Metal measurement in aquatic environments by passive sampling methods: Lessons learning from an in situ intercomparison exercise.

Passive sampling devices (PS) are widely used for pollutant monitoring in water, but estimation of measurement uncertainties by PS has seldom been undertaken. The aim of this work was to identify key parameters governing PS measurements of metals and their dispersion. We report the results of an in situ intercomparison exercise on diffusive gradient in thin films (DGT) in surface waters. Interlaboratory uncertainties of time-weighted average (TWA) concentrations were satisfactory (from 28% to 112%) given the number of participating laboratories (10) and ultra-trace metal concentrations involved. Data dispersion of TWA concentrations was mainly explained by uncertainties generated during DGT handling and analytical procedure steps. We highlight that DGT handling is critical for metals such as Cd, Cr and Zn, implying that DGT assembly/dismantling should be performed in very clean conditions. Using a unique dataset, we demonstrated that DGT markedly lowered the LOQ in comparison to spot sampling and stressed the need for accurate data calculation.

Indices of stress in three-spined sticklebacks Gasterosteus aculeatus in relation to extreme weather events and exposure to wastewater effluent.

Whole-body concentrations of cortisol and glucose were measured in three-spined sticklebacks Gasterosteus aculeatus from two rivers (Rivers Ray and Ock) in southern England during a 30 month period in order to assess effects on the stress axis of (1) remediation of a wastewater treatment works (WWTW) effluent (River Ray) and (2) episodic changes in flow rate arising from periods of high rainfall (Rivers Ray and Ock). The postcapture concentrations of cortisol and glucose in fish from both rivers did not exhibit a seasonal periodicity but did show significant between-sample, between-site and between-river variation, superimposed upon a consistent downward trend for each analyte during the monitoring period. Corticosteroid and glucose concentrations following capture were inversely linked with a progressive increase in condition of the fish during this period. Site-dependent trends possibly related to exposure to the WWTW effluent were detected for both analytes in fish from the River Ray. For fish in the River Ray, a significant proportion of variation in both corticosteroid and glucose concentrations, additional to the downward trend with time, was accounted for by temporal proximity of the sample to exceptional flow events arising from episodes of high rainfall and high turbidity. This relationship was not statistically significant for fish from the River Ock. These data suggest that the responsiveness of the stress axis in free-living G. aculeatus may be altered by exposure to WWTW effluent and by exposure to physical changes in the aquatic environment such as those arising from extreme weather events. The magnitude of these effects may be increased by exposure to both stressors concurrently.

Endocrine disrupting activities in sewage effluent and river water determined by chemical analysis and in vitro assay in the context of granular activated carbon upgrade.

As part of endocrine disruption in catchments (EDCAT) programme, this work aims to assess the temporal and spatial variations of endocrine disrupting chemicals (EDCs) in River Ray, before and after the commissioning of a full-scale granular activated carbon (GAC) plant at a sewage treatment works (STW). Through spot and passive sampling from effluent and river sites, estrogenic and anti-androgenic activities were determined by chemical analysis and in vitro bio-assay. A correlation was found between chemical analyses of the most potent estrogens (estrone (E1), 17ß-estradiol (E2), 17α-ethinylestradiol (EE2)) and yeast estrogen screen (YES) measurement, both showing clearly a reduction in estrogenic activity after the commissioning of the GAC plant at the STW. During the study period, the annual average concentrations of E1, E2 and EE2 had decreased from 3.5 ng L(-1), 3.1 ng L(-1) and 0.5 ng L(-1) to below their limit of detection (LOD), respectively, with a concentration reduction of at least 91%, 81% and 60%. Annual mean estrogenic activity measured by YES of spot samples varied from 1.9 ng L(-1) to 0.4 ng L(-1) E2 equivalent between 2006 and 2008 representing a 79% reduction. Similarly, anti-androgenic activity measured by yeast anti-androgen screen (anti-YAS) of spot samples was reduced from 148.8 to 22.4 µg flutamide L(-1), or by 85%. YES and anti-YAS values were related to each other, suggesting co-existence of both types of activities from chemical mixtures in environmental samples. The findings confirm the effectiveness of a full-scale GAC in removing both estrogenic and anti-androgenic activities from sewage effluent.

The development of a rapid screening technique to measure antibiotic activity in effluents and surface water samples.

Use of antibiotics in medicine, farming and aquaculture results in a continual supply of these pharmaceuticals and their breakdown products reaching the environment. A method has been developed to use for screening environmental samples to establish whether they contain antibiotics. The assay is based on a commercially available test kit and uses some modifications of the test procedure and SPE techniques to deliver a fast, semi-quantifiable result. Development of the assay and results from spiked and environmental samples are discussed.