PRELIMINARY BRIEFING – TIM DEERE-JONES
6/29/2014 5:16:25 PM
BLACKWATER ESTUARY ENVIRONMENTAL PARAMETERS & RADIOACTIVITY
Marine Issues & FED Dissolution
A Preliminary Briefing
Marine Radioactivity Consultant
Essex coastal parameters
Water column movement off the Essex coast
The definitive MAFF Atlas of the Seas around the British Isles (MAFF 1981) indicates that the general near surface pattern of water movement along this coastline is a strong, prevailing inshore current, which moves southwards down the coast from the Wash to the Thames. (Studies clearly demonstrate that this major movement may be temporarily disrupted by strong winds and such phenomena as storm surges.)
The MAFF Atlas indicates that tidal current speeds at mean spring tides may reach 2 knots and that the tidal range is generally approx 2 metres, though it increases to approx 5 metres, southwards towards the Thames Estuary.
The MAFF Atlas indicates that mean summer sea surface temperatures reach 17 degrees C, while mean winter sea surface temperature sink to 5 degrees C. The long- term impacts of global warming and rising sea water temperatures cannot be discounted, although long-term trends still remain an area of some debate.
Essex coastal/inshore sediments:
The waters off the Essex coast are recognised as part of a high turbidity zone long identified off the East Anglian coast and are thus characterised by high concentrations of suspended sediments. In this high turbidity zone, suspended sediment concentrations are routinely above 50 mg/litre. Concentrations are further elevated; and peak, in response to storms, extreme wave conditions, storm surges, trawling, seismicity, aggregate and navigation maintenance dredging.
Suspended fine sediment loadings of the water column consist of silt/clay/organic particles derived from the eroding coastlines of the Holderness peninsula and the East Anglian coastline, inputs from the fluvial and freshwater systems to the north (Humber, Wash, etc.), and residual material collected from elsewhere further north.
There is relatively little deposition of fine sediment material on the Essex open coast. This is due largely to a combination of the relatively high residual current speeds, the geomorphology of the coast, which does not provide sufficient sheltered (low energy) environments to permit deposition of “fines” and the relatively low inputs of freshwater (which also inhibits deposition of fines). However, a relatively high proportion of the water column suspended fine particles are deposited out in the extensive estuarine systems of the south Suffolk and Essex coasts.
[Section ref: Moffat, T.J. “Distribution & Transport of Suspended Sediment in the Southern North Sea”. Institute of Marine Studies, June 1995. pps 11 – 17)]
Blackwater Estuary Environmental Parameters:
The Blackwater Estuary is Essex’s largest estuary. It is 23 km long and receives freshwater from 2 river catchment systems (Blackwater and Chelmer).
The Blackwater Estuary has relatively low freshwater inputs and larger tidal inputs, so is considered to be tidally dominated, therefore, tidal domination drives the import of marine derived sediments and the estuary is defined as predominantly “well mixed”.
Thus the Blackwater Estuary has high concentrations of “marine sediments” which are composed of Blackwater Estuary sediments (which had entered the “sea” during previous ebb flows and are returned to the estuary by subsequent floods tides) and those sediments (already entrained in coastal marine water columns and moving south with the residual currents) which also enter the estuary during flood tides.
As a result of these mechanisms, the Blackwater Estuary has extensive inter-tidal sediment deposits, including mudflats and consolidated salt marsh, and some shingle banks and sand flats, and muddy, shingly, sandy shorelines.
Backwater estuarine sedimentation processes
River flow, from the Blackwater and Chelmer, brings organic and non-organic particles to the estuary, tides bring marine organic and non-organic particles in from the sea, and the estuarine system also creates its own sediments as a result of phyto-plankton growth or excretion of organisms. Local (in-estuary) seasonal erosion and deposition mechanisms also contribute to suspended sediment load concentrations in the estuarine water column.
Sediment deposition mechanisms are strongly reliant on biological, chemical and electro-chemical processes. Thus flocculation (the formation of particle aggregates, or flocs) occurs under the influence of electro-chemical parameters driven by changes in salinity (meeting of freshwater and saline water bodies). Heavier aggregated particles are formed by flocculation and these are able to sink OUT of the water column and create mud flats and salt marshes in “low energy” environments where wave action and current/tide speeds are reduced.
Estuarine suspended particle concentrations vary in response to tidal range and seasonal meteorological factors such as rainfall (freshwater and freshwater sediment inputs), tidal range and sea-state conditions (which create variations in the marine influence)
Behaviour and fate of anthropogenic radioactivity in estuarine environments
Some radio nuclides are identified as being soluble in water columns (e.g. Cs, Tc, Tritium). Soluble radioactivity is shown to travel extensively in marine water columns and to re-concentrate in marine biota, marine and estuarine sediments, sea spray and marine aerosols
Other radio nuclides are identified as being in-soluble in water columns (e.g.
