field testing of copper alloy cages in british columbia ... · –30-day average concentration ≤...

Field testing of copper alloy cages in

British Columbia: comparison of

measured copper to ambient water

quality criteria.

H. E. Gray1,3, L. Gace2, R.L. Dwyer2, R. C. Santore4, J. McGeer1 and D. S. Smith1

1Department of Chemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada 2Copper Alliance/International Copper Association, New York, NY, 10016, US 3Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, ON 4HDR Inc.

Problem

• Antifoulant coated nylon nets • Net integrity is a concern

• Easily damaged due to predator attacks • Product loss or animal stress

• Decreased pen size during “storm events” • Overcrowding and poor oxygen levels

• High costs associated with maintenance, repairs

and replacement of nylon nets. • Biofouling

2

Copper-Alloy Cages

• Currently in use in several countries

– Chile (70)

– Australia (28)

– Asia (200 - 300)

• Trials are also being conducted

– Scotland, China, Panama, South Africa, Turkey, United States

• Copper-alloy cages are used for a variety of species

– Salmon, Trout, Sea Bream, Sea Bass, Cod, Cobia….

3 Copper Alloys in Marine Aquaculture (2011) Report by European Copper Institute,

International Copper Association, EcoSea.

Copper-Alloy Cages

Advantages of Copper Alloy Pens

• High strength

• Prevent the loss of fish through escapes and predator attack

• Rigid flexibility

• Maintain shape during “storm events”

• Cages remain in water for life expectancy

• 6 - 8 years (3 - 4 production cycles)

• Minimal in situ cleaning (1 – 2 /annum)

4 Photo Credit: [1] EcoSea; [2] University of New Hampshire.

[1] [2]

Copper

• Useful and important component in industry

– Copper is an essential micro-nutrient

• Necessary for normal metabolism in both plants and animals

• Fish food and dietary supplements

– At high concentrations is toxic to aquatic species

• Antifouling paints

5

• Water Quality Guidelines for British Columbia[1]

– 30-day average concentration ≤ 2 μg Cu/L

– Maximum concentrations cannot exceed 3 μg Cu/L

• Total copper

• Alaska[2,3]

– Protected Waters

– 4-day average concentration (chronic) - 3.1 μg Cu/L

– 24-hour average concentrations (acute) - 4.8 μg Cu/L

• Dissolved copper

6

Copper Guidelines

[1] Water Quality Criteria for Copper (Ministry of the Environment, Government of British Columbia)

[2] Alaska Water Quality Criteria Manual for Toxic And Other Deleterious Organic and Inorganic Substances (Department of

Environmental Conservation)

[3] U.S. EPA, 2007

Objectives

• To assess the potential for ecological risk

from the introduction of copper alloy nets

to a site in British Columbia

– monitor Cu concentrations (contributions

above background)

– assess the potential for impacts.

7

Installation

8 Photo Credit: Langley Gace and [4, 5] EcoSea

[4] [5]

Fortune

Channel

Warn

Bay

Dawley

Passage

Sampling Locations

9 Photo Credit: Google Maps

3 km

Sampling Locations

10 Photo Credit: Google Maps and Mainstream Canada

Sampling Method

• Samples for background concentrations were

collected prior to cage installation

• Sampling occurred daily once installation

commenced • Only intermittent sampling during install of cage two

• Sampling linked to tidal cycle • Flood

• Slack

• Ebb

11

Sampling Method

12

Flow

Upstream Downstream

1 m

5 m

1 m

5 m

30 m

Sampling Method

• U.S. EPA (2004) SOP 1229 TRACE METAL CLEAN SAMPLING OF

NATURAL WATERS

– derived from EPA Method 1669, Sampling Ambient Water for

Determinations of Metals at EPA Water Quality Criteria Levels

• Polytertrafluorethylene (PTFE) Tubing

• Samples were collected into pre-cleaned PTFE bottles

– Filtered samples were filtered on site

– 0.45 μm membrane filter

13

On Site Measurements:

• Salinity

• Temperature

Sample Shipping Preparation:

• Acidified (trace metal grade)

• Sealed Bottles (Parafilm®)

Sampling

14

Experimental Methods

• Total and Dissolved Cu Measurements

– Inductively Coupled Plasma Mass Spectroscopy

(ICP-MS)

• Maxxam Analytical

– Anodic Stripping Voltammetry (ASV)

• Wilfrid Laurier University

• Total and Dissolved Organic Carbon • Wilfrid Laurier University

15

Salinity

16

0.0

5.0

10.0

15.0

20.0

25.0

30.0

Salin

ity (

pp

t)

22.6 ± 3.8 ppt

N = 48

Temperature

17

9.5 ± 0.7 °C

N = 48

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Tem

pera

ture

(°C

)

Total and Dissolved Organic Carbon

18

TOC 1.432 ± 0.2 mg C/L

N = 48

DOC 1.411 ± 0.2 mg C/L

N = 42

0

0.5

1

1.5

2

2.5

T/D

OC

mg

C/L

19

Background Cu Levels

Upstream of

Cages

Downstream of

Cages

Dawley

Passage

[Cu]Total

- Day 1 (Nov. 26)

