Global Distribution of Linear and Cyclic Volatile Methyl Siloxanes in Air

Abstract

The global distribution of linear and cyclic volatile methyl silxoanes (VMS) was investigated at 20 sites worldwide, including 5 locations in the Arctic, using sorbent-impregnated polyurethane foam (SIP) disk passive air samplers. Cyclic VMS are currently being considered for regulation because they are high production volume chemicals that are potentially persistent, bioaccumulative, and toxic. Linear and cyclic VMS (including L3, L4, L5, D3, D4, D5, and D6) were analyzed for in air at all urban, background, and Arctic sites. Concentrations of D3 and D4 are significantly correlated, as are D5 and D6, which suggests different sources for these two pairs of compounds. Elevated concentrations of D3 and D4 on the West coast of North America and at high elevation sites suggest these sites are influenced by trans-Pacific transport, while D5 and D6 have elevated concentrations in urban areas, which is most likely due to personal care product use. Measured concentrations of D5 were compared to modeled concentrations generated using both the Danish Eulerian Hemispheric Model (DEHM) and the Berkeley-Trent Global Contaminant Fate Model (BETR Global). The correlation coefficients (r) between the measured and modeled results were 0.73 and 0.58 for the DEHM and BETR models, respectively. Agreement between measurements and models indicate that the sources, transport pathways, and sinks of D5 in the global atmosphere are fairly well understood.

Using air, soil and vegetation to assess the environmental behaviour of siloxanes

“…S1 (Supplementary Material). This is in line with their reported presence in the atmosphere (Genualdi et al 2011). In fact, most linear siloxanes are not detected, and the highest incidence is of only 6 % of the total siloxanes for L3 in the winter sample from Outeiro (Fig.…”

“…The disks will be protected by the common "flying saucer" stainless steel chamber, formed by two domes with external diameters of 30 and 20 cm, which protects the sampler from precipitation, UV sunlight and most particle depositions. Based on the work team's expertise and in related literature (Genualdi et al 2011;Krogseth et al 2013b), a deployment time of 3 months was chosen. Therefore, in order to evaluate seasonal extremes, SIPs were set-up at the beginning and collected at the end of summer and winter of 2014, completing two sampling campaigns.…”

“…D4 is classified by the European Union (EU) as an endocrine disruptor. Their presence was proven in different environmental media such as biota (Warner et al 2010;Hong et al 2014;Sanchís et al 2015), wastewater, surface water and seawater (Sparham et al 2008;Bletsou et al 2013;Hong et al 2014), air (Genualdi et al 2011;Krogseth et al 2013b), sediments (Warner et al 2010;Hong et al 2014), sludge (Bletsou et al 2013) and soil (Sánchez-Brunete et al 2010;Sanchís et al 2015). However, there is a general lack of information about siloxanes from the production to the levels in the environment and monitoring studies are scarce.…”

“…The extraction of siloxanes from this kind of matrices usually relies in techniques such as Soxhlet or sonication followed in some cases by further clean-up steps (Sánchez-Brunete et al 2010;Genualdi et al 2011). In this study, it was decided to use a more environment-friendly approach employing the quick, easy, cheap, effective, rugged and safe (QuEChERS) method for the soils and pine needles, following previous work done in our group to extract musks from personal care products (Homem et al 2013).…”

Problemas en el análisis de metilsiloxanos volátiles (VMS): origen y soluciones

“…Dentro de esta familia de compuestos los metilsiloxanos de cadena corta conocidos como metilsiloxanos volátiles (VMS), han recibido una especial atención en los últimos años debido a su elevada capacidad de bioacumulación, [1][2][3][4][5][6][7] potencial cancerogenicidad [8][9][10] y amplia distribución ambiental. [11][12][13][14][15][16][17][18][19][20][21] Estos compuestos se presentan en conformaciones lineales o cíclicas tal y como se ilustra en la Figura 1, y se caracterizan principalmente por presentar una elevada presión de vapor (2.3 -5620 Pa a 25 o C) y baja solubilidad en agua (0.07 -1560 µg L -1 a 25 o C). [22][23][24] Entre sus principales aplicaciones se encuentra su uso como constituyentes básicos en cosméticos y productos de higiene personal, como materiales de partida para la síntesis de polisiloxanos de elevado peso molecular, y su empleo como aditivos en productos de limpieza, desengrasantes, lubricantes, disolventes, pinturas, lacas y barnices.…”