Methyl Siloxanes in Environmental Matrices around a Siloxane Production Facility, and Their Distribution and Elimination in Plasma of Exposed Population

Abstract

In this study, we systematically investigated methyl siloxanes (D4−D6, L3−L16) exposure to workers from and residents living near a siloxanes manufacturing facility by measuring their concentrations in both environmental matrices (air, dust/soil, n = 62) and human plasma samples (n = 201). For the seventeen target compounds, the average concentrations in indoor matrixes from six workshops of the facility ranged from 0.6 μg/m 3 to 2.7 mg/m 3 in air samples and from 0.36 μg/g to 1.16 mg/g in dust samples, which were 3−5 orders of magnitudes higher than those levels at the reference zone. In plasma samples from the current workers in six workshops and residents living near the facility, the average concentrations of methyl siloxanes were 5.61−451 and 4.56− 13.5 ng/g, respectively, which were 1−2 magnitudes higher than those in the reference group. Plasma methyl siloxanes concentrations of people from different workshops were positively correlated with their exposure levels, indicating that high occupational exposure in siloxane production process elevated human plasma concentrations. However, there was no significant correlation between human plasma concentrations with their duration of occupation. These methyl siloxanes were eliminated from human plasma with half-lives ranging from 2.34 to 9.64 days, which increased with the increasing number of Si−O bonds for most analogues.

Methyl siloxanes in environmental matrices and human plasma/fat from both general industries and residential areas in China

“…General population In 519 plasma samples from general population, no linear siloxane was detected, while three cyclic siloxanes (D4-D6) were detected, with concentrations ranging from 1.10-5.95 ng/mL (df = 3.7%), 1.98-6.22 ng/mL (df = 3.7%), and 1.85-7.50 ng/mL (df = 1.7%) for D4, D5, and D6, respectively (Table 1). This result was consistent with previous studies from China and Germany (Xu et al, 2012;Flassbeck et al, 2001), which reported that methyl siloxanes were hardly found in plasma of general population. Although Hanssen et al (2013) reported higher detection frequencies of cyclic siloxanes -85%, 18%, and 5% for D4, D5, and D6, respectively -in plasma of general population (postmenopausal women) from Norway, their concentrations were also at low levels -2.93-12.7 ng/mL, 1.44-3.94 ng/mL, and 2.67-3.17 ng/mL for D4, D5, and D6, respectively.…”

“…Meanwhile, 519 participants from seven cities in northern China, without industrial work experiences, served as the control group. It should be noted that although some control participants in the present study were from the same city with the participants in our previous study (Xu et al, 2012), the participants had no overlap between these two studies. During January to March 2012, each of 487 occupational participants and 270 control participants provided one plasma sample (5 mL) voluntarily.…”

“…One previous study demonstrated that plasma concentrations of methyl siloxanes in workers from one siloxane production facility in China were much higher than those in general population (Xu et al, 2012). However, besides the workers involved in siloxane production, people in some general industries, such as building, textile, and automobile industries, also have potential exposure to methyl siloxanes due to the large usage of siloxane products (Kaj et al, 2005;Lassen et al, 2005;SEHSC, 2011), which should attract our attention because these three industries have a large amount of employed population -approximately 100 million in China (Zhang, 2002).…”

“…However, despite the wide use in general public, methyl siloxanes were scarcely detected in plasma of general population (Flassbeck et al, 2001;Xu et al, 2012). It was difficult to efficiently evaluate non-occupational exposure to siloxanes basing on plasma samples.…”

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.…”