Jon Barry

Levels and trends of brominated diphenyl ethers in blubber of harbor porpoises (Phocoena phocoena) from the U.K., 1992-2008.

Controls were placed on the production and use of the penta-mix polybrominated diphenyl ether (PBDE) formulation within the European Union in 2004. In porpoises stranded or bycaught around the U.K., BDE congeners from this product predominate. Lipid-normalized concentrations of 9 (summed) BDE congeners in the blubber of 415 porpoises sampled during the period 1992-2008 have been investigated for possible time trends resulting from the regulatory action. Our analysis suggests that, overall, median Sigma9BDE concentrations peaked around 1998 and have since reduced by between 53.8% and 73.5% to 2008. Our best point estimate is that the reduction has been 67.6%. This decline was highly statistically significant (p < 0.001) and was not confounded by a range of other factors which were also considered (area, season, nutritional status, bycaught/stranded, and age class).

Effects of dissolved organic carbon on the toxicity of copper to the developing embryos of the pacific oyster (Crassostrea gigas)

The effects of humic acid (HA) on copper speciation and its subsequent toxicity to the sensitive early life stages of the Pacific oyster (Crassostrea gigas) are presented. Differential pulse anodic stripping voltammetry with a hanging mercury drop electrode was used to measure the copper species as labile copper (LCu; free ion and inorganic copper complexes) and total copper (TCu) with respect to increasing HA concentration. The TCu and LCu 50% effect concentrations (EC50s) in the absence of HA were 20.77 microg/L (95% confidence interval [CI], 24.02-19.97 microg/L) and 8.05 microg/L (95% CI, 9.6-5.92 microg/L) respectively. A corrected dissolved organic carbon (DOC) concentration (HA only) of 1.02 mg/L was required to significantly increase the TCu EC50 to approximately 41.09 microg/L (95% CI, 44.27-37.52 microg/L; p < 0.05), almost doubling that recorded when DOC (as HA) was absent from the test media. In contrast, the LCu EC50 was unaffected by changes in DOC concentration and was stable throughout the corrected DOC concentration range. The absence of change in the LCu EC50, despite increased HA concentration, suggests that the LCu fraction, not TCu, was responsible for the observed toxicity to the oyster embryo. This corresponds with the current understanding of copper toxicity and supports the free-ion activity model for copper toxicity.

Chlorobiphenyls in the blubber of harbour porpoises (Phocoena phocoena) from the UK: levels and trends 1991-2005.

Harbour porpoises sampled within the UK Cetacean Strandings Investigation Programme have been analysed for 25 chlorobiphenyl congeners. In all, 440 porpoises stranded or bycaught during the period 1991-2005 were studied. There are regional differences in the trend in summed congener concentrations over time but, despite controls on PCBs having been in place for decades, they are declining only slowly. Their toxic impacts in UK porpoises - increased susceptibility to infectious disease mortality in the most contaminated individuals - looks likely to continue for some time yet. Further efforts to limit or eliminate PCB discharges to the marine environment are still needed.

Imposex in the dogwhelk (Nucella lapillus): 22-year monitoring around England and Wales

Six imposex surveys in the dogwhelk (Nucella lapillus) have been conducted over the past two decades to assess legislation effectiveness controlling the use of tri-butyl tin (TBT) by the maritime shipping industry. This study firstly analysed the results of the 2014 survey and secondly carried out a trend assessment of the same 88 sampled sites between 1997 and 2014 of which 65 showed statistically significant reductions. To highlight the magnitude of change, the Vas Deferens Sequence stages (VDS) of the same 56 sites sampled in 1997 and 2010 showed that the Vas Deferens Sequence Index (VDSI) reduced statistically significantly from 2.89 and 0.42, respectively. These data confirm that the legislation enacted, latterly through the International Maritime Organization (IMO) during 2003 to 2008, has been effective in progressively reducing the impact of TBT in the marine environment. Nevertheless, the 2014 results show that two of 18 sampled sites (Gurnard Bay and St. Mawes) are still above the Ecotoxicological Assessment Criteria (EAC) derived for TBT (VDSI ≤ 2).

Changes in the water quality conditions of Kuwait's marine waters: Long term impacts of nutrient enrichment.

This work analyses a 30 year water quality data set collated from chemical analyses of Kuwaits marine waters. Spatial patterns across six sites in Kuwait Bay and seven sites located in the Arabian Gulf are explored and discussed in terms of the changing influences associated with point and diffuse sources. Statistical modelling demonstrated significant increases for dissolved nutrients over the time period. Kuwait marine waters have been subject to inputs from urban development, untreated sewage discharges and decreasing river flow from the Shatt al-Arab River. Chlorophyll biomass showed a small but significant reduction; the high sewage content of the coastal waters from sewage discharges likely favouring the presence of smaller phytoplankton taxa. This detailed assessment of temporal data of the impacts of sewage inputs into Kuwaits coastal waters establishes an important baseline permitting future assessments to be made as sewage is upgraded, and the river continues to be extracted upstream.

Impacts of maintenance dredged material disposal on macrobenthic structure and secondary productivity

The results of a monitoring programme to assess the spatial impacts associated with ongoing dredged material disposal activity at a dispersive, coastal disposal site (southwest UK) are described. Benthic impacts were assessed using benthic community structure and secondary productivity estimates. Analyses of univariate indices (including secondary production) and multivariate community structure revealed differences between stations inside and those outside the disposal site were minimal. Generally, stations within and outside the disposal site were characterised by the same species. Regression models indicated that the variability in biological structure and secondary production was predominantly accounted for by natural variables (e.g., depth, sediment granulometry) with only a small amount of residual variability being due to contaminant variables. Thus, the elevated levels of certain contaminants in the vicinity of the disposal area were not sufficient to result in significant ecological or ecotoxicological changes. We ascribe such findings partly to the dispersive nature of the disposal site.

