“The main rule in toxicology is that ‘the dose makes the poison’. At some level, every chemical becomes toxic, but there are safe levels below that,” wrote Bruce Ames, who is the creator of the Ames Test which determines if a chemical is mutagenic.
A Prop 65 sign in a Starbuck’s Coffee outlet. Photo by the author.
Ames says that in the 1970s the prevailing thinking was that “we should assume that even low doses might cause cancer, even though we lacked the methods for measuring carcinogenic effects at low levels.” The assumption has never left, one need only to look at the ever-present Proposition 65 signs or listen to Vani Hari (aka the Food Babe).
At the time experts also assumed that:
only a small proportion of chemicals would have carcinogenic potential
testing at a high dose would not produce a carcinogenic effect unique to the high dose; and
carcinogens were likely to be synthetic industrial chemicals. It is time to take account of information indicating that all three assumptions are wrong. – Bruce Ames, 2005. (my emphasis)
Ames points out that our test for carcinogenicity of feeding animals near-fatal doses of the chemical is flawed because, “High doses can cause chronic wounding of tissues, cell death, and consequent chronic cell division of neighboring cells, which would otherwise not divide.”
How should a “safe” level be arrived at?
The basic steps to arriving at a safe level are:
Determine a Point of Departure:
This means to review the scientific data available on the toxicity of a compound and select the most sensitive endpoint. So if a chemical causes liver toxicity at a concentration of 1 mg/kg, kidney toxicity at 50 mg/kg and stomach ulcers at 0.1 mg/kg – the 0.1 mg/kg would be selected as the point of departure because if you pick a concentration that prevents stomach ulcers, you will by design also protect against the liver and kidney toxicity (because you need higher concentrations of the chemical to cause those). Furthermore, typically you are looking to pick a NOAEL (No Observable Adverse Effect Level) as a Point of Departure (POD), as this is the highest concentration of a “substance at which there are no biologically significant increases in frequency or severity of any effects in the exposed humans or animals.” (International Council on Harmonisation, 2011)
2. Determine how many modifying factors or uncertainty factors you should use.
The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) appendix 3 gives examples of the modifying factors to use, depending on what kind of study was conducted to determine the POD. Modifying (or uncertainty) factors provide a cushion to human exposure based on factors like which animal was used for the study, the duration of the study and whether the POD is a “No Observable Adverse Effect Level” (NOAEL) or LOAEL.
The “safe” level is really a concentration that would be highly unlikely to cause an adverse effect in even the most sensitive individuals. Using the modifying factors (in step 2 of appendix 3), this concentration results in a very conservative value. These “safe” levels are referred to as PDE (Permissible Daily Exposure), ADI (Acceptable Daily Intake), RfD (Reference Dose) and other things depending on the agency that is generating them, but they all mean the same thing: the level that would not be expected to produce an adverse effect. These values are expressed as either mg/day (where an adult body weight of between 50 and 70 kg is used as a “typical” body weight) or expressed as mg/kg body weight/day.
That’s it. The equations used, and the modifying factors suggested also differ slightly between agencies, but the general concept remains the same.
So when a safe level is determined by toxicologists using best available science, and regulators arbitrarily increase the safety factors, Schnell correctly notes, “the general public commonly misinterprets those bureaucratically generated ‘safe’ levels of exposure as legitimately established thresholds of effect…”
As Frank Schnell, who is a Board Certified PhD in Toxicology, explained, “If you’re standing near the rim of the Grand Canyon admiring the view, you’re probably safe. Nevertheless, as improbable as it is, it’s not entirely impossible that a very strong gust of wind might blow you over the edge. To make sure that you were safe, even under very windy conditions, you could step back ten paces or so–that’s what regulators call a ‘safety factor.’ But, to imagine that stepping back 100 paces, or even a mile, would make you even more safe under implausible conditions (a tornado?) would be not only misguided, but counterproductive, as well, because then you couldn’t see the Grand Canyon, at all.”
