Ear To The Ground

Noise can alter the composition of an ecosystem

Prior posts have reviewed the wide variety of "selection factors" than can drive evolution in a species. Now it appears that noise can alter the makeup of an entire ecosystem.

Researchers have found that noise can drive away some species and sometimes encourage others, which in turn can influence the presence or absence of plants. Researching a northwest New Mexico wood which had noisy gas wells, researchers found a reshuffling of birds and small mammals, which in turn changed the odds of success for crucial steps in plant reproduction. They noted, for example, that pollination by hummingbirds, important for certain wildflowers, increased. In contrast, birds that were likely to spread pine seeds without eating them all gave way to mice that ate more of their seed cache. Thus, they noted that whole ecosystems could be restructured by noise.

Noise also was found to matter to nesting birds. Although approximately the same absolute number of birds nested around both roaring and quieter wells (the roar being the result of which wells had compressors), the quieter areas had a greater variety of bird species. Species variety in term influences the impact on food sources, which in turn impacts what plants and trees come to be in an area.

The study can be found at http://rspb.royalsocietypublishing.org/content/early/2012/03/15/rspb.2012.0230.

Amount of plastic trash in the ocean may be vastly underestimated

Prior posts have noted the various plastic debris wastes that are located in the oceans. Prior posts have also suggested that there may be plastic waste in the water column, though its quantification was uncertain. A recent assessment suggests that the amount previously estimated using surface sampling techniques may be low by a factor of several hundred percent or much more, depending on wind conditions at the time of the surface sampling.

Researchers used a specialized tow net to capture waste at different depths. The results were then combined into a mathematical model. The model allowed the researchers to calculate the amount of debris at different depths on average as well as look at how that amount changed with different conditions, such as on a windy day. They found 2.5 times more debris in the layers of water below the "surface water" (defined as the top 9.8 inches or 25 centimeters) as was found in that surface section. The debris was distributed down to a depth of about 65 to 82 feet (20 to 25 meters).

The findings mean the estimates of plastic litter in the ocean, as measured solely by skimming the surface water only, may in some cases vastly underestimate the amount of plastic debris which is present. Because churning of the water column affects the distribution of plastic debris, the contrast between surface measurements and measurements at depth can vary considerably. For example, the researchers believe that overall the amount of trash in the water column exceeds surface measurements alone with up to 250%. In high wind conditions, with lots of churning, the differential could be as much as 27 times.

The report can be found at http://www.agu.org/pubs/crossref/2012/2012GL051116.shtml.

Ninth Circuit holds that dry cleaning equipment manufacturers must engage in active, not merely passive, activities to be liable under RCRA

In litigation involving soil and/or groundwater contamination from releases related to dry cleaning equipment and PCE, it has been common for injured property owners to sue the dry cleaning equipment manufacturers, among others. One of the primary legal tools used in such litigation is the citizen-suit provision of RCRA, 42 U.S.C. Section 6972.

In Hinds Investments, L.P., et al v. Angioli, et al, 654 F.3d 846 (9th Cir. 2011), the Ninth Circuit addressed this issue. In the case, the owners' shopping centers had housed dry cleaning stores, and their groundwater was contaminated with PCE used in dry cleaning. The owners claimed that the manufacturers were liable under the citizen-suit provision of RCRA because they employed faulty machine design and distributed manuals that instructed users to dispose of contaminated waste in drains or open sewers. The Court of Appeals held that the owners did not state a claim for contributor liability under 42 U.S.C. Section 6972(a)(1)(B). The Cour held that Section 6972 required active involvement in or some degree of control over the waste disposal process. Designing machinery, even if the machinery produced waste as a byproduct, did not cause a manufacturer to be a contributor to waste disposal; a more active role with a more direct connection to the waste was required, such as handling, storage, treatment, transportation, or disposal of the waste.

Having been involved in numerous dry cleaning sites, and having seen operators follow exactly what was prescribed in the equipment manufacturers' manuals, resulting in contamination of the site, the Court's reasoning seems rather flawed. If poorly designed equipment is put into the stream of commerce, and its operating instructions lead to site contamination, then the classification of such activities as "passive" and not "contributing" to site contamination under RCRA seems of questionable logic, especially given the broad interpretation given by many courts to the "contribute" aspect of RCRA.

