Changes to EPA Method 625 – How do They Affect You?

With the prevalence of contaminants in wastewater today, it is important to have a method for properly extracting and quantifying those compounds, to allow our wastewater treatment plants to remove them during the treatment process, when and where they need to.

The U.S. EPA has written a number of methods for determining contaminants in wastewater – compounds from organophosphorus pesticides (Method 614.1) to organochlorine pesticides (Method 608.3) to chlorinated hydrocarbons (Method 612) have EPA-published methods for guidance. The method I want to focus on here is that for determining bases, neutrals and acids (Method 625.1) and I’m highlighting it because there’s been a change in how this method can be executed, which could have a significant impact on your laboratory. Curious about what I’m alluding to? Read on!

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Pesticide Contamination – Is That Water Safe to Drink?

Have you ever spent the day walking through the woods, paused to take in the natural sights, smells and sounds of a babbling brook or flowing waterfall and thought….“I wonder how many pesticides are in that water?”

I recently experienced this when I escaped from the stress and chaos of real life to spend a day hiking through the woods. I mapped out my route, packed plenty of snacks and water, and tossed my camera (i.e. my iPhone which has a camera) into my backpack, and I was off. I wasn’t far into my hike before I heard the familiar rush of moving water. Excited at the thought of finding a natural stream or brook, I rushed toward the noise until I reached the edge of a bank that overlooked a flowing river. As I took in the breath-taking scenery, I found myself lost in thoughts like “I wonder how polluted this water is?” or “I bet there are pesticides in this water. Is it safe to drink?”

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Tuesday Trivia – October 2, 2018

Happy Tuesday! This week’s question will focus on one of the EPA methods used for extracting semivolatile organic compounds (SVOCs) prior to analysis by GC/MS. Are you ready to Expand Your Horizon?

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Tuesday Trivia – Answer for September 18

It’s now 1 week past World Water Monitoring Day – tell us what you did to celebrate in the comments below:

For those who took last week’s quiz to measure their water quality knowledge, read on. The questions and answers are below:

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Alternative to Sodium Sulfate Drying

If you are performing oil & grease analyses according to EPA Method 1664, you are familiar with the requirement to dry your extract prior to evaporation. There are those who might perform this step for reasons such as “this is the way we’ve always performed our extractions” or “the government-regulated method told me so” or “we have a giant container of sodium sulfate in the lab, so we might as well use it”; however, there is sound logic in removing water from your organic solvent prior to evaporating it.

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Tuesday Trivia Answer for September 11, 2018

On the eve of World Water Monitoring Day, we thought we would post last Tuesday’s response a day earlier! Celebrations for tomorrow’s epic event might otherwise interfere.

Just a reminder of last week’s post:

According to EPA Method 1664 A/B, n-hexane is used as an extraction solvent and must have a minimum purity level of…

Answer: 85%

EPA Method 1664 B outlines the use of n-hexane as an extraction solvent and Section 1.7.2 specifies a minimum purity level of 85% (Method 1664 A has the same requirement).

Believe it or not, hexane solutions typically contain a mixture of 5 structural isomers (i.e. same molecular formula, different arrangement of atoms). N-hexane is the longest (least branched) of the 5 isomers, which gives it the highest boiling point and lowest vapor pressure. Therefore, specifying a minimum purity level of 85% means you’re dictating that at least 85% of the solution must contain the x-hexane isomer.

Join us next week to Expand Your Horizon!

Can you live a PFAS free Life?

PFAS chemicals can be found in every aspect of our life from nonstick pans and cleaning products to firefighting foam. This group of chemicals has caused concern nationwide as it has been found in drinking water and has shown to have negative effects on our health. Starting in the 1980s, chemicals in the PFAS family, PFOS and PFOA, were linked to a number of health concerns, from cancer to hormonal disruption. (See our earlier blog for terms and definitions). These chemicals are extremely difficult to get rid of because they do not break down in the environment and they build up in the body.

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Tuesday Trivia – September 11, 2018

Happy Tuesday! This week’s question will focus on the EPA method for performing n-hexane extractions, otherwise known as “oil and grease” extractions. If you are ready to Expand Your Horizon, read on.

Today’s question: According to EPA Method 1664 A/B, n-hexane is used as an extraction solvent and must have a minimum purity level of…

(a) 80%
(b) 85%
(c) 95%
(d) 98%
(e) None of the above

Hazard a guess in the comments below! (need a hint? The answer isn’t “none of the above”)

Stay tuned next Tuesday….

Tuesday Trivia Answer – August 28, 2018

Just to recap last week’s Tuesday Trivia post: Due to rising levels of ______ (fill in the blank) ________, some species of fish are slowly losing their ability to smell.

Answer: Carbon dioxide (CO2)

As the levels of carbon dioxide rise in a body of water, carbon dioxide converts to carbonic acid which increases the acidity of the water. It turns out, acidic conditions reduce the sensitivity of the olfactory sensors in a fish (i.e. the nerves responsible for being able to smell).

As we’ve demonstrated with posts and trivia questions in the past, protecting, testing and treating our fresh water sources is important to the health of everyone. Read through this helpful infographic for a quick review of the potential contaminants that could find their way into our water sources.

Join us next week to Expand Your Horizon!

SVOCs – Should I be Worried About Those?

If you’ve ever taken on a home renovation project and needed to purchase wall paint, you may have looked at “low VOC” or “no VOC” paint. Even if you don’t know what VOCs are, you are likely familiar with the terrible, headache-inducing smell that greets you when you pry the lid off a new can. Not only is the odor unpleasant, but the fumes are harmful when you breathe them in over a prolonged period of time.

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