Presentation is loading. Please wait.

Presentation is loading. Please wait.

Characterisation of the South West European Marine Sites W.J.Langston and B.S. Chesman.

Similar presentations

Presentation on theme: "Characterisation of the South West European Marine Sites W.J.Langston and B.S. Chesman."— Presentation transcript:


2 Characterisation of the South West European Marine Sites W.J.Langston and B.S. Chesman.

3 Six SW European Marine Sites Characterisation of European Marine Sites in South West England Severn Estuary pSAC Exe Estuary SPA Poole Harbour SPA Plymouth Sound and Estuaries cSAC, SPA Fal and Helford cSAC Chesil and the Fleet cSAC, SPA

4 Characterisation of the South West European Marine Sites To characterise the sites in terms of environmental quality (water, sediment and biota) -published and unpublished data (WIMS) To consider activities and sources which have, or are likely to have, a significant effect on the site - FW, discharges and tidal W To provide a synthesis of information on vulnerability and biological impact (from bioaccumulation to community-level response) To highlight gaps in our understanding of these systems and make recommendations which will assist the statutory authorities to target future monitoring and remedial activities  THE WAY FORWARD Objectives

5 Toxic contamination: direct effects  Non-synthetics (metals e.g.Hg,Cd, Pb; hydrocarbons)  Synthetic organic compounds (e.g. pesticides, TBT, PCBs)  Radionuclides Non-toxic contamination: indirect effects  Nutrient enrichment (e.g. agricultural run-off, outfalls)  Organic enrichment (e.g. mariculture, outfalls)  Changes in turbidity (e.g. dredging, outfalls, agricultural run-off) Characterisation of European Marine Sites in South West England Types of contamination Types of contamination (in view of emphasis on RoC) Pathways and inputs considered Diffuse sources - rivers (land run-off) Point sources domestic and industrial Atmosphere - fossil fuels Discharges, dumping and antifouling from shipping

6 Characterisation of the South West European Marine Sites To present results: Reports comprehensive, difficult to précis 1.Run through contaminants (categories) – some key issues and weaknesses 1.Toxic contaminants (metals, organics) 2.Nutrients and related parameters 2.Biological condition- evidence for effects 3.Conclusions and recommendations to address limitations

7 Catchment and sediments of the Fal reflect underlying geology : Mining since the Bronze Age ; Carnon Valley in particular. Much deposited in Restronguet Creek Wheal Jane mine closed residual drainage from old mines, spoil heaps and groundwater continue to influence sediment geochemistry Toxic contaminants – impact of Metals on site characteristics Major (W-E) geological influence coupled, locally, with recent anthropogenic inputs Fal and Helford cSAC

8 Restronguet outside the cSAC, but some metals transported to other parts of the system, (NB adjacent creeks on the W. side - Mylor and Pill) and to upper Fal depth profiling over tidal cycles in the Fal show metals may be exported on surface (low salinity) salinity Zn LW Data source MBA

9 Low salinity surface water at the mouth of Restronguet may be important, if variable, source (e.g. Zn up to 425 µg l -1 ) At EA monitoring sites elsewhere occasional elevated values: upper Fal (STW?) Falmouth Dockyard, Mylor Zn Metals l EQS 40ppb Cu - Also elevated at mouth of Restronguet and Falmouth

10 As As - elevated off Restronguet, Mylor Variability over tidal cycle due to stratification Metals NEED BETTER DATA AND MODELS To characterize distributions and apportion sources Data source: EA

11 Significant geological / historic component in upper estuaries e.g.Tamar Metals in estuarine waters may still originate from both point- and diffuse sources As (3+) Mn NH 4 As (5+) Fe Point sourceDiffuse Metals - Plymouth Sound and Estuaries cSAC, SPA Data source MBA

12 In comparison with historic sources, current industrial process and STW discharges probably have a low impact, though they may increase concentrations locally. Industrial sources in Yealm, upper Plym, also occasional high Cu Several metals including Cu elevated in landfill run-off Metals Need better loadings estimates to apportion sources and action Data source: EA

13 Traditionally a major concern because of smelting and other metal industries Largest Cd input of all UK estuaries (now ceased) Notable quantities of Zn, Cu, Hg, As Cd, Cr and Hg high % from industrial sources Cu, Mn and Ni mainly riverine + some trade and sewage discharges Relative loadings (Owens, 1984) - out of date? Metals: Severn Estuary pSAC, SPA Multiple sources

14 Cd inputs in mid- estuary Also As, Cr, Zn Some originate substantially from rivers Perhaps modified by discharges Mid-Axial profiles partly reflect the relative importance of sources… Metals 

