CRWA creates a water budget

By Nigel Pickering/ Special To The Tab

 

Charles River Watershed Association is finding a way to meet human water demands while preserving water resources.

CRWA was selected to perform a statewide water budget analysis for the Executive Office of Environmental Affairs for 351 towns in Massachusetts. Our ground-breaking work in water budgeting began in the Charles River watershed, but is applicable in other watersheds as well. A water budget, comparable to balancing a checkbook, accounts for the amount of water that enters or leaves a watershed while quantifying the human impact on streamflow. This project, which commenced in November 2005 and will continue until June 2007, dovetails with CRWA’s flow trading efforts. Statewide maps of streamflow stress will aid in prioritizing restoration efforts and could form the basis for initiating a trading program using water banking.

For several years CRWA scientists have calculated water use patterns for all the months and all sub-watersheds ranging in size from one to five square miles. This water budget approach includes water lost from well withdrawals, transfers via water supply and wastewater pipes, and evaporation from irrigation. Also accounted for is reduced recharge from impervious surfaces (roads, parking lots, buildings) as well as flows returned to the ground from septic systems. CRWA scientists compare these water losses against data on natural streamflow in each sub-watershed to determine the level of human impact on rivers and streams. CRWA maps these results, which graphically depict river flow variations from month-to-month and the magnitude and timing of the human impact on all the sub-watersheds.

CRWA applied this specialized methodology to the Town of Blackstone to help prioritize recharge sites since the Blackstone River sub-watershed is impacted by water withdrawals, a large amount of impervious area, and wastewater losses. The town's water budget calculation identified the Lower Mill River and the Quick River as the most stressed sub-watersheds in the town, primarily because the public water wells are in, or near, their sub-watersheds. The impacts of impervious surfaces and sewering were greatest in the spring since high groundwater levels aid infiltration into sewer pipes, and runoff from impervious surfaces is not absorbed by adjacent soil. The impacts of pumping and irrigation peak in the summer. Streamflow impacts were greater in the summer when streamflows are naturally low. But with more development there will be more withdrawals, irrigation losses, impervious areas, and sewered areas, which will further reduce streamflows in the town.

Newton is different from Blackstone in a number of ways. Newton does not have any public water supply wells so there is no direct local impact in any sub-basin from a public water withdrawal well. There are a number of small golf course wells but their cumulative withdrawal volume is small. The impact of the evaporation losses from irrigated lawns is likely to be somewhat larger because, even though both communities have similar summer-to-winter ratios of water use, there are many more residential lots in Newton. Newton is on the MWRA water supply and sewer system so more water leaves as wastewater than is supplied. This apparent anomaly is because groundwater and stormwater leak into the sewer system and augment the outgoing wastewater flow. The net amount of water lost could be fairly large because of Newton's large population. Newton is also more highly paved than Blackstone so more recharge is blocked from entering the groundwater.

In summary, most of Newton is likely to have a negative water budget or a net deficit of water, thus contributing to lower streamflows during the dry periods. More exact analysis of Newton's water budget will be performed by CRWA in the next year under EOEA's new Statewide Water Budgets Analysis program.

Nigel Pickering, Senior Engineer and Project Manager, is CRWA's computer modeling and mapping expert. He earned his PhD in Agricultural Engineering from Cornell University.

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Planting trees in Senegal: more than meets the eye

By John Leary/ Special To The Tab

 

Confronting the Sahara desert, a mere 150 miles to the north and moving steadily southward, the farmers of Kaffrine in central Senegal are facing an environmental disaster.

The Wolof people have unknowingly punished their soils with over a century of uninterrupted peanut farming. The annual harvest, which entails ripping peanuts out of the ground, leaves farmlands exposed to the intense sun and harsh winds that last the long dry season. The need for fuelwood and construction materials has depleted local forests. The Wolof are desperate for new ideas to deal with irregular rainfall, locust attacks, and the encroaching desert. For many, food security is only a dream. The baobab, tamarind, and bush mangoes that dot the horizon are all that remain of a once thriving forest, and even native Acacia trees are struggling to regenerate.

Trees for the Future's International Program Manager John Leary explains multipurpose windbreaks to Senagalese farmers.