California, chemaphobia, and the ‘Erin Brockovich chemical’ (Chromium-6)
Chromium 6 found in elementary school’s drinking water
On March 11, 2016, Coyote Valley Elementary School near Middletown, California (north of San Francisco), started handing out bottled water following reports that the Hidden Valley Lake municipal water supply had levels of chromium-6 higher than were allowed by the state division of drinking water. As a result the school turned off its drinking fountains and handed out bottled water.
How much higher? Three parts per billion (ppb) higher. In California, 10 parts per billion of chromium-6 is the Maximum Contaminant Level (MCL) for drinking water. Their water tested at 13 ppb. (The regulations are found in California’s Drinking Water Law Book.) One billion is a lot. One billion drops of water (at five ml per drop) is enough to fill more than two Olympic-sized swimming pools.
“Logistically, its been a nightmare,” Coyote Valley Principal Shane Lee is quoted saying in the Lake County Record-Bee, “I’m looking forward to turning our faucets back on.”
The Record-Bee article goes on to say, “Chromium-6, also known as hexavalent chromium, is a highly toxic heavy metal and a known carcinogen made famous by law clerk Erin Brockovich…”
Here is what is correct about the above sentence:
Chromium-6 is also known as hexavalent chromium, or CR(VI)
It is a known carcinogen when inhaled in high concentrations over long periods of time.
It was made famous by Erin Brockovich, a law clerk for the legal firm of Masry & Vittitoe.
Chromium, the stuff of bumper coatings, is an odorless and tasteless metallic element. It is found naturally in rocks, plants, soil and volcanic dust, and animals. The most common forms of chromium that occur in natural waters in the environment are trivalent chromium (CR(III) or chromium-3) and hexavalent chromium (also referred to as CR(VI) or chromium-6). Chromium-6 occurs naturally in the environment from the erosion of natural chromium deposits. It can also be produced by industrial processes. (Source: Chromium in Drinking Water, EPA.gov)
Chromium, the stuff of bumper coatings, is an odorless and tasteless metallic element. It is found naturally in rocks, plants, soil and volcanic dust, and animals. The most common forms of chromium that occur in natural waters in the environment are trivalent chromium (CR(III) or chromium-3) and hexavalent chromium (also referred to as CR(VI) or chromium-6). Chromium-6 occurs naturally in the environment from the erosion of natural chromium deposits. It can also be produced by industrial processes. — Source: Chromium in Drinking Water, EPA.gov
Welcome to Cheomphobifornia
Welcome to California, home of chemophobia and flawed risk assessment. Photo of a Starbucks Proposition 65 warning by the author.
To say California “errs on the side of caution” would be putting too fine a point on things. California, home of Proposition 65, is chemophobic.
As I wrote on this blog previously, “In 1986, we Californians passed Proposition 65, ‘The Safe Drinking Water and Toxic Enforcement Act,’ and Prop 65 is the reason you see signs everywhere, including Starbucks, saying, ‘Warning! Detectable amounts of chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm may be found in or around this facility.’” As a side note, you won’t find these signs at the smaller coffee houses. It’s not that they don’t have the same chemicals warned of in the signs; they are not worth suing–not deep enough pockets.
California’s 10 parts per billion–ppb (10 µg/L) maximum contaminant level (MCL) for chromium-6 became effective on July 1, 2014. Up until that time, the school’s water supply had been considered safe (note: at 13 ppb, nearly one-tenth of the federal standard, it still is very safe). The community’s well, on which the school relies, provided water significantly below California’s pre-2014 super-cautious 50 ppb (50 µg/L) MCL for chromium-6. This is 1/10 of the very cautious federal limit set by the Environmental Protection Agency of 100 ppb (100 µg/L) for total chromium.
For added irony, the bottled water the school handed out needed to meet the federal standard only of 100 ppb. The bottled water could have have more chromium-6 than the water fountains had. You can’t make this stuff up.