15 ….but may be higher at near-shore stations close to outfalls Last 10 years data Cd  Cu more diverse sources (includes STW)Metals Cu -  Cd Avonmouth) Data source: EA

16  Zn - also multiple sources Reduction in some areas (Avonmouth)  Metals Also Cd (But difficult to access raw data for IPPC sites) EQS values occasionally exceeded in waters of the mid-upper estuary (Cd, Cr, Cu, Hg and Zn) Data source: EA

17 Still some uncertainty over scale of reduction in estuarine waters: due to tidal, daily, seasonal variabilityMetals Need for continued comprehensive data, including recent loadings and budget estimates Data source: EA

18 Historical concern ? - Holes Bay (Secondary embayment) Chemical plant, light industries and STW at Poole likely sources Inputs in 1970s and 1980s thought responsible for poor performance of oyster larvae in hatchery at mouth of Holes Bay (Cd and Zn in water at the hatchery intake were 5.7 and 177 µg l -1 ) Metals: Poole Harbour SPA Current monitoring mostly below EQS - (but mainly in outer harbour) ; Poole Bridge tends to be highest - continuing influence of Holes Bay? - further investigation Cu Data source: EA

19  Zn EQS = 40 µg/l Elevated Zn levels Lake Pier and Lytchett Bay: possible sources antifouling paints and sacrificial anodes (Bird et al., have shown elevated levels in marina waters and sediments) Metals Data source: EA

20 Classification based (ISQG’s) and (PEL’s) (CCME 1999) RedGreyGreen Red = effects expected; Grey = possible effects cannot be excluded; Green = no harm expected Similar for Zn, Pb etc. Metals: sediments  Issues: Few sediment data (mostly MBA); How useful are guidelines? Historic, diffuse --beyond control?

21 Tamar Reflect the influence of mineralisation As e.g As  Mostly decrease downstream Several other metals similar distribution e.g. Cu, Hg, Zn RedGrey Green Red = effects expected; Grey = possible effects cannot be excluded; Green = no harm to the environment expected Metals: sediments Data source MBA

22 Industrial and domestic inputs significant for Cd (Plym) Distinguishing natural and anthropogenic sediment metal important Other sources possibly important for Pb Metals: sediments Exceptions: Data source MBA

23 Poole: As might expect from the low energy environment, metals retained close to source: highest Holes Bay (occasionally above guidelines) RedGrey Green Red = effects expected; Grey = possible effects cannot be excluded; Green = no harm to the environment expected CCME 1999) Metals: sediments Also e.g. Cd and Zn Data source MBA

24 Classification based (ISQG’s) and (PEL’s) (CCME 1999) Grey Grey = possible effects cannot be excluded; Fines+Contamination dispersed and homogenous Most metals above ISQG but exceedences of PEL rare (Zn and Pb) Some reductions Metals: sediments In tidally energetic Severn: anthropogenic vs natural? Data source MBA

25 Bioaccumulation - Metals Compliance monitoring emphasis on commercial species - may not give complete picture in estuaries (distributions/regulation) benefits to using range of bioindicator species including algae, infauna (MBA-data set used extensively) bioavailability of (dissolved) Cu in Fal and Helford cSAC - Fucus Data source MBA

26 Fal, Tamar, Poole, Severn Infaunal species such as Nereis, provide useful information on bioavailability in estuarine sediments: Fal, Tamar, Poole, Severn Generally bioaccumulation patterns resemble sediments - BIOACCUMULATION - METALS Sound Re-evaluation - spatial and temporal trends; Consequences for birds; Offshore (Sound) needs better characterisation- Cu elevated in the Tamar complex Cd bioavailability highest in the Plym Data source MBA

27 Effects of Metals Community level: obvious if contamination acute Sampling sites Restronguet (circles)) other creek PCA environmental variables Metals in sediment Somerfield et al., Fal cSAC extremely good test-bed for techniques

28 Somerfield et al., Useful to apply more extensively to address spatial and temporal trends

29 Toxicity assessment -SEDIMENT BIOASSAYS -Explains removal of sensitive species Data source MBA

30 Cellular/subcellular studies help explain underlying mechanisms May act as more subtle markers of chronic conditions E.g. MT in mussels Example of value of integrated tiered approach to assess condition -useful for other sites? Data source MBA

31 Infaunal communities differ between upper (east and west) and lower areas of the Bay; some correlation with metals (White, 1991) Immunocompetence in shellfish (Pipe et al) Precise cause unknown –cocktail of chemicals - need biomarkers Poole - Some indication of biological impact but little diagnostic evidence of cause Holes Bay

