EFFECTS ASSESSMENT. Doug Clarke. Dredged Material Assessment and Management Seminar September 2009, Detroit, MI

Transcription

1 EFFECTS ASSESSMENT Doug Clarke

2 RISK FRAMEWORK RISK ASSESSMENT PARADIGM Exposure Assessment Economic Analysis, Socio-Political, Engineering Feasibility Problem Formulation Risk Characterization Risk Management Effects Assessment Risk = f (Exposure + Effect)

3 Topics Typical Receptors Modes of impact Dose-Response Relationships Characteristics of Exposure Characteristics of Response Hypothetical examples

4 Sssssome Receptors of Interest SUBMERGED AQUATIC VEGETATION SEA TURTLES STRIPED BASS STURGEON SALMON SHAD SHELLFISH SEAGULLS SPAWNING HABITAT SENSITIVE LIFE HISTORY STAGES

5 Some Receptors of Interest AND DON T FORGET TIGER BEETLES PIPING PLOVER MANATEES OYSTERS FLOUNDER WALLEYE CORAL FW MUSSELS LEAST TERN NURSERY OR FORAGING HABITAT

6 Stressors Chemical Contaminants WQ (e.g., ammonia, sulfides, nutrients, DO) Physical Total Suspended Solids/Turbidity Light Attenuation Deposition Altered Habitat Hydraulic entrainment Noise Blasting

7 Factors That Influence Effects Ambient conditions Static versus dynamic dose Duration of exposure Intensity of exposure Life history stage Egg Larval Juvenile Adult Species-specific behavior

8 THRESHOLD MODEL RESPONSE NO OBSERVED ADVERSE EFFECT LEVEL Linear CONTROL DOSE (CONC. X DURATION)

9 THRESHOLD MODEL Non-Linear RESPONSE NO OBSERVED ADVERSE EFFECT LEVEL CONTROL DOSE (CONC. X DURATION)

10 Hypothetical Receptors Outmigrating juvenile salmon Adhesive fish eggs at offshore spawning habitat Endangered freshwater mussels

11 LAKE IMPERIAL Spawning Habitat Mussel Bed Mussel Bed Placement Site Spawning Habitat BURNING BRIDGES, TODDAHO Dredging Site

12 Hypothetical Fish Receptor Ironhead Salmon (Oncorhynchus whopperi)

13 Fish Exposure to Plumes Concentration (mg/l) Contours of depth Fish Migration Corridor

14 Dynamic Dose Concentration Time

15 Hopper Dredge TSS Time Series Top 40 Middle 35 Bottom Concentration (mg/l) Aug 17-Aug 18-Aug 19-Aug 20-Aug 21-Aug 22-Aug Time (days)

16 Bucket Dredge TSS Time Series Top 400 Middle Concentration (mg/l) Bottom D Cdt kg*hr/m Aug 17-Aug 19-Aug 21-Aug 23-Aug 25-Aug Time (days)

17 Depth (m) Bucket Dredge Plume Hopper Dredge Plume Cross-section Distance (m)

18 Response Characteristics Severity of effect Behavioral Sublethal Lethal Reaction Distance (cm) EL50s Brook trout Chinook salmon Brook, Lake, and Rainbow trout Rosyside dace Turbidity (NTU)

19 SEV EFFECT 0 No effects 1 Alarm reaction 2 Abandonment of cover 3 Avoidance response 4 Short-term reduction of feeding rate or success 5 Minor physiological stress; coughing or increased respiration rate 6 Moderate physiological stress 7 Moderate habitat degradation or impaired homing 8 Major physiological stress; long-term reduction in feeding rate or success 9 Reduced growth rate; delayed hatching; reduced fish density % mortality; increased predation; severe habitat degradtion 11 >20-40% mortality 12 >40-60% mortality 13 >60-80% mortality 14 >80-100% mortality (based on Newcombe and Jensen 1996)

20 Juvenile Salmonids Behavioral Sublethal Lethal Concentration, mg/l Limits of Probable Exposure to Dredge Plumes Duration, days