Chromium-6: The Legacy of Erin Brockovich
By Alison Cassidy [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons
By now everyone know the story of the “busty” “gutsy” legal assistant Erin Brockovich, who, in 1993, gathered 600 prospective plaintiffs from the tiny tumbleweed of a desert town of Hinkley, California to sue the electrodes off the evil corporation of Pacific, Gas, and Electric (PG&E) for leaching chromium-6 (hexavalent chromium) into Hinkley’s groundwater supply. In 2000, it was made into a movie starring Julia Roberts as “busty” “gutsy” Erin Brockovich.
What the movie doesn’t mention is that according to Quackwatch, “In December 1987, PG&E determined that 10 domestic wells serving 14 families contained chromium at levels only slightly above the U.S. Department of Evironmental Protection’s drinking water standard. In response, PG&E provided bottled drinking water and offered a free medical evaluation to these families.”
In the movie, “Everybody and everything from the chickens to frogs to people were purportedly keeling over with illnesses including breast cancer, chronic nosebleeds(1), Hodgkin’s disease (lymphoma), lung cancer(2), brain stem cancer, stress, chronic fatigue, miscarriages, chronic rashes, gastrointestinal cancer, Crohn’s disease, spinal deterioration, kidney tumours, ‘intestines eaten away,’ and other things unlisted because that’s as fast as I could write in a dark theatre,” according to investigative reporter Michael Fumento. Brockovich decides that chromium-6 must be the culprit because PG&E had the deepest pockets.
The law firm’s team persuaded the jury that chromium-6 leached into the groundwater by PG&E had afflicted Hinkley’s population with this plague of diseases and won a record (at the time) $333,000,000.
That PG&E had leached chromium-6 into Hinkley’s groundwater supply is true; that chromium-6 caused all those afflictions is not.
“Stupid nonsense dressed up to look like complicated science is still just stupid nonsense.” – Frank Schnell, Board Certified PhD in Toxicology
According to the American Council on Science and Health (ACSH), “The problem is this: there is no way that hexavalent chromium was responsible for the cluster of health problems in Hinkley. And there is ample, peer-reviewed scientific evidence backing that conclusion.”
“[The movie, Erin Brockovich] encouraged exactly the wrong way to think about data, elevating individuals’ medical histories to the level of proof and distorting the notion of risk….The first question to ask is whether residents of Hinkley really did have more sickness than people living elsewhere.”
Yet the movie plays up what looks like science. “While it is easy to see that the sex and violence in movies are fantasies,” Gina Kolata wrote in the New York Times, “it is hard for any but scientists to discern when science in movies crosses the line from verity to hyperbole and indoctrination.” That is, it’s hard for us non-science types to distinguish the pepper from the fly shit. Hollywood hides the difference by suspending our disbelief for the purpose of telling a tale. Consider the scene where Brockovich visits Hinkley and is offered tea made with well water. She leaves the cup untouched and the camera dwells on the cup leaving the audience with foreboding; it’s contaminated with chromium-6. The truth is rather more prosaic and not nearly as dramatic: the chemical makeup of the tea will change CR(VI) to the nutrient CR(III).
According to scientists, “[T]he movie encouraged exactly the wrong way to think about data, elevating individuals’ medical histories to the level of proof and distorting the notion of risk….The first question to ask is whether residents of Hinkley really did have more sickness than people living elsewhere,” Kolata wrote.
“The problem is this: there is no way that hexavalent chromium was responsible for the cluster of health problems in Hinkley. And there is ample, peer-reviewed scientific evidence backing that conclusion.”