32 Size-exclusion chromatograms of cadmium-binding in winkles and mussels from Holes Bay (Poole) and reference sites showing induction of metallothionein (MT) at the former site (MBA data) MT- Metals a possible contributory factor L.littorea M.edulis

33 Highest in the upper estuary (proximity to STW) - only region where deterioration expected but inputs probably decreasing - Zn Sediment: Zn only metal sediment above PEL though Cd, Hg, Pb, Cu and As sometimes exceed ISQG Classification based (ISQG’s) and (PEL’s) (CCME 1999) Red Grey Green Red = effects expected; Grey = possible effects cannot be excluded; Green = no harm to the environment expected Metals: Exe Unlikely threat - regional baseline ? (bioaccumulation/MT)

34 No data for rivers or consented discharges Monitoring of tidal waters limited to a single site in E.Fleet (the Narrows) No cases of EQS exceedences (though Cu and Zn elevated in Portland) Metals: Chesil and the Fleet cSAC, SPA Tidal waters  Cu EQS = 5µg/l Sediment e.g Zn  Metal data few Most < ISQG- None above ‘PEL’ Grey Green Grey = possible effects cannot be excluded; Green = no harm expected Unlikely threat: regional baseline bioaccumulation/MT?

35 Metals: limitations and recommendations Little chemical data- Hole bay Little known of metal impact offshore in Sound Effects of minewater treatment and implications for biota Remobilisation of metals from sediment, increased bioavailability in cSAC)specific Generic Chesil and The Fleet Exe Estuary Poole Harbour Severn Estuary Plymouth Sound & Estuaries The Fal & Helford Very little chemical or bioaccumula tion data- Significance/ relevance of historic inputs? Separation of anthropogenic v natural components Up-to-date information on distributions, loadings (source apportionment) and bioavailability (birds?) Better data on biological condition -including baselines for bioaccumulation and diagnostic biomarkers Better chemical and biological information at hotspots- Avonmouth

36 Impact difficult to quantify: EQS guidelines (Shellfish & Bathing Waters Directives) subjective e.g ‘tainting’ and ‘visible film’ (though latter triggers sampling and recommended 300ppb EQS under BW) Little information for hydrocarbon oils in most SWEMS Hydrocarbons - Oils Fal & Helford HC oils not exceeding ‘EQS’ at designated bathing beaches (or shellfish sites) Occasional elevated levels at other sites e.g Helford Mouth Also Plymouth Sound & EstuariesExe, Poole (Fleet No data) Also Plymouth Sound & Estuaries, Exe, Poole (Fleet No data) Possible sources: shipping (large and small), spills, boatyards, run-off Data source: EA

37 Hydrocarbons - Oils Severn Estuary Industrial discharges can also be significant source (e.g. drains near Lydney Industrial Estate and Kingsweston Rhyne) Sediment UCM indicates degraded, or chronic oil contamination at several sites; Severn, Plymouth (Hamoaze). Data source: EA

38 Oil pollution - Oil pollution - existing impact hard to define but potential threat to all inshore marine habitats where contamination can be washed ashore – NB semi-enclosed areas Threat more pronounced in SWEMS with intensive shipping activity and operations e.g. Fal Estuary Plymouth Sound Poole Harbour parts of Severn Estuary Most vulnerable habitats probably intertidal; Sheltered rocky coasts Intertidal sand and mudflats Saltmarshes - of semi-enclosed inlets and bays Hydrocarbons – Oils

39 Hydrocarbons - PAHs (now declining?) Discharge concern for PAH in estuarine water focused on Lydney/Purton (paper mill and O/F sewer) Elsewhere combination of sources (fossil fuel combustion, shipping, urban run-off, STW and industrialised areas) Coal bearing strata of S. Wales + oil bearing shales in Bridgwater Bay contribute to PAHs in the Severn Severn Estuary An issue, locally, in the more industrialised SW EMS e.g. Severn Estuary Tidal waters Tidal waters: Few recent data ExeFleet PAHs generally low in Exe and Fleet compared to industrialised estuaries (> 1 µg l -1 environmentally important - Cole et al., 1999) anthropogenic natural Data source: EA

40 Hydrocarbons - PAHs Tamar Estuary, Plymouth Some enrichment at turbidity maximum, (suspended solids) from atmosphere, run-off Further PAH peak associated with urbanised portion of Estuary (Hamoaze): Exhaust gases Road run-off (Tamar Bridge) Airborne particulates Domestic/industrial waste water Dockyards *Readman et al, (1986)

41 Principal fate of PAHs is sediment deposition Tamar Sound) distribution often reflects sources - peak associated with the urbanised portion of estuaries e.g Tamar - (lower offshore Sound) Hydrocarbons – PAHs in sediments ISQGs and PELs sometimes exceeded; Anthracene Benzo(a)anthracene Benzo(a)pyrene Chrysene Phenanthrene Naphthalene Pyrene Contribution to chronic effects?

