Fabien Mercier

Occurrence and fate of antibiotics in the Seine River in various hydrological conditions.

Occurrence and fate of 17 antibiotics were investigated in the aqueous phase of river water under different hydrological conditions at 5 sampling locations in the Seine River inner estuary. The target analytes belonged to 4 groups: quinolones, sulfonamides, nitro-imidazoles and diaminopyrimidines. This six-month survey (from January to June 2006) showed that different compounds were occurring at individual concentrations reaching 544 ng L(-)(1) (sulfamethoxazole). All 17 compounds were detected at least once in the survey. Sulfamethoxazole was detected in every sample, and showed the highest concentrations. Norfloxacin and flumequine were found to be the most ubiquitous quinolones, with detection frequencies of 33 and 75% respectively at the most contaminated site (Poses). Investigations concerning the origins of this contamination were made by means of a longitudinal profile along the Seine River between Paris and Poses. It showed large inputs of norfloxacin, ofloxacin, trimethoprim and sulfamethoxazole from wastewater treatment plants, with an increase in norfloxacin and sulfamethoxazole concentrations of 84% and 70% respectively, both reaching 155 ng L(-)(1) in the river, downstream from a wastewater outlet. The detected compounds showed different dissipation patterns and behaviours under different hydrological conditions. Higher inputs of norfloxacin were found in low flow conditions, which were rapidly attenuated along the stream. In contrast, sulfamethoxazole inputs were increasing in high flow conditions, and dissipation of this compound was found to be slow. Similar behaviour was observed for the synergist trimethoprim. Flumequine was also frequently detected and its input increased during flood events.

Organic Contamination of Settled House Dust, A Review for Exposure Assessment Purposes

People spend a considerable amount of time indoors. As a result, exposure to indoor contaminants is of great concern, notably via settled dust ingestion in particular for infants and toddlers. This paper proposes a critical review on the organic contamination of settled house dust and human exposure over the past 10 years and focused on sources, contaminations and measurement methods (sampling, pretreatment, storage and analysis). As many compounds were identified, arises the question of which ones to consider. Sensitive and selective analytical methods for simultaneous determination of targeted substances should be developed and evaluated. Various methods were described for sampling and sample preparation. Harmonization and standardization are needed to enable comparison of results from similar studies. Finally, an integrated multipollutant and multicompartment (settled dust, suspended particles and air) approach appears essential in order to determine the extent of the threat to public health posed by indoor contaminants.

Semivolatile Organic Compounds in Indoor Air and Settled Dust in 30 French Dwellings

Semivolatile organic compounds (SVOCs) are ubiquitous contaminants in indoor environments, emanating from different sources and partitioning among several compartments, including the gas phase, airborne particles, and settled dust. Nevertheless, simultaneous measurements in the three compartments are rarely reported. In this study, we investigated indoor concentrations of a wide range of SVOCs in 30 French dwellings. In settled dust, 40 out of 57 target compounds were detected. The highest median concentrations were measured for phthalates and to a lesser extent for bisphenol A, synthetic musks, some pesticides, and PAHs. Di(2-ethylhexyl)phthalate (DEHP) and diisononyl phthalate (DINP) were the most abundant compounds. A total of 34 target compounds were detected both in the gas phase and airborne particles. The highest concentrations were measured for diisobutyl phthalate (DiBP), diethyl phthalate (DEP), dibutyl phthalate (DBP), and synthetic musks in the gas phase and for DEHP, DiBP, DBP, and DINP in the airborne particles. This is the first study on the indoor concentrations of a wide range of SVOCs in settled dust, gas phase, and airborne particles collected simultaneously in each dwelling.

A multi-residue method for the simultaneous analysis in indoor dust of several classes of semi-volatile organic compounds by pressurized liquid extraction and gas chromatography/tandem mass spectrometry

People are exposed to multiple pollutants, especially indoors, in particular through ingestion of indoor settled dust. In the perspective of a cumulative risk assessment, a multi-residue analytical method based on pressurized liquid extraction (PLE) and gas chromatography/tandem mass spectrometry (GC/MS/MS) was developed for the simultaneous analysis in indoor dust of several classes of semi-volatile organic compounds (SVOCs) of health concern, from trace to highly concentrated compounds, including musk fragrances, organochlorines (OCs), organophosphates (OPs), polycyclic aromatic hydrocarbons (PAHs), polybromodiphenylethers (PBDEs), polychlorobiphenyls (PCBs), phthalates and pyrethroids. The method was validated in terms of limits of quantification (LOQ), and accuracy and precision via spiking experiments on an inert material (Celite(®) 545) and replicate analysis of the standard reference material SRM 2585 supplied by the National Institute of Standards and Technology (NIST). Method LOQs for 200 mg samples of sieved dust were 26 ng g(-1) for PCBs and some OCs, 65 ng g(-1) for musks, OPs, PAHs, PBDEs, pyrethroids, other OCs and some phthalates, 132 ng g(-1) for butylbenzylphthalate (BBP), 197 ng g(-1) for tributylphosphate and 1579 ng g(-1) for other phthalates. Quadratic calibration curves were established for each compound by analyzing at least five calibration solutions and exhibited determination coefficients higher than 0.999. The method was successfully applied to the SRM 2585 and seven real indoor dust samples. The results obtained on SRM 2585 demonstrate both excellent reproducibility and agreement with the indicative, reference or certified values and provide, for the first time, indicative concentrations for chlorpyrifos, diazinon, diisononylphthalate (DiNP) and tetramethrin. The results obtained on real dust samples illustrate the ability of the proposed method to quantify a wide range of SVOCs in a single analysis, making it appropriate for environmental monitoring programs or large-scale studies with a large number of samples.