A 2003 study by Paustenbach, Finley, Mowat, and Kerger. says, “available information clearly indicates that Cr(VI) [chromium-6] ingested in tap water at concentrations below 2 mg/L is rapidly reduced to Cr(III) [chromium-3]” and that “Cr(VI) [chromium-6] in water up to 10 mg/L (ppm) does not overwhelm the reductive capacity of the stomach and blood.” In fact, chromium-3, as ACSH notes, “is an essential dietary nutrient required for normal glucose, protein, and fat metabolism, and is found in fresh vegetables, fruit, meat, beef, grain, and yeast.”
The Paustenbach study notes: “Because Cr(VI) [chromium-6] in water appears yellow at approximately 1-2 mg/L [1-2 parts per million], the studies represent conditions beyond the worst-case scenario for voluntary human exposure.”
“Because Cr(VI) [chromium-6] in water appears yellow at approximately 1-2 mg/L [1-2 parts per million], the studies represent conditions beyond the worst-case scenario for voluntary human exposure.” — Human health risk and exposure assessment of chromium (VI) in tap water
Mything Safety Hazards
Where did California get its 10 ppb limit?
Frankly, it looks like California’s political bureaucrats in the state’s Water Resources Board just pulled the number out of their collective asses. I have heard that the water board’s staff suggested 25 ppb for chromium-6, one half the WHO’s 50 ppb.
There’s scant evidence for us to be concerned with chromium 6 as a carcinogen in our drinking water. There’s no good evidence to backstop California’s Maximum Contaminant Limit (MCL) of 10 ppb for chromium 6 in drinking water. As noted before, the U.S. EPA sets the limit for all types of chromium at 100 ppb, and the uber-cautious United Nations World Health Organization (WHO) sets the limit at 50 ppb for chromium-6. From what I’ve seen, it looks like the European Union uses the WHO 50 ppb limit, which is still five times higher than California’s new MCL.
“Many states compete with the USEPA, and each other, to see who can be the most conservative. ” Frank Schnell, a Board Certified PhD in Toxicology told me in a phone interview.(3) He said even though the EPA’s MCL has a built in safety factor of 100, some states strive to be more conservative than the EPA, which sounds reasonable. “In reality, however, once you’re safe, having a limit 10 times lower does not make you 10 times safer. It just means you are unnecessarily alarming your citizens and wasting their money.”
He offered the analogy of standing at the Grand Canyon. “If you’re standing near the rim of the Grand Canyon admiring the view, you’re probably safe. Nevertheless, as improbable as it is, it’s not entirely impossible that a very strong gust of wind might blow you over the edge. To make sure that you were safe, even under very windy conditions, you could step back ten paces or so–that’s what regulators call a ‘safety factor.’ But, to imagine that stepping back 100 paces, or even a mile, would make you even more safe under implausible conditions (a tornado?) would be not only misguided, but counterproductive, as well, because then you couldn’t see the Grand Canyon, at all.”
“Chromium carcinogenicity via the oral route is more a matter of fiction than science,” Dr. Schnell told me in an email exchange. “Unfortunately, the non-scientists who saw the 2000 movie Erin Brokovich went away thinking they had seen a documentary rather than an entertaining fictionalization of a legal drama in which the scientific facts played no part.” There is a scene in the movie where Julia Roberts avoids the tea made for her and the camera focuses on it several times, making the point that it is contaminated with the dreaded chromium-6. “The fact is that, when consumed in contaminated water or beverages, Cr(VI) [chromium-6] is reduced to the required nutrient Cr(III) [chromium-3] which is essential for sugar & fat metabolism.”(emphasis in the original)
“Mice are not little men,” we should not ban a chemical “at the drop of a rat.” –Dr. E. Whelan, Founder, ACSH
