The Dilution Effect

By Jill Hahn / Special To The Tab

 

Here’s a story about a blacklegged tick, a white-footed mouse, an unpleasant

bacterium, and how reducing biodiversity in our own backyards can literally make us

sick.

Lyme disease, which now accounts for about 90

percent of the vector-borne disease (spread by an

animal carrier) in the U.S., is caused by the

bacterium Borrelia burgdorferi, transmitted by the

bite of an infected blacklegged tick, Ixodes

scapularis. A new-born tick does not carry the

bacterium. In order to acquire the bacterium, the

larval tick must take its blood meal from an infected

animal. And here’s where the I. scapularislarvae are

the kind of eaters you wish your children were: they

are not picky. They will feed on a wide variety of

mammalian, bird, or even reptile hosts. The larva

takes one blood meal from the host it happens to

encounter, and then molts into its next stage, called

a nymph.

Most people contract Lyme disease from the nymphal stage of the blacklegged tick,

partly because the nymph is small and hard to spot, partly because it is active in June

and July, when we’re likely to be out enjoying the woods.

What determines whether the nymphal tick that just bit you is likely to give you Lyme

disease? Dr. Richard Ostfeld, senior scientist at the Institute of Ecosystem Studies

(Millbrook, NY), conducted a series of elegant, if messy, experiments to find out. Since

a nymph can only acquire B. burgdorferi during its larval meal, Dr. Ostfeld’s first task

was to determine whether feeding on different animals resulted in differing proportions

of infected nymphs. To do this, he and his colleagues trapped individuals from every

potentially important bird and mammal species in his study site in Duchess County,

NY. This list included deer, robins and other songbirds, white-footed mice, chipmunks,

raccoons, possums, skunks, shrews, and squirrels. The animals (deer excepted) were

caged for 72 hours. Any tick larvae attached to them fell off into pans of water under

the cages. They were collected (a dirty job, because more than just ticks dropped into

those pans during the 72 hours) and tested for the presence of the Lyme disease

bacteria.

Dr. Ostfeld discovered that over 90 percent of the ticks that fed on white-footed mice

tested positive for B. burgdorferi. 40-55 percent of the ticks from shrews or chipmunks

tested positive, and the proportion of positive ticks collected from the other species

ranged from around 15 percent to less than 2 percent. So the host species a larval tick

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Photo courtesy of Frontiers in Ecology

and the Enivronment

White-footed mouse female

and pups

fed on dramatically affected whether the resulting nymph would be able to transmit

Lyme disease.

Since different species of animal have differing abilities to pass the Lyme disease

bacterium to the tick, this suggests that increased host biodiversity might lower the

prevalence of infected ticks. Dr. Ostfeld dubbed this hypothesis the Dilution Effect.

Ecologists know that, as you fragment forest into smaller and smaller pieces, the

number of animal species found in those forested “islands” declines. If the Dilution

Effect holds true, then the proportion of infected nymphal ticks should increase as

forest area goes down and biodiversity decreases. Dr. Ostfeld and his colleagues set

out to test that prediction.

They measured the density of nymphal ticks in forest fragments of different sizes

(ranging from less than two acres to almost 19 acres) by dragging drop cloths through

the forest and counting the number of nymphs collected. When Dr. Ostfeld tested the

ticks, he discovered that, as the Dilution Effect predicted, the proportion of ticks

infected with B. bergdorferi increased as the forested area decreased.

Why would this be? In the smaller forest fragments,

many potential host species disappeared. One

species, however, whose numbers conspicuously

explode as forest area decreases is the white-footed

mouse. White-footed mice, as Dr. Ostfeld had

already shown, are incredibly efficient at infecting

ticks with Lyme disease.

What does this mean for human health? Simply put,

biodiversity protects us from Lyme disease. If you go

hiking, say, in the White Mountains of New

Hampshire, and you get bitten by a blacklegged tick

nymph, you know that tick had a wide variety of

species from which it could have taken its larval

meal, and most of those wouldn’t be likely to infect it

with the Lyme disease bacterium. On the other

hand, if you’re out on a small plot of forested land in

your suburban hometown – especially if it’s smaller than about five acres – that nymph

that bit you most likely got its last meal from a white-footed mouse, and most likely did

contract the bacterium during that meal. So your chances of contracting Lyme disease

from a tick bite are much higher in the forest fragment near your house than in the

National Forest.