42 Sources may include airborne particulates, urban run-off, various trade and domestic inputs, and marina activity Poole Harbour Poole Harbour - PAH concentrations in some sediments (in Holes Bay) of potential biological relevance (above Threshold, but not PEL) Hydrocarbons – PAHs Adapted fromWoodhead et al., 1997 Contribution to chronic effects?

43 Sources may include airborne particulates, urban+motorway run-off, sewage inputs, and boat activity Exe (..also in Chesil & Fleet Sediment PAHs can sometimes be elevated even in less industrialised estuaries e.g. Exe (..also in Chesil & Fleet ) Exe: PAHs low in marine sands, higher in upstream muds (Turf) > ISQG, <

44 S ome individual PAHs >ISQG Hydrocarbons - PAHs  15 PAHs (dw) (MPMMG, 1998) Severn Estuary Moderately high levels of total PAHs in sediments of Severn Estuary Attempts to address - PAHs may contribute towards induction of enzymes (EROD), seen in eels and flounder from the Severn ( UWE) (potential for chronic effects in other burrowing species e.g. lamprey?) Chronic effects?

45 Hydrocarbons: some limitations and recommendations Recommendations General: More extensive biomarker information needed e.g. EROD, to establish threats Threat posed by bioaccumulation and food chain transfer needs to be quantified Limitations General: Lack of data potential for food chain transfer and bioconcentration of toxic contaminants has scarcely been addressed in EMS EQS’s for hydrocarbons are difficult to define Chesil & the Fleet The Exe Estuary Poole Harbour Severn Estuary Plymouth Sound & Estuaries The Fal & Helford Concentrations not extreme, but of potential biological relevance -useful to broaden the data on PAHs and quantify sources and effects.

46 RiversExe, Tamar, Fal Rivers e.g. Exe, Tamar, Fal EQS 20ng/l Synthetic organics Synthetic organics pesticides, herbicides, organic solvents, PCBs and other endocrine disruptors  -HCH in Exe,Trews Weir Similar for other OC pesticides (most banned) Severn - In the past, diazinon, dichlorvos, PCSD, dieldrin, atrazine and simazine > EQS - exceedences now rare (95-99 EA data)  -HCH in Plym, Marsh Mills Toxicological impact from DDT, ‘drins’, endosulphan, OPs, triazines probably small, (most

47 Synthetic organics Tidal waters Tidal waters Probably low overall impact - well below the EQS Poole and Exe e.g Poole and Exe …although little information to assess the most-likely affected areas such as Holes Bay, where there are small inputs e.g.  -HCH  -HCH in tidal Poole  -HCH in tidal Exe EQS 20ng/l Data source: EA

48 Plymouth Sound & Estuaries Lindane, dieldrin and DDT sometimes exceed ISQGs and PELs Synthetic organics - sediments Sediment data sparse, dated - many EA detection limits above ISQG NB Severn, Fleet* Better data on organics in sediments needed - NB Severn, Fleet* Better definition of sources - diffuse agricultural inputs +STW * Portland Harbour (no data for Fleet) Exe Estuary, Poole (outer) Holes Bay: Exe Estuary, Poole (outer) only lindane > PEL. Holes Bay: total PCBs Effects likely to be localised and chronic?

49 Threat of bioaccumulation and food chain transfer small but poorly defined by current monitoring Threat of bioaccumulation and food chain transfer small but poorly defined by current monitoring -emphasis on commercial species Exe Estuary Exe Estuary Organics in commercial shellfish in lower estuary

OSPAR upper limits in places

50 Reduction in cholinesterase activity in Tamar flounder muscle (marker of exposure to neurotoxins, particularly OPs) -CEFAS* Highlights need for more extensive ‘effects’ studies in inner estuaries (NB infauna and species in contact with sediments) (ChE) activity in flounder muscle from English estuaries. *(from Kirby et al., 2000) Synthetic organics - biota Plymouth Sound Plymouth Sound - residue data scarce - in mussels (Sound) not unduly high

51 Synthetic organics – Synthetic organics – Very little data on EDs and effects Poole Harbour, Exe Estuary All alkylphenols