 

These local environmental catastrophes on the tip of West Africa reflect global trends that affect all of us. Clearing forests releases massive amounts of greenhouse gases into the atmosphere, leading to alterations of planetary weather patterns and reducing the planet’

s capacity to sequester the greenhouse gases emitted from industries. As a result, every country is facing climate extremes, such as droughts, floods, melting glaciers, and hurricanes.

Fortunately, local people are coming to understand that some of the solutions to these profound problems often lie within the collective wisdom of their own communities - in agricultural practices that have been ignored for decades.

The initial response of desperate farmers has often been to ask international development organizations to construct water pumps. In fact, access to fresh water often quickly creates a boom in vegetable and animal production. However, pumps have been only a short-term solution. What at first appeared to be a springboard to sustainable development has proven to be the Trojan Horse of the African Sahel.

It is a tragic, but common, scenario. Herds of animals concentrate at the water sources, trampling stressed soils and eating all that remains of local vegetation. New gardening industries further deplete the remaining forest resources as communities cut trees to build wooden fences in order to protect precious gardens.

At the request of village leaders and local forestry officials I began working with these Senegalese farmers in 2001 while serving as an agroforestry extension agent in the Peace Corps. They were ready to listen to anybody with a workable plan. To develop a plan that would accommodate their needs, expectations and capabilities, I knew I needed to listen carefully to what these traditional people had to say.

Agroforestry is a complex systems approach, and it takes a lot of listening to understand the needs of local agricultural systems and to ensure that a tree-planting program will meet those needs. Planting trees is the first line of defense, but it is not an end in itself- it is a preventive strategy to address many environmental, social, and economic problems simultaneously.

For that first year, I mostly listened. I learned that the Wolof people are tired of working - literally and figuratively - for peanuts. More and more, it is taking far too long to produce far too little. Production keeps falling. Soils have lost strength, and the scant remaining topsoil is badly eroded by fierce winds in the dry season. Fertilizers are expensive, and farmers get only one payday per year, in November, after peanuts have been processed. The rest of the year is a painful waiting game. Animals have nothing to eat in the dry season after all grasses have been cut or burned, and women become exhausted from walking miles to collect wood for fuel. As I listened to their stories, it became clear that these farmers actually knew the solution to their problems, and they just needed an outside catalyst.

The farmers told me that first they needed to protect their fields from animals and wind erosion. They told me they needed sources of animal forage, organic matter, and wood for fuel. They said they needed to diversify the types of crops and the timing of production. My role was to bring in outside knowledge and experiences to help communities utilize untapped resources. My solution was windbreaks - double rows of trees that protect fields and produce great quantities of useful products.

The reason these communities had not established multipurpose windbreaks decades ago was simply that no one had ever seen or heard of windbreaks. When the French colonized Senegal, they taught farmers how to use every square inch of their land to produce peanuts- techniques that became the so-called “traditional”

farming methods. But long before the French arrived, Senegalese were experts at integrating millet production in pockets of brush and forests, leaving environments intact to regenerate and serve as natural windbreaks, while keeping available a supply of native fruit and nut trees. The deeper traditional knowledge inherent in this system had been lost when lands were cleared to expand peanut production.

The first year, I worked with a few farmers to surround their field with thick hedges of seedlings. We planted thorny trees on the outside to keep animals out, and we planted fast-growing trees on the inside to establish a tall windbreak. Everyone was surprised by the rapid rate of growth of these species- many grew more than 20 feet in 16 months, starting from seed! I had selected trees that quickly grow back after branches are cut, trees whose leaves drop lots of nitrogen into the starved soils and trees and shrubs that produce beans, fruits and high-protein animal forage (leaves and seed pods).

Farmers in Kaffrine have seen that the solution works. What started with three pilot farmers has expanded into 25 communities and is growing at a rate of 15 villages every year. Families have changed the way they farm, collect firewood, improve soil, feed animals and protect crops. These proud local people, with some encouragement and agroforestry knowledge from an outsider, were able to generate a local solution to a profound environmental problem.

There is much more work to do, and funding is often inadequate, although these programs are not expensive. The global community has a stake in ensuring food security for communities experiencing more droughts due to climate change, but the programs have ripple effects far beyond those communities.

