Why 28 years have passed since the EPA’s last chemical risk review

Tens of thousands of chemicals have not been reviewed by the EPA, and people are starting to ask questions

by Peter Moskowitz

Think before you drink

Are newly discovered chromium-6 levels in Boulder’s drinking water dangerous?

By Matt Cortina

Introductory Note:  Chromium-6 comes and goes as a news item, but we appear to be no nearer a clear understanding of the real danger of the substance or a workable regulatory standard for water suppliers than when Erin Brochovich blew the whistle bringing it to public attention in the mid nineteen nineties.  Matt Cortina’s article provides a really good overview of the dilemma.–Hardly Waite. 

A potentially carcinogenic form of the element chromium is in Boulder’s drinking water and there are no plans to remove it anytime soon.

Hexavalent chromium, or chromium-6, has been linked to cancers of the liver, stomach, small intestine and more when it is consumed through water sources. It is unclear just how much chromium-6 must be consumed — and for how long — before any carcinogenic effects occur; research to date has been inconclusive and incomplete.

Because of the lack of data, there is no standard for chromium-6 levels in drinking water in Boulder, the state of Colorado and the rest of the country, besides California. What does exist is a standard for total chromium, (which includes chromium-6 and the benign trivalent chromium, chromium-3), a nascent wave of research and a lot of unanswered questions.

If hexavalent chromium sounds familiar, it’s likely for its co-starring role opposite Julia Roberts in the 2000 film Erin Brockovich. The true story on which the movie was based featured a legal clerk (Brockovich) who, from 1993 to 1996, built and won a classaction settlement against the utility company Pacific Gas & Electric (PG&E) that had contaminated the town of Hinkley, California’s water supply with chromium-6 between 1952 and 1966. The case was built on the correlation between the drinking water’s chromium-6 levels and an increase in tumor and cancer cases. The $333 million settlement was the largest settlement in U.S. history, and PG&E has since paid $315 million more in claims to victims.

The groundwater in Hinkley was found to have chromium-6 concentrations between .2 to 2.69 parts per billion (ppb), according to a PG&E survey, with higher contamination from the PG&E plant in pockets around town.

Chromium-6 levels in Boulder’s water currently range from .03 to .34 ppb, according to Boulder’s 2014 Water Quality Report. By comparison, the height of that range is more than five times higher than a .06 ppb public health goal set by California for chromium-6 in drinking water.

For some reason, Boulder’s chromi um-6 level is higher than nearby communities. Longmont sites registered from .035 and .061 ppb in 2013. Lafayette measured chromium-6 levels at .00026 ppb last year. Louisville reported “nondetect,” or zero, levels of the contaminant.

Out of 2,100 samples across Colorado taken since 2011, 78 percent were “non-detect” for total chromium, according to the Water Quality Control Division of the Colorado Department of Public Health and Environment (CDPHE). The CDPHE does not keep a database of chromium-6 levels, but said the highest recorded total chromium reading in its database in Boulder was 10 ppb.

Until this year, Boulder did not track chromium-6 levels and only tested previously for the contaminant’s presence in wastewater. Boulder now tracks for chromium-6 to comply with the EPA’s Unregulated Contaminant Monitoring Rule, which surveys communities around the country and collects data on certain contaminants.

In a 2010 Environmental Working Group study, 31 of 35 cities tested positive for chromium-6 in their drinking water. Norman, Okla. registered 12.9 ppb of chromium-6 in their water; a distant second was Honolulu at 2 ppb. Neither Boulder nor Denver were tested for the study, but Boulder’s .18 average would have tied it for 18th on the list with Chicago and Milwaukee.

Despite the widespread monitoring for chromium-6, there is no national chromium-6 standard and California’s public health goal (PHG) of .02 ppb and, later, .06 ppb on chromium-6 in drinking water supplies is the only state initiative.

Culminating that initiative, California will enact the nation’s first chromium-6 standard on July 1 at 10 ppb, nearly 500 times larger than the original PHG of .02 ppb. Environmental groups like EWG questioned the motives behind putting the standard at such a high level and said “24 million Californians would be exposed to potentially dangerous levels of hexavalent chromium” with the 10 ppb standard.

“Ideally you want nothing,” says Renée Sharp, Environmental Working Group director of research. “Chromium is known to be a carcinogen and creates a host of other health effects.”