Transgenerational epigenetic effects demonstrated in animals to occur from a variety of pollutants

Prior posts have discussed the interplay between DNA, the various forms of RNA, and proteins regarding gene "expression"; prior posts have also noted the process of methylation of genes [see http://en.wikipedia.org/wiki/Methylation], which often reflects the interface between life's experiences and genetic expression (it is also the reason why the genes of "identical twins" become, in terms of expression, less and less similar as the twins grow older). Another component to gene expression is epigenesis (how heritable changes in genome function occur without a change in DNA sequence). [See http://epigenome.eu/en/1,1,0.] An epigenetic change in a gene adds chemical tags that influence the manner in which a gene is regulated, often locking a gene in the "on" or "off" position.

In one sense, epigenetic changes to gene expression have not been a major concern with regard to pollutants because the accepted wisdom was that, early in development, a fetus erases any epigenetic changes acquired during its parents' lifetimes, resetting those genes back to their "healthy," default programming. Now, a study indicates that such is not the case.

In a study with rats, researchers looked at a variety of pollutants. Because the study was funded by the military, the study focused on pollutants to which soldiers were likely to be exposed (dioxins, DEET, permethrin, bisphenol A (BPA), phthalates, and jet fuel). As is SOP with many animal experiments, the rat exposures used were relatively high; however, these exposures were not high enough to cause fetal deaths or signs of toxicity in either exposed rat moms or their pups. Yet all promoted epigenetic transgenerational changes; in other words, the tags were not deleted, but existed across generations.

This was a major surprise to the researchers. Because all the pollutants resulted in epigenetic changes that went from one generation to the next and the next, it suggested to the researchers that epigenetic changes that get passed down through the generations are not some unique quirk of any one chemical; the researchers now suspect that most pollutants have the potential to do this (though it must be remembered that the experiment dealt solely with the pollutants listed above).

Each group of pollutants caused a different constellation of epigenetic changes that were linked with various reproductive problems in subsequent generations, although there was some overlap. The researchers note that this suggests that there may be a means in the future to use epigenetic biomarkers to assess what you or your ancestors were exposed to earlier in life, and perhaps apply that knowledge to predict disease and limit risk.

This also means that there is a whole new field of adverse impacts from pollutants that are not encompassed by today's risk assessment methods. It is also important to remember that there is no such thing as all-bad pollutants and all-good "natural" substances. As noted in prior posts, many so-called natural substances can be quite harmful. Until more studies are done, we will not know if the researchers have uncovered a general rule applicable to the huge variety of chemicals to which humans are exposed, including through food and the environment, or if the conclusion is limited to particular classes of substances.

In toxic torts, as noted in prior posts, we are use to thinking of cause and effect, and not transgenerational manifestations of harm. Like the field of risk assessment, that accepted mode of analysis may be in need of reformation.

The report can be found at http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0031901.

Steps are being taken by various entities to reduce consumer exposure to BPA

Numerous prior posts noted that nearly everyone in the U.S. has low levels of BPA in their body, and have reviewed the animal and laboratory studies which indicate that BPA exposure may have adverse health effects on humans. It has also been noted that recent evidence indicates that the major vector for BPA exposure is cash-register receipts (thermal paper).

Responding to concern about BPA, to date 11 states have banned BPA-containing baby products, and many other states are considering a ban on BPA in food containers, especially those used by infants. In October 2011 California passed legislation banning (effective July 1, 2013) the manufacture, sale, or distribution of any bottle or cup that contains bisphenol A, at a detectable level above 0.1 parts per billion (ppb), if the bottle or cup is designed or intended to be filled with any liquid, food, or beverage intended primarily for consumption by children 3 years of age or younger. [See http://www.leginfo.ca.gov/pub/11-12/bill/asm/ab_1301-1350/ab_1319_bill_20111004_chaptered.html.] In June 2009, Connecticut became the first state to ban the chemical in reusable food and beverage containers and in containers for infant formula and baby food.

