Gas chromatographic analysis of free fatty acids and fatty acid salts extracted with neutral and acidified dichloromethane from office floor dust

Bioaccessibility of pesticides and polychlorinated biphenyls from house dust: in-vitro methods and human exposure assessment

Semi-volatile chemicals like pesticides and polychlorinated biphenyls (PCB) tend to accumulate in house dust. This may result in residues of some parts per million (p.p.m.), closely associated with health impairments and diseases like cancer. To explain these associations, we must establish whether a relevant absorption from house dust into human organisms occurs, and most crucially the release of chemicals, that is, their bioaccessibility. Digestive as well as dermal bioaccessibilities were examined using in-vitro methods. On average, the digestive bioaccessibility was ~40% for the pesticides and ~60% for the PCB. The dermal penetration availability reached ~60% for the pesticides and ~70% for the PCB (percentages of the concentrations in the dust). Based on the bioaccessibility, an estimate of internal exposure was calculated and expressed as percentages of acceptable or tolerable daily intake (ADI/TDI) values. Exposure via the respiratory tract proved to be very low. Exposure via the digestive tract had maximum values of 4% for pesticides and 12% for PCB. Dermal exposure was much higher. Even for average concentrations in house dust (≈0.5 p.p.m.), children exposed to DDT and PCB showed up to 300% of the ADI/TDI values, and adults about 60%. With high concentrations of contaminants in house dust, the maximum doses absorbed through the skin reached 5000%.

Indoor air pollutants in office environments: assessment of comfort, health, and performance

Concentrations of volatile organic compounds (VOCs) in office environments are generally too low to cause sensory irritation in the eyes and airways on the basis of estimated thresholds for sensory irritation. Furthermore, effects in the lungs, e.g. inflammatory effects, have not been substantiated at indoor relevant concentrations. Some VOCs, including formaldehyde, in combination may under certain environmental and occupational conditions result in reported sensory irritation. The odour thresholds of several VOCs are low enough to influence the perceived air quality that result in a number of acute effects from reported sensory irritation in eyes and airways and deterioration of performance. The odour perception (air quality) depends on a number of factors that may influence the odour impact. There is neither clear indication that office dust particles may cause sensory effects, even not particles spiked with glucans, aldehydes or phthalates, nor lung effects; some inflammatory effects may be observed among asthmatics. Ozone-initiated terpene reaction products may be of concern in ozone-enriched environments (≥0.1mg/m(3)) and elevated limonene concentrations, partly due to the production of formaldehyde. Ambient particles may cause cardio-pulmonary effects, especially in susceptible people (e.g. elderly and sick people); even, short-term effects, e.g. from traffic emission and candle smoke may possibly have modulating and delayed effects on the heart, but otherwise adverse effects in the airways and lung functions have not been observed. Secondary organic aerosols generated in indoor ozone-initiated terpene reactions appear not to cause adverse effects in the airways; rather the gaseous products are relevant. Combined exposure to particles and ozone may evoke effects in subgroups of asthmatics. Based on an analysis of thresholds for odour and sensory irritation selected compounds are recommended for measurements to assess the indoor air quality and to minimize reports of irritation symptoms, deteriorated performance, and cardiovascular and pulmonary effects.

Recent trends in the advanced analysis of bioactive fatty acids

The consumption of dietary fats have been long associated to chronic diseases such as obesity, diabetes, cancer, arthritis, asthma, and cardiovascular disease; although some controversy still exists in the role of dietary fats in human health, certain fats have demonstrated their positive effect in the modulation of abnormal fatty acid and eicosanoid metabolism, both of them associated to chronic diseases. Among the different fats, some fatty acids can be used as functional ingredients such as alpha-linolenic acid (ALA), arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), gamma-linolenic acid (GLA), stearidonic acid (STA) and conjugated linoleic acid (CLA), among others. The present review is focused on recent developments in FAs analysis, covering sample preparation methods such as extraction, fractionation and derivatization as well as new advances in chromatographic methods such as GC and HPLC. Special attention is paid to trans fatty acids due its increasing interest for the food industry.

Building-related symptoms and inflammatory potency of dust from office buildings

The aim was to investigate the association between building-related symptoms (BRS) in office buildings and the inflammatory potency of dust (PD). Furthermore, the association between dust potency and various building characteristics was investigated. Occupants of 22 office buildings received a retrospective questionnaire about BRS (2301 respondents). Dust was collected from groups of offices and building characteristics were recorded. The potency of a dust sample to induce interleukin-8 (IL-8) secretion from the lung epithelial cell line A549 was measured as the slope of the initial linear part of the concentration-response curve. Symptoms of the central nervous system (CNS) were associated with the potency of surface dust (OR = 1.4). This association may be due to an association between an index of CNS symptoms and dust potency in offices of 1-6 occupants (OR = 1.5). No single symptoms correlated with the potency of surface dust. The PD was not related to single building factors. The inflammatory PD may be used as an integrated proxy measure of biologically active compounds in dust, reflecting health relevant properties of the dust.

