Effects of a mixture of tetracyclines to Lemna gibba and Myriophyllum sibiricum evaluated in aquatic microcosms.
The impact of a mixture of oxytetracycline, chlortetracycline, tetracycline and doxycycline on Myriophyllum sibiricum and Lemna gibba was investigated using fifteen 12,000-L microcosms (k=5, n=3). Significant concentration-response relationships were only found for M. sibiricum, where dry mass was 69, 47, 30, and 7% of controls at respective treatment concentrations of 0.080, 0.218, 0.668, and 2.289 micromol/L. Somatic endpoints were strongly and negatively correlated with percent light transmission, except plant length, which was positively correlated. Treated microcosms experienced a reduction in the percent of surface irradiance penetrating the water column as high as 99.8% at a depth of 70 cm, relative to controls. Position relative to the water column was likely responsible for the differential effects observed between floating (L. gibba) and submerged (M. sibiricum) species of macrophytes. A hazard quotient assessment of the lowest EC10 value indicated significant risk, exceeding the critical HQ value, but not the lowest EC25 value.
Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1. rbrain01@uoguelph.ca
Richard A
RA
Brain
Christian J
CJ
Wilson
David J
DJ
Johnson
Hans
H
Sanderson
Ketut Jim
KJ
Bestari
Mark L
ML
Hanson
Paul K
PK
Sibley
Keith R
KR
Solomon
D000890:Anti-Infective Agents / Q000032:analysis / Q000633:toxicity*; D029064:Araceae / Q000187:drug effects; D002751:Chlortetracycline / Q000032:analysis / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D004318:Doxycycline / Q000032:analysis / Q000633:toxicity; D017753:Ecosystem; D004781:Environmental Exposure / Q000009:adverse effects; D005618:Fresh Water / Q000737:chemistry; D008027:Light; D019684:Magnoliopsida / Q000187:drug effects*; D010118:Oxytetracycline / Q000032:analysis / Q000633:toxicity; D018517:Plant Roots / Q000187:drug effects; D018570:Risk Assessment / Q000379:methods; D013752:Tetracycline / Q000032:analysis / Q000633:toxicity; D013754:Tetracyclines / Q000032:analysis / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
D000890:Anti-Infective Agents; D013754:Tetracyclines; D014874:Water Pollutants, Chemical; D013752:Tetracycline; D004318:Doxycycline; D002751:Chlortetracycline; D010118:Oxytetracycline