The application of Diffusive Gradients in Thin Films (DGT) for improved understanding of metal behaviour at marine disposal sites

Assessment of the effects of sediment metal contamination on biological assemblages and function remains a key question in marine management, especially in relation to disposal activities. However, the appropriate description of bioavailable metal concentrations within pore-waters has rarely been reported. Here, metal behaviour and availability at contaminated dredged material disposal sites within UK waters were investigated using Diffusive Gradient in Thin films (DGT). Three stations, representing contrasting history and presence of dredge disposal were studied. Depth profiles of five metals were derived using DGT probes as well as discrete analysis of total metal concentrations from sliced cores. The metals analysed were: iron and manganese, both relevant to sediment biogeochemistry; cadmium, nickel and lead, classified as priority pollutants. DGT time-integrated labile flux profiles of the metals display behaviour consistent with increasingly reduced conditions at depth and availability to DGT (iron and manganese), subsurface peaks and a potential sedimentary source to the water column related to the disposal activity (lead and nickel) and release to pore-water linked to decomposition of enriched phytodetritus (cadmium). DGT data has the potential to improve our current understanding of metal behaviour at impacted sites and is suitable as a monitoring tool. DGT data can provide information on metal availability and fluxes within the sediment at high depth-resolution (5mm steps). Differences observed in the resulting profiles between DGT and conventional total metal analysis illustrates the significance of considering both total metals and a potentially labile fraction. The study outcomes can help to inform and improve future disposal site impact assessment, and could be complemented with techniques such as Sediment Profile Imagery for improved biologically relevance, spatial coverage and cost-effective monitoring and sampling of dredge material disposal sites. Additionally, the application of this technology could help improve correlative work on biological impacts under national and international auspices when linking biological effects to more biologically relevant metal concentrations.

Butyltin compounds in liver of harbour porpoises (Phocoena phocoena) from the UK prior to and following the ban on the use of tributyltin in antifouling paints (1992-2005 & 2009).

Liver butyltin concentrations (monobutyl, dibutyl and tributyltin (TBT)) in harbour porpoises (n=410) have been determined during 1992-2005, and again in 2009 following a ban on the use of tributyltin-based antifouling paints on ships. The aim was to assess the effectiveness of the regulation, which was implemented during 2003-2008. Since the ban was put in place summed butyltin concentrations have declined. Also, the percentage of animals in which TBT was detected has fallen sharply, indicating the cessation of fresh inputs. In 1992, 1993 and 1995, TBT was detected in 100% of samples analysed. In 2003-2005, once the implementation of the ban had begun, this fell to 61-72%, and in 2009, following the completion of the ban, had reduced to 4.3% (i.e. in only 1 of 23 samples analysed). Thus we conclude that the ban has proved effective in reducing TBT inputs to the seas from vessels.

A temporal and spatial assessment of TBT concentrations at dredged material disposal sites around the coast of England and Wales

Despite legislative interventions since the 1980s, contemporary concentrations of organotin compounds in marine sediments still impose restrictions on the disposal of dredged material in the UK. Here, we analyse temporal and spatial data to assess the effectiveness of the ban on the use of TBT paints in reducing concentrations at disposal sites. At a national scale, there was a statistically significant increase in the proportion of samples in which the concentration was below the limit of detection (LOD) from 1998 to 2010. This was observed for sediments both inside and outside the disposal sites. However, this temporal decline in organotin concentration is disposal site-specific. Of the four sites studied in detail, two displayed significant increases in proportion of samples below LOD over time. We argue that site-specificity in the effectiveness of the TBT ban results from variations in historical practices at source and unique environmental characteristics of each site.

Cetacean Stock Assessments in Relation to Exploration and Production Industry Activity and Other Human Pressures: Review and Data Needs

The impacts of manmade underwater sound on cetaceans have become an important environmental issue. A number of studies have documented effects on individuals such as behavioural response; masking of biologically relevant signals; and hearing loss, either temporary or permanent (reviews by Richardson et al., 1995; Southall et al., 2007). Little is known, however, about the population-level consequences of acoustic impacts. Methodologies addressing this issue, such as risk-based and cumulative impact assessments, are still in their infancy (e.g., National Research Council [NRC], 2005; Boyd et al., 2008; Wright, 2009). There is also limited information on levels of human activities generating sound and uncertainties in cetacean stock assessments that hamper quantitative investigations. Yet, sound generating industries are active in many parts of the world’s oceans and, therefore, qualitative assessments could provide a first step in managing potential conflicts between industry sectors generating sound and cetacean conservation. The Exploration and Production industry (E&P industry) generates underwater sound potentially affecting individual cetaceans, with most concerns expressed about the effects of seismic surveys (review by OSPAR, 2009). However, the relationship between E&P industry activities and trends in cetacean stocks has rarely been investigated. We provide a global overview of E&P industries and cetacean stock data in order to identify hot spots for more detailed investigations. Thus, in four case studies, we quantified the E&P industry activity in a specific region, investigated the status and trends of seven cetacean stocks therein, and assessed other factors presumably influencing the populations in question.