As I noted, there is scant evidence, but there is some, suggesting that chromium-6 can be ingested in amounts so high that they overwhelm the stomach’s acids and affect the stomach and intestines. In one paper, the population of Liaoning Province, China, drank well water contaminated with chromium-6 from a ferrochromium factory in the province. The high levels of chromium-6 turned the water yellow. The “poor” data (the researchers agree the data are messy and haphazard) have been manipulated three ways from Sunday. At present, the statistical reviews conclude that the results are “consistent with” increased exposure. In another study, “F344/N rats and B6C3F1 mice were administered sodium dichromate dihydrate, a hexavalent chromium compound, in drinking water for 2 years.” (EPA Draft, 2010) The 2010 EPA draft cites the “NTP Technical Report on the Toxicity Studies of Sodium Dichromate Dihydrate (CAS No. 7789-12-0) Administered in Drinking Water to Male and Female F344/N Rats and B6C3F1 Mice and Male BALB/c and am3-C57BL/6 Mice.” Catchy, huh? Wonder why it wasn’t a New York Times bestseller? Rats and mice received concentrations of 6.25 62.5, 125, 250, 500, or 1,000 milligrams (mg) of sodium dichromate dihydrate per liter (L) of water. At the highest dosage of 1,000 mg/L the rats had “ulceration, hyperplasia, and metaplasia of the forestomach and histiocytic infiltration of the small intestine.” They conclude that “Exposure to sodium dichromate dihydrate caused hyperplasia and ulceration of the stomach in rats and an anemia and lesions of the small intestine in rats and mice.”
Which brings me back to another study, “Human health risk and exposure assessment of chromium (VI) in tap water,” Paustenbach’s 2003 study’s conclusion: “Based on a physiologically based pharmacokinetic model for chromium derived from published studies, coupled with the dose reconstruction studies presented in this article, the available information clearly indicates that (1) Cr(VI) ingested in tap water at concentrations below 2 mg/L is rapidly reduced to Cr(III), and (2) even trace amounts of Cr(VI) are not systemically circulated. This assessment indicates that exposure to Cr(VI) in tap water via all plausible routes of exposure, at concentrations well in excess of the current U.S. Environmental Protection Agency (EPA) maximum contaminant level of 100 microg/L (ppb), and perhaps those as high as several parts per million, should not pose an acute or chronic health hazard to humans.” (Emphasis mine)
Recall that Chromium-6 in water appears yellow at approximately 1-2 mg/L. Would you drink water the color of fluorescent urine?
It’s really that simple. If chromium-6 worries you, don’t drink yellow tap water.
If chromium-6 worries you, don’t drink yellow tap water.
The Bottom Line: Chemaphobia Costs You more than money
Biased reports get dressed up in sciency jargon all the time. They are as Schnell told me, “designed to make your head hurt, so that you won’t hear that soft little voice of common sense in the back of your head whispering ‘this is all bullshit, isn’t it?.’..Stupid nonsense dressed up to look like complicated science is still just stupid nonsense.”
Studies conducted with agendas to prove a chemical is harmful, rather than determine facts, harm the science of toxicology. “More importantly,” Dr. Schnell points out, “they harm the very people they were designed to protect by diverting limited resources from the solution of real problems to the promotion of make-believe ones.”
Why does being “too safe” matter to you or me?
This type of excessive caution costs you and me time–in that it takes more time at work to pay for the testing for contaminants and, if necessary, upgrading of water treatment facilities (I work in water treatment; everything costs dearly.) You pay in the form of higher taxes, utility rates, and prices. Costs get passed on down to the consumer. “Ok but…,” I hear you saying, “This doesn’t matter if it makes me safer.”
Aye, there’s the rub. This type of excessive caution does not make you safer. Not even an itty-bitty bit.
The Unbearable Lightness of Wallet
The ignorance and laziness of public officials to accept the word of activists over pragmatic scientists costs you money (which is in fact, time). And this is real money. The Mercatus Center at George Mason University, puts the amount of money lost since 1980 due to added regulation at $4 trillion; a drag of 25 percent on our gross domestic product (GDP). “If regulation had been held constant at levels observed in 1980, the US economy would have been about 25 percent larger than it actually was as of 2012….This amounts to a loss of approximately $13,000 per capita, a significant amount of money for most American workers.”
