Development and validation of a thermally regulated atmospheric simulation chamber (THALAMOS): A versatile tool to simulate atmospheric processes

Atmospheric simulation chambers,are unique tools for investigating atmospheric processes in the gas and heterogeneous phases.They can provide a controlled yet realistic environment that simulates atmospheric conditions.In the current study,a Teflon atmospheric simulation chamber of 600 L,named THALAMOS(thermally regulated atmospheric simulation chamber) has been developed and cross-validated.THALAMOS can be operated over the temperature range 233 to 373 K under both static and flow conditions.It...     

Airborne PBDEs in specialized occupational settings, houses and outdoor urban areas in Greece

Airborne polybrominated diphenyl ethers (PBDEs) were measured in workplaces, homes and urban outdoor air in Greece. The geometric mean concentrations of total PBDEs (sum of 19 congeners) in offices (205pgm(-3)), internet cafes/computer rooms (127pgm(-3)) and computers/electronics shops (85pgm(-3)) were significantly higher than those in furniture stores (12pgm(-3)), homes (8pgm(-3)) and outdoor air (18pgm(-3)). The daily inhalation intake of PBDEs estimated for the employees of the four occupational settings ranged from 0.2 to 1.4ngday(-1) and it was significantly lower than the expected dietary intake ( approximately 77ngday(-1)). Although inhalation generally represented a small fraction of the overall daily exposure to PBDEs ( approximately 1%), the results from a heavily contaminated office (10 848pgm(-3) of total PBDEs) indicated that the intake from this route (65ngday(-1)) may, in some extreme cases, be as important as diet.     

Gene expression changes in blood RNA after swimming in a chlorinated pool

Exposure to disinfection by-products(DBP) such as trihalomethanes(THM) in swimming pools has been linked to adverse health effects in humans, but their biological mechanisms are unclear. We evaluated short-term changes in blood gene expression of adult recreational swimmers after swimming in a chlorinated pool. Volunteers swam 40 min in an indoor chlorinated pool. Blood samples were drawn and four THM(chloroform,bromodichloromethane, dibromochloromethane and bromoform) were measured in exhaled breath before and after swimming. Intensity of physical activity was measured as metabolic equivalents(METs). Gene expression in whole blood m RNA was evaluated using Illumina Human HT-12v3 Expression-Bead Chip. Linear mixed models were used to evaluate the relationship between gene expression changes and THM exposure. Thirty-seven before-after pairs were analyzed. The median increase from baseline to after swimming were: 0.7 to 2.3 for MET, and 1.4 to 7.1 μg/m~3 for exhaled total THM(sum of the four THM).Exhaled THM increased on average 0.94 μg/m~3 per 1 MET. While 1643 probes were differentially expressed post-exposure. Of them, 189 were also associated with exhaled levels of individual/total THM or MET after False Discovery Rate. The observed associations with the exhaled THM were low to moderate(Log-fold change range:-0.17 to 0.15). In conclusion, we identified short-term gene expression changes associated with swimming in a pool that were minor in magnitude and their biological meaning was unspecific. The high collinearity between exhaled THM levels and intensity of physical activity precluded mutually adjusted models with both covariates. These exploratory results should be validated in future studies.     

First compound-specific chlorine-isotope analysis of environmentally-bioaccumulated organochlorines indicates a degradation-relatable kinetic isotope effect for DDT

Compound-specific chlorine-isotope analysis (CSIA-Cl) of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethene (p,p'-DDE) in blubber from Baltic Grey seal (Halichoerus grypus) was performed in order to investigate if a kinetic isotope effect (KIE) could be observed concomitant to environmental degradation of DDT. The delta(37)Cl of p,p'-DDT and p,p'-DDE were -0.69 +/- 0.21 per thousand and -2.98 +/- 0.57 per thousand (1s igma, n = 3), respectively. Both samples were enriched relative to the hypothesized initial isotope composition (-4.34 per thousand), thus indicating a composite KIE associated with the degradation mechanisms pertaining to DDT. An isotope fractionation factor for degradation of dichloromethane, from the literature, was adapted and modified for use in the calculation of DDT degradation. A subsequent simplified Rayleigh distillation model of the DDT chlorine-isotope composition yielded an estimated fraction (f) of 7 +/- 2% of released DDT presently remaining as undegraded compound in the environment. The consistency between the result of the Rayleigh model (f approximately 7%) and the use of the DDT/(DDT + DDE) ratio as a measure of DDT degradation ( approximately 10% undegraded DDT) suggests that the KIE of DDT degradation may be significant, and that the novel approach of CSIA-Cl may be a valuable tool for degradation/persistence studies of lipophilic organochlorines in the environment.