PRACTICAL IMPLICATIONS

The potency of surface dust may be used as a crude measurement of the chemical and biological exposures present in the building, and being associated with the development of central nervous system symptoms. However, additional research is needed to establish the predictive value of the potency of surface dust.

Development of a high-throughput method for the determination of organochlorinated compounds, nitromusks and pyrethroid insecticides in indoor dust

Investigation of chemical exposure inside the homes and offices where people spend the majority of their lives has only recently begun. These chemicals are degraded much more slowly than outdoor because they are more protected from sunlight, severe environmental conditions and microbial activity. Hence, indoor dust has been recognized as an important exposure pathway for organic contaminants. Pyrethroids are synthetic insecticides widely used in domestic environment for numerous applications and also in agriculture. Chlorobenzenes are a family of compounds used as intermediates in the production of a wide range of household consumer products. Nitromusks are a kind of synthetic musks used in the production of cleaning agents, detergents, and personal care products. A high-throughput method for the determination of these compounds in indoor dust samples has been developed. Microwave-assisted solvent extraction was used as the extraction technique whereas quantification of compounds was carried out by gas chromatography with micro-electron-capture detection. Several cleanup procedures were tested and finally a non-classical "on batch" procedure was selected, which allows increasing the throughput of the analysis while decreasing sample manipulation. Extraction conditions were optimized using a multifactorial experimental design approach. Quantitative recovery (84-103%) was achieved for all compounds and method precision was satisfactory. Limits of detection ranged from 0.22 ng g(-1) for lindane to 40 ng g(-1) for 1,4-dichlorobenzene. Standard reference material SRM 2585 was analyzed and the obtained values were in good agreement with the reported reference values for organochlorinated compounds and nitromusks. Pyrethroids and polychlorobenzenes have been analyzed for the first time in this reference material and some of them have been found. In addition, real samples collected in houses of north-western Spain have been analyzed by the proposed method and 17 of the 22 target compounds have been detected in the samples.

Do indoor chemicals promote development of airway allergy?

Allergic asthma has increased worldwide in the industrialized countries. This review evaluates whether the major groups of indoor chemical exposures possess allergy-promoting (adjuvant) effects; formaldehyde was excluded, because of the size of the literature. Volatile organic compounds (VOCs) are used as an example of gases and vapors. The precipitation of asthmatic symptoms by VOC exposures is probably because of VOC levels considerably above typical indoor levels, or VOCs may be a surrogate for exposure to allergens, combustion products or dampness. Indoor particles possessed adjuvant effects in animal studies and allergy-promoting effects in humans. Quaternary ammonium compounds may possess adjuvant effects in animal studies and promoted sensitization in humans in occupational settings. The use of cleaning agents, anionic and non-ionic surfactants are not considered to possess an important adjuvant effect in the general population. Regarding phthalate exposures, results from animal and epidemiological studies were found to be discordant. There is little evidence that the indoor chemicals evaluated possess important adjuvant effects. If buildings are kept clean, dry and free of combustion products, the important question may be would it be profitable to look for lifestyle factors and non-chemical indoor exposures in order to abate airway allergy?

PRACTICAL IMPLICATIONS

Indoor chemicals (pollutants) have been accused to promote development of airway allergy by adjuvant effects. In this review, we evaluated the scientific literature and found little support for the supposition that indoor chemicals possess important adjuvant effects. This rises the question: would it be profitable for abatement of airway allergy to look for non-chemical indoor exposures, including lifestyle factors, and exposures to allergens, microorganisms, including vira, and their interactions?

