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STRATUS CONSULTING STRATUS CONSULTING Toxicity of Cadmium and Copper: Implications for Adverse Impacts to Salmonids in Mining-Impacted Waters Prepared for: Federal Review Panel Prosperity Gold-Copper Mine Project Prepared by: Jeff Morris, PhD Stratus Consulting Boulder, CO April 26-30, 2010

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Page 1: Toxicity of Cadmium and Copper: Implications for Adverse ... · PDF fileToxicity of Cadmium and Copper: Implications for Adverse Impacts to ... experiments in a laboratory. STRATUS

STRATUS CONSULTINGSTRATUS CONSULTING

Toxicity of Cadmium and Copper: Implications for Adverse Impacts to

Salmonids in Mining-Impacted Waters

Prepared for: Federal Review Panel

Prosperity Gold-Copper Mine Project

Prepared by:Jeff Morris, PhD

Stratus ConsultingBoulder, CO

April 26-30, 2010

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STRATUS CONSULTING

Aquatic Toxicology Terminology

“Acute” effects– Adverse effects that occur during short-term

exposures (e.g., 1-96 hours)– Also refers to severity of effect, e.g., lethality is

often referred to as an “acute” effect

“Chronic” effects– Adverse effects that occur during longer

exposures (e.g., weeks – months).– Also refers to “sub-lethal” effects,

e.g., reduced growth, behavioral changes, impaired reproduction

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STRATUS CONSULTING

Terminology (cont.)

LCX = Concentration that results in X% mortality of exposed organisms over a given time

– “96-h LC50 ” = the concentration resulting in 50% mortality in the test organism population within 96 hours

– An LC50 is not a threshold for adverse effects: it implies that half the organisms are killed by the chemical exposure

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STRATUS CONSULTING

Terminology (cont.)

LC50 = a value determined from controlled experiments in a laboratory

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STRATUS CONSULTING

Terminology (cont.)

For metals such as copper and cadmium, a common convention in estimating an acute lethality “threshold” is to divide the LC50 by 2. This value roughly approximates 1-10% mortality level in the test organism population in most experiments (US EPA, 1996).

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STRATUS CONSULTING

Toxicity of Copper and Cadmium to Fish

Both metals are highly toxic to fishToxic effects include:– Death– Impaired growth– Impaired behavior– Physiological alterations that can reduce

“fitness”

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STRATUS CONSULTING

Toxicity of Copper and Cadmium (cont.)

Direct effects from “dissolved” metal in water column

Indirect effects through invertebrate prey– Water column and sediment

• Toxic metal concentrations in prey (dietary exposure to fish)

• Decrease in overall available prey base

Young fish (swim-up fry) = most sensitive life stage

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STRATUS CONSULTING

Effects of Metals on Fish: Water

Geochemical interactions- hardness, pH, DOC, etc.

Uptake through gills

Mortality, cardiac arrest, suffocation, reduced growth, behavioral changes, physiological

impairment

Effects

Metals in water

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STRATUS CONSULTING

Metals Effects on Fish: Mechanisms

Lethality related to:– Ionoregulatory failure

• Fish take up ions (e.g., Na+) from the water through their gills

• Metals such as copper can impair this process leading to cardiac arrest

– Respiratory failure• Metals can cause thickening

of cell walls in gill tissues leading to reduced oxygen exchange and death

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STRATUS CONSULTING

Heavy Metals: Sublethal Effects

Reduced growthBehavioral avoidance– May impair

outmigration of smolts

– May impair returning adults

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STRATUS CONSULTING

Adverse Impacts to Salmonid Populations

MortalityDecreased recruitment– Young fish are the most sensitive– Spawning adults avoid contaminated areas– Social structures are disrupted and

population fitness suffers (olfactory impairment)

Reduced growth– Increased metabolic burden– Impaired olfactory system

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STRATUS CONSULTING

Water-Column Effects of Metals

Toxicity of both copper and cadmium is strongly influenced by water chemistry

– Hardness toxicity

– Dissolved organic carbon (DOC) toxicity • Dependent on chemical nature of the DOC

– pH: strongly influences toxicity, but relationship more complex than hardness, DOC

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STRATUS CONSULTING

Water Column Effects of Metals

Toxicity dependent on sensitivity of the exposed species– Salmonids (trout, salmon) among the

most sensitive species to copper and cadmium

– Many freshwater invertebrates that serve as food for juvenile salmonids (e.g., mayflies) also highly sensitive to metals

McCafferty 1981

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STRATUS CONSULTING

Potential Toxicity of Cadmium and Copper at the Prosperity Project

Examples based on published toxicity tests– Rainbow trout, including controlled laboratory

tests we have performed

Examples assume generalized relationships– No site-specific data available on relative

sensitivity of resident fish strains

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STRATUS CONSULTING

Potential Toxicity of Cadmium and Copper at the Prosperity Project

Examples focus solely on water column effects of metals to fish. Other potential effects include:

– Toxicity of contaminated sediments to fish eggs and prey species

– Toxicity of contaminated prey to fish (dietary)– Physical effects of sedimentation – Changes in hydrology (dewatering, increased

scouring)– Changes in thermal regime

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

10

20

30

40

50

60

96-h LC50 (m ortality, rainbow trout)

Hansen et al. 2002

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

10

20

30

40

50

60

96-h LC50 (m ortality, rainbow trout)96-h LC50/2

Hansen et al. 2002

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

10

20

30

40

50

60

96-h LC50 (m ortality, rainbow trout)96-h LC50/2IC20 (grow th, rainbow trout)

Hansen et al. 2002

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

10

20

30

40

50

60

96-h LC50 (m ortality, rainbow trout)96-h LC50/2IC20 (grow th, rainbow trout)BC W Q G M axim um

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

10

20

30

40

50

60

96-h LC50 (m ortality, rainbow trout)96-h LC50/2IC20 (grow th, rainbow trout)BC W Q G M axim umBC W Q G 30-day

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STRATUS CONSULTING

Prosperity Gold-Copper Project Estimates

Estimates of contaminant concentrations from the EIS for period corresponding to spring freshet on Fish Creek (March-May) and subsequent low-flow in Taseko RiverRelevant for:– Resident salmonid populations– Migrating/spawning steelhead and rainbow

trout– Early life-stage bull trout and Chinook and

sockeye salmon

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STRATUS CONSULTING

Prosperity Gold-Copper Project Estimates

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

10

20

30

40

50

60

96-h LC50 (m ortality, rainbow trout)96-h LC50/2IC20 (grow th, rainbow trout)BC W Q G M axim umBC W Q G 30-dayProsperity prediction

Fish Creek

TSF (5%)

Taseko R iver

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

10

20

30

40

50

60

96-h LC50 (m ortality, rainbow trout)96-h LC50/2IC20 (grow th, rainbow trout)BC W Q G M axim umBC W Q G 30-dayProsperity predictionBackground copper in the Taseko R iver in M ay

Fish Creek

TSF (5%)

Taseko R iver

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

10

20

30

40

50

60

96-h LC50 (m ortality, rainbow trout)96-h LC50/2IC20 (grow th, rainbow trout)BC W Q G M axim umBC W Q G 30-dayProsperity prediction x10

Fish Creek TSF (5%)

Taseko R iver

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

20

40

60

80

100

120

140

160

96-h LC50 (m ortality, rainbow trout)96-h LC50/2IC20 (grow th, rainbow trout)BC W QG M axim umBC W QG 30-dayProsperity prediction x10

Fish Creek

TSF (5%)

Taseko River

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

5

10

15

20

25

30

96-h LC50/2

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

5

10

15

20

25

30

96-h LC50/2Prosperity = LC50/2

TSF (5%)

4.0x

Factor increase in copper that could result in mortality

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

5

10

15

20

25

30

96-h LC50/2Prosperity = LC50/2

Fish Creek TSF (5%)

1.3x

4.0x

Factor increase in copper that could result in mortality

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

5

10

15

20

25

30

96-h LC50/2Prosperity = LC50/2

Fish Creek TSF (5%)Taseko R iver

4.0x

1.3x

4.0x

Factor increase in copper that could result in mortality

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

5

10

15

20

25

30

96-h LC50/2Prosperity = LC50/2

Fish Creek TSF (5%)Taseko R iver

4.0x

8.4x1.3x

4.0x

Factor increase in copper that could result in mortality

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

5

10

15

20

25

30

96-h LC50/2IC20 (grow th, rainbow trout)Prosperity = LC50/2

Fish Creek TSF (5%)Taseko R iver

4.0x

8.4x1.3x

4.0x

Factor increase in copper that could result in mortality

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STRATUS CONSULTING

Toxicity of Copper

Hardness (m g/L as CaCO3)

0 25 50 75 100 125 150

Cop

per (μg

/L)

0

5

10

15

20

25

30

96-h LC50/2IC20 (grow th, rainbow trout)Prosperity = LC50/2

Fish Creek TSF (5%)Taseko R iver

8

1719

27

Concentration increase in copper that could result in

mortality

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STRATUS CONSULTING

Sub-Acute Effects (copper)

Mortality or changes in behavior after exposure to lower concentrations over a longer time (e.g., 30-60 days)

– Copper can accumulate in the olfactory system• Causes changes in behavior (social)

predator avoidance, and avoidance of contaminated waters (e.g., 0.8-1.6 µg/L)

– Other sub-acute effects include mortality and decreased growth

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STRATUS CONSULTING

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0

1

2

3

4

96-h LC50 (mortality, rainbow trout)

