Spatial Analysis of Dissolved Cadmium, Zinc, and Copper in the Impaired Little Cottonwood

Creek, Utah.

Ethan Cowgill , Brooke Garza, Lily Wetterlin Christopher Johnson

1 Geosciences Dept., Salt Lake Community College, Salt Lake City, Utah

Abstract

The Utah Division of Water Quality (UDWQ) lists Little Cottonwood Creek (LLC), Salt Lake County,

Utah, as impaired by zinc, cadmium and copper. This study aims to determine the extent to which Red

and White Pine Creeks are contributing to heavy metals in LCC. Samples were taken from 10

locations, 8 along LCC and one from Red and White Pine Creeks, metal concentrations were found to

generally decrease downstream due to attenuation but increases were present near the White Pine

confluence, Tanner’s Flat Campground, and near the Little Cottonwood Creek Bridge. Copper

concentrations were highest in White Pine Creek at 19.1 ppb. Downstream of the White Pine

confluence, concentrations increased from 5.6 to 6.4 ppb. Concentrations increased near Tanners Flat

Campground from 6.4 to 9.8 ppb. Red Pine Creek had copper levels of 0.8 ppb, but concentration in

LCC decreased from 9.8 to 5.3 ppb at the Red Pine Confluence. Further downstream near Little

Cottonwood Bridge copper levels increased from 5.3 to 8.4 ppb. The highest concentrations of

cadmium, 0.98 ppb, and zinc, 120 ppb, were found upstream from the White and Red Pine

confluences. Slight increases in zinc concentrations, 100 ppb to 102 ppb, and cadmium, 0.91 ppb to

0.93 ppb, appear downstream of the White Pine Creek confluence. Zinc and cadmium levels decrease

downstream with no further increases. Further sampling will be done to better assess the sources of

impairment.

Methods

• Water samples were taken using 15ml vials as ves-sels.

• 10 locations were sam-

pled, 8 along LCC and one from Red and White Pine Creeks.

• Samples were tested for

heavy metals at the University of Utah using mass spectrometry (ICP-MS).

References

Environmental Protection Agency (EPA), 1980. “Ambient Water Quality Criteria for Zinc.” EPA 440/5-80-079. October

Finley, H. (2016) Unpublished Independent Research Study -

Evaluating the contributing source of Cadmium in Little Cot-tonwood Creek located in Little Cottonwood Canyon,

Wasatch Range Province. Salt Lake Community College. Shepherd Miller. (2002). Total Maximum Daily Load for Dis-

solved Zinc in Little Cottonwood Creek.

Background

• A 1994 study by the UDWQ and Salt Lake City found zinc concentrations in LCC to exceed criteria

for a cold water fishery (Miller, 2002).

• A 1998 survey by the USGS found copper concentrations downstream of the White Pine Creek con-

fluence to exceed water quality criteria for dissolved copper (Miller, 2002).

• In 2001, the Tanners Flat Campground and Red Pine Creek area were found to contain high levels of

dissolved copper and zinc (Miller, 2002).

• A history of Mining around the town of Alta, Utah has left mine dumps and drain tunnels, the most

probable sources of the heavy metals.

• White Pine Creek has been shown to be a significant source of copper (Miller, 2002).

Problem

• LCC is impaired by dissolved zinc, cadmium, and copper. • LCC is a vital watershed for the Salt Lake valley. • Zinc can pose ecological threats directly to fish and the macroinvertebrates upon which they depend. -The source(s) of the heavy metals must be determined to address the pollutants.

Purpose

• Determine dissolved metal concentration of copper, zinc, and cadmium along Little Cottonwood Creek

and at the White and Red Pine Creek confluences.

• Determine the most probable sources of metals.

Results

• The sample taken from WPC contains the greatest concentration of copper. WPC is therefore a likely source of dissolved copper LCC.

• Red Pine Fork contained relatively low levels of cop-per, 0.8 ppb, zinc, 4 ppb, and cadmium, 0.12 ppb. It appears to not be a significant source of these metals to LCC.

• Copper concentration increased in LCC from 6.4 to 9.8 ppb near Tanners Flat Campground.

• Copper concentration increased near Little Cotton-wood Bridge from 5.3 to 8.4 ppb.

Future Research

• Samples will be collected from Lisa Falls and Hogum

Fork to determine the source of the copper spike near

Little Cottonwood Bridge (LCB).

• Samples will be collected between the confluence of

Red and White Pine Forks to better gauge where the

increase in Copper near Tanners Flat Campground.

• Samples will be collected further downstream of LCB

to see if there are any further spikes.

Zinc

Cadmium

Copper

This material is based upon work supported by the National Science Foundation under Grant No. 1701031. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National

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