Providing clean water to the developing world

Household water treatment offers the best hope for nearly 900 million people.

by Michael D. Robeson

Many Americans take clean drinking water for granted. However, much of the developing world is still grappling with the challenges of supplying water that is safe for human consumption. The problem affects nearly 900 million people around the globe and leads to 2.2 million deaths by waterborne diseases annually. More than half of the victims are under the age of six.

While the danger in urban areas stems from aging or inadequate water treatment infrastructure, the risk is most acute in rural communities lacking the density or the resources to build and support water treatment facilities.

Many rural residents still fetch water from rivers, lakes, ponds and streams contaminated with human and animal waste, whether from open defecation or factors such as seepage from septic tanks and pit latrines. Even people with access to cleaner water from common wells, collected rainwater or centralized taps face the risk of pollution by an unsanitary container or improper storage in the home.

For these reasons, groups such as UNICEF and the World Health Organization (WHO) have long recognized that the most practical immediate strategy for improving rural drinking water quality is to provide solutions for treating and safely storing water at the household level.

The upshot has been the development of a variety of household water treatment and safe storage (HWTS) technologies designed to improve water quality at the point-of-use (POU), as well as the publication of WHO specifications for evaluating the microbiological performance of different HWTS systems in 2011. That 2011 WHO document was the first to establish target performance levels for bacteria, virus and protozoa in POU water treatment, providing a benchmark for measuring the relative effectiveness of each technology option.

From chlorination to filtration

One common POU solution involves chlorination — essentially the same treatment used to disinfect public water supplies in the early 1900s. The most widely adopted model in this scenario was developed by the Centers for Disease Control and Prevention (CDC) and the Pan American Health Organization in response to a 1990s cholera epidemic in South America. Under this model, diluted sodium hypochlorite is manufactured locally, bottled and added to water by the capful for disinfection. Users agitate the water and wait 30 minutes before drinking.

Benefits of this approach include low cost per treatment and proven reduction of most bacteria and viruses. Drawbacks include relatively low protection against parasites such as Cryptosporidium, potentially objectionable taste and odor, lower effectiveness in turbid waters and the need for a reliable supply chain as well as the financial resources to continually replenish the chlorine-bleach solution.

An alternative household water treatment is solar disinfection. Initiated by the Swiss Federal Institute for Environmental Science and Technology in 1991, this strategy requires users to fill plastic soda bottles with low-turbidity water, shake them for oxygenation and place them on a roof or rack for six hours in sunny weather or two days in cloudy conditions. Ultraviolet (UV) light from the sun works in conjunction with increased temperature to improve water quality.

The pros include ease of use, virtually no cost and effective pathogen reduction. The cons include the need to pretreat even slightly turbid water, long treatment times, especially in cloudy weather, the need for a large supply of clean bottles and the limited volume of water that can be treated at one time.

Most other POU options involve some form of filtration designed to remove pathogens by passing water through porous stones and a variety of other natural materials.

Multiple filter varieties

Clay-based ceramic filters, for example, remove bacteria through micropores in the clay and other materials such as sawdust or wheat flour that are added to improve porosity. The best-known design in this category is a flowerpot-shaped device by the nonprofit organization Potters for Peace that holds eight to 10 liters of water and sits inside a 20- to 30-liter plastic or ceramic receptacle, which stores the filtered water. Some ceramic filters are also coated with colloidal silver to ensure complete bacteria removal and prevent growth of the bacteria within the filter itself.

Slow sand filters, on the other hand, remove pathogens and suspended solids through layers of sand and gravel. One common household biosand filter consists of a concrete container incorporating layers of large gravel, small gravel and clean medium-grade sand. Prior to use, users fill the filter with water every day for two to three weeks until a bioactive layer resembling dirt grows on the surface of the sand. Microorganisms in the bioactive layer consume disease-causing viruses, bacteria and parasites, while the sand traps organic matter and particles.

As with chlorination and solar disinfection, both varieties have virtues as well as limitations. Ceramic filters are effective against bacteria and protozoa but not as effective against viruses, are breakable, typically last only two years, require as often as weekly cleaning and have a flow rate of only one to three liters of water per hour. Slow sand filters have a flow rate of 30 liters of water per hour — enough to suit a family’s needs — but again, lack adequate virus reduction abilities, are costly and difficult to transport at 170 lbs. and require periodic agitation and regrowth of the biolayer that can reduce filter efficiency if done improperly.