Sharp says a realistic goal, given financial burdens and corporate realities, was 1 ppb of chromium-6 in the drinking water. Given that Boulder’s chromium-6 levels were above California’s initial PHGs, but below the 1 ppb recommendation, Sharp says, “I’m not going to be raising a crazy amount of alarm for those levels, but I also don’t want to say that they’re completely safe.”

Indeed, that’s the crux of the issue. With few standards in place, few carcinogenicity studies and zero comprehensive, long-term studies on chromium-6, it’s hard for lawmakers, communities and advocacy groups to know what danger, if any, chromium-6 levels in drinking water presents.

“There isn’t any direct drinking water quality standard [for chromium-6] we can compare it to right now,” says Michelle Wind, Boulder Drinking Water Program supervisor. “Our standards are set by the EPA and state public health department, so we’ll go by direction from them.”

That EPA standard is a 100 ppb limit on total chromium, which includes both chromium-3 and chromium-6.

The EPA combines them because chromium can change between chromium-3 and chromium-6 depending on its environment. Both chromium-3 and chromium-6 can be naturally occurring; chromium-3 is an essential nutrient found in soil and food, while chromium-6 found in water supplies is typically the byproduct of industrial processes that use it to rustproof and finish metal machinery, and also tan leather.

So because chromium-6 can become the benign chromium-3 in certain environments, and because one such environment is the human stomach, regulators treat both chromium states together when it comes to drinking water.

However, studies including a 2011 study by the California Office of Environmental Health Hazard Assessment (OEHHA), which ultimately determined the .02 PHG, have shown that although the majority of chromium-6 introduced to the human body by drinking water is likely reduced to chromium-3 in the digestive process, “it does not occur at a fast enough rate to prevent [chromium-6] from reaching and being taken up by tissues.” Furthermore, the study found that there were genotoxic — or DNA-damaging — effects in rodent organs that were given water containing chromium-6 levels “not likely to overwhelm the reductive capacities of the stomach, intestines and blood.” When DNA is damaged within cells, the cells can mutate and cause cancers.

The OEHHA study — in addition to others — even says gulping contaminated water too fast or having a full belly could determine how the human body processes ingested chromium-6.

Certain populations are likely more susceptible to chromium-6 toxicity than others. According to the EPA, “hexavalent forms can persist under conditions where there is a low concentration of reducing materials.” These forms include people with high pH levels in their stomachs, such as newborns and those who regularly take antacids. The 2011 OEHHA California study found that mice with a stomach pH of 4 or higher — typical of antacid users and newborns — showed a significant increase in tumors when given chromium-6 orally.

The EPA will meet in July to determine how it will “update its hazard identification and dose-response assessment of hexavalent chromium carcinogenicity by ingestion” in light of research done since a 1998 EPA study that couldn’t determine if ingested chromium-6 was carcinogenic.

One thing we know is that chromium-6 causes cancer when it’s inhaled. The EPA classifies chromium-6 as a “known human carcinogen by the inhalation route of exposure.” What’s not clear is if it’s carcinogenic when ingested, as in drinking water.

“I think it’s important to note that there’s no conclusive evidence right now of chromium-6 being a carcinogen,” said Nicole Graziano of the Water Quality Control Division of the CDPHE. “That’s one of the reasons why we evaluate total chromium in the drinking water, as opposed to one or the other of those chromium elements.”

The best resource available, then, to determine oral chromium-6 toxicity in humans is to look at past cases, like Hinkley, and studies recently finished or currently being done.

Zhang and Li (1987): A village in China reported increases in stomach cancer. Concurrently, there was a contamination of chromium-6 in the drinking water from a chromium ore processing facility. Initial reports finding no correlation were flawed and the case is now unsettled. Issues include that cancer rates were only tracked for 14 years, not all villagers were exposed to the contaminated water, and the initial report failed to note that although overall cancer rates were down, cancers in certain organs (in this case, the stomach) were elevated.

Nebraska (1986-87): Total chromium was measured against mortality rates for certain Nebraska counties. After tracking data for only two years, there was no correlation found between chromium-6 levels and cancer.

Leon Valley, Mexico (1995): Measurements of chromium in groundwater, soil and human urine were taken near a chromate composition facility; however, no cancer data was taken. Researchers did note that residents stopped drinking the water at 500 ppb of total chromium because it was yellow in color.

