title: Toxicity and mutagenicity of low-metallic automotive brake pad materials.
abstract: Organic friction materials are standardly used in brakes of small planes, railroad vehicles, trucks and passenger cars. The growing transportation sector requires a better understanding of the negative impact related to the release of potentially hazardous materials into the environment. This includes brakes which can release enormous quantities of wear particulates. This paper addresses in vitro detection of toxic and mutagenic potency of one model and two commercially available low-metallic automotive brake pads used in passenger cars sold in the EU market. The model pad made in the laboratory was also subjected to a standardized brake dynamometer test and the generated non-airborne wear particles were also investigated. Qualitative "organic composition" was determined by GC/MS screening of dichloromethane extracts. Acute toxicity and mutagenicity of four investigated sample types were assessed in vitro by bioluminescence assay using marine bacteria Vibrio fischeri and by two bacterial bioassays i) Ames test on Salmonella typhimurium His(-) and ii) SOS Chromotest using Escherichia coli PQ37 strain. Screening of organic composition revealed a high variety of organic compounds present in the initial brake pads and also in the generated non-airborne wear debris. Several detected compounds are classified by IARC as possibly carcinogenic to humans, e. g. benzene derivatives. Acute toxicity bioassay revealed a response of bacterial cells after exposure to all samples used. Phenolic resin and wear debris were found to be acutely toxic; however in term of mutagenicity the response was negative. All non-friction exposed brake pad samples (a model pad and two commercial pad samples) were mutagenic with metabolic activation in vitro.
authors.affiliation: University of Ostrava, Institute of Environmental Technology, Chittussiho 10, 710 00 Ostrava, Czech Republic. Electronic address: katerina.malachova@osu.cz.
authors.forename: Katerina
authors.initials: K
authors.lastname: Malachova
authors.affiliation: VŠB - Technical University of Ostrava, Nanotechnology Centre, 17. listopadu 15, 708 33 Ostrava, Czech Republic. Electronic address: jana.kukutschova@vsb.cz.
authors.forename: Jana
authors.initials: J
authors.lastname: Kukutschova
authors.affiliation: University of Ostrava, Institute of Environmental Technology, Chittussiho 10, 710 00 Ostrava, Czech Republic.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Rybkova
authors.affiliation: University of Ostrava, Institute of Environmental Technology, Chittussiho 10, 710 00 Ostrava, Czech Republic.
authors.forename: Hana
authors.initials: H
authors.lastname: Sezimova
authors.affiliation: VŠB - Technical University of Ostrava, Nanotechnology Centre, 17. listopadu 15, 708 33 Ostrava, Czech Republic.
authors.forename: Daniela
authors.initials: D
authors.lastname: Placha
authors.affiliation: VŠB - Technical University of Ostrava, Nanotechnology Centre, 17. listopadu 15, 708 33 Ostrava, Czech Republic.
authors.forename: Kristina
authors.initials: K
authors.lastname: Cabanova
authors.affiliation: VŠB - Technical University of Ostrava, Nanotechnology Centre, 17. listopadu 15, 708 33 Ostrava, Czech Republic; Southern Illinois University Carbondale, Department of Mechanical Engineering and Energy Processes, Carbondale, IL 62901-4343, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Filip
mesh_terms: D001336:Automobiles; D002273:Carcinogens; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D005557:Formaldehyde / Q000633:toxicity*; D008401:Gas Chromatography-Mass Spectrometry; D008670:Metals / Q000737:chemistry / Q000633:toxicity*; D009152:Mutagenicity Tests; D009153:Mutagens; D009930:Organic Chemicals / Q000737:chemistry / Q000633:toxicity*; D052638:Particulate Matter / Q000633:toxicity; D010636:Phenols / Q000633:toxicity*; D011108:Polymers / Q000633:toxicity*; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000235:genetics
chemical_list: D002273:Carcinogens; D008670:Metals; D009153:Mutagens; D009930:Organic Chemicals; D052638:Particulate Matter; D010636:Phenols; D011108:Polymers; D005557:Formaldehyde; C011529:phenol-formaldehyde resin
keywords: Ames test; Bioluminescence assay; Brake pads; SOS Chromotest; Wear debris