Suitability of small environmental chambers to test the emission of biocides from treated materials into the air

doi:10.1016/j.atmosenv.2003.09.024

Atmospheric Environment

Volume 37, Issues 39–40, December 2003, Pages 5477-5483

https://doi.org/10.1016/j.atmosenv.2003.09.024 Get rights and content

Abstract

Biocides are used to protect materials that might be damaged by fungal, microbial or insect activity. The aim of this study is to develop a method for the measurement of these organic compounds, which generally have low or moderate vapor pressures. The biocides considered in this study are permethrin, dichlofluanid, tolylfluanid, iodpropinylbutylcarbamat, octylisothiazolinone, tebuconazole and propiconazole. The emission from two commercial products (plastic foil, wool carpet) containing biocides and of seven types of biocidal formulations applied to wood or clay tiles were investigated in 20-l glass emission test chambers. Each chamber test was performed over a period of 100–200 days, and one investigation was conducted over several years. Compared to volatile organic compounds, low-volatility compounds show totally different emission curves in chamber tests; maximal emission values may be reached in days or weeks. A period of 3 months is sometimes necessary for the determination of area-specific emission rates (SER_a's). The SER_a's (μg m⁻² h⁻¹) from biocide-containing products were determined for permethrin (0.006), propiconazole (0.3), dichlofluanid (2.0), tolylfluanid (1.0), octylisothiazolinone (2.5) and iodpropinylbutylcarbamat (2). In most cases, the SER_a stayed at its maximum value or declined slowly over the test period. Additionally, a chamber test begun in 1994 with a piece of wood treated with a typical mixture of biocides dissolved in a technical solvent was continued. SER_a's (μg m⁻² h⁻¹) for dichlofluanid (0.20), tebuconazole (0.49) and permethrin (0.08) remained detectable after the period of nearly 9 years during which the sample remained continuously in the chamber. This test proved the very slow decrease of emission of low-volatility compounds like permethrin and tebuconazole.

Introduction

The approval procedure for biocidal products, according to the EC biocides directive (98/8/EC), requires the evaluation of possible side effects of biocides on the environment. Materials that are treated with biocides may release biologically active ingredients into the environment. Standard methods for a comparative assessment of predicted biocide emissions from products containing different biocides are therefore required. Procedures for the determination of biocide emissions into air were developed, and the methods were tested using different biocide-containing products. This paper describes only the emission into the air. The emission into water, which was also tested, is presented elsewhere (Marchal et al (1997), Schoknecht et al (2002)).

Generally, the emission of biocides into ambient air is of minor interest because of their rapid dilution. The emission into indoor air is of greater relevance, because people spend most of their time indoors, so the personal uptake rate indoors is much higher than outdoors. The concentration in air of biocides emitted indoors is reduced through natural ventilation and also through adsorption onto dust or soil particles. However, the biocides sorbed on house dust become available for dermal contact and incidental ingestion through surface contact, especially for children. For adults, inhalation is the main path of exposure to biocides.

For measuring the emissions of biocides into the air during field studies, the ASTM guideline D 4861 (ASTM, 2000) and the VDI guideline 4301 part 2 (VDI, 2000) (tested especially for PCP and lindane) were developed. The concentrations of biocides in indoor air range from several ng m⁻³ to a few μg m⁻³. The concentration depends on the behavior of the compound. The low vapor pressures of biocides lead to low emission rates and thus low concentrations in the air. Thus, a cumulative sampling method is required, with a large volume of air drawn through the adsorbent. The sampling procedure is typically based on the use of polyurethane (PU) foam as the adsorption medium. This method was introduced in the first version of the ASTM guideline D4861. A guideline for the determination of volatile organic compounds (VOCs) from products was developed from CEN TC 264, WG 7. In this guideline (EN 13419-1, 2003), emission test chambers are prescribed. Such VOC test chambers were used in the present study. The majority of biocides, however, are semi-volatile organic compounds (SVOCs). Their detection in emission test chambers is more difficult than the detection of VOCs, because sink effects may affect the measurement and can significantly reduce the measured concentrations of SVOCs in chambers. Therefore, small chambers with a high loading factor and an adequate air exchange rate were used to perform the measurements. For compounds with low volatility, the inner surface of the chamber is a sink, which can reduce the measured concentrations of these compounds in chambers. This concentration approaches a constant value once the inner chamber surface is saturated. To reduce sink effects, the surface area of the inner chamber wall is minimized relative to the surface area of the sample; a loading of up to 6.25 m² m⁻³ is used.