Toxicity of Cadmium

Stratus Consulting 1999

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STRATUS CONSULTING

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0

1

2

3

4

96-h LC50 (mortality, rainbow trout)96-h LC50/2

Toxicity of Cadmium

Stratus Consulting 1999

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STRATUS CONSULTING

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0

1

2

3

4

96-h LC50 (mortality, rainbow trout)96-h LC50/2BC WQG 30-day

Toxicity of Cadmium

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STRATUS CONSULTING

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0.0

0.1

0.2

0.3

0.4

0.5

BC WQG 30-day

Toxicity of Cadmium

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STRATUS CONSULTING

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0.0

0.1

0.2

0.3

0.4

0.5

BC WQG 30-dayProsperity, predicted worst case

Fish Creek

TSF (5%)

Taseko River

Toxicity of Cadmium

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STRATUS CONSULTING

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0.0

0.1

0.2

0.3

0.4

0.5

BC WQG 30-dayProsperity, predicted worst caseBackground cadmium in the Taseko River in May

Fish Creek

TSF (5%)

Taseko River

Toxicity of Cadmium

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STRATUS CONSULTING

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0

1

2

3

4

96-h LC50 (mortality, rainbow trout)96-h LC50/2Prosperity, predicted worst case x10

Fish Creek

TSF (5%)

Taseko River

Toxicity of Cadmium

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STRATUS CONSULTING

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

96-h LC50/2

Toxicity of Cadmium

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STRATUS CONSULTING

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

96-h LC50/2Prosperity = LC50/2

TSF (5%)

7.7x

Toxicity of Cadmium

Factor increase in cadmium that could result in mortality

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STRATUS CONSULTING

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

96-h LC50/2Prosperity = LC50/2

Fish Creek TSF (5%)

7.7x

3.7x

Toxicity of Cadmium

Factor increase in cadmium that could result in mortality

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STRATUS CONSULTING

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

96-h LC50/2Prosperity = LC50/2

Fish Creek TSF (5%)Taseko River

7.7x

3.7x

9.4x

Toxicity of Cadmium

Factor increase in cadmium that could result in mortality

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STRATUS CONSULTING

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

96-h LC50/2Prosperity = LC50/2

Fish Creek TSF (5%)Taseko River

7.7x

3.7x

9.4x

23x

Toxicity of Cadmium

Factor increase in cadmium that could result in mortality

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Toxicity of Cadmium

Hardness (mg/L as CaCO3)

0 20 40 60 80 100 120 140 160

Cad

miu

m ( μ

g/L)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

96-h LC50/2Prosperity = LC50/2

Fish Creek TSF (5%)Taseko River

2.1

1.3

0.5

1.2

Concentration increase in cadmium that could result in

mortality

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STRATUS CONSULTING

Sub-Lethal Effects (cadmium)

Mortality or changes in behavior after exposure to lower concentrations (over a longer time, e.g., 30-60 days)

– Cadmium can accumulate in the olfactory system or affect the central nervous system

• Causes changes in behavior (social, foraging) predator avoidance, and avoidance of contaminated waters (0.2 – 0.5 µg/L)

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Evaluating Environmental Risks: Hazard Quotient Approach

The field of Ecological Risk Assessment employs a convention of calculating Hazard Quotients to evaluate potential risks to ecological receptors– Hazard Quotient (HQ) =

Environmental Concentration / Adverse Effects Concentration• Where HQ > 1 = "risk of adverse effects"

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STRATUS CONSULTING

Hazard Index

For contaminants with a similar mode of action (e.g., metals) the convention is to sum HQs to calculate the Hazard Index (HI)– Therefore, individual HQs for copper and cadmium

(and other metals) should be summed to calculate the total HI

HI > 1 = "risk of adverse effects“

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Hazard Index

Location

Hardness (mg/L as CaCO3) Cu HQ Cd HQ Cu+Cd HI

TSF (5%) 141 1.2 6.0 7.1

Fish Creek (mixing point B; waterfall) 92 3.8 11.7 15.5

Taseko River (after Fish Creek confluence) 33 1.0 3.9 4.9

Taseko River (after Fish Creek confluence) 81 1.0 1.8 2.8

Chronic (30-d)

Copper and Cadmium Hazard Index based on Prosperity Project estimates (in May) and BC WQGs (30-d)

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Conclusions

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Copper

Taseko’s copper predictions for the Taseko River or Fish Creek in May:

– Meet or exceed concentrations resulting in significantly decreased growth in rainbow trout

– Would only need to increase by 1.3- or 4-fold to reach acutely lethal concentrations

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Cadmium

Taseko’s cadmium predictions for the Taseko River or Fish Creek in May:– Would need to increase by 4- or 9-fold to

reach acutely lethal concentrations• These increases are equivalent to only

0.5 or 1.3 µg/L

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Other Factors to Consider…

Other metals and metalloids associated with this project are also toxic at elevated concentrations– E.g., arsenic, lead, nickel, selenium, zinc

Metal mixtures can increase toxicity through additive or synergistic effects

Dietary exposure to these contaminants can also cause toxicity to fish