If those cute little white-footed mice are the problem, why not simply get rid of them?

Attempts to eradicate rodents to a level at which they can no longer transmit disease

are notoriously unsuccessful. Attempting to rid the woods of ticks is a similarly

Sisyphean task. There is another solution: let the Dilution Effect work for us by

changing the way we manage our landscape.

Dr. Ostfeld’s work has shown that the loss of biodiversity through the fragmentation of

our native forests has real health consequences. The Dilution Effect holds true for

Lyme disease and may play a role in other vector-borne diseases as well. It’s time to

3

stop thinking of biodiversity as something that would be nice to preserve, but of no

practical value. The next time a local interest in your community wants to break up an

existing parcel of forest into smaller pieces for the sake of development, think about

the health consequences, and think twice.

Jill Hahn, a Newton Highlands resident, is a biologist, a writer, and a mom. All three

roles contribute to her passion about environmental issues. She can be reached at

jkkhahn@comcast.net.

This article is archived at www.greendecade.org/tabarchive.asp.

An IPM Primer

By Ed Cunningham/ Special To The Tab

 

March, by mayoral proclamation, is Alternatives to Pesticides Month in Newton. It’s an opportunity for us to think about the consequences of our habit of adding unnecessary toxins to our city environment, to learn about alternatives, and to do something to reduce our use of toxins in our homes, our yards, our places of worship, and our places of business. The city has been trying to do its part. Ten years ago it became the first municipality in the state to adopt an Integrated Pest Management Policy to be followed in the maintenance of city buildings, parks, and grounds.

The term Integrated Pest Management sounds abstract and technical, and, in a sense, it is. The science of IPM is sophisticated, utilizing advances in computing, operations research, systems analysis, and modeling. But in the end it is common sense: it is safer, more effective, and more economical to “outsmart” pests with non-toxic methods than it is to apply pesticides and herbicides reflexively. 

IPM is a set of practices and strategies that evolved from extensive agricultural research initiated in the early 1950s in response to pesticide misuse problems, reduced effectiveness of pesticide and herbicide treatments, and unintended consequences. Poisoning pests is not only a dangerous approach with unintended adverse affects, but long term it is less effective than IPM strategies.

The genesis of IPM is long and interesting. For at least 5000 years, a mixture of cultural, biological, and chemical methods have been used in agriculture to control crop-destroying pests. Cultural methods include the rotation of crops and manipulation of the dates when planting is done. Biological methods include using predatory ants to control caterpillars and beetles, as the Chinese did as early as 300 AD. Chemical intervention can be traced back to 2500 BC, when the Sumerians used sulphur compounds to control insects and mites. Late in the nineteenth century the use of inorganic chemicals emerged as the most popular means of pest control. By the 1890s it was found that lead arsenate provided very effective insect control, by 1930 synthetic organic compounds began being used for plant pathogen control, and in 1939 the pesticide properties of DDT were recognized. Based on the insecticidal properties of DDT and benezene hexachloride, the early 1940s were seen as the dawn of a new era of blissful insect control in agriculture, horticulture, and public health.

The first report of resistance to DDT was published in 1946, followed in the 50s and 60s by evidence of widespread pest resistance to DDT and other pesticides. Against this backdrop that systems analysis was first applied to efforts to control crop pests. Economic entomologists and agricultural economists weighed the cost of chemical treatment against the cost of crop loss. Chemicals were increasingly perceived as being expensive and ineffective, and alternative methods of control began to emerge under the moniker “integrated control.” In 1959 a group of entomologists from UC Berkley and UC Riverside published a landmark paper which documented pest resistance to pesticides, the destruction of natural enemies, the resurgence of treated species, the appearance of new pests, as well as health hazards resulting from toxic residues and the misuse of chemicals. By 1967 “integrated control” had broadened to encompass not only biological and chemical control, but also climatic factors, cultural control, plant growth analysis, and modeling. UC Berkley entomologists RF Smith and R van der Bosch introduced the term “Integrated Pest Management” to reflect the broadened scope of the science. Two years later the US National Academy of Sciences formalized the term, and within a few more years BS, MS, and PhD degrees were offered in the subject.