Pu, Am, Cm, U, Np). Such radio nuclides are characterised by their ability to adsorb to the outer surface of sedimentary particles suspended in ambient water columns. Such in-soluble radioactivity, adsorbed to suspended sedimentary particles, is shown to travel extensively in marine water columns, deposit out into coastal and estuarine sediments
In-soluble radioactivity is shown to re-concentrate in marine biota, marine and estuarine sediments, sea spray and marine aerosols.
Depending on their specific function, UK unlicensed sites discharge a varying number of radio nuclides in their liquid waste streams. Proposed new build “generic” reactors are expected to discharge at least 59, reprocessing sites (such as Sellafield) discharge more. I cannot find any fully definitive lists of the components of Magnox liquid discharges: similarly I have been unable to find a comprehensive list which defines the “solubility” or “in-solubility” of all of those radio nuclides entering the marine environment from such sources. Thus the long-term behaviour and fate of all discharged radio nuclides remains uncertain.
Both soluble and in-soluble radio nuclides are shown to transfer from the sea to the land.
Suspended sediments (with adsorbed pollutants) deposit out in estuaries in response to a number of factors. The three most significant factors are:
a: the freshwater/salt water interaction, which generates flocculation mechanisms
(see Section 4 above);
b: reduced “settling velocity”, which is the speed of tidal/current movements at
which floc aggregates and other suspended particles are able to deposit out of
the water column; this parameter is less powerful in sheltered, low energy
environments with lower current/tidal speeds and reduced wave action;
c: the estuarine “turbidity maximum”, which is the area of the estuary where the
highest concentration of water column suspended sediments are found.
Such conditions are generally found towards the inland extreme of estuaries where the finest sub-tidal and inter-tidal sediment deposits occur. Such deposits will hold the highest concentrations of adsorbed pollutants, including man-made radioactivity. Independent studies (not carried out by nuclear industry/non government regulating agencies) have proved that radioactivity in fine sediments from the more landward extreme of estuaries may hold over ten times more radioactivity than coarser sediments from the seaward extreme of estuaries.
Nuclear industry/regulating agency studies have demonstrated that “inundation” of the coastal zone adjacent to the landward end of estuaries can transfer radioactivity from the marine environment to the terrestrial environment as a result of storm surge and high tides.
Independent studies (non nuclear industry or government regulating agencies) have demonstrated that estuarine sea to land transfer processes can radiologically contaminate terrestrial agricultural produce at sites between 30 miles and 200 + miles distant from point source inputs of sea discharged radioactivity and deliver dietary doses of man made radioactivity (via consumption of terrestrial crops) to local populations.
Populations in receipt of such doses of sea-to-land transferred marine radioactivity by this pathway have been shown to receive higher doses than
a: some seafood consumption groups adjacent to nuclear power stations; and
b: some populations living next to nuclear power stations eating local foodstuffs
contaminated by gaseous/atmospheric discharges.
Critical analysis of Government marine and estuarine radioactivity monitoring and analysis programmes (sediments and seawater)
Such programmes are characterised by an inadequate sampling strategy, which appears to be based on:
a: a consistent pattern of keeping the sample numbers and the sampling
b: a consistent refusal to acknowledge any independent research outcomes which
question the official hypothesis (that marine radioactivity either dilutes and
disperses to infinity or bonds to seabed marine sediments and there remains
sequestered from human beings: so that it imparts no health risk doses to
c: a consistent refusal to act upon the (independent/academic) scientific
consensus that the highest concentrations of marine radioactivity will be found
in fine sediment deposits near the inland extreme of estuarine systems (i.e. not
focussing on such areas);
d: a refusal to base the structure of estuarine and marine sediment monitoring and
sampling programmes on the outcomes of estuarine system wide sediment
grain size analysis.
In the case of the Blackwater Estuary the annual number of estuarine sediment and water sampling sites has fluctuated over the years:
1997: 3 sediment sampling sites no water sampling sites
2000 & 2001: no sediment sampling no water sampling
2002: 5 sediment sampling sites 1 water sampling site
2005 5 sediment sample sites 1 water sample site
2007 6 sediment sites 1 water sample site
2012 6 sediment sites 1 water sample site
(from Annual Radioactivity in Food and the Environment (RIFE) Reports)
The samples listed above provide the only Blackwater Estuary source for non-biological marine data on an estuary which is described as being 23 km long. However, that is a “straight line” measurement which takes no account of the fact that the estuary has a north and a south coast and that both of those coasts are deeply indented. I can find no estimate of the entire length of the Blackwater Estuary coastline. However I offer a “guestimate” that the combined length of both coasts of the Blackwater Estuary (excluding the islands) may be as high as 100kms. In that context, 6 sediment sampling sites cannot provide an adequate coverage or representation of environmental radioactivity concentrations in the estuarine environment.
The annual number of samples taken from each site is restricted to 2. This cannot possibly provide an adequate representation of the seasonal fluxes of Blackwater Estuary environmental conditions, driven as they are by seasonal meteorological, tidal and sea state fluxes and longer term climate change parameters.
No details are provided of the time of year when the samples were taken (winter erosion cycle? Summer deposition cycle?). No details are provided of sea state, tidal state or meteorological (rainfall, etc.) conditions at the time of sample gathering (these parameters are highly relevant to behaviour and fate of estuarine radioactivity).