Simultaneous extraction of di(2-ethylhexyl) phthalate and nonionic surfactants from house dust. Concentrations in floor dust from 15 Danish schools

Static extraction, supercritical fluid extraction (SFE), pressurized liquid extraction (PLE) and Soxhlet extraction were compared for simultaneous extraction of di(2-ethylhexyl) phthalate (DEHP) and nonionic surfactants from house dust. Homogenized office floor dust from a vacuum cleaner dust bag ("standard dust") was used for the evaluation. One portion of the extracts was used for analysis of nonionic surfactants with LC-MS and another portion was used for DEHP analysis with GC-MS. The extraction yield of DEHP was comparable for all the methods whereas SFE and PLE were the most efficient extraction techniques for the nonionic surfactants. The PLE extraction was found most suitable as a routine method for simultaneous extraction of both types of compounds and was used in a field study of floor dust from 15 Danish schools. The mean concentration of DEHP in the school dust samples was approximately 4 times higher than observed in other studies of dust from homes in different countries. The concentrations of nonionic surfactants were one order of magnitude lower than soap and linear alkylbenzene sulfonates measured in other studies of floor dust from offices and other public buildings. However, for the first time nonionic surfactants have been identified in house dust.

Linear alkylbenzene sulfonates in indoor floor dust

A method was developed to analyse linear alkylbenzene sulfonates (C10-C13 LAS) in vacuumed floor dust in office buildings by the use of HPLC chromatography. Floor dust was sampled with a specially designed vacuum cleaner and fractionated into fibres and particles. The content of LAS in the particle fraction of floor dust sampled from seven different public buildings varied between 34 microg LAS g(-1) dust and 1,500 microg LAS g(-1) dust, while the content of the fibre fractions was generally higher with up to 3,500 microg LAS g(-1) dust. The use of a cleaning agent with LAS resulted in increases approximately 30% of the amount of LAS in the floor dust after floor wash relative to just before floor wash. However, the most important source of LAS in the indoor floor dust appeared to be residues of detergent in clothing. Thus, a newly washed shirt contained 2,960 microg LAS g(-1) clothing. The analysis of the office dust samples indicated that LAS (and probably other detergents) might be of importance for the indoor environment.

Solid-phase microextraction: a promising technique for sample preparation in environmental analysis

Solid-phase microextraction (SPME) is a simple and effective adsorption and desorption technique, which eliminates the need for solvents or complicated apparatus, for concentrating volatile or nonvolatile compounds in liquid samples or headspace. SPME is compatible with analyte separation and detection by gas chromatography and high-performance liquid chromatography, and provides linear results for wide concentrations of analytes. By controlling the polarity and thickness of the coating on the fibre, maintaining consistent sampling time, and adjusting other extraction parameters, an analyst can ensure highly consistent, quantifiable results for low concentration analytes. To date, about 400 articles on SPME have been published in different fields, including environment (water, soil, air), food, natural products, pharmaceuticals, biology, toxicology, forensics and theory. As the scope of SPME grew, new improvements were made with the appearance of new coatings that allowed an increase in the specificity of this extraction technique. The key part of the SPME fibre is of course the fibre coating. At the moment, 27 variations of fibre coating and size are available. Among the newest are a fibre assembly with a dual coating of divinylbenzene and Carboxen suspended in poly(dimethylsiloxane), and a series of 23 gauge fibres intended for specific septumless injection system. The growth of SPME is also reflected in the expanding number of the accessories that make the technology even easier to use Also available is a portable field sampler which is a self-contained unit that stores the SPME fibre after sampling and during the shipment to the laboratory. Several scientific publications show the results obtained in inter-laboratory validation studies in which SPME was applied to determine the presence of different organic compounds at ppt levels, which demonstrates the reliability of this extraction technique for quantitative analysis.

How to measure and evaluate volatile organic compound emissions from building products. A perspective

The primary emissions of VOCs (e.g. solvents) from building products influence the perceived indoor air quality during the initial decay period. However, secondary emissions will continue thereafter (chemical or physical degradation, e.g. oxidation, hydrolysis, mechanical wear, maintenance), in addition to sorption processes. Emission testing for primary VOC emissions is necessary, but insufficient to characterise the impact of building products in their entire life span on the perceived air quality. Methods to distinguish between the two types of emissions are required. Also, the influence of climate parameters on the emission rates is necessary to know for proper testing. Future product development and selection strategies of new building products should consider the secondary emissions, in addition to the contribution from the use of auxiliary agents for cleaning, maintenance, and other potential impacts either physical or chemical in nature. Some of the requirements for emission testing are discussed in terms of secondary vs. primary emissions in order to develop 'healthier/better' building products for the indoor environment. In addition, some of the assumptions about the possible impact of VOCs on health and comfort in the indoor environment are presented. Odour thresholds for VOCs are one or more orders of magnitude lower than the corresponding airway irritation estimates, and it also appears that chemically non-reactive VOCs are not sufficiently strong irritants to cause airway irritation at concentrations normally encountered indoors. Finally, future requirements for analytical laboratory performances is proposed to accommodate the increasing need to establish which VOCs may be responsible for the perception of odour intensity from building products.