In the 1980s the principles and practices which had been developed for agricultural and forestry applications began to be used in urban sites such as schools, parks, hospitals, and nursing homes. The list of what was categorized as pests had grown to include rats, mice, squirrels, raccoons, cockroaches, wasps, yellow jackets, mosquitoes, lice, bed bugs, bats, moths, fleas, flies, birds, ants, termites, grubs, crabgrass, poison ivy–any living thing which causes a problem when it shows up where we don’t want it to be.

IPM deals with pests by identifying the problem pest and then formulating the best plan for removing the problem. Techniques include regular cleaning, eliminating access, controlling the temperature of the environment, removing water sources, ensuring that food is properly stored, and routine monitoring. EPA and USDA (Department of Agriculture) websites provide copious information on IPM symposiums, grants, and newsletters, as well as a Pest Management Strategic Plans database, an IPM Expertise database, and links to topics such as “Current PM Research” and “Information on pesticide use.”  When necessary, careful and judicious chemical treatments are part of the IPM program, but they are only used when natural mortality agents are inadequate and the pesticides used allow natural enemies of the target pest to survive treatment.

Look for an article next month on Newton’s IPM policy, the work that has been done over the past ten years, and the work which remains.

Ed Cunningham is the Green Decade Coalition representative to the Newton IPM Advisory Committee.

This article is archived at www.greendecade.org/tabarchive.asp.

Don’t Poison Your Children and Pets

By Gilbert Woolley/ Special To The Tab

 

 

This is the time of year when the poison salesmen are at their most active.  They want to sign you up to have your lawn regularly sprayed with a liquid that contains synthetic fertilizers and also chemical poisons dangerous to children and pets.  Of course these chemicals are also harmful to adults, but children and pets typically come into more and closer contact with a lawn, and children are more sensitive to small amounts of poisons. The poisons are also tracked into the home on footwear and by pets, so that a baby playing on the carpet can come in contact with them.

The lawn care industry warns you to keep off the lawn until the grass is dry and for 24 hours after application. However, when the lawn is watered either by rain or sprinkler the dry ingredients become liquid again. Furthermore, if the ingredients are “safe” after 24 hours, then presumably they are also ineffective against insects.

The non-fertilizer ingredients of lawn care products are designed to kill insects and “undesirable” broad-leaved plants, such as dandelions. As some of the same “building blocks” of life are present in humans, mammals, insects and even plants, it is a good conservative assumption that any chemical harmful to one form of life is likely to be harmful to other forms, including pets and humans and, most critically, to humans still in the womb. Also, when you kill insect predators that eat the undesirable insects and the birds that eat the insects, you must then rely exclusively on chemicals to keep undesirable insects in check.

Half of the 32 pesticides typically used by lawn care providers are recognized as likely or potential carcinogens, and there are many documented cases of children and animals becoming ill after coming into contact with treated lawns. It has been claimed, although not yet statistically validated, that women living in suburban homes with lawns subjected to “lawn care “have a higher rate of breast cancer and perhaps other cancers.

In the United States more than seventy million pounds of pesticides and herbicides are sprayed on lawns, trees and shrubs each year, and much of this finds its way into groundwater, rivers and streams and drinking water. Lawn care products are a major source of chemical pollution in the US, but the use of these products is simply not necessary.  Organic treatments are available which do not poison your lawn or the environment, and there are many contractors who apply them, utilizing “Integrated Pest Management” (IPM). An article describing how IPM is being implemented by the City of Newton can be found in this month’s Environment page.

How important is it to have a  “perfect lawn” and does it justify the dangers to yourself, children and pets?   My lawn has never been treated with pesticides or herbicides.  It’s not “perfect”; there are small patches of clover, but no dandelions. The secret is that every morning I look for dandelion flowers, which are not hard to see.  When I am in a hurry, I just pull off the flowers and put them in the trash.  If I have time, I uproot the plant with a small two-pronged tool.  At first, when there were a lot of dandelions, this required some time and effort but now, one or two dandelions a day is the most I see. If you stop them seeding they cannot reproduce.  My neighbor has dandelions, but the flying seeds rarely travel very far. Sometimes I deflower my neighbor’s dandelions that are near my driveway.

