1	Metals Content of Benthic Macroinvertebrates in Lefthand Canyon by Drew Bryenton REU Program Summer 2004
2	"Background" Background Macroinvertebrate Sampling Macroinvertebrate Preparation and Analysis Dissolved Organic Carbon Sampling and Analysis Results Conclusions Questions
3	Background
4	Watershed Background Formerly active mining area Captain Jack Mine Superfund site Lefthand Watershed Oversight Group Lefthand Creek provides water to 14,000 downstream consumers CU has run tracer and sediment tests
5	Acid Mine Drainage AMD occurs when water and oxygen contact pyrite The pH of the water drops and metals dissolve into the water (Younger et al., 2002)
6	Background Metals entering creeks from AMD and waste rock Sample benthic macroinvertebrates due to bioaccumulation and biomonitors Will Clements at CSU Use as a reference data set EPA study on species composition in Lefthand Watershed
7	Problem What amount of trace metals are present in benthic macroinvertebrates living in Lefthand, James, and Little James Creeks? Can macroinvertebrates be used as biomonitors to show areas of metals contamination? Are macroinvertebrates more likely to up take trace metals in dissolved or sediment form? Is the Dissolved Organic Matter in these creeks high enough to affect metals concentrations?
8	Bug Collecting
9	The Insects
10	Insect Preparation Followed methods of Will Clements (Clements, 1991) One trial run, one tested run Insects placed on dry ice in the field
11	Insect Preparation Insects dried in oven Mass recorded to normalize data Added 5 mL of nitric acid and 5 mL of hydrogen peroxide to dried insects
12	Insect Preparation Acid digestion occurred in hot water bath for 6 h
13	Testing Digested insect solution was tested for: Al, Ag, As, Cd, Cr, Cu, Pb, Se, and Zn Previous CU and EPA research has shown these metals to be in high concentrations (EPA, 2003; Wood, 2004) Solutions tested on ICP-MS at the LEGS lab
14	Dissolved Organic Carbon (DOC) Sampling Dissolved Organic Matter (DOM) can act as a ligand and bind metals Measure DOM by testing for DOC in the same creeks (Dahm, 1981; Stephenson; 1988 Hare, 1992)
15	Results What amount of trace metals are present in benthic macroinvertebrates living in Lefthand Creek?
16	Results Aquatic organism toxicity
17	Results – Little James Creek
18	Results Can macroinvertebrates be used as biomonitors to show areas of metals contamination?
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20	Results Are macroinvertebrates more likely to up take trace metals in dissolved or sediment form? Zinc more likely to stay dissolved at low pH Lead more likely to remain bound to sediment
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23	Results Lefthand Creek, Mean: 2.5 +/- 0.3 mg C/L James Creek, Mean: 2.6 +/- 0.1 mg C/L Little James Creek, Mean: 3.9 +/- 0.3 mg C/L Pristine streams typically have a [DOC] of 1 – 4 mg C/L (Allan, 1995)
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25	Conclusions Macroinvertebrates do accumulate trace metals, some at toxic levels Macroinvertebrates are useful indicators of where metals sources are entering streams. Macroinvertebrates may uptake metals in both dissolved and sediment form depending on the metal DOC may have been a significant source of metals uptake
26	Recommendations Sample DOC during spring snowmelt Sample only one species (Arctopsyche grandis) Sample before emergence (May) Use same size specimens for testing Remove gut contents prior to testing Sample moving upstream with one person Analyze current data in more detail
27	Acknowledgments Dr. Joe Ryan and Alice Wood EPA: Kathy Hernandez, Richard Evans CSU: Will Clements, Wally Field Volunteers: Pete Kalet, Brendan Cusick, Jamie Fleischfresser, Amalia Anderson, Andrew Archuleta, Dan Wall, Pete Conovitz, Ned Turner, USFS volunteers, Funding from: REU, LWOG, and EPA
28	Questions? Drew Bryenton Dept. of Civil Engineering, Purdue University bryenton@purdue.edu
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