Biocidal Products Research Articles

Testing the antibacterial activity of doped TiO2 for preventing biodeterioration of cultural heritage building materials

Application of biocide products, alone or in combination with protective or consolidants, is a common practice to prevent further colonization on monuments surface. TiO2 is as one of the most fascinating materials characterized by chemical stability, non-toxicity, high photo-reactivity, broad-spectrum antibiosis and cheapness, and it has been used extensively as biocide against various microorganisms: bacteria, fungi and viruses. Its problem is that its reactivity is due to a restricted wavelength in the UV region and thus its application can be limited in certain circumstances (e.g. indoors). Recently, alkaline-earth metal ions have been considered as promising, efficient and economic approaches for doping the TiO2 because they have a larger photocatalytic spectrum.M–TiO2 thus may be more effective in the protection and maintenance of stone surfaces than pure TiO2 in reducing the biodeterioration processes. However before any application on monument surfaces, the products must be tested not only for their biocide efficacy but also for being harmless to cultural heritage material.To fulfil this requirement, a set of experiments has been carried out testing M-doped TiO2 compounds for their efficiency as photocatalysts, for the chromatic changes induced by their application on stone surfaces and for their antibacterial activity against selected Gram positive and Gram negative bacteria.Our results showed that TiO2 doped with Ag alone or in combination Fe3+ or with Sr has antibacterial activity and could be successfully applied in field to prevent stone biodeterioration.

Laboratory leaching tests on treated wood according to different harmonised test procedures

Laboratory leaching tests on treated wood were performed during a European robustness study in the framework of the validation of a tank leaching test procedure that has been proposed for construction products in order to determine the potential release of dangerous substances which can be transferred to soil and groundwater. The release of substances has to be determined also for materials treated with biocidal products according to the requirements of the European Biocidal Products Regulation. A similar leaching test procedure was already harmonised for treated wood for this purpose. Both test procedures were applied in parallel to wood treated with the same preservative to investigate whether the results of these tests can replace each other. Additional experiments were performed to further investigate unexpected effects of L/A ratio on leaching of copper and duration of storage of treated test specimens. Both procedures generate similar results concerning cumulative emissions of tebuconazole, copper, dissolved organic carbon and total nitrogen. The emission rates with time are in comparable ranges for both leaching protocols. Emissions of copper increased with decreasing L/A ratios. Strong correlation of copper concentrations and dissolved organic carbon as well as total nitrogen concentrations in eluates indicates that this observation is caused by co-elution of copper with organic substances. Duration of storage of treated test specimens affected emissions for the investigated wood preservative. Based on these findings, results from both test procedures can be used to describe leaching characteristics and avoid double testing of treated wood to fulfil the requirements of the European regulations for either biocides or construction products. Leaching of substances from treated wood is a complex process that depends on its chemical composition and ageing processes.

Paradigm shift in the risk assessment of cumulative effects of pesticide mixtures and multiple residues to humans and wildlife: German proposal for a new approach