Now, Campbell's has announced that it will begin phasing out the use of BPA in its soup can liners. [See http://www.forbes.com/sites/amywestervelt/2012/03/05/under-pressure-from-parents-advocacy-groups-campbells-goes-bpa-free/.] BPA has been found in a variety of Campbell's products. Also, as noted in a prior post, by the end of March 2012 FDA will announce its conclusions on BPA.

What is ironic is that steps have not been announced to remove BPA from thermal paper used in cash-register receipts, a significant source of exposure to the general populace.

Methylene chloride (dichloromethane) linked to 13 deaths since 2000 from use as paint stripper

Methylene chloride is used in a wide variety of applications: Extraction solvent for decaffeination of coffee, extraction solvent for spices and beer hops, dip-type metal cleaner, vapor degreasing of metals, carrier solvent in the textile industry, aerosol, refrigerant, low temperature heat-transfer agent, and in chemical processing (e.g., manufacture of polycarbonate plastics, insecticides and herbicides, pharmaceuticals). It is also used to fumigate grain and for oil dewaxing. See http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~OG1F60:1:use.  However, it is also used in residential settings because it is a fast, efficient paint stripper; it is available in at least 42 products sold at home improvement stores and on the Internet.  Unfortunately, if proper precautions are not taken, its use can be fatal.

Methylene chloride is rapidly absorbed through the lungs into the circulatory system.  It is also absorbed from the stomach and gut; dermal exposure results in absorption, but at a slower rate than via other routes of exposure.  Methylene chloride is quite rapidly excreted, mostly via the lungs.  It can cross the blood-brain barrier and be transferred across the placenta.  At high concentrations, most of the absorbed methylene chloride is exhaled unchanged.  The acute effects are primarily associated with the central nervous system, lungs, kidneys, and the liver.  The main toxic effects of methylene chloride are reversible CNS "depression" and carboxyhemoglobin formation (replaces oxygen in red blood cells with carbon dioxide).  

Researchers at the Univ. of Michigan recently identified two deaths from workers refinishing bathtubs; methylene chloride paint strippers were apparently being used to remove epoxy paint.  In both cases the workers were using paint stripping materials labeled for use in paint removal from aircraft.  However, in the confined space of a bathroom, they were overcome by the fumes and died.  The researchers identified 13 deaths nationwide related to methylene chloride in paint stripping materials.  A confounding factor is assessing the extent of such deaths is that the mortality can be mistaken for a heart related fatality.

Most regulation in the U.S. focuses on methylene chloride as a carcinogen; it has been listed as such under California's Prop. 65 since 1988.  Last year the EU banned methylene chloride from furniture stripping agents.  The Michigan report suggests that more aggressive warnings should be given on labels, or the U.S. should follow the EU and ban methylene chloride from stripping agents.

The report on the fatalities can be found at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6107a2.htm.  

Do homeowners policies protect against liability from fracking operations? Probably not

My partner Dean Pappas and I recently had an article published by Best's Review (February 2012) that looks at the potential risks that arise from hydrofracking operations, and the extent to which a typical homeowner's insurance policy covers the damages and harms that may arise. For those of you interested in this subject, the article can be found at http://www.rmkb.com/tasks/sites/rmkb/assets/image/2-2012%20-%20Best's%20Review.pdf.

Messrs. Pappas & Clarke wish to thank Best's Review for publishing the article.

EPA releases final health assessment for Tetrachloroethylene (aka Perc)

EPA has posted its final health assessment for tetrachloroethylene (aka perc) to its Integrated Risk Information System (IRIS).

Perc is widely used in the dry cleaning industry, although states such as California are requiring that it be phased out.  See http://epa.gov/oppt/existingchemicals/pubs/perchloroethylene_fact_sheet.html and http://www.arb.ca.gov/toxics/dryclean/dryclean.htm.  Because of design and operational failures in dry cleaning machines and businesses in the past, perc is unfortunately a common pollutant found in groundwater.  It was also a commonly used degreaser in the 1950's and 1960's, and such operations combined with sloppy disposal practices also added to groundwater contamination.