Halting the erosion of the Sahara has direct benefits for people in the Western hemisphere who suffer health problems from the increasing amounts of airborne dust being carried across the Atlantic by trade winds. We live in a profoundly interconnected world, and in the long run, there is no place to hide from the serious consequences of environmental degradation anywhere on the planet.

John Leary is the International Program Manager for Trees for the Future, www.plant-trees.org, Since 1988 TFTF has aided thousands of communities to plant over 43,000,000 trees, returning sustainable productivity to 70,000 acres of land and removing over one million tons of CO2 from the global atmosphere.

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‘Blood and Oil’ author speaks

By John Bliss/ Special To The Tab

 

 

The first of the Green Decade's 2006 Environmental Speakers, Michael Klare, Five College Professor of Peace and World Security Studies, gave a talk entitled, “Global Petro-Politics: The US, China and the Struggle Over the World's Oil,” on Monday, January 23. His main message was that the world is entering a permanent energy crisis that dwarfs the temporary shortages of the 1970's caused by the Middle Eastern oil embargoes.

Speaking to a large audience at the Newton Library, Klare pointed out that all nations are affected by high oil prices, currently approaching $70/barrel, and that no sufficiently large new oil sources are available to relieve the crisis over the next twenty-five years. He was similarly pessimistic about the prospects for new gas supplies. He noted that the U.S. Department of Energy's Energy Information Agency (EIA) had raised last year's estimate of baseline oil prices out to 2025 from $35/barrel to $60/barrel.

Massive new demands for energy are coming from China, India, and many other developing countries. Klare predicted intensified competition among nations to secure the existing fossil fuel sources for themselves, which will greatly increase the chances for armed conflicts. He said that war with Iran is now more likely than not.

Klare stated that in order to satisfy the EIA's fifty-seven percent projected increase in world demand for oil and gas over the next twenty-five years, Middle Eastern output would have to triple, the Gulf of Mexico would have to remain free of large hurricanes, and nations such as Russia, Kazakhstan and Nigeria would need to remain politically stable. He noted that the problem of supply is exacerbated by the decline in oil production in Alaska and the North Sea.

Klare described the “securitization” of oil supplies by the United States over the past twenty-five years and by China more recently. He noted that the U.S. military is our nation's largest single oil consumer and the primary reason that the U.S. is involved in protecting diverse sources of supply around the world. The U.S. has intervened in Latin America and the Middle East numerous times to protect the world oil markets. China is now seeking to form alliances with Nigeria, Sudan and countries around the Caspian Sea to secure new oil sources, and this, too, raises the risk of armed conflict.

In a positive observation, Klare characterized the high baseline price of oil as “revolutionary” and believes it will stimulate investment in alternative sources of energy in ways not seen before. Although he is concerned about the environmental consequences of increased use of traditional fossil fuels, he sees only a limited role for certain alternative sources, such as the Canadian “tar sands,” and coal gasification, or “clean coal.” He noted that extracting such fuels often has negative environmental impact or requires too much energy.

Following the talk, Klare answered many questions about energy supply, international competition and conflict, and alternative energy sources and then he signed copies of his latest book, “Blood and Oil,” which were available for sale.

John Bliss is a member of the Green Decade Coalition/Newton and serves on the Newton Citizens Commission on Energy.

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The importance of oysters

By Peter Sun/ Special To The Tab

 

 

Oysters have been a popular food since ancient times. Roman emperors paid for them by their weight in gold. The Romans were so enthusiastic about these marvelous mollusks that they marched thousands of slaves through rugged terrain all the way to the English Channel to gather them. While oysters have had a reputation as a delicacy for many centuries, we have only more recently begun to appreciate their environmental benefits. Scientific research has shown that oysters are voracious filter feeders. They consume large quantities of algae and excess nutrients - up to 5 liters per hour. They play a major role in maintaining the ecological balance in the waters where they grow.

Take the Chesapeake Bay, for example. Today, the water is often turbid, carrying large amounts of sediment and phytoplankton (microscopic organisms), which limits the biodiversity of the bay. However, if we go back approximately 40 years, <!--[if gte vml 1]>

NNHS Biology students Alissa Becker, left, Peter Sun and Joy Huang, right, at Whole Foods Market with their subject.

