Time trends in the prevalence of Escherichia coli and enterococci in bivalves harvested in Norway during 2007–2012

The objectives of this study were to describe time trends in the prevalence of Escherichia coli and enterococci in cultured blue mussels (Mytilus edulis) harvested from 152 localities along the coast of Norway during the six-year period from 2007 to 2012. Based on the available data, possible co-occurrence of these two indicator organisms of faecal contamination was assessed. Several localities for bivalve cultivation in Norway showed single high counts of E. coli, without any previous history of E. coli detection. For other localities, the pattern of E. coli detection was recurring, however low values were found, with some sporadic findings of higher values. There was a weak positive correlation between the detection of enterococci and E. coli, and a weak positive correlation between counts of E. coli/enterococci and rainfall. Sampling intervals should take into account knowledge of the occurring variation for bacterial faecal indicators, local knowledge on possible exposure to faecal material from livestock or humans, rainfall seasons, topography of the location, as well as tidal and water current patterns.     

Effect of ozonation and γ-irradiation on post-harvest decontamination of mussels (Mytillus galloprovincialis) containing diarrhetic shellfish toxins

Contamination of shellfish with diarrhetic shellfish poisoning (DSP) toxins readily occurs during algal blooms. Such phenomena raise important public health concerns and thus comprise a constant challenge to shellfish farmers, the seafood industry and health services, considering the increasing occurrence of toxic episodes around the world. To avoid the detrimental effects of such episodes, research has focused on the use of various detoxification methodologies that should be rapid, efficient, easy to apply, and will not alter the quality and sensory properties of shellfish. In the present study, both ozonation (15?mg?kg^?1 for 6?h) and γ-irradiation (6 kGy) were utilised in order to reduce the toxin content of contaminated shucked mussels, collected during the DSP episodes of 2007 and 2009 in Greece. DSP toxicity was monitored using the mouse bioassay (MBA) whilst the determination of toxin content of the okadaic acid (OA) group (both free and esterified forms) was carried out by LC/MS/MS analysis. Toxin reduction using γ-irradiation was in the range of 12–36%, 8–53% and 10–41% for free OA, OA esters and total OA, respectively. The appearance and texture of irradiated mussels deteriorated, pointing to a low potential for commercial use of this method. Ozonation of mussels resulted in toxin reduction in the range of 6–100%, 25–83% and 21–66% for free OA, OA esters and total OA, respectively. Reduction of OA content was substantially higher in homogenised mussel tissue compared with that of whole shucked mussels. In addition, differences detected with regard to quality parameters (TBA, sensory attributes) between ozonated and control mussels were not considerable. Even though varying percentage reductions in OA and its derivatives were achieved using ozonation under specific experimental conditions tested, it is postulated that upon optimisation ozonation may have the potential for post-harvest commercial DSP detoxification of shucked mussels.     

Using airborne scanning laser altimetry (LiDAR) to estimate surface connectivity of floodplain water bodies

This study tested the applicability of airborne scanning laser altimetry (LiDAR) for characterizing surface connectivity of floodplain water bodies by comparing it with in situ measurements of water levels, and examined whether LiDAR derived data accurately predicted the occurrence of globally imperilled unionid mussels. We intensively examined 10 isolated and 3 connected floodplain water bodies (IWBs and CWBs, respectively) located within a 15‐km lowland segment of the Kiso River in Japan. Using a digital elevation model (DEM) of floodplain ground surface, which is derived from LiDAR, and water surface DEM, which is obtained from records of water level fluctuations, the frequency of surface connectivity between IWBs and the main channel (inundation frequency) was calculated. Inundation frequency of IWBs was also measured in situ using water level and temperature probes. Also, the occurrence of mussels in CWBs and IWBs were examined. LiDAR derived data well predicted in situ derived one with a high level of accuracy (r² > 0.77), validating the LiDAR‐based approach. Some errors existed in the predictive model, indicating that the applicability of LiDAR data is limited by its spatial resolution and snapshot nature. The occurrence of mussels was positively explained by an increasing level of inundation frequency, and the high accuracies of empirical models were validated using data for other 67 water bodies within the study segment. This study overall demonstrated a high potential of LiDAR data for efficiently monitoring hydrological and biological conditions of floodplain water bodies in the Kiso River and beyond. Copyright © 2010 John Wiley & Sons, Ltd.     

The effects of dreissenid mussels on the survival and condition of burrowing mayflies (Hexagenia spp.) in western Lake Erie

Burrowing mayflies (Hexagenia limbata and H. rigida) are once again prominent members of the benthic community in western Lake Erie. However, this community is now dominated by dreissenid mussels. We conducted a laboratory experiment and field sampling to investigate whether survival and condition of Hexagenia were affected by the presence, density, and quality of dreissenid mussels. In a laboratory experiment, Hexagenia survival was higher in microcosms without dreissenid mussels. We also found Hexagenia density to be higher at field sites with low dreissenid density, suggesting that Hexagenia survival is higher in these areas as well. In microcosm treatments with low dreissenid density, Hexagenia survival was higher in treatments with live dreissenids than in treatments containing only dreissenid shells. These findings suggest that while dreissenid shells degrade the quality of soft sediments for Hexagenia, some of the negative effect is offset by the presence of live dreissenids. The positive effect of live dreissenids is likely due to additional food resources made available to Hexagenia by the filtering activity of dreissenids. Neither dreissenid density nor shell “type” (shells alone or live dreissenids in shells) had an effect on Hexagenia condition. Thus, the interactions between these dominant benthic invertebrates are complex. Recovery of Hexagenia populations in western Lake Erie is likely affected by both changing environmental conditions due to anthropogenic activities and the introduction of exotic species into the benthic community. The results are likely to be continued instability of the benthic food web and unpredictable consequences for human utilization of this ecosystem.     

