This study examines characteristics of atmospheric methylsiloxane pollution in indoor settings where interior renovation/redecoration is being undertaken, in addition to ordinary family homes and inside family cars. Concentrations of atmospheric methylsiloxane in these locations were approximately one order of magnitude higher than that in outdoor areas. The average indoor concentration of methylsiloxane where renovation was being undertaken was 9.4 μg/m3, which is slightly higher than that in an ordinary family home (7.88 μg/m3), while samples from family cars showed lower concentration (3.10 μg/m3). The indoor atmospheric concentration during renovation/redecoration work was significantly positively correlated with the duration of the work. The structure of atmospheric methylsiloxane pollution is basically the same in these three venues. The concentration of annulus siloxane was much higher than that of linear compounds (85% of the total methylsiloxane concentrations). Household dust in average family homes showed total methylsiloxane concentration of 9.5 μg/m3 (average); the structure mainly consisted of linear siloxane (approximately 98% of total concentration), thereby differing from that of atmospheric methylsiloxane pollution. The comparatively high concentration of methylsiloxane in these three venues indicates that interior renovation and decoration work, and even travelling in cars, can involve exposure to more serious siloxane contamination during everyday activities.
Adsorption is one of the main mechanisms of soil contamination by volatile chlorinated hydrocarbons (VCHs). Static equilibrium adsorption experiments were carried out in the study to investigate the adsorption equilibriums of six VCHs to three typical dry paddy soils in Yangtze Delta Region of China . The adsorption equilibriums of the dry soils were fitted well with the Dubinin-Astakhov equation. The equation's parameters were analyzed with the characteristic values of both the soils and VCHs. No apparent correlation was observed between the affinity coefficient (β) and the molecular volume of VCHs, but β tended to increase with the increase in the molecular polarizabilities of VCHs. A positive linear correlation was derived between the adsorption energy value (E 0 ) of the reference compound (tetrachloroethylene) and the pore volume of radius less than average pore radius (V
<p>Studies on particulate inorganic carbon (PIC) in inland waters are relatively scarce due to the low concentration of PIC which makes it difficult to be measured accurately. In other studies, a characteristic ratio of PIC in total suspended solids in the water column has been proposed to estimate the river PIC flux to the sea, and a titration method to measure the PIC fluxes in karst rivers has been reported. Therefore, we used the Gas Bench &#8545;-IRMS coupled technique method to analyze the &#948;<sup>13</sup>C<sub>PIC</sub> and PIC concentration in inland waters. The method has the advantage of being suitable for the accurate determination of the isotopic composition of trace PIC samples.</p><p>The purging time and carbon content of samples are the important factors affecting experimental accuracy. This study proposed the optimal purge time and the lowest carbon content of the inland water sample. The samples in the experiment included laboratory calcium carbonate standard (99.95 % purity) and PIC samples from the Wujiang River. The PIC samples from Wujiang River were collected on glass fiber filters. Datasets from the experiment demonstrated that the ideal purge time is 500-700 s, and at least 25 &#956;g C should be included in the sample. The instrument signal value is low and the isotopic value fluctuates widely when the purge time is less than 500 s. The phosphoric acid cannot be injected into the sample bottle due to the high pressure in it when the purge time is more than 700 s. Therefore, a purging time of 600 s was used for the field sample analyses. The peak area displayed by the device is correlated with the carbon content in the sample, and the datasets show a good linear relationship between the peak area and carbon content in the sample when the sample be analyzed contained more than 25 &#956;g of inorganic carbon. The carbon content of the sample can be calculated from the peak area of the same batch of calcium carbonate standard. While the peak signal is too low to detect the sample accurately when the C content is less than 25 &#956;g. Therefore, the sample should contain more than 25 &#956;g for the field sample analyses. This study will help to provide a reference for the method of determining the PIC content and isotopic composition in inland water.</p>
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