52 Synthetic organics: limitations and recommendations The Fal & Helford Plymouth Sound & Estuaries Severn Estuary Poole Harbour ExeEstuary Chesil & the Fleet Limitations General: Detection limits for many OC pesticides above sediment guidelines Recommendations General: Accurate, up-to-date data needed Priority for research into EDs and potential effects Priority for research into EDs and potential effects *based on recommendations by Allen et al., (2000) MediumHigh low assess accumulation in sediments and food-chain magnification (birds) at hotspots assessment constrained by limited sampling, analytical uncertainty Better definition of sources - diffuse agricultural inputs vs STW need for more extensive ‘effects’ studies in inner ‘estuaries’ (NB infauna)

53 partial ban in the UK in 1987, globally in Still an issue ? Organometals – impact of TBT Plymouth Sound & Estuaries  EQS Hamoaze, Batten Bay, Yealm > EQS Poole Harbour Significant reduction of TBT in water  Levels in tidal waters declining generally But may be high concentrations near dockyards, marinas and outfalls  Fal & Helford  Fal & Helford  EQS Dockyard and Penryn River - Problems complying with EQS

54 Organotin - sources * Harris (2001) Plymouth Sound Low-level contribution from discharges in the Tamar,Yealm, Plympton STW, Chelson Meadow Modelling budgets (ECOS) for Tamar confirms losses offset by low-level inputs Major source docks; Also continuing contribution from and legal and illegal usage and sediments Fal& Helford Fal & Helford May also be a small component arising from STW, marinas, wharves) Inputs sustaining existing concentrations* Little evidence of decline so far - anticipated with active-carbon treatment plant at the docks TBT in Fal outfalls TBT in Plymouth outfalls Data source: EA

55 Organotin - sediment Poole Harbour W Worst case scenario early ‘80s (marinas) Highest concentrations on northern shoreline - (>OSPAR guidelines) Molluscs populations affected Classification based on interim sediment ecotoxicological assessment (OSPARCOM) Red = effects expected CEFAS analysis and bioassays (Arenicola, Tisbe and Corophium) with dredge spoils also highlight TBT sediment issue (Holes Bay) TBT TBT persistence in sediments: may slow recovery (NB oysters and infaunal bivalves Holes Bay) Information on progress needed Half-times > 50months (MBA data) Relative contribution as source still to be resolved adequately - but may be ecotoxicologically significant:

56 Organotin - sediment Fal & Helford: Fal & Helford: TBT distribution in sediments reflects sources Decreases from max 10µg g -1 close to Falmouth Dockyard to ~ 1 µg g -1 in Penryn Creek- sediments elsewhere in Fal display contamination legacy (average 0.5µg g -1 ) May penetrate > 1m - potential for sediment releases during dredging Ecotoxicologically relevant and therefore needs better characterisation in terms of sediment loadings and transport (current EA project) Severn Estuary Little or no recent sediment data for several sites e.g Severn Estuary Plymouth Sound & Estuaries, Exe Estuary, Chesil & Fleet Plymouth Sound & Estuaries, Exe Estuary, Chesil & Fleet

57 Imposex most sensitive and specific biological marker of pollution (TBT) discovered in Plymouth Sound - initiated at 1 ppt TBT At a few ppt, TBT prevents egg laying and dog-whelk populations may become extinct Valuable in monitoring success of legislation - still an issue? Organotin - effects Dog-whelk Nucella lapillus

58 e.g. Plymouth Sound and Estuaries TBTTBT offshore declined after some sites ~ EQS by 1992 Renney Rocks: %-sterilised Nucella females dropped, recolonisation slow Unaffected females still a rarity Batten Bay: Nucella absent - EQS* still regularly exceededOrganotin TBT TBT - continuing impact on dogwhelks in several SWEMS *see also CEFAS data and more recently EA survey in 1998 confirmed continued reductions in imposex levels at open coastal sites (Geileskey, 2000) Inshore: Nucella absent from Stonehouse; eliminated from Cremyll, (previously high RPS scores) Despite general improvements in WQ, recovery slow (partly limited reversibility of imposex) (Gibbs and Langston, 1994)

59 Organotin Fal and Helford dogwhelks common throughout the estuary as far upstream as King Harry Ferry many populations disappeared - only very small numbers present at few sites Most recent information (1996) indicates Castle Drive and Towan Beach Populations sole survivors in area Exe Estuary Nucella eliminated at Maer Rock, Orcombe Point, Exmouth (Dixon, 1986) Yet to recover? Chesil & Fleet imposex in Portland Bill and West Bay Nucella - similar VDSI ~4 (SOAFD) improvement at West Bay, Portland Bill population eliminated - TBT remains high enough to sustain phenomenon Poole Harbour Nucella eliminated at Studland - dogwhelks

60 Severn Estuary EQS exceeded near some STW and trade discharges Dredge spoils may be significant; Cardiff, Newport ppm TBT (CEFAS) Organotin - poorly characterised at some sites (limited data) Exe Estuary Exe Estuary Most Tidal waters