Hinkley, California (1996-2008): Water wells in Hinkley, California were contaminated with chromium-6 released by the Pacific Gas & Electric plant. According to the OEHHA, at least 46 people were exposed to chromium-6 via eight drinking water wells. Even though subsequent studies have found Hinkley had lower relative cancer rates than other communities at the time, the types of cancers were not recorded. Nearly a thousand people were ultimately affected.

Oinofito, Greece (2011): A chromium-6 concentration as high as 54 ppb was found in Oinofito. Cancer rates were monitored and a “statistically significant rate ratio for primary liver cancer mortality” was found, according to the OEHHA.

In sum, only two cases tracked organspecific cancers with relation to chromium-6: one found a link to liver cancer mortality and the other to stomach cancer mortality. The other cases lacked critical data to make meaningful determinations.

Researchers have also done lab tests — mainly with rodents — to try to determine chromium-6 human carcinogenicity via drinking water. In an April 2014 EPA toxicological review, researchers noted that previous studies couldn’t determine if oral ingestion of chromium-6 was carcinogenic but noted five studies since then — by the EPA and National Toxicology Program among others — that found small intestine tumors in rodents given chromium-6 orally.

But do chromium-6 experiments on rodents transfer to human physiology? Though there are small differences, “the human physiologically based pharmacokinetic model (i.e. essentially a diagram of human digestion and nutrient absorption) for chromium shares nearly the same structure as that developed for rats and mice,” according to a 2013 study published in the scientific journal Elsevier.

Chromium-6 has also been linked to other health effects. In fact, Graziano pointed out the EPA set its chromium-6 water limit at 100 ppb “assuming at the time that the most risk was due to dermatitis — as an allergic reaction to skin.”

Water highly concentrated with chromium-6 can even lead to problems from “inhalation of aerosol droplets generated during showering,” according to the OEHHA.

Ingestion of chromium-6 can lead to liver failure, oral ulcers, diarrhea, indigestion, vomiting, anemia, sperm count decrease and developmental issues, according the EPA’s 2014 toxicological review.

Chromium-6 combined with other contaminants may cause health risks for some people.

“Not only do we know that if you ingest chromium that you’ll have a higher risk of cancer, it’s not the only chemical you’re being exposed to,” says Sharp (of the EWG.) “One of the major problems with our drinking water standards are that they consider one single chemical alone when we know we are exposed to many, many chemicals, that combinations of chemicals do have additives, [that] these chemicals have a synergistic effect, and that some people are more sensitive to certain chemicals than others.”

Chemical combinations, studies on mice, case studies with missing data — it all leads to one question: at what level is chromium-6 in drinking water dangerous?

On Boulder’s water, Wind says, “I would classify it as at the current level and with the current standards in place it’s not a concern for us in terms of priority for changing treatment process.”

Cal Youngberg, environmental services manager for the public works department in Longmont, says, “We don’t have any information to say [that it’s not safe]. We don’t know what the effect of longterm exposure is. We don’t have any info on that. The work [to date] hasn’t been scientifically validated or peer-reviewed.”

Graziano, of the CDPHE, says, “For total chromium it’s at a safe level,” but could not comment on the safety of the chromium-6 levels.

That is, the lack of data and of clear case results limits the ability of local regulators to determine if current chromium-6 levels in drinking water are safe.

Another issue is that it’s not clear from where chromium contamination comes.

Graziano, of the CDPHE, says, “Because we regulate for total chromium, we aren’t analyzing for the source of where those particular chromium elements came from.”

“It’s hard to say where chromium comes from,” Longmont’s Youngberg says. “It looks like a lot of this is in the soil formation, or coming from the atmosphere in general.”

Wind suggests chromium-6 could be created during the treatment process.

“I would assume that [the chromium-6 in our water is naturally occurring],” Wind says. “It could be a combination of natural and [man-made]. We have seen some information that it could be something that forms in the treatment process. I can’t really say which portion it might be changing form in. It may be changing form to hexavalent chromium in the treatment process.”

Although chromium-3 can be converted to chromium-6 (through a process called oxidation), this conversion is typically only done to then remove chromium from the water if other methods of removal are not available.

Boulder gets its water from four water sources: Barker Reservoir, Lakewood Reservoir, Boulder Reservoir and Carter Lake. From there it is treated at one of two water treatment facilities: the Betasso Water Treatment Plant and the Boulder Reservoir Water Treatment Plant.