Of course, economics alone should not guide us in decision making. But as Bjorn Lomborg reminds us, “[I]gnoring costs doesn’t make difficult choices disappear; it makes them less clear.”
When we spend money on the wrong priorities, that money is not available for things that could truly save lives. As Schnell told me, “In real life, excess conservatism doesn’t just waste money; it also costs lives.. i.e., the ones that could have been saved had the wasted money been spent more wisely.”
“[I]gnoring costs doesn’t make difficult choices disappear; it makes them less clear.” – Bjorn Lomborg
1. Dr. Schnell told me, “High concentrations of airborne Cr(VI) are sufficiently caustic to corrode the septum of the noses of unprotected workers occupationally exposed over extended periods of time. Hence, the fictional reference in one scene of the movie to PG&E workers having to wear masks to prevent nosebleeds.”
2. Chromium 6 “compounds have been found to cause lung cancer specifically in industry workers who, via inhalation over long periods of time, are exposed to levels in air up to 1,000 times higher than those found in the environment,” wrote the American Council on Science and Health. (emphasis in original)
3. August 26, 2016. Frank Schnell is a retired toxicologist for the Agency for Toxic Substances and Disease Registry (ATSDR), which is part of the Center for Disease Control (CDC), in Atlanta, Georgia. and is a member of the American Council on Science and Health Scientific Advisory Panel.
Ames, Bruce N., M Profet, and Lois Swirsky Gold, Proceedings of the National Academy of Sciences, Vol. 87, pp. 7777-7781, October 1990, Medical Sciences, “Dietary pesticides (99.99% all natural)”
Ames, Bruce and Lois Swirsky Gold. 2005. “Risk, Cancer and Manmade Chemicals.” Spiked. http://www.spiked-online.com/newsite/article/1514#.Vy0E72Yva2A.
Bentley Coffey, Patrick McLaughlin, Pietro Peretto. 2016. “The Cumulative Cost of Regulations | Mercatus.” http://mercatus.org/publication/cumulative-cost-regulations.
International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. 2011. “Impurities: Guideline for Residual Solvents Q3C(R5).” International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. http://www.ich.org/fileadmin/Public_Web_Site/ICH_Products/Guidelines/Quality/Q3C/Step4/Q3C_R5_Step4.pdf
Kerger, B D, R O Richter, S M Chute, D G Dodge, S K Overman, J Liang, B L Finley, and D J Paustenbach. “Refined Exposure Assessment for Ingestion of Tapwater Contaminated with Hexavalent Chromium: Consideration of Exogenous and Endogenous Reducing Agents.” Journal of Exposure Analysis and Environmental Epidemiology 6 (2): 163–79. http://www.ncbi.nlm.nih.gov/pubmed/8792295.
Kolata, Gina. “REFLECTIONS; A Hit Movie Is Rated ‘F’ In Science.” New York Times. http://www.nytimes.com/2000/04/11/health/reflections-a-hit-movie-is-rated-f-in-science.html.
Paustenbach DJ, Finley BL, Mowat FS, Kerger BD. 2003. “Human Health Risk and Exposure Assessment of Chromium (VI) in Tap Water. – PubMed – NCBI.” J Toxicol Environ Health A. . https://www.ncbi.nlm.nih.gov/pubmed/12851114.
Schnell, Frank. 2016. “How Natural Variations Became Environmental Crises: The Numbers Racket.” American Council on Science and Health. http://acsh.org/news/2016/02/15/how-natural-variations-became-environmental-crises/.
Schnell, Frank. 2016. “How Natural Variations Became Environmental Crises: The Word Game.” American Council on Science and Health. http://acsh.org/news/2016/02/16/how-natural-variations-became-environmental-crises-the-word-game/.
Smith, Allan H. 2008. “Hexavalent Chromium, Yellow Water, and Cancer A Convoluted Saga.” Journal of Epidemiology 19 (1): 24–26. doi:10.1097/EDE.0b013e31815c40dc.
