title: Ecotoxicological assessments show sucralose and fluoxetine affect the aquatic plant, Lemna minor.
abstract: Pharmaceuticals and personal care products (PPCP) are prevalent in aquatic systems, yet the fate and impacts on aquatic plants needs quantification for many compounds. We measured and detected sucralose (an artificial sweetener), fluoxetine (an antidepressant), and other PPCP in the Portneuf River in Idaho, USA, where Lemna minor (an aquatic plant in the environment and used in ecotoxicology studies) naturally occurs. Sucralose was hypothesized to negatively affect photosynthesis and growth of L. minor because sucralose is a chlorinated molecule that may be toxic or unusable for plant metabolism. A priori hypotheses were not created for fluoxetine due to lack of previous studies examining its impacts on plants. We conducted laboratory ecotoxicological assessments for a large range of concentrations of sucralose and fluoxetine on L. minor physiology and photosynthetic function. Frond green leaf area, root length, growth rate, photosynthetic capacity, and plant carbon isotopic composition (discrimination relative to a standard; δ13C) were measured among treatments ranging from 0 to 15000nmol/L-sucralose and 0-323nmol/L-fluoxetine. Contrary to our predictions, sucralose significantly increased green leaf area, photosynthetic capacity, and δ13C of L. minor at environmentally relevant concentrations. The increase of δ13C from sucralose amendments and an isotope-mixing model indicated substantial sucralose uptake and assimilation within the plant. Unlike humans who cannot break down and utilize sucralose, we documented that L. minor-a mixotrophic plant-can use sucralose as a sugar substitute to increase its green leaf area and photosynthetic capacity. Fluoxetine significantly decreased L. minor root growth, daily growth rate, and asexual reproduction at 323nmol/L-fluoxetine; however, ambiguity remains regarding the mechanisms responsible and the applicability of these extreme concentrations unprecedented in the natural environment. To our knowledge, this was the first study to show aquatic plants can uptake and metabolize sucralose as a carbon source. This study further supports the common notion that L. minor can be useful in bioremediation of PPCP from wastewaters.
authors.affiliation: Department of Biological Sciences, Idaho State University, MS 8007, Pocatello, ID 83209, United States.
authors.forename: Cherisse
authors.initials: C
authors.lastname: Amy-Sagers
authors.affiliation: Department of Biological Sciences, Idaho State University, MS 8007, Pocatello, ID 83209, United States.
authors.forename: Keith
authors.initials: K
authors.lastname: Reinhardt
authors.affiliation: Department of Biological Sciences, Idaho State University, MS 8007, Pocatello, ID 83209, United States. Electronic address: danellelarson77@gmail.com.
authors.forename: Danelle M
authors.initials: DM
authors.lastname: Larson
mesh_terms: D059001:Aquatic Organisms / Q000187:drug effects*; D029064:Araceae / Q000187:drug effects* / Q000254:growth & development; D054750:Ecotoxicology / Q000379:methods*; D005473:Fluoxetine / Q000633:toxicity*; D016014:Linear Models; D010788:Photosynthesis / Q000187:drug effects; D045332:Photosystem II Protein Complex / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000033:anatomy & histology / Q000187:drug effects; D045483:Rivers / Q000737:chemistry; D013395:Sucrose / Q000031:analogs & derivatives* / Q000633:toxicity; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D045332:Photosystem II Protein Complex; D014874:Water Pollutants, Chemical; D005473:Fluoxetine; D014867:Water; D013395:Sucrose; C026285:trichlorosucrose
keywords: Artificial sweetener; Bioremediation; Duckweed; Pharmaceuticals and personal care products (PPCP); Phytoremediation; Selective serotonin reuptake inhibitor; Water quality