The biocide emissions measured in emission test chambers have been reported in only a few investigations (e.g. Horn and Marutzky, 1993; Marchal et al., 1997; Horn and Marutzky (1993), Jann and Wilke (1999a)). Jann and Wilke (1999a) gave an overview of chamber measurements of biocides. The present paper continues these investigations and applies and enhances their method to measure emissions from several products.

Section snippets

Selected materials

In the biocide Directive of the European Parliament and the Council (98/8/EC) (1998), many different product types (PT) are described. For this study the following PTs were chosen: film preservatives (PT 07); wood preservatives (PT 08); fiber, leather, rubber, and polymerized-materials preservatives (PT 09); and masonry preservatives (PT 10). Carpets and plastic films (PT 09) containing biocides were obtained from industrial manufacturers. Specimens for tests of all other products investigated

Results and discussion

Most published emission tests using test chambers have analyzed VOCs. VOC emissions normally increase to high levels during the first few hours, then decrease to much lower levels over a few days, followed by an extended period of slow release. In contrast, SVOC emissions, such as the biocide emissions monitored in this study, increase slowly until they reach a constant value that persists for a long period of time (see Fig. 1 showing the SER_a of propiconazole from product no. 0803 over

Conclusions

These investigations provide data on biocide emissions from different materials into the air. Laboratory tests are recommended for the estimation of such emissions from products belonging to European Biocides Directive PTs 7, 8, 9 and 10. The biocides considered in this study are permethrin, dichlofluanid, tolylfluanid, iodpropinylbutylcarbamat, octylisothiazolinone, tebuconazole and propiconazole, but with modification of the analytical procedure, the method might also be suitable for other

Acknowledgements

The authors thank the German Federal Environmental Agency for financial support of this research project (UFO-Plan 299 67 410) and Mrs. Sabine Kalus and Mr. Michael Burbiel for their laboratory work.

References (12)

American Society for Testing and Materials, 2000. Standard practice for sampling and analysis of pesticides and...
W. Butte
Occurrence of biocides in the indoor environment
Directive 98/8/EC of the European Parliament and the Council of 16 February 1998 concerning the placing of biocidal...
EN 13419-1, 2003. Building products—determination of the emission of volatile organic compounds—Part 1, Emission test...
C. Friedrich et al.
Pyrethroide im Hausstaub der deutschen Wohnbevölkerung-Ergebnisse zweier bundesdeutscher Querschnittstudien (Pyrethroids in house dust of German inhabitants-Results of the second German survey)
Gesundheitswesen
(1998)
Horn, W., Marutzky, R., 1993. Measuring of organic wood preservatives in indoor air-sampling and 1-m3 chamber tests....

There are more references available in the full text version of this article.

Cited by (27)

