A few notes:
- I culled data for only the last ten years, and only for the snohomish area.
- The contractors who actually performed the contaminant samples often used different units of measure, as a result of using different testing methods. So I have placed a filter for UOM to help verify the test results. In plain english: the time trend and its 'median' value reported is bogus information if you mix your UOM types.
- I removed any concept of what testing method they used, what the baseline observable measurement was, etc.
- you can select a sample type, then lasso some data marks on the timeline to see individual sample reports.
- The Tableau tooltips are nicely formatted; take a look at those!
- clicking on the "links" item will show a bing map of the sample location. Hovering back over that same selected link item will also show two other links, to NIH.gov and wikipedia (for the contaminant in question)
- In short: this was mostly an experiment with Tableau features, as opposed to a deep dive into water quality and contaminant analysis.