Neither Wind nor Youngberg says last September’s flood had any impact on the chromium-6 levels in the water.

The cost of removing chromium-6 — at whatever concentration — certainly impacts how decisions are made to remove it.

“I do know a major reason why the California level was not lower [than 10 ppb] is because chromium is not an inexpensive chemical to remove,” Sharp says.

“Because of that, unfortunately, it means that most water utilities are not going to remove something unless they are required to by law because it’s quite expensive.”

Much of the studies done to determine cost, including a 2014 Water Research Foundation study, found that capital costs for a new treatment plant in an area where the water is heavily saturated with chromium-6 (more than 20 ppb) could cost anywhere between $1 million and $10 million, depending on capacity, efficiency and demand.

Though large-scale operations to remove the contaminant may be expensive, there are options to inexpensively remove low levels of chromium-6 from the water supply in towns with sufficient water treatment facilities, according to a 2004 American Water Works Association study.

That study recommended two technologies for municipalities looking to remove low levels of chromium-6 from their water supply to adopt: anion exchange and reverse osmosis. Both, the study said, are “highly effective, mature technolog[ies]” that interested municipalities could feasibly implement.

In anion exchange, contaminated water is sent through a specialized metal vessel and passed through a resin that exchanges the chromium-6 ions for other, harmless ions in the resin.

In reverse osmosis treatment, water is forced through a membrane that separates the chromium from the water.

According to the American Water Works Association study, both methods are effective but large amounts of water are lost through reverse osmosis, rendering it less efficient.

Water Research Foundation Senior Research Manager Alice Fulmer says, however, that the low-level technologies researched are only proven to remove chromium-6 from water down to 1 ppb.

Given that Boulder’s chromium-6 levels fall below the 1 ppb threshold, Fulmer says, “I don’t see any of these technologies feasible or even necessary for Boulder’s water treatment facility yet.”

However, both reverse osmosis and anion exchange processes have the added benefit of shutting out other contaminants. Says Sharp:

“What’s really interesting is that they’re looking at how much it would cost to treat chromium down to a particular level and the benefits. But, if you install some sort of new treatment technology, you’re going to remove things other than [chromium-6], not everything, but you’re going to be cleaning up other chemicals and so there are other benefits. As far as I can tell, it’s a huge oversight.”

Boulder currently uses a coagulation and filtration method to treat water.

Wind says Boulder will defer action on chromium-6 levels until they get higher or a new standard is put in place.

“We don’t have a threshold right now [for too much chromium-6]. Our main go-by is the total chromium drinking water standard. Right now we’re a couple of orders of magnitudes below that. If we looked at California levels and we got in at something around that, we’d look into it a bit more, particularly if [the chromium-6 level] was increasing.”

Wind adds, “We haven’t even looked at what that [the cost of removing chromium-6 from drinking water] would be.”

Source:  Boulder Weekly.

Previous Gazette articles on Hexavalent Chromium.

Pure Water Gazette Fair Use Statement

Owatonna Dietitian recommends hydrating with infused water

by Tracy Bjerke, RD, LD

The best way to get and stay hydrated is, of course, by drinking water. In our bodies, water helps to digest food, transport nutrients and oxygen to all cells of the body and it helps cushion our joints and organs as well as carry waste products out of our body. Staying hydrated is also important for great heart health, because it is easier for your heart to pump your blood through your body. Water also assists with constipation.

A healthy and tasty way to stay hydrated is to try infused water. Though very healthy, sometimes your traditional, plain water just gets boring. Infused water includes adding different fruits, vegetables and/or herbs and spices to your water. Not only do you get the benefits of getting hydrated, but you also gain flavor without all the excess sugars and chemicals that are in alternative beverages such as pop, sweetened teas or flavored coffees. Another benefit you get, besides how pretty the water looks, is the antioxidants and vitamins that are released into the water from the fruits, vegetables or herbs/spices.

Stakes are high in ongoing battles for water

 by Alan Guebert

Gazette Introductory Note:  America’s agricultural system, designed with the primary goal of making money for agribusiness “farmers,” is highly water intensive.  The system works when there is abundant water to exploit, but, as we are learning, when water runs short, the system will not meet our needs. The question is, will be be able to convert to  more sustainable agricultural practices that are aimed at providing nutritious food for people rather than massive profits for banker-farmers? — Hardly Waite. 