Photocatalytic, hydrophobic and antimicrobial characteristics of ZnO nano needle embedded cement composites
2018, Construction and Building Materials
In this work, ZnO nanoneedles were synthesized employing a co-precipitation method. Further, white cement composites were prepared with ZnO filler of 5%, 10% and 15% by weight ratio. With the increasing concentration of ZnO in cement matrix the synergetic effect between ZnO and white cement matrix was observed through FE-SEM and UV–visible. We studied the photocatalytic degradation of pollutant (Rhodamine 6G) using ZnO nano-needles embedded in white cement matrix under ultraviolet irradiation (UV) along with enhanced hydrophobic nature and the antimicrobial property of the cement. The pseudo-first order kinetics was found in a photocatalytic process, and degradation rate constant was enhanced up to 0.147 min⁻¹ for ZnO modified cement which was significantly higher than the pure cement (0.037 min⁻¹). Antimicrobial studies were performed using bacterial strains Escherichia.coli (JM109, Promega Gram negative), Bacillus subtilis (MTCC121, Gram-positive) and fungal strain Aspergillus niger (MTCC281) for all the composites. A significant improvement in bacterial and fungal degradation was observed in ZnO modified cement than control and pure cement in a dose-dependent manner.
Fate of triazoles in softwood upon environmental exposure
2017, Chemosphere
Determining the fate of preservatives in commercial wood products is essential to minimize their losses and improve protective impregnation techniques. The fate of triazole fungicides in ponderosa pine wood was investigated in both outdoor and controlled-environment experiments using a representative triazole, tebuconazole (TAZ), which was accompanied by propiconazole (PAZ) in selected experiments. The study was designed to mimic industrial settings used in window frame manufacturing. To investigate the TAZ fate in detail, loosely and strongly bound fractions were differentiated using a multi-step extraction. The loosely bound TAZ fraction extracted through two sonications accounted for 85± 5% of the total TAZ, while the strongly bound TAZ was extracted only with an exhaustive Soxhlet extraction and corresponded to the remaining 15± 5%.
A significant fraction (∼80%) of the original TAZ remained in the wood despite a six-month exposure to harsh environmental conditions, maintaining wood preservation and assuring minimal environmental impact. Depletion of loosely bound TAZ was observed from cross-sectional surfaces when exposed to rain, high humidity and sunlight. Water leaching was deemed to be the major route leading to triazole losses from wood. Leaching rate was found to be slightly higher for TAZ than for PAZ. The contribution of bio-, photo- and thermal degradation of triazoles was negligible as both PAZ and TAZ sorbed in wood remained intact. Triazole evaporation was also found to be minor at the moderate temperature (20–25 °C) recorded throughout the outdoor study.
Identification and characterization of tebuconazole transformation products in soil by combining suspect screening and molecular typology
2016, Environmental Pollution
Citation Excerpt :
As TCZ TPs were extracted from the top 5 cm layer of soil, only those TPs present in that soil layer were studied. TP properties can strongly deviate from those of the parent molecule (Giacomazzi and Cochet, 2004) and might be vulnerable to leaching, runoff or volatilization, although the parent molecule is considered as relatively immobile or non-volatile (EFSA, 2008; Horn et al., 2003). Thus, TPs that potentially dissipated from the top soil layer, that were not extractable via our extraction method or that were not listed in the TP library slipped through the net of this study.
Pesticides generate transformation products (TPs) when they are released into the environment. These TPs may be of ecotoxicological importance. Past studies have demonstrated how difficult it is to predict the occurrence of pesticide TPs and their environmental risk. The monitoring approaches mostly used in current regulatory frameworks target only known ecotoxicologically relevant TPs. Here, we present a novel combined approach which identifies and categorizes known and unknown pesticide TPs in soil by combining suspect screening time-of-flight mass spectrometry with in silico molecular typology. We used an empirical and theoretical pesticide TP library for compound identification by both non-target and target time-of-flight (tandem) mass spectrometry, followed by structural proposition through a molecular structure correlation program. In silico molecular typology was then used to group TPs according to common molecular descriptors and to indirectly elucidate their environmental parameters by analogy to known pesticide compounds with similar molecular descriptors. This approach was evaluated via the identification of TPs of the triazole fungicide tebuconazole occurring in soil during a field dissipation study. Overall, 22 empirical and 12 yet unknown TPs were detected, and categorized into three groups with defined environmental properties. This approach combining suspect screening time-of-flight mass spectrometry with molecular typology could be extended to other organic pollutants and used to rationalize the choice of TPs to be investigated towards a more comprehensive environmental risk assessment scheme.
Comparison of resistance improvement to fungal growth on green and conventional building materials by nano-metal impregnation
2015, Building and Environment
Citation Excerpt :
Aspergillus species are frequently recovered on ceramic-type materials (concrete, mortar) and glues and paints [34,36]. Conventional antifungal additives to prevent fungal growth are often added in building materials, such as sodium polyborate, dichlofluanid, and so on [32,37–40]. However, the popularity of antifungal additives for indoor uses is limited due to its short-term effectiveness and potential health concerns [37,39].