Both ceramic and slow sand filters also lack residual protection for filtered water, such as that provided by chlorine, raising the risk of recontamination unless a disinfectant is added after treatment.

A third option is a hybrid of the ceramic and sand designs. This approach utilizes porous ceramic particles blended with silver, zinc and copper, and deploys them in a layered configuration similar to slow sand filtration solutions. The filter is delivered in a barrel-shaped device with a strainer that filters out large debris, a ceramic/metal layer that neutralizes harmful microorganisms through an ion exchange process made possible by the unique properties of the clay itself and a built-in storage chamber for up to 18 liters of clean water.

Advantages consist of validated effectiveness in bacteria, protozoa and virus disinfection including industry-first compliance with WHO’s new household water treatment specifications, ion-based residual disinfection that keeps filtered water safe, minimal maintenance and a 10-year lifespan with no added costs for post-filtering chemical treatment or filtration media replacement, keeping costs low over the life of the filter. Downsides include a higher initial cost compared to other products and difficulty in outsourcing fabrication to developing world factories because the unique filtration materials are not locally available.

Implementation challenges

While household water treatment technologies for developing countries are not new, adoption still falls woefully short of need. According to the CDC, over two million people in 28 developing countries now use solar disinfection for daily drinking water treatment; however, that pales in comparison to the 900 million people who lack access to safe drinking water. Likewise, Potters for Peace has distributed over 200,000 ceramic filters in Cambodia and many more in other countries, but this only scratches the surface of a public health problem killing the equivalent of the entire population of Houston every year.

One stumbling block is the need to work through disparate non-retail channels to reach communities in need. Partnerships must be created with different nongovernmental agencies (NGOs) and multiple local organizations in each country. Finding willing partners is difficult, as is developing sustainable financial models for projects requiring donor funding and subsidies.

Therefore, distribution strategies vary widely. In the case of chlorination, implementations range from a faith-based group in northern Haiti making and bottling its own hypochlorite solution to a large-scale program in which NGO Population Services International both promotes and distributes its own product on a country-by-country basis through local channels such as community health workers and private pharmacies. In the case of ceramic filters, Potters for Peace helps local communities set up filter-making factories that in turn sell their products to NGOs. Each solution and supplier must forge its own path.

Equally challenging is the need to select the most appropriate treatment method for a community’s specific circumstances. Variables such as existing water and sanitation conditions, water quality, cultural acceptability, implementation feasibility and availability of a supply chain for refills or replacement parts will affect the decision. In addition, any implementation must include an education component to teach the use of each technology as well as proper sanitation, food and water handling.

Nevertheless, household water treatment holds the potential to save millions of lives. Until universal access to piped treated water is available, if ever, these decentralized technologies and the small-scale humanitarian models required to deploy them are the best hope for reducing the disease and death toll related to dirty water. Creative solutions, entrepreneurship and new business models will be needed to remove distribution obstacles, provide government funding or microfinancing and bring relief to millions of people who put their lives in danger simply by taking a drink.

Source: Water Technology.

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Think of our water supply as a giant milkshake

by Hardly Waite

Think of our water supply as a giant milkshake, and think of each demand for water as a straw in the glass. Most states permit a limitless number of straws—and that has to change.

You may receive a water bill every month, but you’re not actually paying for water. You’re paying for the cost of service, and this free-rider problem is contributing to the worsening water crisis that threatens to dehydrate the US.

Last year, metro Atlanta—home to 5 million people—came within 90 days of watching its principal water reserves dry up, and one Tennessee hamlet ran out of water entirely. Small towns in Texas and California ran completely out of water in 2014. More than 30 states are now fighting with their neighbors over water, and a surging US population means increasingly less to go around. Proposed solutions range from the expensive (desalination of ocean water) to the just plain unpopular (reuse of municipal waste).

Some may find the idea of charging for water itself immoral, as water authority Robert Glennon counters, “Precisely because water is a public—and exhaustible—resource, the government has an obligation to manage it wisely.”

All Lakes Are Not Alike

by Kacy Ewing and Gene Franks

Lakes have always been a source of awe and mystery for human beings. Their formation can be just as amazing and mysterious.