Quantification of Historical Changes of Submerged Aquatic Vegetation Cover in Two Bays of Lake Ontario with Three Complementary Methods

Submerged aquatic vegetation (SAV) distribution and coverage were quantified in two bays of Lake Ontario in 1972, 1980 (1982), and 1999–2002, using a combination of aerial photograph interpretation (API), hydroacoustics, and rake sampling. The three methods gave similar estimates of SAV presence in 2002, supporting our use of API for quantifying SAV changes across decades in bays of a large lake. The SAV coverage in Sodus Bay increased by 5% between 1972 and 1980 and by 35% between 1980 and 1999–2002 whereas the maximum depth of SAV colonization extended from 5.5 to 6.4 m during this period. In Chaumont Bay, the SAV coverage tripled while its maximum depth of occurrence increased from 5.1 to 6.1 m from 1982 to 2002. Although the difference in SAV coverage between 1972 and 1980 was not larger than the difference between consecutive years in the 2000s, the large increase in SAV coverage between the 1980s and 2000s represents a major ecosystem change in these bays. This change was likely caused by increased water clarity in Lake Ontario, which could be associated with the implementation of the Great Lakes Water Quality Agreement (GLWQA) and the dreissenid mussel invasion. Although other factors such as water level, wave exposure, bottom slope, and sediment nutrients may be important, they have not changed in a fashion that would predict local increases of SAV coverage.     

Enhancing the Adhesion of a Biomimetic Polymer Yields Performance Rivaling Commercial Glues

Marine mussels clinging to rocks inspire the development of novel materials. Characterization of mussel adhesive plaques describes a matrix of proteins containing 3,4‐dihydroxyphenylalanine (DOPA), which provides cross‐linking chemistry that allows mussels to attach firmly. Several synthetic polymer systems have been developed based on this DOPA chemistry. High strength bonding has been achieved with poly[(3,4‐dihydroxystyrene)‐co‐styrene], a simplified mimic of mussel proteins in which 3,4‐dihydroxystyrene provides the cross‐linking and adhesion of DOPA. The poly(styrene) host polymer stands in for a protein backbone. Prior efforts showed that a monomer ratio of 1:2 3,4‐dihydroxystyrene:styrene within the statistical copolymer poly[(3,4‐dihydroxystyrene)‐co‐styrene] yields the highest adhesion. To enhance adhesive performance of this biomimetic polymer, a systematic study is carried out in which a range of cross‐linking agents, cure times, cure temperatures, polymer concentrations, and fillers are examined. Lap shear adhesion testing revealed substantial increases in bond strength from each study. Consensus conditions are then determined and bonding performance is assessed on several substrates. Adhesion of this system turns out to be one of the strongest of all biomimetic polymers. These studies show that DOPA chemistry may be able to stand alongside of cyanoacrylate (e.g., Super Glue) and epoxy when it comes to high strength bonding.     

Environmental experts in the pharmaceutical industry — production

The processes employed in the Industry cover a wide range and bring problems of effluent disposal and deposit of solid wastes, and of emissions to the air of smoke, dust, smell and noise. It is necessary to relate legislation to required standards and to process operations and to prepare forward plans on the basis of present environmental trends. This involves the cooperation of a number of departments covering different disciplines. The actual control of environmental hazards must occur in the operating stages of manufacture and is therefore a line responsibility. The type of person suitable for the role of Environment Adviser as a staff function is discussed.     

Monitoring metal and persistent organic contaminant trends through time using quagga mussels (Dreissena bugensis) collected from the Niagara River

Historically, the Niagara River received the discharge of persistent bioaccumulative and toxic chemicals from municipal and industrial outfalls and hazardous waste landfills. American and Canadian governments have coordinated investigations of chemicals entering the river and initiated remedial measures and monitoring programs with a goal to reduce loadings of toxic chemicals to the river. This study, a component of the Ontario Ministry of Environment Mussel Biomonitoring Program, compares contaminant concentrations in quagga mussels (Dreissena bugensis) collected from nine locations in the Niagara River in 1995 and 2003 to assess anticipated changes in tissue concentrations of contaminants in response to ongoing remedial efforts by government agencies and local industries. The concentrations of persistent organic compounds (e.g., PCBs, hexachlorobenzene, hexachlorobutadiene, octachlorostyrene) in quagga mussels in 2003 were lower than concentrations measured in 1995, consistent with a decrease in reported mean annual concentrations of these compounds in water. Significant differences in total PCB concentrations in mussels between stations (F = 4.6; P < 0.001) suggested sources of PCBs on the American side of the upper Niagara River. In general, highest concentrations of persistent organic compounds were found downstream of the Occidental Chemical Corporation Buffalo Avenue facility suggesting local sources of these contaminants notwithstanding remedial efforts. In contrast, metal concentrations in quagga mussels in 2003 were similar to concentrations found in 1995 and to values reported in the literature for mussels collected from industrialized areas in the Great Lakes. Overall, our results suggest that remedial efforts to improve water quality in the Niagara River have been successful.     

Ready‐to‐eat mussel meat processed in retort pouches for the retail and export market

A processing method has been developed to prepare ready‐to‐eat mussel meat, retaining its natural texture and succulence. The product was vacuum‐packed in an indigenously developed retortable pouch and processed in a still over‐pressure retort. Time and temperature data was collected during heat processing using an Ellab data recorder cum F₀ and cook value integrator. The heat penetration characteristics were determined using a formula method. The total process time was 35 min with a F₀ value of 9.8 and a cook value of 90.3 min. These vacuum‐packed retort‐processed samples were rated excellent by the taste panel and remained in good condition even after storage for 1 year at room temperature. Copyright © 2004 John Wiley & Sons, Ltd.