This study is aimed for comparing the biological resistance of green and conventional building materials (BMs) before and after nano-metal treatment, as well as exploring best nano-metals to improve fungal growth resistance of BMs. The selected BMs include wooden flooring (WF), green wooden flooring (GWF), gypsum board (GB), green gypsum board (GGB), calcium silicate board (CSB), green calcium silicate board (GCSB), mineral fiber ceiling (MFC) and green mineral fiber ceiling (GMFC). The Aspergillus brasiliensis or Penicillium funiculosum was inoculated on each sample and their growth was visually evaluated according to ASTM G21-09.
The fungal growth without nano-metals on test materials did not show that green materials were more prone to fungal growth. After nano-metal treatment, the observed order of fungal growth resistance of nano-metals at their highest selected concentrations on test materials was nano-zinc = nano-copper > nano-silver for WF and GWF, nano-zinc > nano-silver = nano-copper for GB, nano-zinc > nano-silver > nano-copper for GGB, CSB and GCSB, nano-silver > nano-copper = nano-zinc for MFC, and nano-silver > nano-copper > nano-zinc for GMFC. Nano-zinc seems to be the most favorable nano-metal for wood and wood composite materials. Green materials were less resistant to fungi attack relative to their conventional counterparts treated by nano-metals, particularly GWF and WF. All test nano-metals failed to provide complete protection against fungal growth on the eight test BMs at the selected concentrations. However, the higher the nano-metal concentration was, the longer the lag period until growth began and fewer fungi grew on the materials.
Investigations on the emissions of biocides and PCBs under low volume conditions
2015, Chemosphere
Citation Excerpt :
The experiment performed at higher temperature has the highest SERa values as expected. Horn et al. (2003) published the SERa of dichlofluanid with a similar progress to the one presented here. The temperature influence was investigated to check if it is possible to obtain faster results as well as to achieve measurable emissions of higher SVOCs at higher temperatures as it could successfully be done for small samples in a Micro-Chamber/Thermal Extractor™ (μ-CTE™, Markes International) at 23 °C and 80 °C (Mull et al., 2013).
The aim of this study was the development of a low volume air sampling strategy for biocides and polychlorinated biphenyls (PCB) at low air change rates in modern, air-tight showcases as they are present in museums. Lindane, pentachlorophenol, dichlofluanid, tolyfluanid, isodrin, p,p-dichlorodiphenyl trichloroethane and permethrin were the biocides and PCB 28 and PCB 153 were the PCBs studied, all of which are semi volatile organic compounds (SVOC). Their occurrences in the museum environment originate from various sources e.g. preventive treatment of organic exhibits or organic building materials. Exhibits are long-term exposed to these pollutants due to storing in showcases or other storage equipment at low air change rates. To achieve air sampling under the aforementioned conditions the influences of temperature, air circulation, air change rate and relative humidity on the emission behavior of the selected biocides and PCBs had to be determined. This was carried out with pre-soaked wood samples in low volume air sampling experiments using 27 L test showcases and 23 L and 24 L emission test chambers and also diffusive sampling with glass as the sampling material.
Method development for the determination of wood preservatives in commercially treated wood using gas chromatography-mass spectrometry
2011, Analytica Chimica Acta
Citation Excerpt :
Up to date, the quality of a protective treatment and/or the determination of fungicide residue in various matrices (soils/sediments, aqueous samples, foods, pharmaceutical formulations, and wood) was assessed by means of gas (GC) or liquid chromatography (LC). Based on the fungicide or insecticide nature and chromatographic method applied, electron capture, nitrogen phosphorous, UV, mass spectrometric (MS), or ion mobility mass spectrometric (IMS) detectors were employed [2–13]. The majority of these studies focused only on determination of fungicides possessing similar chemical properties, such as triazoles [2,5,6,9].
Fungicides and insecticides are commonly used preservatives to protect wood products against microbiological degradations. Currently, there is a lack of analytical methods addressing the quantitative determination of a wide range of wood preserving species in wood matrices. In this study, a reliable method was developed for the determination of a mixture of wood preserving agents with differing chemical structures (i.e., properties), including tebuconazole (TAZ), propiconazole (PAZ), 3-iodo-2-propynyl butylcarbamate (IPBC), and permethrin (PER), in pine wood. The analyte recoveries obtained by Soxhlet and multiple-stage sonication extractions were compared. While both extraction methods yielded similar results (80–100%), Soxhlet extraction was found to be less labor-intensive and thus preferred providing also lower RSDs of 1–6%. In comparison to methanol, commonly used as an extraction solvent for triazoles, acetone yielded similar extraction efficiencies for all analytes while reducing the time of sample concentration. The solid phase extraction method for triazoles was adapted to allow for a separation of IPBC and PER from the wood matrix. As opposed to previous studies, three recovery standards were employed, which enabled the correction of individual analyte losses during the sample preparation. The matrix-affected limits of detection (LODs) using gas chromatography with mass spectrometric detection were nearly the same for triazoles 0.07 and 0.21 ng g⁻¹ for PAZ and TAZ in sapwood and 0.18 and 0.21 ng g⁻¹ in heartwood, respectively. Higher LODs were observed for IPBC and PER: 3.9 and 1.7 ng g⁻¹ in sapwood, and 2.0 and 6.0 ng g⁻¹ in heartwood, respectively. The recoveries in the wood submitted to commercial sample treatment showed gradient distribution of analytes depending on the penetration of the treatment.

View all citing articles on Scopus

View full text