A paradigm shift is underway in the risk assessment of chemicals leaving behind the traditional ‘‘individual substance approach.’’ This simplified approach has long been criticized for not adequately taking into consideration the well-known occurrence of chemical mixtures in relevant exposure matrices (foodstuff, environmental media) and thus ignoring the ‘‘added risk’’ resulting from multiple exposure and associated mixture toxicity. More recently, the adequacy of this approach was also questioned from the political arena in Europe (Council of the European Union 2009; European Commission 2012). As a consequence, several reviews of the state-of-thescience as well as opinions on the implementation of mixture risk assessment in chemicals regulation have been delivered. Further, the principal request for taking the risk of mixtures into due account has been introduced in recently updated European chemicals legislations, e.g. for plant protection products (PPP) and biocidal products (BP). For PPP, regulation (EC) No 1107/2009 (European Commission 2009) requires in article 29 that ‘‘interaction between the active substance, safeners, synergists and co-formulants shall be taken into account’’ in the evaluation and authorization. This explicitly refers to marketed PPP, which are by origin technical mixtures containing one to several active substances plus typically several co-formulants. Consequently, the ‘‘mixture toxicity issue’’ for these technical mixtures is already mirrored in the standard data requirements for PPP. However, common agricultural practice comprises also the application of two or more PPP simultaneously (tank-mixtures prepared by the farmers directly before application) as well as the sequential application of several different PPP during the growing season (serial applications). Hence, there is well-justified concern for exposure of humans and non-target organisms towards ‘‘coincidental’’ pesticide (residue) mixtures resulting from common agricultural practice. Regarding human health risk assessment, a general and explicit request is laid down in the regulation (EC) No. 1107/2009, stating that PPP and their residues ‘‘[...] shall have no immediate or delayed harmful effect on human health, [...], taking into account known cumulative and synergistic effects where the scientific methods accepted by the Authority to assess such effects are available; [...].’’ With regard to the environmental risk assessment in the standard data requirements for PPP a quite similar sentence is included. While there are clear regulatory requirements on adequately considering the risk from exposure to PPP (residue) mixtures, often the lack of agreed and sufficiently specific technical guidance is the major obstacle for a consistent and adequate implementation of mixture risk assessment under regulation M. Streloke (&) Federal Office of Consumer Protection and Food Safety (BVL), Messeweg 11/12, 38104 Brunswick, Germany e-mail: martin.streloke@bvl.bund.de

Human health risk assessment from combined exposure in the framework of plant protection products and biocidal products

Cumulative risk assessment (CRA) is of major importance and one of the biggest challenges for the future as a legal requirement within the EU for active substances used in plant protection products (PPP) and biocidal products (BP). Therefore, it is important to develop a methodology to take into account cumulative and synergistic effects for both active substances and substances of concern (SoC). The implementation of cumulative aspects in regulatory decisions is highly demanded and promoted by EU parliament, EU commission, European Food Safety Authority (EFSA), European Chemicals Agency (ECHA) and national authorities. Based on EFSA’s and ECHA’s work on CRA, the Federal Institute for Risk Assessment (BfR) drafted a concept on how to take cumulative aspects into account in the regulatory context in risk assessments for operators, consumers and other uninvolved third parties. Application of this concept as part of the routine risk assessment for PPP and BP is envisaged as soon as suitable experience has been gained in a testing phase. The BfR draft concept uses dose-addition of individual active substances and SoC as the toxicological standard concept for CRA and proposes a tiered approach. It recommends to start with calculation of a hazard index (HI) for all relevant substances contained in the PPP or BP under consideration. Proceeding to higher tiers is currently foreseen if the HI is larger than 1, i.e., an unacceptable risk cannot be excluded. In higher tiers, the HI should be calculated with respect to common targets and might consider effect-specific NOAEL’s (No Observed Adverse Effect Level) or relative potency factors, if available. Refinements should consider both the toxicity and the exposure part of the CRA and will depend on availability of relevant data. BfR acknowledges the complexity of the refinement work in mixture risk assessment to be done. The exposure assessment for operators, bystanders/residents and workers as well as the acute exposure assessment for consumers rely mainly on the active substances in a PPP or BP under consideration or on combinations of products for which simultaneous use is notified. Chronic consumer exposure assessment needs to take into account all relevant substances contained in the PPP or BP under consideration, but also the residue background of other pesticides in food, which have to be derived from representative food monitoring programmes. A representative food monitoring database is currently being developed. The assessment requires the application of complex probabilistic methods. It is planned that BfR will review the chronic CRA for each active substance and each CAG regularly as soon as all essential monitoring data are available. It is planned to carry out case studies on the impact on regulatory decisions. The paper is intended to promote further discussions of risk assessors, risk managers as well as stakeholders in this area on the applicability of CRA in routine authorisation procedures for PPP and BP and to encourage the flexible use of strategies in CRA.

