title: Effect of thiram and of a hydrocarbon mixture on freshwater macroinvertebrate communities in outdoor stream and pond mesocosms: I. Study design, chemicals fate and structural responses.
abstract: Higher-tier ecological risk assessment (ERA) in mesocosms is commonly performed in lotic or lentic experimental systems. These systems differ in their physico-chemical and hydrological properties, leading to differences in chemical fate, community characteristics and potential recovery. This raises the issue of the relevance and sensitivity of community-level endpoints in different types of mesocosms. In this study, macroinvertebrate abundance and biomass estimates were used to assess the effects of a dithiocarbamate fungicide, thiram (35 and 170 µg l(-1)), and a petroleum middle distillate (PMD; 0.01, 0.4, 2 and 20 mg l(-1)) in outdoor stream and pond mesocosms. Streams were continuously treated during 3 weeks followed by a 2-month long post-treatment period. Ponds were treated weekly for 4 weeks, followed by a 10-month long post-treatment period. Taxonomic structure of macroinvertebrate communities was characterized using the α, β and γ components of taxa richness, Shannon and Gini-Simpson indices. Computations were based either on abundance or biomass data. Results clearly highlighted that the effects of chemicals depended on the exposure regime (for thiram) and type of system (for the PMD). Causes of the differences between streams and ponds in the magnitude and nature of effects include differential sensitivity of taxa dwelling in lentic and lotic systems and the influence of hydrology (e.g., drift from upstream) and mesocosm connectivity on recovery dynamics. This study also showed complementarities in the use of both types of mesocosms to improve the characterization of chemical effects on communities in ERA.
authors.affiliation: INRA, UMR985 Écologie et Santé des Écosystèmes, Équipe Écotoxicologie et Qualité des Milieux Aquatiques, Agrocampus Ouest, 65 rue de Saint Brieuc, CS 84215, 35042, Rennes, France. y.bayona@gmail.com.|Service Environnement, TOTAL, Pôle d'Etude et de Recherche de Lacq RN 117, BP 47, 64170, Lacq, France. y.bayona@gmail.com.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Bayona
authors.affiliation: INRA, UMR985 Écologie et Santé des Écosystèmes, Équipe Écotoxicologie et Qualité des Milieux Aquatiques, Agrocampus Ouest, 65 rue de Saint Brieuc, CS 84215, 35042, Rennes, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Roucaute
authors.affiliation: Service Environnement, TOTAL, Pôle d'Etude et de Recherche de Lacq RN 117, BP 47, 64170, Lacq, France.
authors.forename: Kevin
authors.initials: K
authors.lastname: Cailleaud
authors.affiliation: INRA, UMR985 Écologie et Santé des Écosystèmes, Équipe Écotoxicologie et Qualité des Milieux Aquatiques, Agrocampus Ouest, 65 rue de Saint Brieuc, CS 84215, 35042, Rennes, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Lagadic
authors.affiliation: Service Environnement, TOTAL, Pôle d'Etude et de Recherche de Lacq RN 117, BP 47, 64170, Lacq, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Bassères
authors.affiliation: INRA, UMR985 Écologie et Santé des Écosystèmes, Équipe Écotoxicologie et Qualité des Milieux Aquatiques, Agrocampus Ouest, 65 rue de Saint Brieuc, CS 84215, 35042, Rennes, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Caquet
mesh_terms: D000818:Animals; D017753:Ecosystem; D005602:France; D005659:Fungicides, Industrial / Q000633:toxicity*; D007448:Invertebrates / Q000187:drug effects* / Q000502:physiology; D059392:Petroleum Pollution / Q000009:adverse effects*; D061005:Ponds / Q000032:analysis; D045483:Rivers; D013893:Thiram / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D005659:Fungicides, Industrial; D014874:Water Pollutants, Chemical; D013893:Thiram
keywords: Abundance; Biomass; Diversity components; Ecological risk assessment; Fungicide; Petroleum middle distillate; Recovery