<![endif]-->we know that nature provided 3-4 million bushels of oysters annually in the bay, which was in great shape ecologically. These oysters filtered all of the bay’s water in a mere 4 to 5 days. During this filtering process the oysters use their cilia to strain out microscopic plants and to wrap whatever they cannot digest in mucus, which they then transport to the mouth. The mouth then does the job of breaking down the material, which moves to the stomach and is eventually expelled as feces or pseudofeces (material excreted, but not through the gut) that contribute to the sediment of the bay. Oysters consume phytoplankton so rapidly that several large oysters can clear an aquarium filled with green water within hours. When oysters strain out microscopic plants in the bay, they create room for other organisms to survive, thus maintaining the ecological balance that fosters species diversity in the bay.

Sadly, the ecology of Chesapeake Bay is now very unhealthy. Oysters are nearly absent from the bay. They have been reduced to one percent of their population of 40 years ago. This is because enormous quantities of nitrogen and phosphorus (over 300 million pounds) are deposited in Chesapeake Bay each year in the form of man-made fertilizers. These provide a tremendous source of nutrients for phytoplankton and algae. When these phytoplankton and algae are overabundant they gather to form large green masses that block the light that would normally filter to the bottom and allow healthy aquatic vegetation like seaweed and ell grass to grow. The excessive phytoplankton absorbs enormous amounts of oxygen very rapidly in a given location, causing anoxia, which means that no oxygen is left to circulate in the water. The result is devastating; it kills off many animals that require oxygen to live. During the summer, when the temperatures are high and there is little vertical mixing of water in the bay, the warmer water remains afloat because it becomes less dense, while the cooler, denser water remains at the bottom. The water at the bottom can be anoxic for many weeks. This destroys many or even most of the living organisms, such as fish, leaving acres of the bay’

s bottom barren.

How did such a healthy bay change so dramatically in just 40 years? There are many answers to this question, but they all boil down to this: humans have been over-harvesting a most precious natural resource. There is historical evidence that the over-harvesting of Chesapeake Bay goes back 140 years, to about 1865. Oyster harvest dropped precipitously between 1890 and 1905; even so, 12-15 million bushels of oysters were still harvested during that time period. Since 1905, the oyster harvest has declined from 5 million bushels annually to a meager 100,000 bushels in 1993. There is clear evidence that it is the drastic decline in oysters that is responsible for the drastic decline in the water quality of Chesapeake Bay.

Fortunately local governments have recognized the nature and the severity of the problem. Laws have been passed to limit the over-harvesting of oysters. For example, the 1927 10 Percent Shell Tax Law required oyster processors to make 10 percent of their shucked shell available for state use in planting, a method to create new oyster beds. The 1953 55 Percent Shell Tax, increasing the tax on oyster processors by 50 percent, was passed to slow the market demand for oysters. The 1972 Moratorium on New Leases suspended awards of new leases of oyster grounds so that the over-harvested oyster grounds could recover. Although these steps taken by governments were inadequate, they were milestones that acknowledged past mistakes and attempted to rectify them. Such laws, when combined with efforts to raise public awareness of the problem, are ways to help bring back the oysters that are so essential to the heath of the environment.

Oysters are much more than a human delicacy. They perform amazing environmental services, not only in Chesapeake Bay but also in many coastal areas all over the world. We humans should do whatever we can to preserve this delicate and delectable creature that quietly works environmental wonders.

Peter Sun was assisted by NNHS classmates Alissa Becker and Joy Huang in writing this article as part of an Environmental Service Project in Zachary Snow’

s Biology class.

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Cleaner cleaners in the home

By Jill Hahn/ Special To The Tab

 

The eye-watering smell of chlorine. The tang of ammonia. It’s great to come home to a clean house. Breathe deep. Or maybe you’d better not.

Cleaning products are among the most hazardous chemicals in your home. And because the chemicals found in cleaners are not as easily dispersed indoors as outdoors, a 5-year EPA study found concentrations of 20 toxic compounds to be as much as 200 times higher inside homes and offices than outdoors.

Then there’s the environmental impact.

Take chlorine bleach, that ever-popular cleaning product. There’s a reason why bleach is great at killing mold and bacteria: it’s toxic. Its fumes are a respiratory irritant. And when bleach, also known as sodium hypochlorite, runs down the drain, it can react with other chemicals to form toxic or carcinogenic chlorinated organic compounds, including chlorofluorocarbons which damage Earth’s ozone layer.