Outcome of the Public Consultation on the draft EFSA Guidance Document on the Assessment of Exposure for Operators, Workers, Residents and Bystanders in Risk Assessment for Plant Protection Products

EFSA Supporting PublicationsVolume 11, Issue 10 681E Technical reportOpen Access Outcome of the Public Consultation on the draft EFSA Guidance Document on the Assessment of Exposure for Operators, Workers, Residents and Bystanders in Risk Assessment for Plant Protection Products European Food Safety Authority (EFSA), European Food Safety Authority (EFSA)Search for more papers by this author European Food Safety Authority (EFSA), European Food Safety Authority (EFSA)Search for more papers by this author First published: 23 October 2014 https://doi.org/10.2903/sp.efsa.2014.EN-681 Published date: 23 October 2014 Question number: EFSA-Q-2014-00081 AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat References EC (European Commission), 2009. Directive 2009/128/EC of the European Parliament and of the Council of 21 October 2009 establishing a framework for Community action to achieve the sustainable use of pesticides. EFSA Panel on Plant Protection Products and their Residues (PPR), 2008 Scientific Opinion of the Panel on Plant protection products and their Residues (PPR) on the Science behind the Guidance Document on Risk Assessment for birds and mammals. Revision of Guidance Document under Council Directive 91/414/EEC (SANCO/4145/2000 – final of 25 September 2002). EFSA Journal (2008) 734: 1– 181 EFSA Panel on Plant Protection Products and their Residues (PPR), 2013. Scientific Opinion on the developmental neurotoxicity potential of acetamiprid and imidacloprid. EFSA Journal 2013; 11(12): 3471. doi:10.2903/j.efsa.2008.734. EFSA Scientific Committee, 2013. Scientific Opinion on the hazard assessment of endocrine disruptors: Scientific criteria for identification of endocrine disruptors and appropriateness of existing test methods for assessing effects mediated by these substances on human health and the environment. EFSA Journal 2013; 11(3):3132 84 pp. doi:10.2903/j.efsa.2013.3132. Fantke P, Juraske R, 2013. Variability of Pesticide Dissipation Half-Lives in Plants, Environmental Science & Technology, 47 (8), pp 3548– 3562 Koenker R, 2005. Quantile Regression. Economic Society Monographs No 38, ed. by A Chesher and M Jackson, Cambridge University Press, 368 pp. Krishnamoorthy K, 2006. Handbook of statistical distributions with applications, Chapman & Hall, section 10.4.3, p. 130 OECD (Organisation for Economic Co-operation and Development), 1997. Guidance document for the conduct of studies of occupational exposure to pesticides during agricultural application. Series on testing and assessment no 9. Geisser S, 1993. Predictive inference: an introduction, Chapman & Hall, section 2.1, example 2.2, p. 9– 10. PSD (Pesticide Safety Directorate). Bystander exposure guidance. Available online: http://www.pesticides.gov.uk/Resources/CRD/Migrated-Resources/Documents/B/Bystander-exposure-guidance.pdf Siebers JN, Binner R and Wittich KP, 2003. Investigation on downwind short-range transport of pesticides after application in agricultural crops. Chemosphere, 51, 397– 407. TNsG (2002) Human exposure to Biocidal Products—Guidance on exposure estimation (June 2002), TNsG (2007) Human exposure to Biocidal Products (June 2007). US Environmental Protection Agency (EPA) Advisory Panel on reentry exposure (http://www.epa.gov/opp00001/science/USEPA-OPP-HED_ExpoSAC%20Policy%203_July2012.pdf). US Environmental Protection Agency (EPA) Health Effects Division Office of Pesticide Programs (2012). Standard Operating Procedures for Residential Pesticide Exposure Assessment (available at http://www.epa.gov/opp00001/science/USEPA-OPP-HED_Residential%20SOPs_Oct2012.pdf) Volume11, Issue10October 2014681E ReferencesRelatedInformation

Regulacja prawna wprowadzania do obrotu produktów biobójczych w świetle rozporządzenia Parlamentu Europejskiego i Rady nr 528/2012 - wybrane zagadnienia