The definition of a lake is any body of water that is not an ocean, that is of reasonable size, and that impounds water with little or no horizontal movement. There are a great variety of lake sizes and types. On one hand, you have pools that are slightly larger than ponds. The line between a pond and a lake is hazy and subjective. Where I come from, the body of water that Thoreau called Walden Pond would definitely be called a lake.  On the other hand, you have giant lakes such as Lake Superior which contains enough water to submerge all of North and South America under a foot of water. All lakes, large or small, are part of the diverse ecosystem known as a lentic (Latin for sluggish) habitat. Probably even Thoreau didn’t know that.

Much of what causes lake formation is due to the work of glaciers. Glacial activity caused the creation of most of the natural lakes in the world. The process of glaciers scraping over time creates depressions that hold surface water, forming lakes. In mountain regions a cirque lake can form if glacial debris block the upper reaches of a mountain valley and then fill with water. Cirque lakes (from the French word for circus, named because of their concave amphitheater shape) are common to many mountain ranges in the United States and Canada including most ranges of Colorado, Wyoming, Montana, Alberta, and British Columbia.

A Cirque Lake

While glacial activity is responsible for many lakes, lakes form in dry climates due to changes in precipitation during seasonal climate changes. Pluvial lakes are formed in this manner. These lakes, however, have long since disappeared through evaporation.  They are also referred to as paleolakes.

A Pluvial Lake in the Mojave Desert

In addition to climate changes and glaciers, some lakes were formed by extraterrestrial forces. Almost eerie in its perfection, Lake Chubb (now called the Pingualuk lake) in Quebec is a perfectly shaped circle that occupies a meteorite crater that is 1.4 billion years old. At 876 feet (267 meters) deep it is one of the deepest lakes in North America. It is also one of the most transparent lakes in the world with objects used to measure water transparency visible more than 115 feet (35 meters) deep. There is a similar meteor crater near Flagstaff Arizona formed about 50,000 years ago that contained a much smaller, but similarly shaped pluvial lake.

Lake Chubb

While these two lakes were created by forces out of this world, Kettle lakes are created by what lies beneath the earth’s surface. They are depressions formed by stranded blocks of buried glacial ice that slowly melted during the Pleistocene epoch. As they melted the land surface above them collapsed and created a hole. If the collapse created a hole large enough to reach groundwater, a lake was formed. Kettle lakes are found generally in Ohio, Minnesota, North Dakota, Wisconsin, Michigan, Alaska, Colorado, Idaho, Pennsylvania, British Columbia, Manitoba, Ontario, Saskatchewan, Quebec, and central and northern Europe. Most lakes in Michigan, in fact, could be described as kettle lakes.

Kettle Lake

The age of a lake can have a great impact on its characteristics. Lakes can be young, middle-aged, or old. Young lakes are known as oligotrophic lakes, and have bottoms that are very clean and lacking in organic material. A clean lake may sound pristine, but lacking this material means the lake also lacks a sufficient food source to provide appropriate habitat to produce plants and freshwater organisms. Over time, however, earthen particles and other organic materials from decaying plants and animals can build layers of materials making the lake a suitable home for plants and animals.

Middle aged lakes that have allowed for aquatic growth are referred to as mesotrophic lakes. When a lake ages, the amount of organic material and mineral deposits may become excessive and actually inhibit or stop the growth of aquatic plants and animals. An old lake of this type is called an eutrophic lake and is typically filled with an excess of organic and mineral materials.

In addition to all the naturally formed lake varieties, humans have formed many lakes as well. A reservoir is a human-made feature created by construction of a dam or dike. These man-made lakes are created for a variety of reasons including hydroelectricity, direct water supply, and of course, recreation. Salty or fresh lakes are some of the only freely available water sources on land. Mysterious and majestic, they are an important part of human and animal life.

Hoover Dam Created Lake Mead, a Man-Made Lake or Reservoir

Reference: Thomas V. Cech, Principles of Water Resources and the Wikipedia.

 The Dangerously Clean Water Used to Make Your Iphone

 The ultra-pure water used to clean semiconductors and make microchips would suck vital minerals right out of your body.  Plus it tastes really nasty.

by Charles Fishman

Plan targets farmers in 3 states to reduce Lake Erie algae

by John Seewer

TOLEDO, Ohio (AP) — Farmers in Ohio, Michigan and Indiana are being asked to be part of the solution in fixing the algae problem in Lake Erie. Federal officials on Friday outlined a program that will make $17.5 million available to farmers who take steps to reduce the pollutants that wash away from the fields and help the algae thrive.