Sodium hypochlorite is just one of a buffet of toxic chemicals you bring into your home with your cleaning supplies. Glance at a few Material Safety Data Sheets that the Occupational Health and Safety Administration requires companies to publish: Formula 409 Cleaner Degreaser: “Reports have associated [exposure to ethylene glycol monobutyl ether with] blood and bone marrow damage...” Lysol Brand Basin Tub & Tile Cleaner:”This product contains [diethylene glycol monobutyl ether] which... has been reported to cause liver, kidney, spleen, thymus and blood effects in laboratory animals when exposed to high levels...” Parsons Ammonia All Purpose Cleaner: “Mild inhalation of ammonia vapors may cause irritation of the nose and throat with coughing and sneezing. A more severe exposure may cause ... labored breathing, and pulmonary edema.”

Not good.

But if you don’t snort the ammonia, or bathe in the Lysol, are these chemicals really a problem? Research shows that they can be. Volatile organic compounds (VOCs), such as xylene, ketones, and aldehydes, are found in many aerosol products and air fresheners. In one study, babies less than six months old in homes where air fresheners were used on most days had 30 percent more ear infections than those exposed less than once a week.

So what is the conscientious homemaker to do? The first thing you need to do is retrain your nose. Your house doesn’t have to smell like a chemistry experiment in order to be clean enough. Before the golden age of synthetic chemicals arrived in the mid-twentieth century, people didn’t have access to such miracles of modern science as Fantastik with Scrubbing Bubbles. Instead, they used a handful of simple yet effective substances, such as soap (not detergent, which is usually petroleum-based), vinegar, baking soda, borax, alcohol, and cornstarch to deodorize, polish, disinfect, scrub, remove stains, and wash clothes. These ingredients are still available, and still effective.

And maybe we need to redefine “clean enough.” We’ve become germ-phobic, with consequences that, paradoxically, may be endangering our health. The Centers for Disease Control have shown that antibacterials such as triclosan and benzalkonium chloride, which have proliferated in household products recently, are resulting in an increase in bacteria resistant not only to those antibacterials but to antibiotics such as penicillins and cephalosporins as well. This is particularly troubling considering that, according to Stuart B. Levy of Tufts University School of Medicine, no current data demonstrate any health benefits from having antibacterial-containing cleansers in a healthy household.

In addition, evidence is mounting that people who have been raised in an environment overly protective against microorganisms may suffer from an increased frequency of allergies, asthma, and eczema.

So when you’re buying your next batch of household cleaners, what should you look out for?

First, avoid products labeled “antibacterial.” For those instances when you really need to disinfect (you’ve just spilled icky chicken water all over your countertop and you’re worried about salmonella), bleach, alcohol, or peroxide will kill those germs without selecting for resistant bacteria.

Don’t buy products with bleach added. If you want chlorine bleach in the house, buy a small bottle and use it sparingly, only when something less toxic won’t work. Otherwise, look for oxygen-based bleach.

Examine labels, and if a product has a VOC concentration higher than 10% of its weight, put it back.

Choose products with a phosphates concentration of 0.5% or less (phosphates aren’t a threat to your immediate health, but they wreak havoc on the health of the waterways near your house). Even if you alternate use of a low-phosphate product with use of a conventional cleaner, it’s an improvement.

Which is a rule to live by. Small steps count. If you succeed in reducing, rather than eliminating, your dependence on toxic chemicals in the home, you’re still doing yourself, your family, and the environment a big favor. And who knows, someday you may find that the fresh, orangey smell of citrus oil means a clean house, and the smell of chlorine only reminds you of a swimming pool.

Jill Hahn, a Newton Highlands resident, is a biologist, a writer, and a mom. All three roles contribute to her interest in environmental issues. She can be reached at jkkhahn@comcast.net. This article is archived at www.greendecade.org/tabarchive.asp

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Winter’s assault of rock salt

By Bruce Wenning/ Special To The Tab

 

During the winter our environment is inundated with road salt. Millions of tons of de-icing salt, commonly called rock salt (sodium chloride) is applied to roads, parking lots, sidewalks, driveways, and stairs to melt ice or prevent ice formation. This is done to reduce the hazard of pedestrian slips and falls and vehicle accidents. However, it is not effective below 20 °F.

