Field testing of copper alloy cages in British Columbia ... · –30-day average concentration ≤...
Transcript of 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
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• 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
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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.
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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
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Sampling Method
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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
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On Site Measurements:
• Salinity
• Temperature
Sample Shipping Preparation:
• Acidified (trace metal grade)
• Sealed Bottles (Parafilm®)
Sampling
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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
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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
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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.
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Acknowledgements
• Eddie Frank
• Rodrigo Fuenzalida
• Site Manage (Ron)
• Jessie Cunningham
• Tara Tait
28
Copper-Alloy Composition
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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
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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