4 research outputs found
Perylene toxicity in the estuarine environment of Ria de Aveiro (Portugal)
Perylene, a 5-ring polycyclic aromatic hydrocarbon is common in estuarine sediments and its toxicity in the benthic and planktonic compartments is not yet clarified. The objectives of this work were: (1) to follow the toxicity of high concentrations of perylene (110 mg lâ1) on benthic bacteria and macrofauna (amphipod Corophium multisetosum); (2) to determine the effects of a low load of perylene (2 Îźg lâ1) on the metabolism of suspended bacteriobenthos after 9-day exposure, mimicking the effects of tidal erosion; (3) to contrast the effects of this low perylene load on the particle-free bacterioplankton and on the suspended and particle-adhered bacteriobenthos. No impact was detected in bacterial abundance exposed to 110 mg perylene lâ1 for 9 days. This concentration of perylene evoked no acute effects in C. multisetosum but, chronic toxicity assays revealed statistically significant negative effects on survival, growth and number of pregnant females. The bacterioplankton and the suspended bacteriobenthos, exposed to 2 Îźg perylene lâ1 during 2 weeks, responded with altered profiles of activity when compared to the control suspension. These values ranged, respectively, for bacterial biomass production from 134 to 210 and from 24 to 184 Îźg C lâ1 hâ1, for aminopeptidase from 1824 to 11,127 and from 1464 to 15,488 nmol lâ1 hâ1, and for β-glucosidase from 87 to 400 and from 57 to 1278 nmol lâ1 hâ1. The rate of oxygen consumption in the perylene-exposed suspension (0.04â2.85 mmol O2 kgâ1 dw sed hâ1) exhibited a clearly distinct profile in relation to the control (0.57â1.60 mmol O2 kgâ1 dw sed hâ1). The overall reactivity of the bacteriobenthos to perylene was interpreted as the result of toxic pressure followed by evolution of a diverse bacterial community