Patricia E. Frickers

Improved removal of estrogenic and pharmaceutical compounds in sewage effluent by full scale granular activated carbon: Impact on receiving river water

Sewage effluents are widely recognised as the main source of emerging contaminants, such as endocrine disrupting chemicals (EDCs) and pharmaceuticals in surface waters. A full-scale granular activated carbon (GAC) plant has been installed as an advanced technology for the removal of these contaminants, in a major sewage treatment works (STW) in South-West England as part of the UK National Demonstration Programme for EDCs. This study presented for the first time, an assessment of the impact of a recently commissioned, post-tertiary GAC plant in the removal of emerging contaminants in a working STW. Through regular sampling followed by solid-phase extraction and analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS), a significant reduction in the concentrations of steroidal estrogens was observed (>43-64%). In addition, significant reductions were observed for many of the pharmaceutical compounds such as mebeverine (84-99%), although the reduction was less dramatic for some of the more widely used pharmaceuticals analysed, including carbamazepine and propranolol (17-23%).

Sediment–Water Exchange of Nutrients in the Intertidal Zone of the Humber Estuary, UK

Abstract Nutrient pore-water profiles, sediment–water exchange and sediment characteristics were measured for six intertidal mudflat sites throughout the Humber Estuary over the different seasons. The Humber is a highly dynamic, non steady state system and hence neither the biogeochemical zones nor the macrofaunal communities were sustained for long periods of time. Sediment mixing and resuspension on tidal, episodic or seasonal timescales was the predominant control on nutrients. Over an annual cycle, mean measured fluxes were −8.7 mmoles/m 2 /day nitrate, 3.7 mmoles/m 2 /day ammonia and 0.2 mmoles/m 2 /day nitrite. Net phosphate and silicate fluxes were very small. The intertidal mudflats were a sink for nitrate (−1000 kmol/day), a major source of ammonia (430 kmol/day) and a minor source of nitrite (25 kmol/day). Nitrate influxes decreased in a seaward direction (−13.4 mmoles/m 2 /day in inner estuary, −11.0 mmoles/m 2 /day in mid-estuary, −5.2 mmoles/m 2 /day in outer estuary), but when the area of the mudflats in each area is taken into account, both the mid and outer estuary were sinks for approximately 40% of the total nitrate taken up. In contrast, the outer estuary was the source of c. 90% of the ammonia and 105% of the nitrite (the inner estuary being a minor sink of nitrite).

Merging nano-genotoxicology with eco-genotoxicology: an integrated approach to determine interactive genotoxic and sub-lethal toxic effects of C(60) fullerenes and fluoranthene in marine mussels, Mytilus sp.

Whilst there is growing concern over the potential detrimental impact of engineered nanoparticles (ENPs) on the natural environment, little is known about their interactions with other contaminants. In the present study, marine mussels (Mytilus sp.) were exposed for 3 days to C(60) fullerenes (C(60); 0.10-1 mg l(-1)) and a model polycyclic aromatic hydrocarbon (PAH), fluoranthene (32-100 μg l(-1)), either alone or in combination. The first two experiments were conducted by exposing the organisms to different concentrations of C(60) and fluoranthene alone, in order to determine the effects on total glutathione levels (as a measure of generic oxidative stress), genotoxicity (DNA strand breaks using Comet assay in haemocytes), DNA adduct analyses (using (32)P-postlabelling method) in different organs, histopathological changes in different tissues (i.e. adductor muscle, digestive gland and gills) and physiological effects (feeding or clearance rate). Subsequently, in the third experiment, a combined exposure of C(60) plus fluoranthene (0.10 mg l(-1) and 32 μg l(-1), respectively) was carried out to evaluate all endpoints mentioned above. Both fluoranthene and C(60) on their own caused concentration-dependent increases in DNA strand breaks as determined by the Comet assay. Formation of DNA adducts however could not be detected for any exposure conditions. Combined exposure to C(60) and fluoranthene additively enhanced the levels of DNA strand breaks along with a 2-fold increase in the total glutathione content. In addition, significant accumulation of C(60) was observed in all organs, with highest levels in digestive gland (24.90 ± 4.91μg C(60) g(-1) ww). Interestingly, clear signs of abnormalities in adductor muscle, digestive gland and gills were observed by histopathology. Clearance rates indicated significant differences compared to the control with exposure to C(60), and C(60)/fluoranthene combined treatments, but not after fluoranthene exposure alone. This study demonstrated that at the selected concentrations, both C(60) and fluoranthene evoke toxic responses and genetic damage. The combined exposure produced enhanced damage with additive rather than synergistic effects.

Lysosomal cytotoxicity of carbon nanoparticles in cells of the molluscan immune system: An in vitro study

The toxicity and ecotoxicity of nanomaterials is poorly understood and the risks of environmental exposure are largely unknown. In vitro cellular toxicity of C60-fullerene and carbon nanotubes was investigated by measuring the retention of a cationic probe (neutral red) within the lysosomal compartment of phagocytic blood cells (hemocytes) from marine mussels (Mytilus galloprovincialis). Intra-lysosomal retention of neutral red, over time, is a measure of the stability of the lysosomal membrane and the health of the cell. Aqueous suspensions of carbon nanoparticles (C60-fullerene – 1.0 and 10 µg.ml−1) induced cytotoxicity in circulating phagocytic hemocytes, which are a key component of the molluscan innate immune system. Hemocytes exposed to the same concentration range of carbon nanotubes were unaffected. These findings are consistent with the hypothesis that C60-fullerene is cytotoxic on uptake into the endocytic-lysosomal system and that cell injury may be mediated by generation of reactive oxygen species (ROS).