According to 2013 data compiled by the U.S. Environmental Protection Agency, you and I owe our very existence towater. After all, 92 percent of our blood, 75 percent of our brains and muscles, 60 percent of our bodies and 22 percent of our bones are plain, simple old water.

 Iowa cities remove nitrates, recycle in rivers

DES MOINES — Most of the water-treatment departments that remove nitrates from Iowans’ drinking water dump the chemical back into the water supply, so other cities downstream have to remove it again.

The law sets a safe level for nitrates in drinking water, but it doesn’t dictate what must be done with nitrates after they are removed, the Des Moines Register reported Sunday.

“Des Moines Water Works customers like me have to pay a lot more to take nitrates out. When they put the nitrates back into the water, then it potentially costs cities downstream, like Ottumwa, a lot of money,” Seaman said. “It’s a cycle.

Source: Iowa.com

Pure Water Gazette Fair Use Statement

Why Chloramines?

by Hardly Waite

One of the more puzzling issues to the public is the change from chlorine to chloramines as the disinfectant in public water supplies. When a city changes to chloramines, there is usually significant controversy.  A switch to chloramine is seldom met with approval.  What is lost in the discussion, often, is the reason for the change.  The most frequent cause is the city’s effort to meet federal standards for trihalomethane (THM).

The following town board meeting was reprinted in Water Efficiency.  It illustrates well the dilemma that small cities face when their THM levels get out of control. It is a write-up of a town board meeting that took place in March 2014 in Ulysses, NY, in New York’s Finger Lakes region.  It does a good job of explaining how THM is created, while looking at what makes this small town water system vulnerable. It also underlines the challenges of coordinating among different water districts and residents.  What is really interesting is that the most frequent THM solution–the switch from chlorine to chloramine as the disinfectant–was not mentioned.

At the Ulysses regular town board meeting on Tuesday, Town Supervisor Liz Thomas reported on options to eliminate a buildup of trihalomethane, found in the town’s water source three times. “When the system went in it never had any problem, until 2012 in August there was one reading of 80 parts per million,” Thomas said. Bolton Point tests the water quarterly for contaminants.

Trihalomethane, THM, is a chemical compound usually found in industry refrigerants or solvents. THM forms in water systems when chlorine reacts to organic matter, which had settled on the bottom of water pipes, Thomas said. The Environmental Protection Agency’s maximum allowable level of THM in water is 80 parts per million. Bolton Point reported three readings equal or higher than the maximum allowable level. One of these readings was in 2012; in August and October 2013 the elevated THM levels showed up again.

The four water districts in the Town of Ulysses service 203  residents [let’s assume this is a misprint–Ed.] within the town’s borders. According to the EPA, “Some people who drink water containing total trihalomethanes in excess of the limit over many years could experience liver, kidney, or central nervous system problems and increased risk of cancer.”

“When water gets warmer, organic matter and chlorine react and create a byproduct (THM). We found this happened at Van Dorn Corners Road. The highest traces were found while testing in August and October of last year,” Thomas said. “Of course the first course of action we took was to warn all residents because this byproduct is volatile.”

THM found in the town’s water supply is a result of low water usage. In attempt to clear up the low water usage problem, in October 2013 the town flushed the water pipes to clear out the organic matter. Hunt Engineers reported the flushing did not fix the problem and may have further agitated the organic matter and chlorine. The next reading, in December, found the THM levels at allowable limits.

“I said ‘let’s pretend we have an eraser and could erase all of the municipality lines.’ This way we could figure out what’s best for all of the people here. I really want to emphasize looking at this from a bigger picture,” Thomas said.

Thomas sat down with Bolton Point Municipal Water System, the Town of Ithaca, the Village of Trumansburg, and the Tompkins County Department of Health Department to discuss the possibility of distributing the cost of a $100,000 for a water aerator. A water aerator increases the oxygen saturation in water, which in turn releases volatile elements from the water into the air.

“I brought up splitting the cost of the mixer with Ithaca, the department of health, the village, town and Bolton Point looking for solutions as a unified group instead of us alone. Ithaca didn’t seem very interested in the idea though,” Thomas said.

Thomas also suggested a plan to connect the village and town’s water sources at Cold Springs Road and Podunk Road. Thomas also suggested connecting the town’s water source in with the village’s second source.