The legal regulation of the placing of biocidal products on the market is currently characterized by coexistence of national non-harmonized legal acts and directly effective EU legislation, such as the Regulation No. 528/2012 of the European Parliament and of the Council dated 22 May 2012 concerning the making available on the market and use of biocidal products, that as of 1 September 2013 superseded the previous directive 98/8/EC. The above inconsistency stems partially from the ongoing biocide active substance review program, the conclusion of which (planned on 31 December 2024) is to lead to realization of a coherent system of rationing of biocides within the EU.The study contains the most important modifications of the legal status resulting from the establishment of the Regulation No. 528/2012. It briefly referred to the material scope of the act and its basic assumptions, the legal definition of biocidal products and the classification thereof, and it indicated the modes of granting and changing the authorisations for biocides, as well as the issue of active substances and biocides data protection.In the summary, a synthetic assessment of the act was made, emphasizing its role in establishing integrated administrative procedures in the cases of individual authorisations for biocides, issued by both national bodies and the European Commission.

Risk assessment of biocidal product containing a substance of concern

Risk assessment of biocidal product containing a substance of concern

Acute toxicity of tralopyril, capsaicin and triphenylborane pyridine to marine invertebrates.

A need for environmentally acceptable alternative antifouling (AF) biocides has arisen through restrictions in the use of many common biocides in the European Union through the Biocidal Product Regulation (Regulation EU No. 528/2012). Three such alternatives are triphenylborane pyridine (TPBP), tralopyril and capsaicin. This study aims at extending the available information on the toxicity of these three emerging AF biocides to key marine invertebrates. Here we investigate the toxicity of tralopyril and capsaicin to the early life stages of the mussel Mytilus galloprovincialis and the sea urchin Paracentrotus lividus and also of tralopyril, capsaicin and TPBP to the early life stages of the copepod Tisbe battagliai. The EC50 that causes abnormal development of mussel's D-veliger larvae and impairs the growth of sea urchin pluteus larvae are respectively 3.1 and 3.0 μg/L for tralopyril and 3,868 and 5,248 μg/L for capsaicin. Regarding the copepod T. battagliai, the LC50 was 0.9 μg/L for tralopyril, 1,252 μg/L for capsaicin and 14 μg/L for TPBP. The results obtained for the three substances are compared to a reference AF biocide, tributyltin (TBT), and their ecological risk evaluated. These compounds pose a lower environmental risk than TBT but still, our results suggest that tralopyril and TPBP may represent a considerable threat to the ecosystems.

Spraying It Safe

Mosquitoes can sniff out carbon dioxide and lactic acid generated by humans 100 feet away. Along with their ability to detect heat and movement, this makes them highly effective hunters. Europeans collectively spray and pour hundreds of tons of repellents onto their skin every year in a bid to deter these bloodsucking insects—as well as gnats, midges, and more—from taking a bite. However, the safety of these repellents isn’t fully understood. To address that lack, an assessment is now under way in Europe via the recently introduced Biocidal Products Regulation. Under BPR, toxicology data for each active ingredient must be submitted to the European Chemicals Agency by the end of 2015. Toxicology data gathered in recent years under legislation that preceded BPR can also be used. The ingredients must then pass a vote by the 28 European member states to determine if they should be licensed for sale. The process ...

The Conferral of Power to the Commission Put to the Test

Case C-427/12 Commission v European Parliament and Council (not yet reported)- Article 290 TFEU- Article 291(2) TFEU- Article 80(1) of Regulation (EU) No 528/2012 of the European Parliament and of the Council of 22 May 2012 concerning the making available on the market and use of biocidal products, OJ 2012 L 167/11.The EU legislature has discretion when it decides to confer a delegated power on the Commission pursuant to Article 290(1) TFEU or an implementing power pursuant to Article 291(2) TFEU. Consequently, judicial reviewis limited tomanifest errors of assessment (official headnote)2.The Commission appears to have more liberty under Article 290 TFEU than Article 291(2) TFEU, however this may be misleading. The difference between adding “further details” (implementing act) and supplementing or amending non-essential elements to a basic act (delegated act) is difficult to gauge. Furthermore, the control foreseen to be exercised by the Member States and the Parliament and Councilmay not function as planned (author's headnote).