Integration of biochemical, histochemical and toxicogenomic indices for the assessment of health status of mussels from the Tamar Estuary, U.K.

The aim of this study was to examine whether a combination of biochemical, histopathological and toxicogenomic data could be used as a valuable tool for the assessment of biological risk associated with pollutants within the Tamar River and Estuary, S.W. England, U.K. Accordingly, biochemical and histopathological biomarkers (protein carbonyls, lipofuscin, neutral lipids, lysosomal stability [N-acetyl-β-hexosaminidase and neutral red], lysosomal volume, ferric reducing antioxidant power [FRAP] and malonaldehyde [MDA]) and gene expression profiles were assessed in 5 sites from the Tamar River and Estuary (Neal Point, Town Quay, Wilcove, Cremyll Ferry and Whitsand; and a reference site, Trebarwith Strand, N. Cornwall). PAHs were measured in mussel tissue and sediment and metals were measured in mussel tissue only. Data from the biomarkers was integrated into a Mussel Expert System (MES) model to produce a simple assessment of mussel stress. Clear gradients of mussel toxicity were identified by the biomarkers (with the exception of neutral lipids) with the highest impacted animals found furthest up the Tamar, whilst the MES was unable to identify a gradient of effect. Gene expression profiles also indicated a gradient of stress with the greatest number of significantly up- or down- regulated genes found at the uppermost 2 sites. The MES did, however, determine that mussels from all sites, except the reference site, were highly stressed; a conclusion that could not be inferred from the biomarker data alone. It is concluded that the MES is a valuable tool that permits integration and interpretation of complex sets of biomarker data by identifying the biological meaning of biomarker changes.

Antifouling biocides in discarded marine paint particles

Antifouling paint fragments collected from marinas and leisure boat maintenance facilities and in the vicinity of abandoned boats have been chemically characterised. High concentrations of Cu (23-380mgg(-1)) and Zn (14-160mgg(-1)) in the samples (n=14) are consistent with the use of these metals in the principal biocidal and non-biocidal pigments in contemporary antifouling formulations. Up to about 2% and 7% of the respective metals were solvent-extractable, suggesting that organo-forms of Cu and Zn (e.g. pyrithiones) were also present. Of the organic biocides, dichlofluanid was present in most samples and at concentrations up to about 20mgg(-1). Chlorothalonil and Irgarol 1051(R) were only detected in one and four cases, respectively, and Sea Nine 211(R) was not detected in any sample. Results are discussed in terms of UK legislation regarding biocide usage and the likely effects and fate of discarded paint particles in coastal environments where boats are repaired or moored.

A study of processes affecting the uptake of contaminants by intertidal sediments, using the radioactive tracers: 7Be, 137Cs and unsupported 210Pb

Abstract The vertical distribution of the radio-nuclides 7 Be, 137 Cs and unsupported 210 Pb were used to describe the processes of accretion, mixing, mixing depth and focusing, that influence the responses of intertidal bed sediments to contaminant inputs. These processes were studied in the mid and lower Tamar Estuary at six different sites sampled on eight occasions, over a period of 2 years. The maximum depth to which sediment deposits were mixed ranged from 10 cm to greater than 40 cm. Mixing coefficients derived from the 7 Be and unsupported 210 Pb profiles ranged from 0·56 × 10 −7 to 34·2 × 10 −7 cm 2 s −1 . The sediment inventories of 7 Be, 137 Cs and unsupported 210 Pb, the maximum depths of mixing and the mixing coefficients were significantly higher in the bed sediments of the creek site and at two sites situated 12–14 km up the estuary than those observed at sites situated nearer to the seaward end of the estuary. With the exception of the site closest to the mouth of the estuary, the 7 Be inventory at all sites was consistently higher during the period October–November than during the period March–September. Using data derived from the 7 Be and unsupported 210 Pb sediment profiles, the profiles of 137 Cs were simulated and compared with the observed data recorded at each site.

Extending the environmental risk assessment for oseltamivir (Tamiflu ® ) under pandemic use conditions to the coastal marine compartment

In case of an avian-influenza-derived human flu pandemic, an inordinately high use of medicines over several weeks is predicted, in particular for the recommended influenza antiviral oseltamivir (Tamiflu). While the risk of oseltamivir to sewage works and freshwater bodies has already been assessed, the fact that a large percentage of the human population worldwide lives relatively close to the sea raises concern for its environmental compatibility in coastal marine waters. The potential risk of high oseltamivir use to the marine compartment is assessed in this publication, based on the 2003 European Community Technical Guidance Document (TGD) for risk assessment. Subchronic embryo-larval ecotoxicity tests with three marine invertebrates (Pomatoceros triqueter, Annelida; Mytilus edulis, Mollusca; Paracentrotus lividus, Echinodermata) and chronic growth inhibition tests with two different groups of marine microalgae (Isochrysis galbana, Haptophyta; Skeletonema costatum, Heterokontophyta) were performed with the active substance oseltamivir carboxylic acid to derive a dependable marine predicted no-effect concentration (PNEC). This was compared to a predicted environmental concentration (PEC) for oseltamivir in coastal waters, based on the worst-case freshwater PEC. The PEC/PNEC risk characterisation ratio for the marine compartment is well below 1, which in the terminology of the TGD signifies no immediate concern. Further, while oseltamivir may be persistent (P), it is not bioaccumulative (B) nor highly ecotoxic (T) and therefore not a PBT substance. In conclusion, even a high pandemic use of oseltamivir would not lead to a significant risk for the marine compartment, in confirmation of the risk assessment for sewage works and freshwaters.