“We may need a water tank to connect the village with Jacksonville, which would be an additional cost but I’m not totally sure that’s necessary,” Thomas said.

The board agreed further consideration and discussion of all options is necessary before any plans are made.

 

Source of town meeting notes: Water Efficiency.

Pure Water Gazette Fair Use Statement

TDS

by Gene Franks

TDS stands for “Total Dissolved Solids.”  Solids might also be called dissolved minerals, ionic species, or salts. TDS is usually measured in ppm (parts per million) or mg/L (milligrams per liter), which are essentially the same.  TDS is, in short, a measurement of all the dissolved mineral content of the water. A test for TDS does not measure chemicals or pathogens; a low TDS count does not mean that water is safe to drink.

TDS is measured often by laboratories with a conductivity meter, which quantifies the water’s ability to conduct electricity. The higher the mineral content, the better it conducts electricity. For more practical purposes, a TDS meter, which works on the same principle, is used. Conductivity is read in micromhos per centimeter. The familiar TDS meter, an inexpensive and very handy tool, converts conductivity to ppm TDS for convenience.

 The TDS Tester is an effective tool that gives an instant reading of any water. Just turn it on and insert the bottom part of the tester into the water. More information.

There is often confusion about TDS meters and what the readings mean. TDS meters measure the performance of reverse osmosis units, distillers, and deionizers, but except for limited use by professionals, they do not measure the performance of filters or water softeners. Softeners and filters do not affect TDS readings significantly. A softener, to illustrate, removes calcium and magnesium ions but the TDS reading will not be affected significantly because the softener adds a more-or-less equal amount of sodium in exchange. The TDS reading of softened water is usually slightly higher than the TDS of the untreated water. You need a hardness test to judge softener performance, not a TDS meter. Filters, especially when they are new, usually add TDS (the phenomenon is called “TDS throw”). Likewise, the performance of softener alternatives, either tank-style or electronic, cannot be measured by a TDS meter.

Classifying Water by TDS

Although other TDS classifications  may differ slightly, here is a good basic TDS breakdown from a publication of the Water Quality Association of America:

Note that in standard usage these classifications are applied loosely. “Brine,” is used in water treatment for the salty water used to regenerate a softener or for the reject water from a reverse osmosis unit. In the case of the RO unit, the “brine” (a.k.a. “concentrate”) could be less than 50 mg/L in TDS. And although the song says that the moon was bright and shiny out on the briney,  even sea water doesn’t technically qualify as brine. Similarly, saline often means any salty solution,  and brackish is often used just to mean really bad water without specific reference to its TDS.

The EPA suggests an upper TDS limit for drinking water of 500, although many cities exceed this limit without dire consequences. For residential water use, when water gets above 1,000 TDS it is starting to border on being unusable, although some well owners grit their teeth and put up with problems like badly stained fixtures, stopped up plumbing, or water so high in sodium that it isn’t good for plants. Actually fairly high TDS water can be usable but it isn’t pleasant to deal with.

Hardness does not always result from high TDS. In our area in Texas, for example, much of the well water is high in sodium but naturally soft. If water has a TDS of 600 and a hardness reading of 2 grains (about 35 ppm), you can be virtually certain that it has a lot of sodium in it. If the high TDS consists mainly of calcium and magnesium (the hardness minerals), it can be softened, but the resulting water will be high in sodium.

Treating High and Low TDS

Treating low TDS is not common, but it can be done by using filters with a sacrificial medium like calcite. As water passes through the filter, it dissolves some mineral content and the TDS goes up. This can be done for point of entry (whole house) or point of use (drinking water only) applications. Small filters are now often used to “remineralize” reverse osmosis water. Minerals are dissolved by the low TDS water passing through the filter, raising the TDS count.

Lowering TDS is done by reverse osmosis, the most common method used in residential settings, distillation, or deionization. Reverse osmosis reduces TDS 90%+ (99% for larger, high pressure units), while distillation and DI (deionization) units can reduce TDS to a zero meter showing. Filters do not reduce TDS, not even the extremely tight ones.

Practical TDS Tips for Residential RO Users

The main use for a handheld TDS tester is to verify the performance of your RO unit’s membrane. While TDS is not in itself a targeted “contaminant” like lead, arsenic, or nitrates, the TDS meter verifies the health of the RO membrane. If the RO unit is reducing dissolved solids by 90%, you can be sure it’s also doing a good job on aluminum and fluoride.

