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 l−1) on benthic bacteria and macrofauna (amphipod Corophium multisetosum); (2) to determine the effects of a low load of perylene (2 μg l−1) 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 l−1 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 μg perylene l−1 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 μg C l−1 h−1, for aminopeptidase from 1824 to 11,127 and from 1464 to 15,488 nmol l−1 h−1, and for β-glucosidase from 87 to 400 and from 57 to 1278 nmol l−1 h−1. The rate of oxygen consumption in the perylene-exposed suspension (0.04–2.85 mmol O2 kg−1 dw sed h−1) exhibited a clearly distinct profile in relation to the control (0.57–1.60 mmol O2 kg−1 dw sed h−1). The overall reactivity of the bacteriobenthos to perylene was interpreted as the result of toxic pressure followed by evolution of a diverse bacterial community

Use of microcosms to determine persistence of Escherichia coli in recreational coastal water and sediment and validation with in situ measurements

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Distribution and seasonality of microbial indicators and thermophilic campylobacters in two freshwater sites on the River Lune in North West England.

Two freshwater bathing sites, the Crook O'Lune and the University Boathouse, on the River Lune in the north-west of England, were monitored over a 2 year period for the faecal indicators, faecal coliforms and faecal streptococci, the pathogens, Salmonella and Campylobacter, and compliance with the EU Directive on Bathing Water Quality. Faecal indicator numbers showed no seasonal variation, with numbers in the bathing season similar to those in the non-bathing season. They were consistently above the EU Guideline and Imperative standards so that if the EU Bathing Water Quality Directive (76/160/EEC) were applied, neither site would comply. Faecal indicator numbers in the sediments were an order of magnitude higher than in the overlying water. Campylobacter numbers showed seasonal variation in the water with higher counts in winter than in the summer, although numbers were low. Higher numbers were found in the sediments but there was no seasonal variation. Analysis of various inputs showed that indicators and campylobacters came from a mixture of sources, namely a sewage treatment works, agricultural run-off, streams and mallards. Microbial numbers in the water at the Crook O'Lune, which is closer to the sources of pollution, were twice those at the Boathouse. In the sediments they were six to eight times higher. Faecal coliforms were all identified as Escherichia coli of which 80% were a single biotype. Faecal streptococci were all enterococci of which 55% were E. avium, 38%E. faecalis and 7%E. durans. Salmonella was not isolated from either the water column or the sediments. Campylobacters were mainly Camp. jejuni, followed by Camp. coli, UPTC and Camp. lari