Algae in water at Toledo’s water uptake point.

How will it work?

First, it’s a voluntary program so farmers won’t be forced to take part. And it only applies to those who have land in the western Lake Erie watershed, which is mostly made up of northwestern Ohio, southeastern Michigan and northeastern Indiana.

The U.S. Department of Agriculture will work with those farmers to reduce their field runoff by developing a plan that could include planting strips of grass or cover crops that help soil absorb and filer the phosphorus found in farm fertilizers and livestock manure.

Farmers would receive a payment from the government.

“We will not go to a farm and say ‘you will do this,'” said Terry Cosby, the USDA‘s state conservationist in Ohio. “They’re in charge of their farm.”

But that doesn’t mean all farmers who apply will be selected or get a payment.

The agriculture department will rank the applications based on what farms are most likely to have the biggest impact on reducing runoff. The department has been working with university scientists and soil experts to determine what areas they should target.

“We have hot spots,” Cosby said. “We’ve identified all that.”

Why target farm runoff?

Researchers have found that agriculture is the leading source of the phosphorus that feeds the algae in Lake Erie and other fresh water sources. Some researchers say as much as two-thirds comes from agriculture.

The algae blooms produce the type of toxins that contaminated the drinking water supply for Toledo and a sliver of southeastern Michigan for two days last August.

Source: Seattle Pi.

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Pure Water Annie’s FAQ Series.

Pure Water Gazette Technical Wizard Pure Water Annie Answers All the Persistent Questions about Water Treatment.

This week’s topic:  Reverse Osmosis Flow Restrictors.

What’s the purpose of the flow restrictor?

The flow restrictor, as the name suggests, restricts the flow of brine (reject water) in drain line leaving the membrane. It provides resistance, creating pressure against the membrane and  forcing some of the water, the permeate, or product water, through the membrane.  Without the resistance provided by the drain line flow restrictor, all the water entering the membrane housing would simply take the path of least resistance and exit through the drain line.  In short, without the flow restrictor, the reverse osmosis process wouldn’t take place.

Where is the flow restrictor located on my home RO unit?

The most common situation is to insert a tiny restrictor into the 1/8″ threaded fitting where the reject water leaves the membrane housing.  Better units now normally use larger capillary restrictors that are inserted into the drain line itself.  These are easily visible and have the advantage of having the “size” of the restrictor printed on the surface. This is especially valuable, because if you can read the output of the restrictor you can guess the size (output capacity) of the membrane.

In RO units larger than undersink, flow restrictors are often electronically controlled or variable-output hand-controlled needle valves that allow adjustment to suit different treatment challenges.

Tiny fitting-insert-style flow restrictor that inserts into the elbow fitting where drain water leaves the membrane housing.

Capillary-style flow restrictor.

Are flow restrictors all the same output?

No, the fixed-output flow restrictors used in undersink and countertop RO units are sized in accordance with the membrane output.  In other words, a membrane that produces 25 gallons per day product water does not need as much drain water to keep it rinsed as a membrane that produces 50.  The higher the membrane’s permeate output, the looser the flow restrictor. In small units, sizing is usually done so that the restrictor size is about four times the membrane’s permeate rating: a 25 gpd membrane is matched with a 100 gpd flow restrictor.

Are restrictors rated by their GPD (gallons per day) output?

Some are, but most manufacturers use MLM (milliliters per minute).  This leads to confusion.  If the restrictor size is stated in mlm, it can be roughly converted to gpd by multiplying by 0.38.  Thus, a 400 milliliter per minute flow restrictor would flow around 150 gallons of water per day to drain if it ran continuously for 24 hours.

Can I save water by reducing the flow size of the flow restrictor–for example, replacing  my 250 mlm restrictor with a 180 mlm?

Yes, you can, but in most cases it’s a bad idea.  Unless the water has very low TDS and little hardness, you’ll probably get poorer TDS performance, reduced production because of hardness scaling of the membrane,  and reduced membrane life. The water that flows to drain is not “waste.”  It’s an essential part of the RO unit’s operation.  Its function is to rinse the membrane, keep it clean, and to wash the impurities rejected by the membrane down the drain.

