Les pressings : exposition au tétrachloroéthylène et risques sanitaires

National audienceTetrachloroethylene is a solvent widely used in French dry-cleaning facilities. In 1995, the International Agency for Research on Cancer (IARC) classified it as probably carcinogenic to humans (group 2A). Chronic exposure through inhalation also has non-carcinogenic effects, mainly renal and neurological; toxic effects on reproduction have also been reported. Five exploratory tetrachloroethylene measurement campaigns were conducted to assess the health risk in the general population. These measurements took place in one dry-cleaning facility located in a shopping mall and in four dry-cleaners on the ground floor of residential buildings, all of them with different types of machines and ventilation systems. Concentrations ranged from 0.050 to 0.680 mg/m3 in the shopping mall, from 8 to 53 mg/m3 in the dry-cleaners in residential buildings and from 0.29 to 2.9 mg/m3 in the flats immediately above them. These results show a reduction of tetrachloroethylene concentrations in some flats and thus the potential effect of the type of dry-cleaning machine and of ventilation on the tetrachloroethylene concentrations in indoor air. A worst-case health risk assessment based on the toxicological reference value for inhalation was conducted for the general population. The hazard quotients calculated for non-carcinogenic effects indicate that there is no reason for concern about the health of mall customers chronically exposed to it. The results in residential buildings suggest that people living immediately above ground-floor dry-cleaners may have health risks if the dry-cleaner uses a type-3 machine in a shop without mechanical ventilation. Individual excess risks, estimated with available unit risks, exceed the WHO benchmark of 10-5 regardless of the machine technology or type of ventilation. The principal uncertainties of this study are related to : measurements ; lack of knowledge about variables influencing the atmospheric emissions, seasonal effects of dry-cleaning activity, and residents' lifestyle ; working assumptions about the duration of population exposure ; the toxicological reference values used which could be questioned following the publication of the Toxicological Review by the US EPA in 2008.Le tétrachloroéthylène (C2Cl4) est un solvant utilisé dans le secteur du nettoyage à sec. Ses effets sanitaires non cancérigènes, observés chez l'homme par inhalation suite à une exposition chronique, sont principalement de type neurologique et rénal ; des effets toxiques sur la reproduction ont également été rapportés. Il est classé probablement cancérogène pour l'homme par le Centre international de recherche sur le cancer (CIRC) depuis 1995. Un travail d'évaluation des risques sanitaires pour la population générale a été engagé à partir des résultats de cinq campagnes de mesures exploratoires portant sur un pressing situé dans la galerie marchande d'un centre commercial et sur quatre pressings situés en bâtiments résidentiels, présentant différents types de machine et de ventilation. Les concentrations mesurées étaient comprises entre 0,050 et 0,680 mg/m3 dans le centre commercial. Les concentrations moyennes variaient entre 8 et 53 mg/m3 dans les pressings résidentiels et entre 0,29 et 2,9 mg/m3 dans les appartements situés à l'étage supérieur. Ces résultats révèlent la potentielle influence d'une ventilation mécanique contrôlée (VMC) et d'une machine de nouvelle génération sur les concentrations en tétrachloroéthylène mesurées dans les appartements et les pressings. Les risques sanitaires associés aux niveaux d'exposition estimés à partir de ces concentrations ont été évalués par une approche majorante. En l'état des connaissances toxicologiques actuelles, le risque d'apparition d'effets non cancérigènes pour les clients du centre commercial (machine de quatrième génération, absence de VMC) est non préoccupant. En ce qui concerne les personnes résidant au-dessus d'une installation de nettoyage à sec non munie d'une VMC et utilisant une machine de troisième génération, le risque est préoccupant. Pour les personnes résidant au-dessus d'une installation de nettoyage à sec munie d'une VMC et utilisant une machine de quatrième génération, le risque est non préoccupant. La caractérisation du risque cancérigène permet de calculer des excès de risque supérieurs à la valeur de 10-5 vie entière considérée comme risque " acceptable " par l'Organisation mondiale de la santé (OMS), quelle que soit l'installation concernée. Les principales incertitudes de cette étude relèvent : de la mesure ; de défauts de connaissances : paramètres influençant les émissions atmosphériques, effet saisonnier de l'activité de nettoyage à sec, habitudes de vie des résidents ; d'hypothèses de travail majorantes concernant la durée d'exposition des populations ; des valeurs toxicologiques de référence (VTR) utilisées qui pourraient être remises en cause du fait de la parution du Toxicological review de l'United States Environmental Protection Agency (US EPA) en 2008

Measurement Error in Research on Human Resources and Firm Performance: Additional Data and Suggestions for Future Research

Gerhart and colleagues and Huselid and Becker recently debated the presence and implications of measurement error in measures of human resource practices. This paper presents data from three more studies, one of large organizations from different industries at the corporate level, one from commercial banks, and the other of autonomous business units at the level of the job. Results of all three studies provide additional evidence that single respondent measures of HR practices contain large amounts of measurement error. Implications for future research are discussed

