those CN homologue groups. Based on CN congener pattern and results of multivariate analysis three main layers were separated in the sediment core. Starting from 1981 the emission sources related to combustion marker congeners become substantial contributors to flux of annually deposited CNs, while relative significance of the evaporative source marker congeners decreased after 1985. The annual flux of CNs into sediments of the Lake Kitaura was 0.073-0.31 pg/cm2 before 1926, increased to 5.5-14 pg/cm2 in 1963-1970 and next sharply increased to 50-107 pg/ cm2 in 1971-1985, and after that decreased to 17 pg/cm2 in 1997-2000.
Assuntos
Compostos Clorados/química , Sedimentos Geológicos/química , Resíduos Industriais/análise , Naftalenos/química , Água Doce , Humanos , JapãoRESUMO
A follow-up case study was performed after two incidents of recent illegal import and use in Japan both of technical PCNs mixture and contaminated with those compounds an industrial raw material. In case 1, above 18 tons of PCNs mixture, resembling Halowax 1001, which is a technical PCNs formulation, were imported from the United Kingdom. An illegally imported PCNs mixture was used for manufacture of a wide spectrum of industrial materials and commercial goods including sealants, putty, shock absorbing materials, adhesive materials, insulating materials and rubber belts. About 1.3 tons of PCNs contained in the Neoprene FB manufactured reached domestic market and 9.3 tons could reach other markets. In case 2, which became known in 2001, the Japanese company imported from Canada 54 tons of PCNs contaminated raw rubber material for industrial use. In weathering test (40 degrees C for up to 168 h) of the feral rubber coated sheets for rubber bands 98% of di- and 66% of tri-CNs vaporized. A loss rate of tetra-, penta-, and hexa-CN during initial 12 h of the weathering test ranged from approximately 10 to approximately 20%, while from 12 to 168 h remained negligible.