Do flow restrictors have to be replaced?

Sometimes–if they fail.  Some manufacturers say that you should replace the restrictor each time you replace the membrane, but most of us let them run until they have a problem.  Usually this is never.

What are symptoms of flow restrictor failure?

Either too much water or not enough water (which can be no water at all) flowing to drain.  If the restrictor stops up and no water goes to drain, the RO unit is in effect constipated and the water quality gets bad, then it stops making water completely.  If the restrictor is too loose, you waste water, and if the problem is bad enough, the unit won’t make enough water and it won’t shut off properly.

How do you know if the flow is too much or too little?

The best way is to pull the drain tube out of its fitting and measure the amount of water that comes out with a measuring cup.  250 mlm means that literally 250 mlm should be coming from the drain.  Catch the water from the drain tube in a measuring cup and see how much comes out in one minute. It won’t be exactly the rated figure, but it should be in the ballpark. Remember that the TDS of the water, the temperature, and the water pressure are variables that make it unlikely that you’ll come up with a perfect reading.

There’s a lot more about flow restrictors on the Pure Water Products website.

Dirty Water Is Leading to Obesity and Diabetes in California

by Colleen Curry

A lack of access to clean drinking water in rural California farm communities is leading residents to turn to sugary drinks and soda, contributing to obesity and Type 2 diabetes, researchers said in a new policy paper.

The report, from the University of California Davis Center for Poverty Research, finds that many agricultural immigrant communities in California’s Central Valley have difficulty obtaining clean, drinkable water. And even in those that do have clean water, a persistent belief in the contamination of water leads individuals to buy alternatives, including soda and other sugar-heavy drinks.

Researchers at the school interviewed mothers in poor, rural, unincorporated towns in the Central Valley for the report. They found that the women would not drink the water or give it to their children because of its “unpleasant taste, dirty or yellow appearance, excessive iron, and/or general contamination.” Instead, the women purchased bottled water or other drinks at nearby stores. They reported that their children drink soda or sugary drinks at least two to three times per week.

“The prevalence of obesity and Type 2 diabetes in California is higher among low-income minority populations than white affluent populations. A combination of environmental factors, including a lack of access to healthy foods and nutrition education — and safe drinking water — likely contribute to these disparities,” the team wrote. “Decreasing sugar-sweetened beverage consumption is key to preventing obesity and nutrition-related chronic disease.”

According to information provided by the Community Water Center, the San Joaquin Valley, which is part of the Central Valley, has the highest rates of drinking water contamination and the greatest number of public water systems with contaminant violations in the state. The water supply is tainted with nitrates, arsenic, coliform bacteria, pesticides, disinfectant byproducts, and uranium, according to the group, which attributes the contaminants to fertilizers, pesticides, large-scale animal feed operations, and mining.

Ryan Jensen, a community organizer with the Community Water Center, an advocacy group serving the region, explained that it’s not just environmental issues at play.

“It’s also an institutional and structural issue,” he told VICE News. “You’re dealing with a lot of very small unincorporated communities, a very poor population. So they don’t have the resources to deal with issues or the technical knowledge to be able to address it effectively.”

Jensen said some studies have found that as many as one-quarter of all of the communities in the Central Valley don’t have drinkable water.

“At one time the pinnacle of modernization was that you could walk into your home or apartment and turn on the water and it would be safe to drink,” said Harold Goldstein, the director of the California Center for Public Health Advocacy.

Goldstein told VICE News that the policy report from UC Davis highlights the dangers of sugary drinks and their disproportionate effect on poor immigrant communities. He said that nearly one-third of all patients over 35 admitted to hospitals in California have diabetes, while that figure jumps to 43 percent among Latinos.

“People have come from countries where the water wasn’t good to drink. There may be a sense that the water isn’t safe to drink from their own history and this enforces that,” he said.

“If that’s the case you’ve got to go to the store and buy something, and there’s a lot of marketing to induce people to consume the growing plethora of sugary drink. There are signs, ‘buy 12 packs of soda for the price of 2,’ you know? So making sure people have access to water is absolutely essential.”

He criticized the soda companies for their slogans, including Pepsi with “Live for Now,” and Coca-Cola with “Open Happiness.”

