Benthic invertebrate response to heavy metal contamination in the Panther Creek drainage (Idaho): A case study using McQuire’s Metal Tolerance Index (MTI) Gary T. Lester – EcoAnalysts, Inc., Moscow, Idaho Karen Kuzis – Kuzis Consulting, Boise, Idaho

Purposes: - Give a brief description of the metal tolerance index (MTI) - Give an overview of the Blackbird mine and associated water quality issues - Discuss the MTI response to copper during a baseline study conducted last fall.

OVERVIEW OF THE MTI McGuire’s Metal Tolerance Index (MTI) was developed using benthic invertebrate communities and associated metal data (copper) in Montana’s Clark Fork River Calculated as a weighted average of tolerance values assigned to each species (similar to HBI) Score ranges from zero (highly intolerant) to ten (highly tolerant) 0-3 = no impact; 7-10 = significant impact; 3-7 = ???

OVERVIEW OF THE MTI (CONTINUED) - The index has not been published in a peer-reviewed journal - The index has been criticized for lack of peer review

Blackbird Mine Located 20 miles SW of Salmon, ID in the Salmon NF Currently inactive Mined from 1900 – 1982; most active from 1949 – 1967 Mining operations have created 10 miles of tunnels, 4.8 million tons of waste rock, 2 million tons of tailings, numerous adits and portals Tailings originally dumped directly into Blackbird Creek until 1950’s, after which tailings were dumped into an impoundment

Blackbird Mine (continued) In 1982 a water treatment facility brought online to treat discharge from several adits that drain into Panther Creek. Several sources still contaminating surface waters in the area

Metal Contaminants Present in Surface Waters: ARSENIC COBALT COPPER MANGANESE ZINC NICKEL

NATURAL RESOURCE USES: Panther Creek historically served as spawning and rearing for Chinook and Steelhead Anadromous runs dropped sharply following development of the mine In 1954 fish kills of salmon, steelhead, trout and whitefish occurred – believed related to acid releases from the mine Currently, aquatic biota are either non-existent or severely damaged in Meadow, Bucktail, SF Big Deer and Big Deer Creeks

THE STUDY A proposed expansion for a cobalt mine requires a pre-operation baseline inventory. On August 17-18, 2001 benthic macroinvertebrates were collected from the following locations:

Sampling Stations: South Fork Big Deer Creek SF-3 Above Bucktail Cr.SF-2 Below Bucktail Cr.

Sampling Stations: Big Deer Creek BD-5 Above SF Deer Cr.BD-4 Below SF Deer Cr.

Sampling Stations: Panther Creek (no photos available)

FIELD METHODS Benthic invertebrates collected using modified Hess, 500 micron mesh, 0.10 meters sq. 3-Hess composite (across a transect) in riffle habitat 3 riffles sampled per site (3 reps/site) Total of 0.9 meters sq. sampled at each site

LAB METHODS Fixed count/known area subsampling approach (500 count) using a modified Caton subsampler Invertebrates identified to genus/species where possible including Chironomidae and Oligochaeta

RESULTS

Water Quality – Dissolved Copper

TOTAL DENSITY

TAXA RICHNESS AND EPT RICHNESS

% Dominance (3 taxa )

THE DOMINANT CRITTERS Micropsectra sp. Baetis bicaudatus Pagastia sp. Diamesa sp. Pagastia sp. Baetis bicaudatus SF-3 SF-2

THE DOMINANT CRITTERS Heterlimnius sp. Cinygmula sp. Stempellinella sp. Pagastia sp. Orthocladius (Orthocladius) sp. Orthocladius (Euorthocladius) sp. BD-5 BD-4

THE DOMINANT CRITTERS Baetis tricaudatus Cladotanytarsus sp. Optioservus sp. Baetis tricaudatus Optioservus sp. Cladotanytarsus sp. P-1 P-2

Taxa eliminated or reduced: SENSITIVE MAYFLIES CHIRONOMIDAE IN THE TRIBE TANYTARSINI

MTI

MTI vs. Dissolved Copper* R-squared = 0.809, n=5 *No copper data at P2 MTI Dissolved Cu

MTI vs. HBI R-squared = , n=6

TOLERANCES CAN DIFFER SIGNIFICANTLY FOR ORGANIC VS. METAL CONTAMINANTS!!!

Parting Shots: In this case study the MTI was useful in tracing the impact of metals as contaminated water flowed from headwaters to Panther Creek The MTI shows promise as a diagnostic tool for stressor identification (metal contamination), although a more rigorous evaluation is suggested In addition to EPT, Chironomidae are useful bioindicators of metal impacts when identified at least to genus level. The MTI was negatively correlated with HBI

Parting Shots (continued): The next generation of bioassessment tools is focusing on impact source determination (stressor identification) In order to develop these tools, we can help by having our invertebrate samples accurately identified to lowest practical level In addition, good physical and chemical data collected with invertebrate samples over a range of conditions will be extremely helpful Over time, enough real-world data will be collected to develop the associations necessary to assign accurate tolerance values to each taxon (e.g. Brandt, Relyea)