Transcript 14520_2667RaissaMendoncax

Effects of nickel-contaminated sediments on benthic
macroinvertebrate communities
Raissa Mendonca, Christian Schlekat, Emily Garman, Jennifer Daley, Michelle
Hudson, G. Allen Burton, David Costello
Funding:
Society for Freshwater Science Annual Meeting | Sacramento, CA | 22 May 2016
Metals
Metals
Free ion (Ni2+)
Dissolved organic carbon
Particulate organic carbon
Association with Fe, Mn, Al oxides
Precipitation with sulfide complexes
Current risk assessment models
BIOTIC LIGAND MODELS:
pH, HARDNESS, DOC, MAJOR CATIONS
Association with Fe, Mn, Al oxides
SEM-AVS MODELS:
IF [SULFIDE] Precipitation
> [METALS]:
NOsulfide
TOXICITY
with
complexes
IF [SULFIDE] < [METALS]: POTENTIAL TOXICITY
1) What is the role of metal
oxides in metal bioavailability in
oxic sediments?
Association with Fe, Mn, Al oxides
Difficult to replicate and
assess oxic layers in
laboratory and field tests
1) What is the role of metal
oxides in metal bioavailability in
oxic sediments?
Association with Fe, Mn, Al oxides
2) Integrating geochemistry and
community ecology may improve
our understanding of
contamination effects
Assess Ni bioavailability
in lotic sediments exposed to
effluent from mining operations by
coupling spatially-explicit sediment
geochemistry to the indigenous
macroinvertebrate community.
-based study
community assessment
sediment analysis
Birchtree and Thompson-Weir mines | Thompson, MB, Canada
Birchtree and Thompson-Weir mines | Thompson, MB, Canada
Paired geochemistry, water chemistry and invert samples
Sediment cores
Sediment chemistry:
Sulfide, org C, metal oxide
minerals, metal bound to
oxides, metal bound to sulfide
Surface (0–2 cm)
Deep (2–4 cm)
Invertebrate samples:
Individuals identified to family
Surface water chemistry:
Dissolved Ni, sulfate, chloride
Ponar grabs
Sediment
chemistry
Ephemeridae concentrationresponse threshold
Multivariate analysis
of whole community
SEDIMENT CHEMISTRY
Exposure sites had high sediment nickel, with a gradient of
~300 mg/kg Ni from downstream to upstream
TOTAL SEDIMENT NICKEL: 40–540 mg/kg Ni
SEDIMENT CHEMISTRY
Surface sediments had less sulfide and more iron oxides
Acid volatile sulfide
(0–2 cm)
(2–4 cm)
SEDIMENT CHEMISTRY
Surface sediments had less sulfide and more iron oxides
Acid volatile sulfide
(0–2 cm)
(2–4 cm)
[sulfide] > [metals]
[sulfide] < [metals]
SEDIMENT CHEMISTRY
Surface sediments had less sulfide and more iron oxides
Acid volatile sulfide
(0–2 cm)
(2–4 cm)
SEDIMENT CHEMISTRY
Surface sediments had less sulfide and more iron oxides
Acid volatile sulfide
(0–2 cm)
(2–4 cm)
SEDIMENT CHEMISTRY
Surface sediments had less sulfide and more iron oxides
Acid volatile sulfide
(0–2 cm)
(2–4 cm)
SEDIMENT CHEMISTRY
Sediment nickel corrected for iron oxides (NiTOT–NiHFO) was the
best bioavailability measure predicting Ephemeridae dose–
response in the two distinct mine sites
Source: Google
Mine
EC10 (mg kg-1 Ni)
Birchtree
174
Thompson-Weir
236
SEDIMENT CHEMISTRY
Sediment nickel corrected for iron oxides (NiTOT–NiHFO) was the
best bioavailability measure predicting Ephemeridae dose–
response in the two distinct mine sites
Source: Google
SEDIMENT CHEMISTRY
Sediment nickel corrected for iron oxides (NiTOT–NiHFO) was the
best bioavailability measure predicting Ephemeridae dose–
response in the two distinct mine sites
Source: Google
REDUNDANCY ANALYSES
The final simplified model for water chemistry
indicated conductivity and pH as the main overlying
water variables driving community variation
DYT: Dytiscidae
Source: Google
TAL: Talitridae
RDA Variables
Conductivity
pH
Chloride
Sulfate
CAE: Caenidae
Dissolved nickel
Source: Google
REDUNDANCY ANALYSES
RDA with deep sediment variables could not significantly explain
community variation
RDA Variables
Acid-volatile sulfide
Carbon (%)
Acid extracted Fe (%)
Acid extracted Mn (%)
Acid extracted Ni (%)
Total Fe
Total Mn
Total Ni
Amorphous-bound Ni (%)
Crystalline-bound Ni (%)
Amorphous Fe oxides (%)
Crystalline Fe oxides (%)
Oxidized Mn (%)
RDA all surface sediment variables
p = 0.028
RDA all deep sediment variables
p = 0.127
REDUNDANCY ANALYSES
The final simplified model for surface sediment
indicated FeHFO and total sediment nickel as the main
environmental variables driving community variation
SPH: Sphaeriidae
Source: Google
RDA Variables
Acid-volatile sulfide
Carbon (%)
TAL: Talitridae
Acid extracted Fe (%)
Acid extracted Mn (%)
Acid extracted Ni (%)
Total Fe
Total Mn
CAE: Caenidae
Total Ni
Amorphous-bound Ni (%)
Crystalline-bound Ni (%)
Amorphous Fe oxides (%)
Crystalline Fe oxides (%)
Source: Google
EPH: Ephemeridae
Oxidized Mn (%)
Source: Google
REDUNDANCY ANALYSES
The final simplified models from RDA effectively distinguished
invertebrate taxa based on their habitat preference
– In lotic sediments, naturally-formed oxic layers are
substantially lower in AVS than deeper sediments
– Sediment nickel in the surface layer was largely associated
with oxide minerals
– Fe-corrected Ni models rather than sulfide-based models
decreased inter-site variation in effect concentration
thresholds for Ephemeridae
– Multivariate analysis of the invertebrate community
further established the significant role of Fe oxides in
determining sediment nickel bioavailability
– Metal oxide ligands may play a large role in determining Ni
bioavailability, and this has consequences for the current
approaches used for sediment risk assessment
– Sediment sampling needs to be spatially resolved to
capture the conditions that the biota actually encounter
– Thorough mechanistic understanding of Ni partitioning to
oxide-rich sediments is warranted to determine
complementary bioavailability coefficients based on major
oxide minerals