Childhood exposure to polybrominated diphenyl ethers and neurodevelopment at six years of age.

Mixtures of polybrominated diphenyl ethers (PBDEs) are present in indoor environments. Studies of the developmental effects of exposure to these chemicals in large prospective mother-child cohorts are required, with data on prenatal exposure and long-term follow-up of the children. We aimed to investigate the relationship between prenatal and childhood exposure to PBDEs and neurodevelopment at the age of six years. We determined the levels of PBDEs and other neurotoxicants in cord blood and dust collected from the homes of children for 246 families included in the PELAGIE mother-child cohort in France. We assessed two cognitive domains of the six-year-old children using the Wechsler Intelligence Scale for Children-IV. Verbal comprehension scores were lower in children from homes with higher concentrations of BDE99 (βDetects<median_vs_NonDetects=-1.6; 95% CI: -6.1, 2.9; βDetects≥median_vs_NonDetects=-5.4; -9.9, -1.0; p trend=0.02) and of BDE209 (β2nd_vs_1st_tertile=-1.8; 95% CI: -6.1, 2.5; β3rd_vs_1st_tertile=-3.2; -7.5, 1.2; p trend=0.15) in dust, particularly for boys (p trend=0.02 and 0.04, respectively). Working memory scores seemed to be lower in children with higher BDE99 concentrations in dust (p trend=0.10). No association was observed with cord blood levels of BDE209. Our findings are in agreement with those of four previous studies suggesting adverse cognitive outcomes among children associated with early-life exposure to penta-BDE mixtures, and provide new evidence for the potential neurotoxicity of BDE209. Several countries are in the process of banning the use of PBDE mixtures as flame-retardants. However, these compounds are likely to remain present in the environment for a long time to come.

Distributions of the particle/gas and dust/gas partition coefficients for seventy-two semi-volatile organic compounds in indoor environment.

Particle/gas and dust/gas partition coefficients (Kp and Kd) are two key parameters that address the partitioning of semi-volatile organic compounds (SVOCs) between gas-phase, airborne particles, and settled dust in indoor environment. A number of empirical equations to calculate the values of Kp and Kd have been reported in the literature. Therefore, the difficulty lies in the selection of a specific empirical equation in a given situation. In this study, we retrieved from the literature 38 empirical equations for calculating Kp and Kd values from the SVOC saturation vapor pressure and octanol/air partition coefficient. These values were calculated for 72 SVOCs: 9 phthalates, 9 polybrominated diphenyl ethers (PBDEs), 11 polychlorinated biphenyls (PCBs), 22 biocides, 14 polycyclic aromatic hydrocarbons (PAHs), 3 alkylphenols, 2 synthetic musks, tributylphosphate, and bisphenol A. The mean and median values of log10Kp or log10Kd for most SVOCs were of the same order of magnitude. The distribution of log10Kp values was fitted to either a normal distribution (for 27 SVOCs) or a log-normal distribution (for 45 SVOCs). This work provides a reference distribution of the log10Kp for 72 SVOCs, and its use may reduce the bias associated with the selection of a specific value or equation.

Temperature dependence of the particle/gas partition coefficient: An application to predict indoor gas-phase concentrations of semi-volatile organic compounds

The indoor gas-phase concentrations of semi-volatile organic compounds (SVOCs) can be predicted from their respective concentrations in airborne particles by applying the particle/gas partitioning equilibrium. The temperature used for partitioning is often set to 25°C. However, indoor temperatures frequently differ from this reference value. This assumption may result in errors in the predicted equilibrium gas-phase SVOC concentrations. To improve the prediction model, the temperature dependence of the particle/gas partition coefficient must be addressed. In this paper, a theoretical relationship between the particle/gas partition coefficient and temperature was developed based on the SVOC absorptive mechanism. The SVOC particle/gas partition coefficients predicted by employing the derived theoretical relationship agree well with the experimental data retrieved from the literature (R>0.93). The influence of temperature on the equilibrium gas-phase SVOC concentration was quantified by a dimensionless analysis of the derived relationship between the SVOC particle/gas partition coefficient and temperature. The predicted equilibrium gas-phase SVOC concentration decreased by between 31% and 53% when the temperature was lowered by 6°C, while it increased by up to 750% when the indoor temperature increased from 15°C to 30°C.