- Day 2 (Nov. 27)

[Cu]Dissolved

- Day 1 (Nov. 26)

- Day 2 (Nov. 27)

20

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Co

nc

en

tra

tio

n (

µg

Cu

/L)

Upstream of

Cages

Downstream of

Cages

- Floatation device installed

- Lift bag was removed

Day 6 and 8 (Dec. 4 and 6)

Cage 1 in water

Dawley

Passage

- Walls of cage was installed

- Floatation pipes were delivered for cage 1 Day 6

Day 8

21

Day 9 (Dec. 7)

Upstream of

Cages

Downstream of

Cages

- Bottom of Cage 2 installed Cage 1 in water

for 24 hours

Dawley

Passage

22

Day 15 (Dec. 13)

Upstream of

Cages

Downstream of

Cages

Cage 1 and Cage 2 in water - Floatation device installed

- Lift bag was removed

Dawley

Passage

23

Day 20 (Dec. 18)

Upstream of

Cages

Downstream of

Cages

Cage 1 and Cage 2 in water

for 4 days

Dawley

Passage

24

Downstream Samples Over Time

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Co

nc

en

tra

tio

n (

µg

Cu

/L)

6 8 9 15 20

Day

25

Downstream Samples Over Time

6 8 9 15 20

Day

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Co

ncen

trati

on

( µ

g C

u/L

)

[Cu]Total

[Cu]Dissolved

26

Downstream Dissolved Cu Concentrations

6 8 9 15 20 Day

[Cu]Diss

SMAV

[Cu]Diss

-Species Mean Acute Value (SMAV)

- Average of EC50 data

-Mytilus edulis

-Most sensitive organism in marine database

Conclusions

• Measured values are below applicable British

Columbian water quality standards for copper.

• No consistent patterns to indicate detectable

amounts of copper are being released from the

newly-installed cages.

27

Acknowledgements

• Eddie Frank

• Rodrigo Fuenzalida

• Site Manage (Ron)

• Jessie Cunningham

• Tara Tait

28

Copper-Alloy Composition

29

Mitsubishi Shindoh Co. Ltd. (Sambo Copper Alloy Co. Ltd.) provides technical information

about the alloy UR30 on its internet website.

Element Cu Sn Ni Zn

Content, wt. -% 64.0 0.6 0.3 bal.

According to Mitsubishi Shindoh’s data sheet, at least one further mircoelement is added to the CuZn-

alloy.

-Brass - Copper and Zinc

30

Melting Point Specific Weight Electrical Conductivity Coefficient of Thermal

Expansion

920 °C 8.4 g/cm3 26% IACS 21 x 10-6 / °C

Physical Properties

Mechanical Properties (wire, Ø 4 mm)

Corrosion resistance:

-Excellent resistance against dezincification

-Corrosion in seawater after 5 years exposure: max. corrosion depth 20 μm, mean corrosion depth 10μm.

Temper RpO2 Rm Elongation Young’s Modulus

1/8 H 330 MPa 440 MPa 22 % 100 GPa

Copper-Alloy

Biotic Ligand Model (BLM)

31

M-DOC M2+ M-Biotic

Ligand

Ca2+

Na+

H+

MOH+

MHCO3+

MCl+

Inorganic Ligand

Complexation

Site of

Action

Free

Metal

Ion Organic Matter

Complexation

Competing Cations

Di Toro et al., Environ. Toxicol. Chem., 20 (2001), pp. 2383–2396.

Bioavailable Cu Concentrations

32

4.0

6.0

8.0

10.0

12.0

14.0

16.0

-lo

g[C

u]

6 8 9 15 20

Day

[Cu]Dissolved

[Cu]Free

[Cu]Free

SMAV

Values

-Species Mean Acute Value (SMAV)

- Average of EC50 data

-Mytilus edulis

-Most sensitive organism in marine database

Still in progress…

• Still measuring samples:

• 518 samples (filtered and unfiltered)

• Flood and Ebb tidal samples

• Anodic Stripping Voltammetry (ASV)

33

Background Cu Levels

34

Upstream of

Cages

Downstream of

Cages

Dawley

Passage

Day one from sampling for background Cu concentrations

(Total Values)

35

Background Cu Levels

Upstream of

Cages

Downstream of

Cages

Dawley

Passage

Day one and day two measurements from sampling for background Cu concentrations

(Total Values)

36

Background Cu Levels

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Co

ncen

trati

on

( µ

g C

u/L

)

Upstream of

Cages

Downstream of

Cages

Dawley

Passage

Day one and day two measurements from sampling for background Cu concentrations

(Total and Dissolved Values)

37

Day 6 and 8 (Dec. 4 and 6)

Upstream of

Cages

Downstream of

Cages

- Walls of cage was installed

- Floatation pipes were delivered for cage 1

Dawley

Passage

38

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Co

nc

en

tra

tio

n (

µg

Cu

/L)

Upstream of

Cages

Downstream of

Cages

- Floatation device installed

- Lift bag was removed

Day 6 and 8 (Dec. 4 and 6)

Cage 1 in water

Dawley

Passage