title: Immediate and mid-term effects of pyrimethanil toxicity on microalgae by simulating an episodic contamination.
abstract: Since pesticides can represent a threat for non-target aquatic communities, including microalgae, we looked at the effects of the fungicide pyrimethanil on the growth of the freshwater green microalgae Selenastrum capricornutum. Additionally, attenuation of the toxicity of pyrimethanil due to its dissipation in the water was assessed. Pyrimethanil-contaminated samples were taken from outdoor mesocosms one (1.4 mg L(-1) of pyrimethanil) and ten (0.78 mg L(-1) of pyrimethanil) days after pyrimethanil application. Different dilutions were prepared using both nutrient-rich culture medium (LC Oligo) and non-contaminated mesocosm samples, and cell growth inhibition was assessed. Reference mesocosm samples were also diluted with LC Oligo in order to verify how the nutrient concentration in the LC Oligo could improve cell growth. Comparing cell growth of population exposed to pyrimethanil-treated sample taken at day 1 with cells growing in reference sample and LC Oligo, the growth inhibition was 80% (± 6.5) and 95% (± 2.0), respectively. The toxicity of samples taken from contaminated mesocosms at day 10 was attenuated to 34% (± 15) (when compared with reference sample) and 88% (± 3.0) (when compared with LC Oligo), as pyrimethanil concentrations in the mesocosms decreased. In conclusion, (i) pyrimethanil can be an environmental disturber for the microalgae; (ii) the toxicity of pyrimethanil in water was reduced almost 2.4 times (when compared with the reference sample) at as short a period as 10d if assuming that pesticide entrance is not continuous; (iii) toxicity of an environmental sample could be underestimated if the sample/medium used in dilution presents different nutrient levels.
authors.affiliation: IMAR-Instituto do Mar & MARE-Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, Apartado 3046, 3001-401 Coimbra, Portugal; Escuela de Ciencias Agrícolas y Ambientales, Pontificia Universidad Católica del Ecuador - Sede Ibarra, Ibarra, Ecuador. Electronic address: candida.shinn@gmail.com.
authors.forename: Cândida
authors.initials: C
authors.lastname: Shinn
authors.affiliation: Center for Water Resources and Applied Ecology, University of São Paulo, São Carlos, Brazil.
authors.forename: Danieli
authors.initials: D
authors.lastname: Delello-Schneider
authors.affiliation: Center for Water Resources and Applied Ecology, University of São Paulo, São Carlos, Brazil.
authors.forename: Lucas B
authors.initials: LB
authors.lastname: Mendes
authors.affiliation: Center for Water Resources and Applied Ecology, University of São Paulo, São Carlos, Brazil.
authors.forename: André L
authors.initials: AL
authors.lastname: Sanchez
authors.affiliation: Biodiversity and Climate Research Centre (BiK-F), Department Climate and Adaptation, Frankfurt, Germany.
authors.forename: Ruth
authors.initials: R
authors.lastname: Müller
authors.affiliation: Center for Water Resources and Applied Ecology, University of São Paulo, São Carlos, Brazil.
authors.forename: Evaldo L G
authors.initials: EL
authors.lastname: Espíndola
authors.affiliation: IMAR-Instituto do Mar & MARE-Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, Apartado 3046, 3001-401 Coimbra, Portugal; Central Department of Research, Universidad Laica Eloy Alfaro of Manabí (ULEAM), Ciudadela Universitaria, vía San Mateo, Manta, Ecuador.
authors.forename: Cristiano V M
authors.initials: CV
authors.lastname: Araújo
mesh_terms: D000460:Chlorophyta; D005659:Fungicides, Industrial / Q000633:toxicity*; D058086:Microalgae / Q000187:drug effects*; D011743:Pyrimidines / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D005659:Fungicides, Industrial; D011743:Pyrimidines; D014874:Water Pollutants, Chemical; C108337:pyrimethanil
keywords: Environmental contamination; Phytoplankton; Pyrimethanil degradation; Selenastrum capricornutum