If you want to have a beautiful lawn and don’t want to use poisons, the first thing to do is to make sure that you have sufficient depth of healthy soil to support a healthy lawn.  The builder of my house had dumped debris on the garden and covered it with a couple of inches of soil. I replaced this muck with six inches of topsoil and compost, and seeded it.  With a sufficient depth of healthy soil you need to water much less.  In the summer of 2005 I did not have to water the lawn even once.

Toxics Action Center, www.toxicsaction.org, is leading the campaign in New England to stop the use of possible carcinogens in lawn care treatment.

 

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.

This article is archived at www.greendecade.org/tabarchive.asp.

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

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.

This article is archived at www.greendecade.org/tabarchive.asp.

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.

This article is archived at www.greendecade.org/tabarchive.asp.

 

What is a pesticide?

By Lucia Dolan/ Special To The Tab

 

A pesticide is a poison. It is designed to kill an insect, weed or fungus. Unfortunately pesticides do not limit themselves to just what we wish to kill. They travel. They run off into water. They vaporize and drift. They come into our home on shoes and pets.

Pesticides can spread very quickly. “Good Morning America” recently reported on an experiment in a classroom at PS 8 in New York City.

They applied Glo-Germ, a nontoxic powder visible only under ultraviolet light, in areas where pesticides are most likely to be sprayed or to settle, such as baseboards and windowsills. Then they invited the children to play. After 20 minutes, UV light showed traces of Glo-Germ all over the children’s clothes, hands and faces.

No pesticide is safe. Federal laws prohibit pesticide manufacturers from making safety claims. The EPA, which has the authority to waive all chronic toxicity testing for consumer pesticides, does not require that pesticides be tested for effects on the immune system or on hormonal systems. Additionally, we know little about “real world” exposures – how pesticides interact with other pesticides or substances such as prescription medicines.

Several studies have shown that dogs are more likely to get cancer when their owners use pesticides. In 2004, Dr. Larry Glickman of Purdue University found that Scottish terriers were four to seven times more likely to get bladder cancer when their owners used pesticides on their lawns. The more time the dogs spent on a treated lawn, the higher their risk. Glickman is now measuring the chemicals levels in children from homes that use pesticides, and he is attempting to discover which chemicals in pesticides cause cancer, the active or the inert ingredients.

One to 3 percent of a pesticide product is “active” ingredients, chemicals designed to kill an unwanted insect, weed or fungus. The other 97 percent consists of ingredients are added to deliver the active ingredient and to make it longer lasting or more effective.

“Inert” ingredients, which are protected by trade secrecy laws, may be more dangerous than “active” ingredients. Pesticide manufacturers can conceal the identity of these ingredients from the public and even from the EPA.

Inert pesticide ingredients can be as benign as water or as toxic as benzene, toluene or xylene. Along with inert ingredients, contaminants, such as dioxin and DDT, sometimes form in pesticides as a result of the chemical production process. When pesticide products are used they interact with the environment, (soil, water, air) and can form toxic metabolites. Only a few of the 613 active pesticide ingredients have been tested for health or environmental effects. But solid knowledge of a pesticides dangers do not automatically lead to a government ban.

Methyle bromide is a neurotoxin, and its effects have been known for years. It destroys the ozone layer and has fatally poisoned farm workers in California. The U.S. government has signed an international treaty to ban methyle bromide in 2005, but it is currently negotiating an exemption to prevent “market disruption.” Fifty-six farm organizations, including the largest, the American Farm Bureau, oppose the ban on methyle bromide. Farmers insist that alternatives to methyle bromide are too costly.

Too costly to whom? When the EPA decides that a pesticide’s benefits outweigh its risks, they do not factor into the equation the cost of illnesses, disabilities or environmental degradation. These costs are difficult or impossible to measure in the short term, but they are substantial and serious.

Pesticides are a quick fix, a short-term approach. Fortunately, there are alternatives to pesticides, such as Integrated Pest Management, which offer long-term solutions that focuses on correcting the cause of insect, weed or fungus problems. IPM protects drinking water, food, soil and air by minimizing, if not eliminating, pesticide use. It is an ecosystem approach that protects biodiversity.

In the coming months GreenCAP will have articles on these pages discussing safer approaches to common pest problems, weedy lawns, bees and wasps, and more. For more information visit www.beyondpesticides.org, www.pesticide.org, and www.greendecade.org.