During its operational phase the Bradwell nuclear site routinely discharged a wide variety of nuclides to the Blackwater Estuary. I have (to date) not been able to identify a comprehensive list of the radio nuclides in the liquid discharge stream from this station. However, the data I have been able to access implies that liquid discharges to the Blackwater consisted of at least 27 beta emitting nuclides and 8 transuranic nuclides (i.e. at least 35 nuclides in total).
In this context, the 2012 RIFE report’s list of radio nuclides of the 8 nuclides monitored for in Blackwater Estuary sediments, seawater, sea foods and seaweeds marine plainly does not represent a comprehensive cover of radiological monitoring and cannot provide definitive answers to questions concerning the behaviour and fate of radio nuclides in the Blackwater Estuary environment and the potential (total radioactivity) doses to local residents.
Blackwater sediment samples were only analysed for 3 nuclides in 2012. Blackwater sea water samples were only analysed for 2 nuclides in 2012. Thus the state of knowledge of radioactivity in Blackwater Estuary sediments and sea water is minimal.
The mechanisms of adsorbtion of pollutants to sedimentary particles is widely recognised by marine pollution researchers and there is an equally wide consensus that the finest particles will accumulate the highest concentrations of radioactivity. There is an additional consensus that coastal and estuarine fine sediment deposits similarly accumulate the highest concentrations of radioactivity.
In this context it is evident that attempts to provide data on the distribution of radioactivity in estuarine and coastal sediments should be informed by comprehensive grain size analysis in order to identify (and then sample) a representative range and number of fine, medium and coarse sediments. I have found absolutely no evidence that any of the UK coastal or estuarine sediment radiological sampling and analytical programmes have undertaken such research or based their sampling on the consensual understanding of the relationship between sediment grain size and pollutant concentrations.
Blackwater Estuary seafood sampling programmes
1997 fin fish sampling programme took 1 sample each of Sole, Herring, Bass and Mullet. The 2005 fin fish sampling programme took 2 samples of Sole, and 1 each of Bass and Mullet. The 2012 fin fish sampling programmes took 2 samples of sole and 1 sample each of Bass and Thornback Ray.
As with the sediment/seawater monitoring programmes, the analysis of fin fish is restricted to both a very small sample number base AND a relatively small number of radio nuclides:
1997: 6 of 12 radionuclides listed in the RIFE report for Bradwell monitoring
2005: 6 of 11 radionuclides listed in the RIFE report for Bradwell monitoring
2012: 2 of 8 radionuclides listed in the RIFE report for Bradwell monitoring
of a total of at least 35 nuclides discharged to the Backwater Estuary.
I have found no scientific or empirical evidence to support the contention that the fin fish chosen for radiological analysis are specifically representative of Blackwater Estuary conditions. Fin fish species and individuals are generally fairly mobile and often (at various life cycle stages) migratory. Unless such fish were tagged, as juveniles, there can be no proof that they are anything other than recent, short-term visitors to the estuary.
Shellfish/crustacean samples taken from within the Blackwater Estuary are more representative of estuarine mid-term radioactivity exposures. However, analysis is only carried out on a small number of the total radio nuclides that the Bradwell site has discharged to the Blackwater Estuary (i.e. less than 12 of a total of at least 35 nuclides).
I have found no empirical/scientific evidence to support any contention that ONLY the 12 radio nuclides which are analysed offer a potential dietary dose via shellfish/crustacean or fin fish consumption and that the other 23 + nuclides from historical Bradwell liquid discharges present no such potential. Thus it may be concluded that the monitoring analysis of Bradwell marine samples does not, and cannot, provide a complete set of data about the behaviour, fate, pathways of human exposure and doses to humans.
Finally, a number of studies by nuclear industry, government regulating agencies, academics and other independent researchers have conclusively demonstrated the sea- to-land transfer of marine radioactivity by way of a number of mechanisms including inundation and cross surf line transfer (in inshore winds) of sea spray and marine aerosols. The sea spray and marine aerosol mechanism has been proved to be responsible for re-concentration and enrichment of marine radioactivity (compared to the ambient water column). The mechanism is also responsible for relatively deep inland penetration (at least 10 miles inland) of marine discharged radioactivity from distant sources.
A number of independent studies (i.e. non nuclear industry or government agency) have demonstrated that such sea to land transfer will irradiate terrestrial food crops in the coastal zone and provide dietary doses of marine radioactivity, which in some cases are shown to be higher than those received by sea food consumers. UK coastal and estuarine monitoring programmes consistently ignore and downplay this data and fail to adequately incorporate it into the monitoring programme.
In the context of the above, it is this Consultant’s opinion that neither the UK nuclear industry nor the UK regulating agencies have gathered (or possess) sufficient data to enable a comprehensive assessment of:
a: the radiological status of Blackwater Estuary marine environments,
wildlife and sea foods;
b: the potential pathways of exposure of Blackwater Estuary human
c: the potential doses received by those populations.