“Yeah, live for today, day of diabetes tomorrow,” he said. “Or Coke’s campaign is open happiness, it doesn’t say open a bottle of insulin.”

Goldstein advocates for a tax and warning label on sodas and sugary drinks, the profits from which could be used to make sure clean water is more readily available.

Ken McDonald, the city manager of Firebaugh, California, a small town about 45 miles outside of Fresno, said that his city has a water treatment system that provides clean drinking water to residents, but the problem is that many outlying residents — some up to 20 miles away — have a Firebaugh address but are not hooked up to the town water system.

“The whole thing is a little larger than just the city,” McDonald told VICE News, explaining that the Central Valley’s history as an ancient seabed made its groundwater vulnerable to mineral deposits trapped underground. “So our water in the municipal system has to go through a treatment process to make it potable. Unpotable water is an issue outside of city limits, out on Interstate 5, which is about 20 miles away.”

The state of California has become more responsive to pleas for help on behalf of the communities, Jensen stressed, though as they lack the resources, it can sometimes take three years to apply for grant money and use it to build water facilities.

“It’s changing and it’s changing very rapidly. The state is making a lot of strides toward improving that situation,” he said. “But there are a lot of communities that don’t have or aren’t very well equipped to deal with the structure.”

Source: Vice News.

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Music festival causes spike in ecstasy and caffeine in nearby river

by Rachel Feltman

Gazette Introductory Note: How do music and sports affect water?  This article will tell you that they may have more  than we thought to do with the growing problem of “emerging contaminants.” A local university professor published research a couple of years back showing how the calendars of our two local universities are reflected in the birth control drug content of our lakes. Are we approaching a time when special hazardous waste assessments are required for football stadiums and concert halls as they are now  for auto repair shops and dry cleaners? –Hardly Waite.

It turns out that massive music festivals might not just be a noise disruption for locals — they might be causing issues for nearby aquatic life, too. According to a study published Wednesday in the journal Environmental Science & Technology, these events could be introducing dangerous drugs like ecstasy and ketamine into the water supply, leaving traces of them in rivers and soil.

The study is part of an effort to research so-called “emerging contaminants,” (ECs) or things like drugs (both prescribed and recreational) and hygiene products that end up in waste water. According to recent studies, only about half of these contaminants are actually removed during the water treatment process. So eventually, they can end up back in our drinking water — and in our fish.

Researchers were particularly interested in how certain events — like football games, holiday weekends, and tourist attractions — could cause spikes or even changes in these sneaky contaminants. After all, it stands to reason that an influx of people (especially a large group all doing the same activity) would have an effect. The researchers measured contaminant levels in Hengchun, a popular vacation destination in Taiwan.

ECs were higher in Hengchun rivers than in other areas, despite the low population of the town. That wasn’t unexpected — since the area is popular with tourists, it often has extra people hanging around flushing their waste. These areas also showed a lower concentration of illicit drugs.

So the researchers also weren’t surprised that contaminants spiked during popular travel times, like weekends and seasons with good weather.

But during the “Spring Scream,” an event that draws over 600,000 young music fans to the beach town, things got a little crazy.

Daily sampling during the week of Spring Scream found big spikes in drugs like ecstasy, ketamine, and caffeine — exactly the cocktail of “fun” drugs one would expect hoards of young music festival goers to partake in. Meanwhile, more benign drugs — like ibuprofen — were fairly consistent before, during, and after the concerts.

This isn’t the first indication that sewage can be affected by one-off events.Studies of water near universities have found spikes in amphetamine (taken illicitly by many students to enhance their studying) during exam periods, for example. Another study found that levels of party drugs like cocaine and ecstasy spike in the London area on weekends.

It’s not as if going for a swim in this water could get you high. But the concern is that people and animals are being exposed to varying mixtures of different drugs at different concentrations — so it’s hard to guess just what the long-term effects might be. And research has indicated that some of the drugs that change behavior in humans might also change the behavior of aquatic animals exposed to them, so this party drug pollution is something that warrants a closer look.

Source: Washington Post.

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The Risk of Benzene in Drinking Water, and How to Get Rid of It

Benzene was featured in the January 2015 Water Technology’s “Contaminant of the Month” feature.

Here are some highlights:

Benzene is  a natural product in some foods, is a hydrocarbon manufactured from petroleum,  and is the base product amid the family of BTEX (benzene, toluene, ethylbenzene, xylene) hydrocarbons.