EQS in Portland Harbour

61 Organotins: Limitations and recommendations Re-survey of benthic biota and TBT levels overdue. Significant time series More information on inputs, environmental inventories, and partitioning needed to simulate the fate of TBT in the cSAC Continue time seriesspecific Generic Chesil and The Fleet Exe Estuary Poole Harbour Severn Estuary Plymouth Sound & Estuaries The Fal & Helford Little threat of impact in estuary on current evidence Sediment and biological analyses needed to confirm Threat often difficult to assess due to inadequate (DL > EQS etc) or old data Better recent information on distributions, nb sediments and bioavailability/ toxicity Re-evaluation of time series (chemical and biological) where still an issue No published records of organotin in Severn water, sediment or biota. Little threat of impact in estuary on current evidence Sediment and biological analyses needed to confirm

62 Plymouth (Devonport) Base for refitting and refuelling UK's fleet of nuclear-powered submarines DML authorised to discharge 3 H, 14 C, 41 Ar, 60 Co etc. FSA/SEPA Environmental radioactivity and dose rates reported by FSA/SEPA indicate low radiological significance 3 H Discharges of 3 H expected to rise : studies on key species and processes needed to assess change (also dredging ) Radionuclides Severn EstuaryPlymouth Sound & Estuaries Not generic concern but merit further consideration in parts of the Severn Estuary and Plymouth Sound & Estuaries

63 (FSA/SEPA) Severn Estuary Installations which could potentially impinge on water quality in the pSAC: 3 nuclear power plants (Berkley and Oldbury, Hinkley Point) Collection of smaller discharges (hospitals and research establishments) Monitoring low levels in Berkley/ Oldbury area (mainly Cs) Most transuranics of little concern in pSAC Occasional elevated levels of 3 H in water and shrimp (Hinkley) Anomaly for (organic) tritium and some 14 C near CardiffRadionuclides (Remedial action initiated at source to reduce future discharges. New STW in 2002 should retain particle-entrained tritium along with the sludge)

64 Radionuclides: some limitations and recommendations Plymouth Sound & Estuaries Severn Estuary Recommendations More data and fundamental studies on tritium behaviour, geochemistry bioaccumulation and effects on marine biota needed Studies to assess potential effects of dredging and bioturbation on distribution of sediment-bound radionuclides needed More extensive monitoring of tritium distributions and source apportionment in the Severn Bioavailability, assimilation pathways and impact of organically-bound tritium require further investigation

65 Nutrients – nitrogen and phosphorus species  Nutrient enrichment of inland and tidal waters considered by the European Environment Agency to be one of the most important water quality issues facing Europe (FWR, 1998)  Also one of the key issues to emerge from the SW EMS characterisation project (effects/potential effects to the integrity of the sites)  N and P not on priority lists (except ammonia - potentially toxic)  No statutory standards for N and P in estuarine and marine waters - number of ‘guideline values’ established/proposed, e.g EU, USEPA, Nixon et al., which can indicate poor water quality and represent benchmarks against which we have drawn comparisons

66 Agricultural run-off important Additional contribution from STW Nutrients In tidal waters distribution of nutrients often reflects sources Phosphate mainly from fw (including agriculture) – but may be locally enhanced from point sources e.g. lower Plym e.g. Plymouth Sound cSAC Data source:EA

67 Nutrients – temporal trends  Levels can be high and may be increasing locally in waters of some SACs e.g. PO 4 in the Helford Estuary and Plymouth Sound estuaries, and NH 3 in Poole Harbour Need to sustain monitoring – targeted sites Data source:EA

68 Nutrients - sources  UK and European basis, diffuse inputs considered principal source of nutrients in surface waters* P ~ 40-60% N ~ 70-80% * (FWR, 1998) The Fleet Lagoon The Fleet Lagoon (Murdoch, 1999) Fal & Helford Fal & Helford (Fraser et al., 2000)  Modelling and load analyses (where available) for SWEMS also indicate diffuse inputs, especially agricultural (fertiliser and livestock) are principal source of N & P  Diffuse component may be increasing  (STWs principal source of NH 3 ) +2.5%+7% +5.48%+0.3%

69 Nutrients - sources ……….however, in some cases, point source inputs may be more significant e.g. PO 4 (and NH 3 ) Severn Estuary; TIN Plym; PO 4 Poole Harbour (EA data) (Owen 1984) (WWA 1981) Need more up-to-date quality data, load estimates, and modelling to characterise sources and distributions