Lucia Dolan, co-chairman of GreenCAP, is on the board of the Green Decade Coalition.

Toxic confusion: a thousand points of … dirt?

By Jill Hahn / Special To The Tab

 

Do you think you ought to be able to find out what toxic chemicals are being released in your community?

So did the U.S. government after the 1984 Bhopal disaster, when chemicals released from a Union Carbide plant in India killed thousands of people. That’s when the Toxics Release Inventory program was created. The TRI program requires companies and federal facilities of a certain size to provide annual reports of their releases of toxic chemicals to the Environmental Protection Agency, which then makes the information available to the public.

For example, let’s look at our own county, Middlesex County. The TRI informs us that from 1988 to 2002 (the period for which reports are available), Middlesex County scored in the top 20 percent of dirtiest counties in the U.S. for pounds released into the air of recognized carcinogens, developmental toxicants, and reproductive toxicants on the TRI list (Scorecard: the Pollution Information site, http://www.scorecard.org/env-releases). Useful information.

However, the EPA now seems to be backing away from its almost twenty-year commitment to keeping the public well-informed about toxic chemicals. It has recently proposed three changes to TRI reporting (http://www.epa.gov/tri/)):

1. Move from annual reporting to every-other-year reporting. But many facilities show huge shifts in emissions from year to year, so every-other-year reporting could be misleading.

2. Allow facilities to release 10 times as much pollution before being required to report. This provision would raise the maximum Annual Reportable Amount from 500 to 5,000 pounds.

3. Permit facilities to withhold details on low-level production of persistent, bioaccumulative, and toxic chemicals like mercury, lead, and dioxin. But PBT chemicals, which the EPA has identified as “chemicals of special concern,” can travel long distances, remain dangerous for long periods of time, and are particularly harmful to children and developing fetuses.

Why do these changes matter? Federal and state policy makers need access to adequate information in order to make decisions that protect our health, safety, and environment. Every regulatory program at the EPA relies on the TRI for data on specific toxic chemicals released to the environment. These data need to be as accurate (able to track the year-to-year variability) and comprehensive (requiring reporting on chemicals of special concern) as possible.

The EPA, in announcing its proposed changes, only cites as its rationale for the changes the burden reporting places on industry (http://www.epa.gov/tri/). It does not offer any health justification, or show any evidence that less than 5000 pounds of toxic output annually is not harmful to the environment. Is the lightening of this reporting burden, which the EPA itself says has been made significantly less costly through improvements in reporting software, a trade-off that benefits the public?

The comment period for the TRI Burden Reduction Proposed Rule extends until January 13, 2006. If you are interested in learning more, a good place to start is the web site of the Union of Concerned Scientists, (http://ucsaction.org/campaign/11_30_05_toxic_release_inventory/explanation), or the EPA’s web site, (http://www.epa.gov/tri/).

Jill Hahn, a Newton Highlands resident, is a biologist, a writer, and a mom. All three roles contribute to her passion about environmental issues. She can be reached at jkkhahn@comcast.net.

More dangers of mercury

By Gilbert Woolley/ Special To The Tab

Mercury, even in very small amounts, is a potent neurotoxin (poison) for the rapidly developing nervous systems of young children and the fetus in the womb. In a previous article we warned that mercury can be ingested by eating some seafoods.¹

Another direct route into the body is from dental amalgam used to fill our teeth. Often referred to as “silver,” 50 percent of amalgam is actually mercury. Saliva gradually erodes the amalgam so that mercury is absorbed into the bloodstream. Also, mercury vapor is emitted from amalgam and inhaled. Mercury from amalgam is suspected of causing certain neurological conditions.

For many years polymeric (non-metallic) compounds have been used widely and successfully to replace amalgam. If you are thinking of having your amalgam fillings removed, this must be done with extreme care, in order to limit the amount of mercury entering your body. Make sure that your dentist knows about this. Women who are pregnant or anticipate becoming pregnant should not have amalgam fillings removed.

Mercury in the environment

Mercury enters the environment in several ways. Dental amalgam is a major source. It is estimated that forty tons of mercury are used every year in the US in dental amalgam and much of that will eventually be removed when fillings are replaced and either flushed into sewers or disposed of in the trash.