21 Suspended Sediment (mg/l) Juvenile Salmonids Severe Risk Moderate Risk Minor Risk Exposure Duration (Days)

22 Suspended Sediment (mg/l) Juvenile Salmonids Exposure Duration (Days) No Effect Behavioral Sublethal 10-25% Mortality 26-75% > 75%

23 Fish Receptor Response Characteristics Aspects of response relevant to risk management Seasonality Migration rate affects duration of exposure species specific (e.g., miles/hr) Threshold with respect to maximum exposure Threshold with respect to duration Reliance on lab versus field-derived data Behavioral effects based on few observations Sublethal effects based on indirect measures (e.g., levels of stress hormones in blood) Lethal effects based entirely on lab data using a static dose

24 Hypothetical Fish Egg Receptor Fallguy (Sander toddahoiensis)

25 12 Number of Days Dredge Rate of Advance (m/hr) SS Plume length (m) Duration of exposure for a sessile receptor such as adhesive fish eggs, bivalve mollusks, or SAV will depend on plume dimensions and dynamics in relation to the rate at which the dredge moves through the project site. (from Wilber and Clarke 2001)

26 Dredging-Induced Deposition > 0.5 mm depicted in red/yellow contours Bucket Dredge Hopper Dredge

27 Time Series of Deposition Deposition (mm) Clamshell Deposition Hopper Deposition 0 14-Aug 19-Aug 24-Aug 29-Aug Time (days)

28 Deposition at Offshore Placement Site Barge Placement Hopper Dredge Placement > 0.5 mm depicted in red/yellow contours

29 4.5 Time Series of Deposition Deposition (mm) Scow Hopper 0 15-Aug 17-Aug 19-Aug 21-Aug 23-Aug 25-Aug 27-Aug 29-Aug Time (days)

30 Effects of SS on Fish Eggs Acute Exposure Abrasion/occlusion of chorion Plugging of micropyle Chronic Exposure Delayed hatching mediated by physiological response to impaired gas exchange Accelerated hatching mediated by turbidity-induced change in water temperature regime

31 Effects of Sedimentation on Fish Eggs Sublethal Interference with fertilization Abraded surface membranes and impaired gas exchange Loss of adhesion (for adhesive eggs) Delayed cell cleavage and differentiation Interrupted or incomplete development Delayed hatching and impaired larval development Lethal Physical removal during dredging process Mortality associated with partial or total burial

32 Summary of Deposition Effects on Fish Eggs Timing of acute exposure could be critical Once fertilized, most eggs are relatively tolerant of SS Net deposition of less than half an egg diameter should be tolerated by most species

33 Hypothetical Mussel Receptor Brainsplitter (Unio idontknowicus)

34 Potential Mussel Exposures Acute exposures Smothering and burial Chronic exposures Elevated sedimentation rates and persistent overburden Elevated TSS

35 Effects of Sedimentation on Mussels Behavioral Responses Use of foot to migrate vertically Temporary valve closure Physiological Responses Increased inorganic/organic intake ratio requires greater metabolic expenditure for clearance Change in excretion rate/excretion products Reduced gonad development and interference with reproductive cycle Decreased calcification / growth Increased respiration rate Greater susceptibility to parasites/pathogens Lethal Suffocation

36 Summary of Effects on Mussels Short-term exposures (up to a week) of elevated SS or deposited sediment tolerated well by clamming up. Thin-shelled lentic species are relatively mobile, capable of migrating upward through overburden Long-term deposition (> month of 2 cm) could cause mortality of thick-shelled lotic species. Thin-shelled lentic species are better adapted to depositional conditions.

37 The End

38 Key References Fleming, S. et al Magnitude-duration based ecological risk assessment for turbidity and chronic temperature impacts: Method development and application to Millionaire Creek. British Columbia Ministry of Environment, Surrey. Newcombe, C. and Jensen, J Channel suspended sediment and fisheries: A synthesis for quantitative assessment of risk and impact. N. Amer. J. Fish. Management 16: Wilber, D. and Clarke, D Biological effects of suspended sediments: A review of suspended sediment impacts on fish and shellfish with relation to dredging activities in estuaries. N. Amer. J. Fish. Management 21(4):