title: Investigation of potential endocrine disrupting effects of mosquito larvicidal Bacillus thuringiensis israelensis (Bti) formulations.
abstract: Bti is successfully used as a biological control agent for mosquito control. It has proven to be ecological friendly, and thus, is used in ecologically sensitive habitats. Recent investigations of groundwater in Germany have detected estrogenic activity in five consecutive groundwater wells in a region where Bti is applied. Therefore, it was suspected that this compound can act as an environmental xenoestrogen. In the present study, five Bti formulations as well as the active ingredient, VectoBac® TP (TP), were investigated regarding their estrogenic activity using the LYES and ER CALUX® assays. Furthermore, their steroidogenesis disruption properties were studied using the H295R Steroidogenesis Assay. Additionally, field samples from a Bti application area as well as samples from an artificial pond were examined. Three of the Bti formulations and the active ingredient TP showed significant estrogenic activity in the LYES (up to 52 ng·l(-1) estradiol equivalents (EEQ) in the 18-fold concentration) and/or the ER CALUX® (up to 1 ng·EEQ·l(-1) in the 18-fold concentration). In the H295R significant but weak effects with no dose-response-relationship on the production of estradiol, and 21-hydroxyprogesterone (WDG) as well as testosterone (TP) by H295R cells could be observed. The field samples as well as the samples from the artificial pond showed no significant increase of estrogenic activity after application of TP or WDG in the ER CALUX®. With the exception of the controlled laboratory experiments with direct application of Bti to the utilized in vitro test systems the present study did not reveal any significant effects of Bti on endocrine functions that would indicate that the application of Bti could cause adverse endocrine effects to organisms in aquatic ecosystems. Instead, our results support previous studies that the use of Bti products against mosquitos would be safe even for sensitive habitats such as conservation areas.
authors.affiliation: RWTH Aachen University, Institute for Environmental Research, Department of Ecosystem Analysis, Worringer Weg 1, 52074 Aachen, Germany.
authors.forename: Sibylle
authors.initials: S
authors.lastname: Maletz
authors.affiliation: RWTH Aachen University, Institute for Environmental Research, Department of Ecosystem Analysis, Worringer Weg 1, 52074 Aachen, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Wollenweber
authors.affiliation: RWTH Aachen University, Institute for Environmental Research, Department of Ecosystem Analysis, Worringer Weg 1, 52074 Aachen, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Kubiak
authors.affiliation: RWTH Aachen University, Institute for Environmental Research, Department of Ecosystem Analysis, Worringer Weg 1, 52074 Aachen, Germany.
authors.forename: Annett
authors.initials: A
authors.lastname: Müller
authors.affiliation: RWTH Aachen University, Institute for Environmental Research, Department of Ecosystem Analysis, Worringer Weg 1, 52074 Aachen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schmitz
authors.affiliation: Heinrich-Sontheimer-Laboratories, Prüfstelle Wasser und Korrosion, Water Technology Center, Wasserwerkstr. 4, 76137 Karlsruhe, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Maier
authors.affiliation: University of Saskatchewan, Toxicology Centre, 44 Campus Drive, Saskatoon, Saskatchewan S7N 5B3, Canada; University of Saskatchewan, School of the Environment & Sustainability, 44 Campus Drive, Saskatoon, Saskatchewan S7N 5B3, Canada.
authors.forename: Markus
authors.initials: M
authors.lastname: Hecker
authors.affiliation: RWTH Aachen University, Institute for Environmental Research, Department of Ecosystem Analysis, Worringer Weg 1, 52074 Aachen, Germany; College of Resources and Environmental Science, Chongqing University, 1 Tiansheng Road, Beibei, Chongqing 400715, China; College of Environmental Science and Engineering and State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, 1239 Siping Road, Shanghai, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, China. Electronic address: Henner.Hollert@bio5.rwth-aachen.de.
authors.forename: Henner
authors.initials: H
authors.lastname: Hollert
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis; D001427:Bacterial Toxins / Q000633:toxicity*; D001681:Biological Assay; D009033:Culicidae; D052244:Endocrine Disruptors / Q000633:toxicity*; D005858:Germany; D009032:Mosquito Control / Q000379:methods; D010572:Pest Control, Biological / Q000379:methods
chemical_list: C049673:Bacillus thuringiensis ovicidal toxin; D001427:Bacterial Toxins; D052244:Endocrine Disruptors
keywords: Bacillus thuringiensis subsp. israelensis; ER CALUX®; Endocrine disruption; Groundwater; H295R Steroidogenesis assay; Surface water; Yeast estrogen screen