The purpose of the TDS test is to tell you when to change your membrane. If you have an excellent TDS reading, that does not mean you don’t need to change your filter cartridges. The membrane should be changed on need—as indicated by the TDS test—but cartridges are changed on time. In fact, keeping the cartridges fresh is the best way to protect your membrane.

The worst time to do a TDS test is immediately after changing your filter cartridges. The new carbon postfilter will produce a “TDS throw” that will make your TDS reading high. Take a TDS test before you change your cartridges. The same principle applies to new RO units. You won’t get a reliable TDS test until the unit is a couple of weeks old. If you want to test shortly after installation, take loose the tube going into the storage tank and take your sample there—before the water goes through the post filter.

An acceptable TDS reading is a matter of personal preference. On our residential RO units, we usually change membranes when the unit consistently fails to reduce TDS by 85% or so.

To determine this, test first the tap water from the faucet, then compare it with the water coming out of the RO unit. This is called “% rejection,” and the formula is TDS of tap water minus TDS of RO water divided by TDS of tap water times 100. To illustrate, our local tap water usually runs around 180 TDS. So, if we test an RO system that shows a TDS reading of 15, the arithmetic would be 180 minus 15 = 165 divided by 180 = around 9.16 X 100 = about 92% rejection.

That’s fine.

The best advice is don’t obsess over TDS readings from a home unit. TDS is somewhat fickle and can be changed by variables like water pressure and the amount of water being used. Don’t be too quick to change a membrane if you get one bad test.

Dried up: Poverty in America’s drought lands

Earth may have underground ‘ocean’ three times that on surface

Scientists say rock layer hundreds of miles down holds vast amount of water, opening up new theories on how planet formed

by Melissa Davey

After decades of searching scientists have discovered that a vast reservoir of water, enough to fill the Earth’s oceans three times over, may be trapped hundreds of miles beneath the surface, potentially transforming our understanding of how the planet was formed.

The water is locked up in a mineral called ringwoodite about 660km (400 miles) beneath the crust of the Earth, researchers say. Geophysicist Steve Jacobsen from Northwestern University in the US co-authored the study published in the journal Science and said the discovery suggested Earth’s water may have come from within, driven to the surface by geological activity, rather than being deposited by icy comets hitting the forming planet as held by the prevailing theories.

“Geological processes on the Earth’s surface, such as earthquakes or erupting volcanoes, are an expression of what is going on inside the Earth, out of our sight,” Jacobsen said.

“I think we are finally seeing evidence for a whole-Earth water cycle, which may help explain the vast amount of liquid water on the surface of our habitable planet. Scientists have been looking for this missing deep water for decades.”

Jacobsen and his colleagues are the first to provide direct evidence that there may be water in an area of the Earth’s mantle known as the transition zone. They based their findings on a study of a vast underground region extending across most of the interior of the US.

Ringwoodite acts like a sponge due to a crystal structure that makes it attract hydrogen and trap water.

If just 1% of the weight of mantle rock located in the transition zone was water it would be equivalent to nearly three times the amount of water in our oceans, Jacobsen said.

The study used data from the USArray, a network of seismometers across the US that measure the vibrations of earthquakes, combined with Jacobsen’s lab experiments on rocks simulating the high pressures found more than 600km underground.

It produced evidence that melting and movement of rock in the transition zone – hundreds of kilometres down, between the upper and lower mantles – led to a process where water could become fused and trapped in the rock.

The discovery is remarkable because most melting in the mantle was previously thought to occur at a much shallower distance, about 80km below the Earth’s surface.

Jacobsen told the New Scientist that the hidden water might also act as a buffer for the oceans on the surface, explaining why they have stayed the same size for millions of years. “If [the stored water] wasn’t there, it would be on the surface of the Earth, and mountaintops would be the only land poking out,” he said.

Source:  The Guardian.

Pure Water Gazette Fair Use Statement

By Joseph Castro

Melted plastic trash on beaches can sometimes mix with sediment, basaltic lava fragments and organic debris (such as shells) to produce a new type of rock material, new research shows.

Plastiglomerate.  Click picture for larger view.

The new material, dubbed plastiglomerate, will forever remain in Earth’s rock record, and in the future may serve as a geological marker for humankind’s impact on the planet, researchers say.

