title: Toxicokinetics of pyrene in the freshwater alga Chara rudis.
abstract: Chara has been suggested a good model to study uptake of xenobiotics into cytoplasm due to their large internode cells surrounded by a layer of cortex cells. We studied the uptake and elimination of pyrene (nominal concentration of 5 μg L(-1)) in the freshwater alga Chara rudis during 22 days in two treatments mimicking epilimnetic (warm and light) and hypolimnetic (cold and dark) conditions. The growth of Chara during the exposure was higher in epilimnetic conditions (40%) compared to both hypolimnetic pyrene exposed Chara and controls (epilimnetic and hypolimnetic, no pyrene). In the water, a more rapid dissipation of pyrene was observed in epilimnetic conditions, possibly as a result of the increased algal growth. In the cortex, pyrene, 1-OH-pyrene (minor metabolite) and an unknown hydrophobic major metabolite was measured. Pyrene amounts decreased over time, while amounts of the unknown metabolite increased. In internode cytoplasm, pyrene and 1-OH-pyrene showed initially increasing followed by decreasing trends, while the unknown metabolite was not detected. The total mass balance showed that we were able to account for the applied pyrene until 4 days of exposure. However, after this time, there was a significant decrease in amounts accounted for by fluorescence, suggesting that the metabolism of pyrene involves degradation of the ring structure. The degradation was larger in epilimnetic than hypolimnetic conditions.
authors.affiliation: Norwegian Institute for Water Research, Gaustadalléen 21, 0349 Oslo, Norway. Electronic address: mgr@niva.no.
authors.forename: Merete
authors.initials: M
authors.lastname: Grung
authors.affiliation: Norwegian Institute for Water Research, Gaustadalléen 21, 0349 Oslo, Norway.
authors.forename: Anders
authors.initials: A
authors.lastname: Ruus
authors.affiliation: Norwegian Institute for Water Research, Gaustadalléen 21, 0349 Oslo, Norway.
authors.forename: Susanne Claudia
authors.initials: SC
authors.lastname: Schneider
authors.affiliation: Norwegian Institute for Water Research, Gaustadalléen 21, 0349 Oslo, Norway.
authors.forename: Dag Øystein
authors.initials: DØ
authors.lastname: Hjermann
authors.affiliation: Norwegian Institute for Water Research, Gaustadalléen 21, 0349 Oslo, Norway; Department of Biosciences, University of Oslo, Pb. 1066 Blindern, 0316 Oslo, Norway.
authors.forename: Katrine
authors.initials: K
authors.lastname: Borgå
mesh_terms: D001673:Biodegradation, Environmental / Q000528:radiation effects*; D044784:Chara / Q000254:growth & development / Q000378:metabolism*; D005618:Fresh Water; D006358:Hot Temperature; D008027:Light; D011721:Pyrenes / Q000378:metabolism / Q000493:pharmacokinetics*; D013997:Time Factors; D066007:Toxicokinetics
chemical_list: D011721:Pyrenes; C030984:pyrene
keywords: 1-OH-pyrene; Bioaccumulation; Biodegradation; Biotransformation; PAH uptake; Phytoremediation