CIV 913 Environmental Assessment and Sustainability

1. CIV 913 Environmental Assessment and Sustainability ESTUARINE AND MARINE POLLUTION

2. ESTUARIES • Definition. • A semi-enclosed coastal body of water which has a free connection with the open sea, and within which sea water is measurably diluted with fresh water derived from land drainage.

3. ESTUARIES • Mixing is a function of: • River flow • Tidal Volume • Width and Depth of the Estuary.

4. ESTUARIES • Characteristics of Mixing • Stratification (Depends on shape and flows) • Denser sea water flows upstream in a wedge shape. • River water flows out to sea over the top of the sea water.

5. ESTUARIES • Mixing Characteristics. • Least mixing when QFW >> Qsea • Stratification causes a salinity gradient. • Stratification results in higher velocities than in the highly mixed estuary. • A vertical salinity gradient results in the upstream movement of sediment.

6. ESTUARIES • Flow • Due to tides net seaward movement may be small • e.g. Thames. • downstream flow high to low water - 15km • upstream flow low to high water - 13 km • net seaward flow - 2 km per tidal cycle.

7. ESTUARIES • Residence Time • Can be long eg 30days in the Thames estuary. • Thus dilution capacity is correspondingly reduced. • More pronounced oxygen sag. • Affects migratory fish and macroinvertebrates.

8. ESTUARIES • Sedimentation. • Important characteristic of estuaries. • elevated by salt / freshwater mixing • Sedimentation of suspended matter. • Flocculation and sedimentation of e.g. clays • Absorption of metals. • Sedimentation of organic matter from river, material from the sea (and dredging) and waste. • Sediment Oxygen Demand (SOD)

9. Marine Pollution

10. MARINE POLLUTIONTypes of Pollution • Organics • Solids • Pathogens • Metals • Halogenated Hydrocarbons (e.g. PCBs) • Oil • Radioactivity

11. MARINE POLLUTIONInputs • Atmospheric deposition • Rivers • Direct outfalls • Sewage • Industrial • Solids disposal • Shipping

12. MARINE POLLUTIONContamination and Pollution Pollution. • The introduction by man, directly or indirectly, of substances or energy to the marine environment, resulting in deleterious effects such as: • hazards to human health • hindrance of marine activities • impairment of quality (in terms of use) of seawater • reduction of amenities.

13. MARINE POLLUTIONInputs • Many inputs are not deliberate: • Vegetation and dead organisms from rivers • Mercury from volcanoes • e.g 5000 to 25000 tpa from volcanoes and weathering of mercury-bearing ores. • 8000 tpa from industry and burning fossil fuels. • Hence knowledge of background concentrations important.

14. MARINE POLLUTIONRegulation • International Conventions • North Sea (Oslo, Paris, North Sea) • Baltic (Helsinki) • Mediterranean (UNEP/Barcelona) • Regional Seas programme (UNEP) • Scientific Committees recommend areas for monitoring and control.

15. MARINE POLLUTIONOil • Sources of Oil to the Marine Environment. Source Estimate (m tpa) Anthropogenic Transportation 1.47 (0.568 spills) Fixed installations 0.17 Municipal & Industrial WWT 0.90 Urban & river run-off 0.12 Atmospheric fallout(oil-derived) 0.3 Natural Marine phytoplankton 36,000 Atmospheric fallout 220

16. MARINE POLLUTIONOil • Effects of Weathering on an Oil Slick Evaporation Rapid (24hr) Dissolution Fairly rapid Dispersion Rapid early stages Emulsification Rapid early stages Photochemical oxidation Dependent on light Adsorption Dependent on SS Biodegradation Fairly rapid early stages.

17. MARINE POLLUTIONOil • Types of Damage to Marine Organisms. Organism Damage Plankton Possible growth inhibition of phytoplankton. Seaweed Major Damage to inter-tidal species. Rapid recovery. Excessive growth if grazers badly affected. Invertebrates Large scale mortality due to toxicity and smothering. Fish Minor effects. Birds Diving birds badly affected. Marine mammals Rarely affected. Coastal populations vulnerable.

18. MARINE POLLUTIONOil • Treatment Techniques. Process Comment Chemical Dispersion enhances degradation. Protects coasts but increases acute toxicity. Containment Small spills, enclosed/calm waters Recovery Small spills, calm waters. Disposal problems. Adsorption/sinking Short term protection/long term benthic contamination. Burning Fresh oil. Leaves tarry residues.

19. MARINE POLLUTIONSewage Sludges • UK ceased disposal of sewage sludge to sea. • Need to consider hydrodynamics of the disposal site • dispersive (low concentrations, but larger area affected). Typical for UK. • accumulating ( local effects/monitoring) • Typically reduces diversity, but increases biomass in the benthic community

20. MARINE POLLUTIONMonitoring • Chemical and Biological • Biological - Population Change • Key species i.e high conservation interest, commercial value, those whose presence or absence has major repercussions on the community. • Indicator species. • Biological - Community Response • Preferred. Avoids errors due e.g. to climatic changes.