Plastic pollution is a worldwide problem affecting every waterway, sea and ocean in the world, according to the Natural Resources Defense Council. First produced in the 1950s, plastic doesn’t break down easily and is estimated to persist in the environment for hundreds to thousands of years. Plastic debris is also lightweight, allowing it to avoid being buried and becoming a part of the permanent geological record.

But while at Hawaii’s Kamilo Beach, Capt. Charles Moore, an oceanographer with the Algalita Marine Research Institute in California, found that plastic, if melted, can actually become one with rocks, sediment and other geologic materials. [See Images of the Plastiglomerate Rock at Kamilo]

“He found some plastic had been melted to rocks, and other pieces of natural material had also been stuck on it,” said study lead author Patricia Corcoran, a geologist at the University of Western Ontario (UWO) in Canada. “He didn’t know what to call it. It’s possible other people have found [the plastic conglomerates] at other locations before Captain Moore did, but nobody had thought to report it or identify it.”

Corcoran attended a presentation Moore gave about his find, and she became immediately interested in investigating the material. So she, along with Moore and Kelly Jazvac, a visual artist at UWO, headed to Kamilo Beach to analyze the plastic formations.

A human origin

Kamilo Beach, located on the southeastern tip of the Big Island of Hawaii, is often considered to be one of the dirtiest beaches in the world. Because of the current flow and high wave energy of the area, the beach is covered with plastic debris pulled in from the ocean, including fishing gear, food and drink containers and multicolored plastic fragments called “plastic confetti.”

The researchers discovered there are two types of plastiglomerates at Kamilo Beach: In situ and clastic.

In situ plastiglomerate is more rare than the clastic variety, and forms when “plastic melts on rock and becomes incorporated into the rock outcrop,” Corcoran told Live Science, adding that the melted plastic can also get into the rock vesicles, or cavities. Clastic plastiglomerates, on the other hand, are loose rocky structures, composed of a combination of basalt, coral, shells, woody debris and sand that have been glued together by melted plastic.

When Moore first discovered Kamilo Beach’s plastiglomerates, he hypothesized that molten lava had melted the plastic to create the new rock. However, the researchers found that lava had not flowed in that area since before plastics were first invented.

After digging further into the mystery and talking with locals, the researchers concluded that people inadvertently created the plastiglomerates after burning plastic debris, either intentionally to try to destroy the plastic or accidentally by way of campfires.

Given this origin for the beach’s plastiglomerates, the team thinks the material could be present at a lot of other beaches around the world, particularly in areas where people camp or live.

“I would say that anywhere you have abundant plastic debris and humans, there will probably be plastiglomerates,” Corcoran said. Additionally, other locations where there is both active volcanism and beaches polluted with plastic, such as Iceland and the Canary Islands, could have lava-produced plastiglomerates, she said.

A global marker

At present, we live in the Holocene Epoch, which began nearly 12,000 years ago. In recent years, scientists have debated whether to formally identify a new geological era called the Anthropocene, which would mark the time period when human influence significantly altered Earth’s physical, chemical and biological landscape. However, scientists can’t agree when the Anthropocene should begin.

Whatever the case, there are several lines of evidence that highlight humankind’s impact on the planet.

For instance, with the onset of the Industrial Revolution, a lot of carbon dioxide and other greenhouse gases have been pumped into the atmosphere. And even further back, the rise of agriculture some 8,000 years ago fundamentally changed land use and led to increased atmospheric carbon dioxide and methane, as evidenced from analyses of ice cores. Additionally, soil profiles from peat bogs indicate that mining activities and the combustion of leaded gasoline have resulted in increased lead concentrations over the past 300 years, the researchers noted in their study.

With plastiglomerates, scientists now have another global marker for the Anthropocene, Corcoran said. “It definitely shows how humans have interacted with Earth’s biophysical system.”

What’s more, Corcoran and her colleagues have analyzed the clastic plastiglomerates from Kamilo Beach, and found the new material is far denser than plastic-only particles. This suggests plastiglomerates have a much greater potential to become buried and preserved in the rock record than normal plastic debris, and that future generations of scientists will be able to look into the planet’s geological record and find the plastiglomerates.

“One day in the future, people can look at this material and use it as a marker horizon to see that in around 2010, humans were polluting the planet with plastic,” Corcoran said. “But that’s not a legacy we really want.”

Source:  Live Science

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