However, rock salt applied for our safety has several non-target pathways in the environment: (1) it seeps into pavement surfaces and creates a reservoir of salt for later transport for contamination, (2) it is splashed to roadside soil and vegetation by vehicles where it is concentrated in plowed and shoveled snow piles (3) it is washed away by surface runoff into soil, ground water, rivers, lakes, ponds, and streams (4) it leaches through soil into the plant root zone (5) it becomes air-borne into our atmosphere and settles on vegetation (6) it gets onto vehicles and roadway structures contributing to corrosion.

Rock salt is toxic to many perennial plant species of trees, shrubs, grasses and herbs. Salt-contaminated snow and ice eventually melt and leach into soil, killing soil microbes, which contributes to soil compaction.

Rock salt in soil breaks down into ions of sodium and chloride. The chloride ions are the more damaging; when taken up by plant roots in spring and summer they are transported to growing points such as buds and branch tips, killing them. Leaves show symptoms of salt damage by exhibiting brown colored leaf margins. This is where chloride ions were deposited and concentrated in the leaf tissue, creating localized cell death that resembles drought stress. Eventually entire leaves can “brown out” and die. Twigs and small branches can soon follow suit.

Vehicular traffic on salted roads releases pavement salt, making it airborne. Rock salt molecules travel in wind currents created by traffic flow and settle on roadside vegetation. This action, called salt spray, can cover trees as high as forty feet and an area as deep as 150 feet from the road, although the most noticeable plant damage is within thirty feet of the road. Contaminated soil and salt spray are the two most common ways plants get injured from road salt.

Repeated exposure to rock salt by salt sensitive deciduous trees will cause bud death and branch dieback, forcing dormant buds below the affected area to grow out in response. This recovery growth response of multiple stems with leaves is called “witches brooms” and it is diagnostic of salt exposure. It is easily observed on cherry and maple trees along heavily salted roadsides. Another sign of rock salt toxicity is summer and early fall defoliation.

Evergreen trees such as hemlocks and pines show brown-tipped needles well into summer. With annual exposure to salt spray from traffic or soil contamination, the needles turn completely brown, die and fall off. Evergreens and salt-sensitive deciduous plants are weakened by repeated exposure to rock salt, increasing their susceptibility to insects, diseases and fertility problems; this can lead to their premature death.

There are protective measures you can take to lessen the effects of rock salt damage to plants. First, switch to sand or use ice melting products that are safer for plants, pets, and the environment, such as potassium chloride or “pet safe” calcium chloride products, which are effective de-icing compounds to -15 °F and below. Although these products are a little more expensive than rock salt, they significantly reduce plant damage and environmental contamination. Second, plant salt-tolerant plants. Third, protect salt sensitive plants with burlap wraps, wooden coverings facing the road and by flushing the root zone in spring and summer with lots of water, although root zone washing is only effective with well-drained soil.

Pirone’s Tree Maintenance (7th ed.), Hartman, Pirone and Sall. ranks trees from “Very tolerant” (least sensitive) to “Intolerant” (most sensitive), as follows: Very tolerant:White oak, red oak, black cherry, and eastern red cedar. Tolerant:Yellow birch, black birch, paper birch, gray birch, black locust, and largetooth aspen. Moderately tolerant: Norway maple, red maple, shagbark hickory, hop-hornbeam, American elm, and linden. Intolerant: Sugar maple, white pine, hemlock, beech, red pine, and speckled alder.

For more information, see: www.UMassGreenInfo.org, www.extension.umn.edu, www.safnet.org.

Bruce Wenning is Horticulturist / Grounds Manager at the Massachusetts Audubon Society’s Habitat sanctuary, Belmont and serves on the Board of Directors for the Ecological Landscaping Association. www.ecolandscaping.org.

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What is ‘perc’?