Alkyl ammonium cation stabilized biocidal polyiodides with adaptable high density and low pressure.

The effective application of biocidal species requires building the active moiety into a molecular back bone that can be delivered and decomposed on demand under conditions of low pressure and prolonged high-temperature detonation. The goal is to destroy storage facilities and their contents while utilizing the biocidal products arising from the released energy to destroy any remaining harmful airborne agents. Decomposition of carefully selected iodine-rich compounds can produce large amounts of the very active biocides, hydroiodic acid (HI) and iodine (I2). Polyiodide anions, namely, I3(-), I5(-), which are excellent sources of such biocides, can be stabilized through interactions with large, symmetric cations, such as alkyl ammonium salts. We have designed and synthesized suitable compounds of adaptable high density up to 3.33 g cm(-3) that are low-pressure polyiodides with various alkyl ammonium cations, deliverable iodine contents of which range between 58.0-90.9%.

Health risks from pest control products

According to European biocide legislation, pest control products require assessment and authorization by the responsible national or European authorities. Biocidal products can only be authorized if they have no unacceptable effects on human health. The health risk assessment performed for authorization comprises (a) the derivation of reference values for the active substances and substances of concern contained in the biocidal product and (b) an exposure assessment. These parameters are required for risk characterization. No unacceptable health risks are expected if the determined exposure is less than the relevant reference value. In addition, the toxicological information is used for classification of the biocidal product. The assessment may, where necessary, result in specific conditions for use or other restrictions aimed at minimizing risk. The risk to human health from pest control products is mainly based on the toxicological properties of their active substances. Commonly, the coformulants used in pest control products are of less concern than the active substances (e.g., food ingredients and animal feed products). For example, most rodenticides belong to the group of anticoagulants, which are also effective in humans. Regarding intoxications through insecticides, the group of pyrethroids is of particular importance. Fumigants containing metal phosphides, hydrogen cyanide, or sulfuryl difluoride are particularly toxic. This toxicity is linked to the high acute inhalation toxicity of the gaseous active substances themselves or, in the case of phosphides, of the released gas phosphane. The aim of health risk assessment for the authorization of biocidal products is to ensure their safe application for users and all other persons involved, assuming an adequate and label-compliant use.

Public health pests. Arthropods and rodents as causative disease agents as well as reservoirs and vectors of pathogens

Globally, infectious diseases pose the most important cause of death. Among known human pathogenic diseases, approximately 50 % are zoonoses. When considering emerging infectious diseases separately 73 % currently belong to the group of zoonoses. In Central Europe, hard ticks show by far the biggest potential as vectors of agents of human disease. Lyme borreliosis, showing an estimated annual incidence between 60,000 and 214,000 cases is by far the most frequent tick-borne disease in Germany. Continually, formerly unknown disease agents could be discovered in endemic vector species. Additionally, introduction of new arthropod vectors and/or agents of disease occur constantly. Recently, five mosquito species of the genus Aedes have been newly introduced to Europe where they are currently spreading in different regions. Uncommon autochthonous transmission of dengue and chikungunya fever viruses in Southern Europe could be directly linked to these vector species and of these Ae. albopictus and Ae. japonicus are currently reported to occur in Germany. The German Protection against Infection Act only covers the control of public health pests which are either active hematophagous vectors or mechanical transmitters of agents of diseases. Use of officially recommended biocidal products aiming to interrupt transmission cycles of vector-borne diseases, is confined to infested buildings only, including sewage systems in the case of Norway rat control. Outdoor vectors, such as hard ticks and mosquitoes, are currently not taken into consideration. Additionally, adjustments of national public health regulations, detailed arthropod vector and rodent reservoir mapping, including surveillance of vector-borne disease agents, are necessary in order to mitigate future disease risks.