Health risk assessment of PCE emissions from dry cleaning activities in France

Tetrachloroethylene (PCE) is a solvent used mostly in the dry-cleaning and metal degreasing industries in Europe. Neurological and renal effects are the main non-cancer human health effects caused by chronic inhalation exposure of PCE. PCE is suspected to be probably carcinogenic to humans by IARC. During dry-cleaning processes, people are likely to be exposed to the chemical in a variety of ways because PCE emissions are not currently regulated in France. Exposed persons include workers, residents living in co-location with dry-cleaning establishments and the general population. This paper presents a literature review assimilating human exposure data to assess public health risk from dry-cleaning emissions. At the average indoor air level of 2 mg/m3 , there is concern for health risk to co-located residents living above dry cleaning establishments. A personal exposure of 15 ug/m3 of PCE should not cause adverse effects on the health of normal population

Why project size matters for contract choice in software development outsourcing

The contractual mechanism of software development outsourcing, typically either fixed-price (FP) or time-and-materials (T&M), determines the nature of incentives, risk sharing, and coordination between client and vendor. While software engineering considers project size as crucial for project planning and success, neither economic nor organizational theory considers size per se among the determinants of contract choice. In this paper, we address the gap between the centrality of project size in the software engineering literature and the attention it receives in software contracting research by modeling and testing the association between project size and contract choice. Existing empirical evidence indicates that FP contracts are appropriate for small development efforts whereas T&M contracts are suitable for larger projects, based on the reasoning that cost and schedule are difficult to estimate in larger projects. This prediction that size is directly associated with contract choice is the basis upon which two models are developed. The first model draws on the contracting efficiency approach to hypothesize that the effect of project size on contract choice is mediated by project detail. The second model draws on the contingency approach to software development risk management to hypothesize that the effect of project size on contract choice is moderated by project detail and vendor familiarity. We test these models using a large portfolio of software development contracts entered into by a leading European bank, and the results confirm that both mediation and moderation are at play

Brief for the United States as Amicus Curiae in Support of Neither Party

Amicus ("friend of the court") brief written by the United States in support of neither party in AMP v. Myriad Genetics (No. 2010-1406)

A numerical investigation of the asymmetric wake mode of a squareback Ahmed body - effect of a base cavity

Numerical simulations of the turbulent flow over the flat backed Ahmed model at Reynolds number $Re\simeq 4\times 10^{5}$ are conducted using a lattice Boltzmann solver to clarify the mean topology of the static symmetry-breaking mode of the wake. It is shown that the recirculation region is occupied by a skewed low pressure torus, whose part closest to the body is responsible for an extra low pressure imprint on the base. Shedding of one-sided vortex loops is also reported, indicating global quasi-periodic dynamics in conformity with the seminal work of Grandemange et al. (J. Fluid Mech., vol. 722, 2013, pp. 51–84). Despite the limited low frequency resolution of the simulation, power spectra of the lateral velocity fluctuations at different locations corroborate the presence of this quasi-periodic mode at a Strouhal number of $St=0.16\pm 0.03$. A shallow base cavity of $5\,\%$ of the body height reduces the drag coefficient by $3\,\%$ but keeps the recirculating torus and its interaction with the base mostly unchanged. The drag reduction lies in a global constant positive shift of the base pressure distribution. For a deep base cavity of $33\,\%$ of the body height, a drag reduction of $9.5\,\%$ is obtained. It is accompanied by a large elongation of the recirculation inside the cavity that considerably attenuates the low pressure sources therein together with a symmetrization of the low pressure torus. The global quasi-periodic mode is found to be inhibited by the cavity.</jats:p

S07RS SGB No. 3 (Election Code)

A BILL To amend Article III, Section 2 of the Louisiana State University Student Government Election Code to better clarify campaign and election day

Incipient Separation in Shock Wave Boundary Layer Interactions as Induced by Sharp Fin

The incipient separation induced by the shock wave turbulent boundary layer interaction at the sharp fin is the subject of present study. Existing theories for the prediction of incipient separation, such as those put forward by McCabe (1966) and Dou and Deng (1992), can have thus far only predicting the direction of surface streamline and tend to over-predict the incipient separation condition based on the Stanbrook's criterion. In this paper, the incipient separation is firstly predicted with Dou and Deng (1992)'s theory and then compared with Lu and Settles (1990)' experimental data. The physical mechanism of the incipient separation as induced by the shock wave/turbulent boundary layer interactions at sharp fin is explained via the surface flow pattern analysis. Furthermore, the reason for the observed discrepancy between the predicted and experimental incipient separation conditions is clarified. It is found that when the wall limiting streamlines behind the shock wave becomes\ aligning with one ray from the virtual origin as the strength of shock wave increases, the incipient separation line is formed at which the wall limiting streamline becomes perpendicular to the local pressure gradient. The formation of this incipient separation line is the beginning of the separation process. The effects of Reynolds number and the Mach number on incipient separation are also discussed. Finally, a correlation for the correction of the incipient separation angle as predicted by the theory is also given.Comment: 34 pages; 9 figure