title: Effects of mixtures of dissolved and particulate contaminants on phototrophic biofilms: new insights from a PICT approach combining toxicity tests with passive samplers and model substances.
abstract: Streams located in vineyard areas are particularly exposed to mixtures of dissolved and particulate contaminants such as metals and organic pesticides. In this context, phototrophic biofilms are increasingly used as indicators of river water contaminations through pollution-induced community tolerance (PICT) assessments based on short-term toxicity tests with individual or mixtures of toxicants. We conducted a laboratory experiment to evaluate the relative influence of the dissolved and particulate fractions on the effects of metals and pesticides on phototrophic biofilms in a context of contamination from a vineyard watershed. Three sets of artificial channels were supplied with (i) unfiltered water from a stream reference site, (ii) unfiltered water from a stream contaminated site, and (iii) filtered water (0.45 μm) from the same contaminated site. Biofilm growth, diatom community structure, and dissolved toxicant concentrations differed slightly between channels supplied with unfiltered or filtered water from the contaminated site. However, PICT assessments with individual toxicants or mixtures of toxicants extracted from passive samplers suggested no significant difference in tolerance to metals and organic pesticides between phototrophic communities supplied with unfiltered or filtered contaminated water. Our results confirm the use of extracts from passive samplers as a promising approach in short-term toxicity tests to characterize impacts of contamination on aquatic communities.
authors.affiliation: Irstea, UR MALY, Centre de Lyon-Villeurbanne, 5 rue de la Doua, CS 70077, 69626, Villeurbanne Cedex, France, arnaud.foulquier@gmail.com.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Foulquier
authors.forename: Soizic
authors.initials: S
authors.lastname: Morin
authors.forename: Aymeric
authors.initials: A
authors.lastname: Dabrin
authors.forename: Christelle
authors.initials: C
authors.lastname: Margoum
authors.forename: Nicolas
authors.initials: N
authors.lastname: Mazzella
authors.forename: Stéphane
authors.initials: S
authors.lastname: Pesce
mesh_terms: D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D017377:Diatoms / Q000187:drug effects*; D004361:Drug Tolerance; D004784:Environmental Monitoring / Q000379:methods / Q000706:statistics & numerical data*; D005602:France; D019216:Metals, Heavy / Q000633:toxicity*; D010575:Pesticides / Q000633:toxicity*; D045483:Rivers / Q000737:chemistry*; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D019216:Metals, Heavy; D010575:Pesticides; D014874:Water Pollutants, Chemical