Reduction of healthcare-associated infections in a long-term care brain injury ward by replacing regular linens with biocidal copper oxide impregnated linens

Contaminated textiles in hospitals contribute to endogenous, indirect-contact, and aerosol transmission of nosocomial related pathogens. Copper oxide impregnated linens have wide-spectrum antimicrobial, antifungal, and antiviral properties. Our aim was to determine if replacing non-biocidal linens with biocidal copper oxide impregnated linens would reduce the rates of healthcare-associated infections (HAI) in a long-term care ward. We compared the rates of HAI in two analogous patient cohorts in a head injury care ward over two 6-month parallel periods before (period A) and after (period B) replacing all the regular non-biocidal linens and personnel uniforms with copper oxide impregnated biocidal products. During period B, in comparison to period A, there was a 24% reduction in the HAI per 1000 hospitalization-days (p<0.05), a 47% reduction in the number of fever days (>38.5°C) per 1000 hospitalization-days (p<0.01), and a 32.8% reduction in total number of days of antibiotic administration per 1000 hospitalization-days (p<0.0001). Accordingly there was saving of approximately 27% in costs of antibiotics, HAI-related treatments, X-rays, disposables, labor, and laundry, expenses during period B. The use of biocidal copper oxide impregnated textiles in a long-term care ward may significantly reduce HAI, fever, antibiotic consumption, and related treatment costs.

Are acute and chronic saltwater fish studies required for plant protection and biocidal product active substance risk assessment?

The acute and chronic toxicity of chemicals to fish is routinely assessed using fish acute and early life stage (ELS) test results, usually with freshwater species. Under some regulations with certain substances, however, data on saltwater species may also be required. Evidence from earlier studies suggests that saltwater fish species are generally no more sensitive than freshwater species and that when they are more sensitive to a substance the difference in sensitivity is usually less than a factor of 10. However, most of these studies concentrated on acute lethal toxicity results for a wide range of substances and across a range of taxonomic groups. In the present study, the authors compare freshwater and saltwater acute median lethal concentration (LC50) and chronic ELS no-observed-effect concentration (NOEC) results from standardized regulatory studies specifically for fish species exposed to the same plant protection or biocidal product active substances to determine the value of testing in both freshwater and saltwater fish. The results suggest that, in most cases, use of a freshwater fish 96-h LC50 or longer-term ELS NOEC should be sufficient to protect saltwater species. In a small number of cases (12%), saltwater ELS NOECs were more sensitive by a factor >10, although differences in sensitivity were not consistent for this small number of substances when 96-h LC50 and longer-term ELS NOECs were compared. It is debatable whether such a low probability merits the additional animal use required to run saltwater fish tests, especially when onshore contaminants released to estuaries and coastal environments are likely to be diluted many-fold when compared with concentrations found in freshwaters.

Human body preservation - old and new techniques.

This review deals with the art of (anatomical) embalming. The first part contains a brief historical review of the history of embalming, starting with ancient cultures such as the Egyptians and the lesser known Chinchorro culture, then going down the centuries and describing the anatomical techniques developed over the last two centuries. The second part deals in detail with the chemicals used for embalming purposes. The third part deals with several approaches to evaluating embalming methods, their suitability for biomechanical testing, antimicrobial properties, histological appearance, and usability. The fourth and final part analyze the European Biocidal Products Directive (98/8/EC) in the light of embalming.

Predicting acute and chronic effects of wood preservative products in daphnia magna and pseudokirchneriella subcapitata based on the concept of concentration addition

The current European legislation requires that combined effects of the active substances and any substance of concern contained in biocidal products are taken into account in environmental risk assessment. The hypothesis whether the consideration of active substances together with all formulation additives that are labeled as presenting an environmental hazard is sufficient for a reliable environmental risk assessment was tested in the present study by investigating 3 wood preservative products. Relevant single substances in the products, some of their generic mixtures, the biocidal products themselves, and aqueous eluates prepared from the products (representing potential environmental mixtures) were tested for effects on algal growth and Daphnia acute immobilization as well as reproduction. Predictions for the products and the eluates were based on the concept of concentration addition and were mostly found to provide reliable or at least protective estimates for the observed acute and chronic toxicity of the mixtures. The mixture toxicity considerations also indicated that the toxicity of each product was dominated by just 1 of the components, and that assessments based only on the dominating substance would be similarly protective as a full-mixture risk assessment. Yet, there remained uncertainty in some cases that could be related to the toxicity of transformation products, the impact of unidentified formulation additives, or synergistic interaction between active substances and formulation additives.

