Wake County Water Quality: A response and analysis of EWG.org’s Interactive PFC Contamination Map

Wow. Did I go down a rabbit-hole today.

If you’re reading this, you’ve probably read this article…

…played with the interactive map, and shit… Wake County. Bright red. Red, the danger color.

Water quality is nothing to take lightly. We drench ourselves in water every day, cook with it, drink it, and feed it to our children. (This was the main motivation for me spending half my day trying to understand what this really meant)

My questions from this article were:

• Why did Wake County get the red mark?
• Wake County is large, how am I (Raleigh) affected in Wake County?
• Are there any specific places in Wake County that are much worse than others?

Let’s start with question one. The summary of the EWG.org article mentioned this for Wake County:

Contaminants detected = PFHpA,PFOA,PFHxS
Maximum concentration = 0.094 µg/L or ppb

More questions.

• What are PFHpA,PFOA,PFHxS?
• What were Wake County’s scores for these chemicals?
• Could I break it down to smaller areas in Wake County?

Ok, Taylor. Breathe… one question at a time.

We’re going to skip the “what are these chemicals” questions for now. They’re probably bad so I’m going to take EWG.org’s word on this. Let’s ask the EPA what is safe.

The EPA released this article in May 2016.

It states that PFOA and PFOS advisory levels are at 70 ppt. Parts per trillion.

Ok, so let’s start with the EWG.org article. We have 0.094 µg/L. µg/L is micrograms/liter. It’s also ppb (parts per billion) meaning 1 µg/L = 1 ppb. The EPA is saying we have a safe level at anything under 70 ppt. So let’s convert 0.094 ppb to ppt.

This one is actually easy. We only have to move the decimal spot 3 spots to the right to get the correct parts per trillion value.

0.094 ppb = 94 ppt

So we’re 35% over the safe upper upper limit (70 ppt) of what EWG.org has in it’s map.

Next up is finding where the offending values were in the data. Luckilly for me, the EPA had a gigantic file of raw data. So gigantic, I was stupid and tried to sort 1 million rows… which crashed Excel. So, I just grabbed the NC data and continued.

To get specific data for Wake County, I took the zip codes in Wake County, crossed those with the EPA’s PWSID* which linked to a column in the raw data file.

So, now I’ve managed to filter out all of the Wake County data so I can determine how much bottled water I’ll need to buy for showering.

From the raw data, the EPA defines a couple fields that I paid attention to.

MRL — Minimum Reporting Level defined by UCMR 3. If a chemical is above this level, they have to put that value in the AnalyticalResultsValue area.
MethodID — Identification code of the analytical method. See footnote if you care.
AnalyticalResultsSign — Less than (<) the minimum reporting level (MRL) or equal to (=) a numeric value at or above the MRL.
AnalyticalResultsValue — Numeric value of the analytical result, null values represent less than MRL.

Let’s start with the chemicals from the article and see if we can find the 94 ppt we saw in the EWG.org article.

PFHpA,PFOA,PFHxS

What I’m looking for in the raw data is anything with an equal sign in the AnalyticalResultsSign. This would indicate the test for a specific chemical returned a higher number than the MRL. Anything lower, and they don’t have to report it.

PFHpA — MLR of 0.01 ppb (10 ppt) with a MethodID of EPA 537

Town of Fuquay-Varina — 0.05 ppb, 50 ppt, (9/23/14)
Town of Fuquay-Varina — 0.04 ppb, 40 ppt, (12/10/14)
Town of Fuquay-Varina — 0.03 ppb, 30 ppt, (6/11/15)
Town of Holly Springs — 0.02 ppb, 20 ppt, (10/23/13)
Town of Cary — 0.01 ppb, 10 ppt, (11/4/15)

PFOA — MLR of 0.02 ppb (20 ppt) with a MethodID of EPA 537

Town of Fuquay-Varina — 0.03 ppb, 30 ppt, (9/23/2014)
Town of Fuquay-Varina — 0.02 ppb, 20 ppt, (12/10/2014)

PFHxS — MLR of 0.03 ppb (30 ppt) with a MethodID of EPA 537

Bayleaf Master — 0.11 ppb, 110 ppt, (3/2/15)
Bayleaf Master — 0.094 ppb, 94 ppt, (10/23/14)

And here we find the number from the article. 0.094 ppb or 94 ppt.

The EPA health advisory was for PFOA and PFOS so let’s throw PFOS in this list.

PFOS — MLR of 0.04 ppb (40 ppt) with a MethodID of EPA 537

None. There wasn’t any place in Wake County that registered PFOA in a minimum reporting level capacity.

Let’s revisit the EPA recommendation for PFOA and PFOS. 70 ppt.

Did any Wake County towns register for >70 ppt for PFOA?

No. The highest was 20 ppt

Did any Wake County towns register for >70 ppt for PFOS?

No. None did.

Back to the EWG.org article.

Contaminants detected = PFHpA,PFOA,PFHxS
Maximum concentration = 0.094 µg/L or ppb

These two lines are really not related to each other so they need more investigation to clarify.

Sure. PFOA was detected, but only at minimum reporting levels in Fuquay-Varina, and it came down from 30 ppt to 20 ppt in 3 months. Until we get the latest statistics for this, it doesn’t seem like a problem.

Here’s where I start to get confused. The original article states that the maximum concentration of PFHpA,PFOA,PFHxS is 0.094 ppb (94 ppt). But from this data, that number is linked to PFHxS and isn’t even the highest concentration. 5 months later, there was another test for this same chemical that was 110 ppt. And by the way, it’s only in one spot in all of wake county, Bayleaf Master. Why is 110 ppt not the highest concentration? How did they generate their map?! WTF is a Bayleaf Master?!! Why isn’t Tom Cruise aging?!?!?!

Ok. I’m back.

Should the residents served by Georges Grant #1 in Bayleaf Master be concerned about their water?

Yes. Bayleaf Master is 27511. You should call your representatives and tell them you care about your water quality.

Should the residents served by Harnett County Water Intertie in Fuquay-Varina be concerned about their water?

Yea. It’s probably a good idea to be proactive, make some calls, and look at the data when it comes out.

Regarding our original EWG.org article, based on this raw data does all of Wake County deserve to have a huge red color? Maybe not THAT red. But it’s important to stay on top of our water providers as it’s one of the most important utilities we often take for granted.

And finally, we can revisit my initial questions for completeness.

My questions from this article were:

• Why did Wake County get the red mark? ✔
• Wake County is large, how am I (Raleigh) affected in Wake County? ✔
• Are there any specific places in Wake County that are much worse than others? ✔

More questions.

• What are PFHpA,PFOA,PFHxS? ✔

PFOA is used in the manufacture of fluoropolymers, substances which provide non-stick surfaces on cookware and waterproof, breathable membranes for clothing

More generally, perfluorochemicals are used to make various products resistant to oil, stains, grease, and water.

• What does the EPA say is safe? ✔
• What were Wake County’s scores for these chemicals? ✔
• Could I break it down than more than Wake County? ✔
• Why doesn’t Tom Cruise age? ❌ No one will ever know.

Data

Want to do some more research on your area? Here’s the raw data that I ended up with. Pleeeease double check my data and method if you don’t agree. We can never be too careful about this stuff.

FOOTNOTES:

What’s a PWSID you ask?

Public Water System Identification Code, 9-character identification code (Begins with the standard 2-character postal State abbreviation or Region code, and the remaining seven numbers are unique to each PWS in the state)

What is EPA 537?