Evaluation of Drinking Water in Weber CountyLaura Wilcock, Analeah Vaughn, Elizabeth Williams, Saige Carter, Megan McNabb, Alex Berniche,

Austin Jensen, Carie FrantzDepartment of Earth and Environmental Sciences

Concentrations of harmful metals are present in drinking water, however levels of copper, lead, and most other metals are under the EPA’s limits.

GIS Map of Utah w/ sample locations

Results of Chemical AnalysisMethods

Data CollectionA total of 24 samples were taken from 12 different locations in the Ogden area, 2 samples for each location. The first sample for each location was taken after water had been sitting stagnant for multiple hours. The second sample was taken after water had been running for 60 seconds. The pH and temperature were measured for each sample. A sample from the Ogden Water Treatment Plant was also taken as a control.

AnalysisSamples were analyzed using Inductively Coupled Plasma- Optical Emission Spectrometry (ICP-OES). ICP-OES is a process used to determine elemental composition using argon plasma and the electron emission for each element. Sample measurements were done by the USU Analytical Laboratory.

Future Work

● For future work on examining the water quality within Weber County, there are multiple considerations we can look at.○ Organometallic chemistry○ Organic components○ Biological contaminants○ Changes in pH○ Overall water quality during storage in between the treatment center

and residential/commercial use.

Acknowledgements

We would like to thank the Utah State University Analytical Laboratory for running the samples using their ICP-OES, Ogden Water Treatment plant employees for access to and a tour of the plant, Marek Matyjasik for his water chemistry expertise and Weber State University’s Office of Undergraduate Research for funding.

References

Environmental Protection Agency, 2019, Drinking Water Requirements for States and Public Water Systems: Lead and Copper Rule, https://www.epa.gov/dwreginfo/lead-and-copper-rule#rule-summary (accessed March 2020).

Portland Water Bureau, 2020, How You Can Reduce Exposure to Lead, https://www.portlandoregon.gov/water/article/123081 (accessed March 2020).

How Safe is Ogden Water to Drink?

● Ogden, Utah has a drinking water delivery system with segments that vary in age and include lead and copper pipes.

● Changes in pH, water flow rates, or high chlorine or fluorine levels can cause lead and other metals to be leached from lead and copper pipes and released into drinking water at the tap.

● Do older parts of the city and older homes and businesses have higher levels of lead, copper, selenium, cadmium, mercury, arsenic, and chromium in their drinking water?

● Are people at greater risk of contaminated water because of where they live?

● Does running the tap water for 60 seconds improve water quality?

● Ogden City does NOT fluoridate their water, so a fluoride triggered release of metals is not a concern, unlike the Sandy, Utah incident in February 2019.

Lead Dissolution Reactions at a pH between 6-8 and Eh from 0.2 - 0.4:

Species Identified: PbCO3Description Equation [Pb] contributed in M Molar Mass (g/mol) [Pb] contributed (mg/L)[Pb2+] KSP=[Pb2+][CO3

2-] 3.87E-08 207.2 8.02E-03

Species Identified: PbSO4Description Equation [Pb] contributed in M Molar Mass (g/mol) [Pb] contributed (mg/L)[Pb2+] KSP=[Pb2+][SO4

2-] 1.14E-04 207.2 2.36E+01

Total Pb contributed to system by PbCO3 and PbSO4: 23.6 mg/L

Figures (above): Control samples and pH being taken from the Ogden Water Treatment Plant Mitigation

● In order to reduce lead and other contaminants within your water there are multiple steps that you can take.○ Do not flush medications or drugs down the toilet.○ Do not dispose of household chemicals or cleaning supplies down the

sink or toilet.○ Use a filter and keep the faucet aerator clean.○ Because lead dissolves more easily in hot water, use only cold water

to make baby formula or for cooking.

Modeling

We found that the metal concentrations had no obvious trends with home age, region, or flushing the system. Most metal concentrations were well below EPA limits, aside from 2 samples containing Arsenic and Cadmium.

Figures: (right & left): Saige Carter prepping samples for ICP-OES, (middle): diagram from ICP-OES General Instrumentation illustrating how process works

By using a rigorous model to demonstrate anticipated values of dissolved solids in our samples, we were able to generate predictions for metal outcomes prior to sample analysis.

Model calculations for lead were derived based on the estimated Eh/pH of the sampled water system. It was determined that PbSO4 and PbCO3 would most likely be the source of lead within the water systems being analyzed in this study.

Dissolution reactions were calculated below and the total Pb contributed by such reactions were added to our model.

EPA Standard Lead Action Level: 0.015 mg/L

Map Above: Sampled Locations in Ogden City, Weber County Utah.

Map Right: Average lead concentrations for sample locations with approximate date of construction.

Photo of Stump in Ogden, Utah Lynn Arave, 2016 https://mysteryofutahhistory.blogspot.com/2016/04/the-stump-north-ogdens-artesian-well.html

EPA Limit

EPA Limit

EPA Limit