21. MARINE POLLUTIONMonitoring • Limitations of Toxicity Testing of Marine Pollution • valency changes, alter form. • metal salt solubility. (Lead citrate>>Lead nitrate) • organic complexes of heavy metals>>inorganic compounds eg mercury (but NOT arsenic) • oil (dissolved and particulate components) • chlorinated hydrocarbon pesticides • low solubility in water, particulate ingestion important

22. MARINE POLLUTIONMonitoring • Sub-Lethal Effects and Biomarkers • Non-specific pre-cancerous growths on flatfish (e.g. observed for sewage sludge, oil and titanium dioxide). • Skeletal deformities in fish e.g. herring affected by chlorinated hydrocarbons, oils and heavy metals. • Detoxification mechanisms • formation of metalothioneins to complex metals (urchins, crabs, seals, rockfish) • production of mixed function oxygenases in livers of fish due to exposure to lipophilic organic compounds

23. MARINE POLLUTIONMonitoring • Analysis of Community Responses. • Use soft sediment invertebrates. • Diversity • Univariate analysis e.g. number of species per unit area, • Graphical methods e.g. abundance-biomass comparison (comparison of sites, but does not differentiate the actual species). • Species composition. • Multi-variate statistical analysis e.g. comparison of similarities of species in different samples.

24. MARINE POLLUTIONPollutant Hazards • Sewage and Sewage Sludge • Affects coastal waters. • Reduced diversity, increased biomass in sediments. • Can get oxygen depletion e.g. New York Bight, the German Bight and some Norwegian fjords. • Nutrient addition - Eutrophication. • Changing nutrient balance affects distribution of plankton, and can stimulate production of toxins.

25. MARINE POLLUTIONPollutant Hazards • Sewage and Sewage Sludge • Direct infection, and contamination of sea food. • Most terrestrially derived bacteria and viruses die within 12-24hrs in the sea. • due to UV, high salt concentrations, low concentrations of antibiotic inorganic and organic chemicals. • Some enter a dormant phase, not measured in routine tests. Can become active when ingested by bathers. • Control bathing and shellfish waters.

26. MARINE POLLUTIONPollutant Hazards • Persistent Organic Compounds. • e.g. List I Substances. Persistence, bioaccumulation potential and toxicity. • Few studied in the marine environment e.g. halogenated compounds. • organochlorine pesticides (DDT, dieldrin, aldrin and endrin, lindane, hexachlorobenzene). Lipophilic. • Banned in developed economies. • Still widespread in emerging and developing economies due to low cost. • Dioxins. • 2,4,5 Trichlorophenoxyacetic acid (Agent Orange) • PCBs. Type important. Coplanar most toxic. Effects sub-lethal. Widespread in the marine environment.

27. MARINE POLLUTIONPollutant Hazards Persistent Organic Compounds • Effects. • Primary production rates of plankton reduced at > 1 mg/l • Fish 96 hr LC50 1-100mg/l • Typical concentration in seas at pg/l and ng/l levels i.e. much below the acute concentrations. • Effects mainly eggshell thinning in birds and reproductive abnormalities in mammals eg seals in the North and Baltic seas.

28. MARINE POLLUTIONPollutant Hazards • Distribution of PCBs Between Different Environmental Compartments. Environment PCB Load(t) % of Load Land&Coast Sediment 130000 35 Sea Water 2400 0.64 Other 10700 2.6 Open Ocean Sea Water 230000 61 Sediment 110 0.03 Other 1060 0.73

29. MARINE POLLUTIONPollutant Hazards • Trace Metals • Take account of metal speciation and condition of organism. • Mercury • Important marine species: Elemental, divalent and methyl mercury. • Key factors • high affinity for organics, hence accumulates in marine biota. • inorganic mercury may be bio-converted to methyl mercury. • Accumulates in fine-grained coastal sediments.

30. MARINE POLLUTIONPollutant Hazards • Lead • Main inputs to the sea are from the air. • Long range effects due to this airborne pathway • Main effects seen in coastal environments with a build-up of lead in sediments. • Lead in the marine environment presents a negligible source to humans.

31. MARINE POLLUTIONPollutant Hazards • Tin • A potentially serious marine pollutant. • Organotin compounds provide the hazard (e.g. tri-butyl tin oxide TBTO) • Main uses, PVC stabilisers and biocides (anti-foulants on ships) • Two main sources • bacterial methylation of inorganic tin. • leaching of aryl and alkyl tin from ant-fouling paints.

32. MARINE POLLUTIONPollutant Hazards • Tin (contd) • Harmful responses in a number of marine organisms. • Commercial stocks e.g. Pacific oysters, dogwhelks, farmed slamon. • Concentrations believed to affect shellfish • 0.01 ug/l • Causes reduced growth in young POs and loss of fertility in female DWs

33. MARINE POLLUTIONPollutant Hazards • Tin (contd) • Acutely toxic to planktonic organisms. e.g. mollusc larvae at 1.0mg/l • Banned in mariculture installations and on boats < 25 m in EU, USA, Australia, NZ • Rapid recovery (few years) of dogwhelks following the ban.

34. MARINE POLLUTIONPollutant Hazards • Radionuclides • natural potassium-40 • detectable at great distance from discharge • accumulation in sediments • local ecological impact • bottom dwelling fish • shellfish (human health risk) • international pressures on nuclear industry • Sellafield

35. MARINE POLLUTIONPollutant Hazards • Conclusions. • Widespread anthropogenic effects can be detected, even in remote regions. • Main impacts are in coastal waters. • Control of risks associated with marine pollution is increasing, but still has a long way to go.