70 Nutrients – temporal trends for discharges  Nitrate in discharges to Exe Estuary SPA from Countess Wear (and Exmouth) STW  Nitrate in Poole STW discharge to Poole Harbour ( Ammonia reduction processes introduced at some STWs - increase in nitrate concentration) Loading estimates needed Increases in concentrations of nutrients in some STW effluents e.g.  Also several reductions e.g PO 4 in Poole STW discharge Data source:EA

71 Nutrients – effects/manifestation chl-a Changes include: Rapid phytoplankton growth - increase in chl-a Blooms can be toxic Blooms can be toxic - e.g. Fal & Helford,Plymouth, Poole, Fleet lagoon)  ‘Red tide’ events and other toxic blooms (ASP, PSP, DSP) have occurred in several of the SW EMS (Fal & Helford, Plymouth, Poole, Fleet lagoon)  Invertebrate mortalities & temporary bans on collection of shellfish  Almost caused economic collapse of Poole Harbour shellfish industry in 2001 Exe Estuary  e.g. phytoplankton blooms in Exe Estuary (roughly centred mid- estuary) – exceed eutrophic ‘benchmark’  Not persistent in Exe due to the flushing characteristics but indicative of enrichment problems Important issue in SW EMS – better characterisation of conditions conducive for blooms needed Data source:EA

72 Nutrients – effects/manifestations  May also occur in Fleet Lagoon, Exe Estuary, Plymouth Sound – reports of thick macroalgal mats; Ullothrix and Enteromorpha spp   Can increase potential for release of ammonia from sediments (ammonifying microbial activity during decline of algal biomass) – more research needed Macroalgal blooms can also occur  e.g. Poole Harbour - problems recorded for several decades  Dense mats of Ulva and Enteromorpha  History of complaints locally Recent aerial photography (CASI) (EA 1998) indicates eutrophication still a problem; shows macroalgal blooms on intertidal mudflats  Recent aerial photography (CASI) (EA 1998) indicates eutrophication still a problem; shows macroalgal blooms on intertidal mudflats Important to monitor extent of algal proliferation - potential for blanketing/smothering effects – sensitive benthic communities, Zostera, Maerl and other important species

73 Nutrients – effects/manifestation Changes include: Fluctuation in DO levels - During growth phase, and following the die-off of blooms - microbial activity = increased potential for DO depletion in water and sediments Fleet Lagoon (west)Plymouth cSAC (Tamar)  e.g. exaggerated DO fluctuations occur - Fleet Lagoon (west), Plymouth cSAC (Tamar)  May be harmful to migratory salmonids (upper Tamar)  DO at night may drop below mandatory levels (shellfish directive and sensitive saltwater life) – spot sampling (daytime) will not detect Data source:EA

74 Nutrients – effects/manifestation Changes can also include: increases in turbidity Plymouth estuaries e.g. Plymouth estuaries; turbidity increasing in Tamar and Lynher  Principal source of turbidity is sediment resuspension  Increasing levels in some SACs suggest additional sources: discharges, chemical flocculation and plankton blooms Data source:EA

75 Nutrients – effects/manifestation  Severn Estuary  Severn Estuary hypernutrified; exceptional levels N & P occur in tidal waters compared to other SW EMS  Exceptionally high levels - widespread algal proliferation might be expected but Chl-a levels not excessive  High suspended solids loadings limit light penetration and hence algal productivity  Eutrophication therefore not a major issue across the pSAC as a whole Elevated nutrient concentrations do not always signify eutrophication;  But localized effects of nutrient enrichment occur - (Avon, East-Severn, Parrett) = intermittent DO sags e.g. upper 20km and in tributary estuaries  Ammonia reported to be very high* despite flushing – toxicity issues? *Ellis (2002) 25 th percentile = approximate background level for tidal waters Data source:EA

76 Nutrients  Generally SW EMS are vulnerable to nutrient enrichment  Potential for enrichment of waters (and effects) is likely to be different for each marine site  Impact of inputs largely determined by physico-chemical and biological characteristics; flow, seasonal variability, flushing, tidal regime, primary production and rates of remineralisation  These variables are unique to individual catchments

77 Nutrients: some of the issues The Fal & Helford Plymouth Sound & Estuaries The Exe Estuary Chesil & the Fleet Poole Harbour Severn Estuary Generic Issues Improved, good quality monitoring needed for much of the SW tidal waters No water/sediment quality standards for N and P Ammonia EQS is for un-ionised form (relevant but difficult to measure) Potential of sediments as sink/source for N, P and NH 3 largely unknown Causes and characterisation of conditions which result in blooms of toxic algal species needed Site Specific Issues Modelling based on incorrect data (Abbotsbury STW )- new modelling exercises needed Issue of P reduction should be addressed No information for Holes Bay Biological monitoring and effects studies (e.g. effects of extreme levels of N, P and NH 3 ) needed