Schwarz, Ph.D., and Joe. 2004. “Erin Brockovich Story Largely Fiction.” http://www.quackwatch.org/01QuackeryRelatedTopics/brockovich.html.
U.S. Environmental Protection Agency. 2015. “Chromium in Drinking Water.” https://www.epa.gov/dwstandardsregulations/chromium-drinking-water#self.
Abaena blue-green algae in the inaptly named Clear Lake
I have heard that there is only one place that is more difficult to produce drinking water in California than Clear Lake, and that is the Sacramento Delta. Those poor bastards.
Clear Lake has never been clear; a fact to which Livingston Stone, a fisheries biologist attested to in an 1873 report:
It is a singular fact, illustrating the inaptness with which names are often given to natural objects, that the water of Clear Lake is never clear. It is so cloudy, to use a mild word, that you cannot see three feet below the surface. The color of the water is a yellowish brown, varying indefinitely with the varying light. The water has an earthy taste, like swamp water, and is suggestive of moss and water plants. In fact, the bottom of the lake, except in deep places, is covered with a deep, dense moss, which sometimes rises to the surface, and often to such an extent in summer as to seriously obstruct the passage of boats through the water. – Livingston Stone, 1873
1. Blue green algae in water from shore of Clear Lake. Each jar has 1 liter of lake water.
It is a naturally eutrophic lake. As Lake County’s page on the lake notes, “Eutrophic lakes are nutrient rich and very productive, supporting the growth of algae and aquatic plants (macrophytes). Factors contributing to its eutrophication include a fairly large drainage basin to contribute mineral nutrients to the water, shallow and wind mixed water, and no summertime cold water layer to trap the nutrients.”
The algae in the southeast fork near the shore of the lake started look like pea soup this week. A biologist friend told me it is Anabaena, a blue-green algae. I’ll take his word for it.
I thought it would be fun to do a jar test on a sample taken along the shore line. Water treatment operators use jar tests figure out what dose of chemical will work best to flocculate (clump) suspended bits of microscopic stuff, which are easier to filter it out the water.
Each water system is different because water is different everywhere. Yes, H2O is H2O, but pure H2O is not drinking water. Drinking water has dissolved minerals and varies in pH (acidity/basic).
2. About ten seconds into the jar test, the jar on the far right (30ml polymer/1 L water) begins to flocculate and takes on a “blizzard” look.
I make no claims to being any kind of expert at jar testing. I will outline what I did. Your mileage will vary for your system.
Scooped up a bucket of water from the lake and distributed one liter each to four clear jars.
Mixed one millilitre of ProPak 9890 to one liter of filtered water.
Placed the jars in the jar test machine and dropped the propellers in the water.
Set the paddle speed for 100 rpm.
Took 5ml, 10ml, 20 ml, and 30ml from the ProPak 1ml/1L solution. (The amount of solute to use is a “fielder’s choice.” It could have been 1, 5, 10, 15. The amount is a way to begin to bracket the right solution.)
Dumped the 5, 10, 20, and 30 ml samples into the jars.
Timed the event for 1 minute, spinning the mixers in each jar.
Judged which (if any) of the jars developed a “flurry” or “blizzard” of flocculant. (See picture 2)
Repeat as necessary to “dial in” the correct amount of millilitres of polymer to one liter of water. For example, I next might try 25 ml, 30 ml, 35 ml, and 45 ml to find out if the 30ml/L is the optimal coagulant mix.
Again, I am a novice and make no claims to being any kind of expert at jar testing. I just found very little on the web about how to do one, so I thought I would share my experience. If you noticed something I missed, or made a mistake on, or anything thing else that is as unclear as Clear Lake’s water, please leave a note in the comments or use the “Contact Page” to let me know how my jar testing could be improved.
3. Several minutes after the paddles have been turned off.