Some uses of mercury are dangerous to people and the environment only when they break or are disposed of after the end of useful life. A common example is the mercury in glass thermometer, often disposed of in regular trash and, as it is in Newton, incinerated. Mercury vapor from the incinerator condenses and falls on gardens, fields, lakes and streams. Alcohol (in glass) thermometers and electronic thermometers are widely available and offer inexpensive replacements.

Many older fluorescent light tubes and some other types of bulbs contain mercury and should be recycled and not disposed of as solid waste.

Another use of mercury is as an electrical contact. It is the only metal that is liquid at room temperature and is also a good conductor of electricity. It is the switching element in the familiar thermostat on the wall of your house and also in “tilt switches” such as those that let a driver know that the trunk lid is open. Mercury for these switches is also enclosed in a glass tube and is no danger to the user. However, unless the switches are removed from a device or appliance when it is no longer in use it is very likely that the glass tube will be broken and the mercury released into the ground – or, worse, in vapor from a trash incinerator.

Temperature controllers in homes mostly last as long as the house is standing, but automobiles have a short life and are usually crushed and turned into scrap metal. It is safe to assume that mercury switches are not commonly removed before crushing, so that mercury vapor is released in the smokestack of the steel furnace. Today, solid state switches can replace mercury in almost all applications, and often at a lower cost.

Recycling

Mercury is very costly and is easily recycled, but in many applications, the quantity used is minuscule and the cost of recapturing it far exceeds its value.

A precautionary approach suggests that mercury should be used only if it can be positively shown that there is no substitute. If this principle were followed, there would be very little mercury in the waste stream. Requiring manufacturers to take back components containing mercury at end of a product’s useful life is probably the most effective way to get them to use the many available replacement materials for this environmental toxin and it would stimulate discovery of new replacement materials.

To learn more about this subject, try Google.

 

¹A recent Harvard School of Public Health study claims that the 2004 FDA/EPA advisory warning pregnant women and young children not to eat certain fish species and to limit their consumption of albacore tuna, may have done more harm than good, by discouraging people who are not at risk from eating all kinds of seafood. However, the advisory clearly warns against only a few fish species and specifically targets pregnant women and young children. Some of us have questioned the part of the advisory that recommends eating as much as 6 oz of albacore a week. We also feel that the advisory is not well written and takes too long to get to the point, so it is confusing, and suspect that it has not always been reported accurately in the media.

 

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.

Fish is still good food

By Lois A. Levin/ Special To The Tab

 

Many species of fish that were once abundant have become scarce. In fact, there is increasing evidence that wild fish stocks are collapsing all over the world.

Fish is an extremely healthy food, despite the serious problem of mercury contamination of many fish species. (The US government has issued warnings that some types of fish are especially risky for pregnant women and children.)

How are responsible shoppers supposed to know which types of fish are harvested sustainably, so that we can all continue to enjoy this healthy food?

In our area, we are fortunate to have markets and restaurants that offer environmentally-responsible fish options. Here is the list of “best Eco-choices”from Environmental Defense’s Oceans Alive Campaign:

Abalone (US farmed)

Anchovies

Arctic char (US & Canadian farmed)

Catfish (US farmed)

Caviar (US farmed)

Clams (butter, geoducks, hard, littlenecks, Manila)

Crab (Dungeness, snow from Canada, stone)

Crawfish (US)

Halibut (from Alaska)

Herring (Atlantic sea herring)

Mackerel (Atlantic)

Mahimahi/dolphinfish (US from the Atlantic)

Mussels (farmed blue, New Zealand green)

Oysters (farmed Eastern, European, Pacific)

Sablefish/black cod (from Alaska)

Salmon (wild from Alaska)

Sardines

Scallops (farmed bay)

Shrimp (Northern from Newfoundland, US farmed)

Spot prawns

Striped bass (farmed)

Sturgeon (farmed)

Tilapia (US)

For more information on these and hundreds of other fish, visit www.oceansalive.org/eat.cfm. Pocket Seafood Selector (c)September 2005 Environmental Defense, New York, NY

Permission to reprint this info given to GDC’s Marcia Cooper (marciac@aol.com) on Oct. 6 by Kathleen Goldstein (KGoldstein@environmentaldefense.org).