Dermal absorption of semivolatile organic compounds from the gas phase: Sensitivity of exposure assessment by steady state modeling to key parameters

Recent research has demonstrated the importance of dermal exposure for some semivolatile organic compounds (SVOCs) present in the gas phase of indoor air. Though models for estimating dermal intake from gaseous SVOCs exist, their predictions can be subject to variations in input parameters, which can lead to large variation in exposure estimations. In this sensitivity analysis for a steady state model, we aimed to assess these variations and their determinants using probabilistic Monte Carlo sampling for 8 SVOCs from different chemical families: phthalates, bisphenols, polycyclic aromatic hydrocarbons (PAHs), organophosphorus (OPs), organochlorines (OCs), synthetic musks, polychlorinated biphenyls (PCBs) and polybromodiphenylethers (PBDEs). Indoor SVOC concentrations were found to be the most influential parameters. Both Henrys law constant (H) and octanol/water partition coefficient (Kow) uncertainty also had significant influence. While exposure media properties such as volume fraction of organic matter in the particle phase (fom-part), particle density (ρpart), concentration ([TSP]) and transport coefficient (ɣd) had a slight influence for some compounds, human parameters such as body weight (W), body surface area (A) and daily exposure (t) make a marginal or null contribution to the variance of dermal intake for a given age group. Inclusion of a parameter sensitivity analysis appears essential to reporting uncertainties in dermal exposure assessment.

Semi-volatile organic compounds in French dwellings: An estimation of concentrations in the gas phase and particulate phase from settled dust

Semi-volatile organic compounds (SVOCs) are present in the gas phase, particulate phase and settled dust in the indoor environment, resulting in human exposure through different pathways. Sometimes, SVOCs are only measured in a single phase because of practical and/or financial constraints. A probabilistic method proposed by Wei et al. for the prediction of the SVOC concentration in the gas phase from the SVOC concentration in the particulate phase was extended to model the equilibrium SVOC concentrations in both the gas and particulate phases from the SVOC concentration measured in settled dust. This approach, based on the theory of SVOC partitioning among the gas phase, particulate phase, and settled dust incorporating Monte Carlo simulation, was validated using measured data from the literature and applied to the prediction of the concentrations of 48 SVOCs in both the gas and particulate phases in 3.6 million French dwellings where at least one child aged 6 months to 6 years lived. The median gas-phase concentration of 15 SVOCs, i.e., 5 phthalates, 2 organochlorine pesticides, 4 polycyclic aromatic hydrocarbons (PAHs), 2 synthetic musks, dichlorvos, and tributyl phosphate, was found to be higher than 1 ng/m3. The median concentration of 5 phthalates in the particulate phase was higher than 1 ng/m3. The impacts of some physical parameters, such as the molar mass and boiling point, on the SVOC partitioning among the different phases were quantified. The partitioning depends on the activity coefficient, vapor pressure at the boiling point, entropy of evaporation of the SVOCs, and the fraction of organic matter in particles. Thus, the partitioning may differ from one chemical family to another. The empirical equations based on regressions allow quick estimation of SVOC partitioning among the gas phase, particulate phase, and settled dust from the molar mass and boiling point.

Indoor air quality in two French hospitals: Measurement of chemical and microbiological contaminants

In addition to being influenced by the environment, the indoor air pollution in hospitals may be associated with specific compounds emitted from various products used, health care activities and building materials. This study has enabled assessment of the chemical and microbiological concentrations of indoor air in two French hospitals. Based on an integrated approach, the methodology defined aims to measure concentrations of a wide range of chemical compounds (>50 volatile and semi-volatile organic compounds), particle concentrations (PM10 and PM2.5), microorganisms (fungi, bacteria and viruses) and ambient parameters (temperature, relative humidity, pressure and carbon dioxide). Chemical and microbiological air concentrations were measured during two campaigns (winter and summer) and across seven rooms (for spatial variability). The results have shown that indoor air contains a complex mixture of chemical, physical and microbiological compounds. Concentrations in the same order of magnitude were found in both hospitals. Compared to dwelling indoor air, our study shows low, at least equivalent, contamination for non-hospital specific parameters (aldehydes, limonene, phthalates, aromatic hydrocarbons), which is related to ventilation efficiency. Chemical compounds retrieved at the highest concentration and frequencies are due to healthcare activities, for example alcohol - most commonly ethanol - and hand rubbing (median concentration: ethanol 245.7 μg/m3 and isopropanol 13.6 μg/m3); toluene and staining in parasitology (highest median concentration in Nancy laboratory: 2.1 μg/m3)).