78 Biological condition In SW EMS, impacts of some contaminants on biota may be apparent…  TBT – molluscs…  Metal pollution - induction of MT - changes in community structure – e.g. loss/reduction of most sensitive species  Nutrient enrichment – eutrophication, micro- and macroalgal blooms, red tide events, fish mortalities - changes in the distribution of rare charophyte - foxtail stonewort Lamprothamnium papulosum (West Fleet)

79 Biological condition -  Zostera beds lost or diminishing - associated flora and fauna low in abundance  Long term decrease in live maerl (Fal & Helford)  CEFAS bioassays with oyster larvae indicate areas of poor water quality (Plymouth Sound, Poole Harbour)  Changes in composition of fish species (Severn) ….sometimes more difficult to establish cause/effects e.g.  Decline of some species may reflect national/Europe-wide trends e.g Eel (Anguilla anguilla) ….area for research? ……….and sometimes only anecdotal evidence e.g.  Poor recruitment of 0-group bass (Fal nursery grounds)  Possible decline in the diversity of algal species for some sites  Possible long-term decline in numbers of birds using Helford River

80 Biological condition - SPAs Severn Estuary - Alerts only triggered for Severn Estuary - …..12 out of 16 species shown declines  Water quality issues are one possible cause requiring investigation  Food chain biomagnification an important exposure route for birds (and other predators) – more research  Decline in numbers for some important species/sites Fleet - Fleet - Dark-bellied Brent Goose Branta bernicla bernicla Exe - Exe - Wigeon, Dark-bellied Brent Goose, Oystercatcher and Avocet Poole Harbour - Poole Harbour - Shelduck BTO review of species/trends for SPAs – 5, 10, 25 yrs

81 Biological condition – diversity indices Plymouth Sound & Estuaries - Plymouth Sound & Estuaries - Community level: Biological indices indicate that biodiversity is relatively good Poole Harbour - Poole Harbour - Biodiversity low in parts Exe - Exe - Faunal biodiversity relatively high and increases toward the mouth of the estuary - abundance may be low for majority of species Severn - Severn - Relatively low biodiversity - principally due to unique physical conditions in Estuary EMS are designated because of interest features and particular range of habitats….. …..should we expect above average biodiversity? Many studies now out-of-date More multivariate statistical analyses studies needed to assess community response to contaminants

82 Biological condition – evidence of impact in SW EMS Seldom unequivocal evidence of biological impact:  Paucity of recent information  Cause/effect relationships not always established  No widespread application of Biodiversity indices  Sub-lethal indicators not applied extensively

83 Conclusions and Recommendations Conclusions and Recommendations Reports have provided (for South West EMS Sites) : Characterisation of the South West European Marine Sites  Overview of existing knowledge (physical properties, uses, vulnerability)  Evaluation of current understanding of contaminant sources, exposure and biological impact  Could provide updates at intervals to chart progress of the site, to help address local and regional management needs  May also feed into DEFRAs national State of the Seas programmes and reports

84 Constraints and uncertainties - Water Quality some generic - some site specific  Traditional compliance monitoring not designed for the type of characterisation attempted (or which is desirable under the Habitats- and Water Framework Directives) e.g. Many values < detection limits: often DLs variable with time  Restricted availability of some data-sets - some major industries now under IPC regulations (reliance on public summaries)  Paucity of recent published research and data: NB sediments (characterise diffuse sources) and bioaccumulation (using appropriate and relevant infauna)  Assessment mainly based on concentration data in water: better loading estimates and models needed to assess sources

85  ‘Risk’ scaled against EQS (ISQG) – is this empirical approach appropriate to protect aquatic life given complex environmental conditions (cocktails of chemicals) ?  Biological information, (esp. in relation to anthropogenic effects) predominantly qualitative - restricted spatial or temporal coverage  How to define Favourable Condition Status (Habitats)? Good Ecological condition (WFD)?  Rarely adequate overlap between chemical and biological monitoring(including biomarkers): needed more integrated approach to establish cause-effect  Pilot multidisciplinary study needed to test new approaches Constraints and uncertainties- Biological Condition

86 Management and communication issues Accessing all available site information is not straightforward – no central repository Greater potential for co-ordinating and integrating the research/monitoring activities of relevant authorities Likely benefits for closer working relationships between the SW research community and Relevant Authorities –Need for a SW Marine Science Forum?

Download ppt "Characterisation of the South West European Marine Sites W.J.Langston and B.S. Chesman."

Similar presentations

Ads by Google