Health risks assessment:

• As with most volatile solvents, benzene can cause drowsiness and headaches at high inhalation levels.
• Benzene is a known human carcinogen — EPA Group A, based upon occupational epidemiology.
• Leukemias are the principal cancer concern.
• EPA’s lifetime risk calculation for inhalation is about one in 100,000 to one in one million for exposure at 1 µg/m³.
• EPA’s calculated risk of one in one million for ingestion through drinking water is between 10 and 100 ppb.
• The other BTEX hydrocarbons have much less chronic risk than benzene.

Benzene is not present in most groundwaters and is most of ten found when wells are contaminated with gasoline from hazardous waste sites or leaking underground storage tanks.

Treatment options:  Activated carbon and aeration are effective for water treatment plants.  For point-of-entry or point-of-use: Activated carbon is effective, but cartridges or carbon beds must be replaced before exhaustion. Although reverse osmosis membranes are not effective because benzene can dissolve and migrate through to the treated water, the carbon filters that go with reverse osmosis units make reverse osmosis a good option.

Regulation figures:

You can find Water Technology’s  Contaminant of the Month assessment of benzene here.

Scientists: Great Lakes Teeming With Tiny Plastic Fibers

Associated Press

TRAVERSE CITY, Mich. — Scientists who have reported that the Great Lakes are awash in tiny bits of plastic are raising new alarms about a little-noticed form of the debris turning up in sampling nets: synthetic fibers from garments, cleaning cloths and other consumer products.

They are known as “microfibers” — exceedingly fine filaments made of petroleum-based materials such as polyester and nylon that are woven together into fabrics.

“When we launder our clothes, some of the little microfibers will break off and go down the drain to the wastewater treatment facility and end up in our bodies of water,” Sherri “Sam” Mason, a chemist with the State University of New York at Fredonia, said Friday.

The fibers are so minuscule that people typically don’t realize their favorite pullover fleece can shed thousands of them with every washing, as the journal Environmental Science & Technology reported in 2011.

Over the past couple of years, Mason and colleagues have documented the existence of microplastic litter — some too small to see with the naked eye — in the Great Lakes. Among the particles are abrasive beads used in personal care products such as facial and body washes and toothpastes. Other researchers have made similar finds in the oceans.

A number of companies are replacing microbeads with natural substances such as ground-up fruit pits. Illinois imposed a statewide ban on microbeads last year. Similar measures were proposed in California and New York.

But microfibers have gotten comparatively little attention. They’ve accounted for about 4 percent of the plastic litter that Mason and her students have collected from the Great Lakes. The group drags finely meshed netting along the lake surfaces, harvesting tens of thousands of particles per square mile, and study them with microscopes.

About three-quarters of the bits they’ve found are fragments of larger items such as bottles. Smaller portions consist of microbeads, Styrofoam and other materials.

But when Mason’s team and a group from the Illinois-Indiana Sea Grant program took samples from southern Lake Michigan in 2013, about 12 percent of the debris consisted of microfibers. It’s unclear why the fibers were three times as prevalent in that area as elsewhere in the lakes, although currents and wave actions may be one explanation, said Laura Kammin, pollution prevention specialist with Sea Grant.

Ominously, the fibers seem to be getting stuck inside fish in ways that other microplastics aren’t. Microbeads and fragments that fish eat typically pass through their bodies and are excreted. But fibers are becoming enmeshed in gastrointestinal tracts of some fish Mason and her students have examined. They also found fibers inside a double-crested cormorant, a fish-eating bird.

“The longer the plastic remains inside an organism, the greater the likelihood that it will impact the organism in some way,” Mason said, noting that many plastics are made with toxic chemicals or absorb them from polluted water. She is preparing a paper on how microplastics are affecting Great Lakes food chains, including fish that people eat.

There’s also a chance that fibers are in drinking water piped from the lakes, she said. Scientists reported last fall that two dozen varieties of German beer contained microplastics.

Because microfibers are used so widely, there’s no obvious solution, Mason said. Persuading people to stop wearing synthetic clothes likely would be a tougher sell than the idea of switching facial scrubs.

But pollution prevention remains the best way to protect the lakes, Kammin said.

“It’s very hard to remove these microplastics once they’re out there,” she said.

Source: New York Times.

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