Detection of Pesticide Residues in Organic and Conventional Fruits and Vegetables Available in Ireland Using Gas Chromotography/Tandem Mass Spectrometry (GC-MS/MS) and Liquid Chromotography/Tandem Mass Spectrometry (LC-MS/MS) Detection

Pesticides are chemical, biocidal products that are used for the control of organisms that effect plant, human or animal health, in particular when the organisms cause damage to natural or manufactured products e.g. food crops.

EN

The REACH (Registration, Evaluation, Authorization and restriction of Chemicals) and BPR (Biocide Product Regulation) regulations strongly promote the use of non-animal testing techniques to evaluate chemical risk. This has renewed the interest towards alternative methods such as QSAR in the regulatory context. The assessment of Bioconcentration Factor (BCF) required by these regulations is expensive, in terms of costs, time, and laboratory animal sacrifices. Herein, we present QSAR models based on the ANTARES dataset, which is a large collection of known and verified experimental BCF data. Among the models developed, the best results were obtained from a nine-descriptor highly predictive model. This model was derived from a training set of 608 chemicals and challenged against a validation and blind set containing 152 and 76 chemicals. The model's robustness was further controlled through several validation strategies and the implementation of a multi-step approach for the applicability domain. Suitable safety margins were used to increase sensitivity. The easy interpretability of the model is ensured by the use of meaningful biokinetics descriptors. The satisfactory predictive power for external compounds suggests that the new models could represent a reliable alternative to the in vivo assay, helping the registrants to fulfill regulatory requirements in compliance with the ethical and economic necessity to reduce animal testing.

Refined Exposure Assessment for Three Active Ingredients of Humidifier Disinfectants

Exposure assessment for three major active ingredients used for humidifier disinfectants, polyhexamethylene guanidine (PHMG), oligo(2-(2-ethoxy)ethoxyethyl guanidinium chloride (PGH), and 5-chloro-2-methylisothiazol-3(2H)-one/2-methylisothiazol-3(2H)-one (CMIT/MIT) mixture, was conducted in a bedroom using an air sampler for a refined risk assessment. The experimental site was selected to reflect consumer exposure conditions. Aerosols formed by a humidifier were sampled during 8 hr at 7.5 L/min. Absorbed PHMG and PGH by the sampler were quantified using a spectrophotometric method, and high performance liquid chromatography-ultraviolet detection was used for CMIT/MIT. Three exposure scenarios were assumed for adding humidifier disinfectants to the humidifier water at 1, 2, and 10 times the volume recommended by the product suppliers, and the humidifier was on at its maximum rate of producing aerosols in order to consider reasonable worst-cases. The sampled mass of PHMG and PGH ranged 200 to 2,800 μg and 140 to 1,900 μg, respectively, under different exposure conditions, whereas the absorbed mass of CMIT/MIT was barely detected at the detection limit of 0.11/0.29 mg/L, only at 10 times the recommended level. The resulting risk quotients for PHMG and PGH ranged 1,400 to 20,000 and 1,000 to 13,000, indicating that health risks could be significant. For CMIT/MIT mixture, risk quotients were much smaller than estimated by assuming that they are conservative in the indoor environment, probably due to oxidative reactions. The refined exposure assessment presented here may provide a useful tool for assessing risks posed by active ingredients in spray-type biocidal products. Keywords: Air sampler, chloromethyl/methyl isothiazolinone (CMIT/MIT), Indoor air, polyhexmethylene biguanidine (PHMG), Risk assessment