By Gilbert Woolley/ Special To The Tab

 

You may have seen a sign in your dry cleaning store: "Perc free cleaning available" and wondered what is "perc " and why you might not want it to be used. “Perc” is short for Perchloroethylene,(C 2 Cl 4), a chlorinated solvent that goes by several other names including PCE and tetrachloroethylene and several trade names. In the forties and fifties perc replaced trichloroethylene, which had replaced carbon tetrachloride (both more hazardous than perc), and is now the solvent used by 90% of dry cleaners in the US. Perc is also widely used in industry as a degreaser. Annual usage in the US is many million of gallons of perc. Some of this undoubtedly finds its way into the groundwater and into drinking water. This cannot be good for the earth or the people living on it!

Chlorinated solvents have been shown to cause cancer in some animals and studies of workers in the US who are in daily contact with Perc vapor have found significantly higher levels of esophageal, bladder, tongue, intestinal, lung and cervical cancer. This is consistent with studies in Canada and the UK.

The US OSHA (Occupational Safety and Health Administration) warns that perc is a possible human carcinogen (04/15/05) and strictly limits exposure in the workplace. The International Agency For Research on Cancer classifies perc as a "possible human carcinogen". (1995). Perc accumulates in body fat. More immediate effects include nausea, headaches, dizzy ness and drowsiness. As a customer you wont be exposed to the same levels but it's a good idea to avoid exposure to harmful chlorinated solvents, and people who are sensitive to chemicals should beware of contact with garments cleaned by perc.

Like tobacco and alcohol, Perc is not a deadly poison, but it is harmful, and dry cleaners should be required to provide a written warning to customers, just as makers of tobacco products and alcoholic drinks are required to do. This warning should give the “possible carcinogen" status and warn chemically sensitive users about perc.

For people who are not exposed to perc in the workplace the most likely pathway into the body is through the lungs. You must have noticed the rather unpleasant odor of newly dry cleaned garments Tests show that, even after a hundred days, 40% of the perc in the garment after cleaning is still present. When you pick up a garment from the dry cleaners you should take it out of the plastic bag and hang it outdoors or in a well-ventilated area for some days to reduce the amount of perc vapor you bring into your home. This is especially important for large, heavy items, such as "comforters" and sleeping bags, and when a number of garments are packed in one bag. People who live over, or near to a dry cleaning operation may be exposed to harmful levels of perc vapor.

NIOSH (National Institute of Safety and Health) studied methods to limit perc emissions. The study confirmed that technology is available in Europe to do so. Germany has imposed regulation to mandate use of such technology. This requires a considerable capital investment, and without similar regulation in the US there is no incentive to make this investment. Government regulations prohibit the disposal of perc or water containing perc into a sewer, but these regulations are largely self-enforced. Sewage treatment does not remove perc and treated wastewater will be discharged into rivers or the ocean. Perc has been detected in drinking water at many locations in the US.

Alternatives to perc

Google "perc alternatives" to find alternatives to perc. One "perc free" option is "wet clean", the use of detergents and water instead of perc. Google "wet clean" for more information. There are fabrics that are difficult to wet clean without shrinking and some stains that are easier to remove using perc, but many garments carrying the "dry clean only" label can be safely wet cleaned. New wet clean technology has tightly-controlled temperatures for washing and drying, which makes if possible to wet clean some articles that would be difficult to wash using conventional methods. The most complete page is by the US EPA, (labeled) PDA which gives information on wet cleaning and also lists providers of non-perc cleaning by state.

Wet cleaning eliminates many of the disposal problems of perc because the wastewater can be safely discharged into the sewer. Another advantage is that "non perc" cleaners do not have to register with the EPA.

Another "perc free" method is to launder articles in liquid CO 2 (carbon dioxide), which is non-toxic but this method is not in widespread use. The dry cleaner I use in Newton advertises "perc-free cleaning available" but his system uses oil based, not water based, cleaning fluid.

How to limit exposure to perc

·      Buy as few garments as you can, which carry the "Dry Clean Only" label

·      Use a "wet cleaner" The US EPA web page lists four wet cleaners in Massachusetts, including one in Newton: Corner Cleaners, 1301 Washington St, West Newton.

·      Google "wet cleaners" to get more information

·      Ask your dry cleaner to offer "perc-free" cleaning.

·      Have garments dry-cleaned less often

·      Try careful hand washing. For guidelines go to Google: "stain removal".

 

Gilbert Woolley is a retired engineer. He has been a very active member of the Sierra Club since 1971, and he served on the Sierra Club National Toxics Committee for six years.

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