EPA states that it does not believe that wearing clothes dry cleaned with perc will result in exposures which pose a risk of concern.  EPA has already taken several significant actions to reduce exposure to perc, including but not limited to setting clean air standards for dry cleaners that use perc (which includes a phase-out of the use of perc by dry cleaners in residential buildings by December 21, 2020). EPA also set limits for the amount of perc allowed in drinking water and levels for cleaning up perc at Superfund sites throughout the country, which will be updated in light of the IRIS assessments.  For the California MCL, see www.swrcb.ca.gov/water_issues/programs/gama/docs/coc_pce.pdf.  

The toxicity values reported in the perc IRIS assessment will be considered in:
• Establishing cleanup levels at the hundreds of Superfund sites where perc is a contaminant.
• Revising EPA’s Maximum Contaminant Level for perc as part of the carcinogenic volatile organic compounds group in drinking water, as described in the agency’s drinking water strategy.
• Evaluating whether to propose additional limits on the emissions of perc into the atmosphere, since perc is considered a hazardous air pollutant under the Clean Air Act.

The IRIS data can be found at http://www.epa.gov/iris/subst/0106.htm. 

Other details on perc can be found at http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~5diRx9:1:FULL.

EPA may be preparing tough report on dioxins in food

Dioxins collectively refers to hundreds of chemical compounds that share certain structures and biological characteristics. See http://en.wikipedia.org/wiki/Dioxin.

Dioxins fall into three closely related groups: the chlorinated dibenzo-p-dioxins (CDD's) chlorinated dibenzofurans (CDF's), and certain polychlorinated biphenyls (PCBs).  The most studied is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).  CDD's and CDF's have been listed as carcinogenic under California's Prop. 65 since 1992 and TCDD has been listed as a carcinogen since 1988 and as a developmental toxicant since 1991.  An overview of the human health effects from TCDD can be found at http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~9r0KTD:1:human.  TCDD is considered to be a Group 1 carcinogen.  See http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~neKgYd:1:care.  PCBs are no longer produced in the U.S.

The primary exposure pathway (at least insofar as TCDD is concerned) is food.  See http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~9r0KTD:1:rtex and http://www.epa.gov/pbt/pubs/dioxins.htm.  It would appear that they enter the food chain, and then as is common with all contaminants, are concentrated as they "move up" the chain.  See, for example, http://www.ajcn.org/content/61/3/682S and http://www.guardian.co.uk/science/2004/jan/09/sciencenews.society.  Some view high-fat animal food as a primary source.  [A 1996 study by EPA of dioxins in beef fat can be found at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=54869.]

EPA has undertaken a study of dioxins in the food supply, and is expected to recommend an intake limit of 0.7 picograms of dioxin per kilogram body weight per day.  [A picogram is one trillionth of a gram.] WHO and the EU have higher limits, from one to four picograms per kilogram per day.  According to news reports, the chemical and food industries are lobbying against release of the report, asserting that the recommended intake limit is too low. 

As they say, stay tuned.

Formaldehyde is found in a broad range of clothing and household products

Formaldehyde is a Group 1 human carcinogen. See http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~rv3mMw:1:care.  In the past, exposure to the populace was often linked to its presence in glues and binders used in furniture and paneling, although it is also found in shampoo, conditioners, and water-based paints.  See http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~rv3mMw:1:use.

An August 2010 study by GAO has shown that it is also present in a range of clothing and household products which are treated with a resin in order to keep them "wrinkle-free"; the resin releases formaldehyde.  Formaldehyde is commonly found in a broad range of consumer products, including sheets, pillow cases, drapes, upholstery, shampoos, lotions, and eye shadow.  The United States does not regulate formaldehyde levels in clothing, most of which is now made overseas. Nor does any government agency require manufacturers to disclose the use of the chemical on labels.  However, in California, it does come within Proposition 65's warning requirements if certain exposure criteria are exceeded.

Most of the 180 items tested, largely clothes and bed linens, had low or undetectable levels of formaldehyde that met the voluntary industry guidelines based on standards in Japan, which are among the most stringent.  However, about 5.5% of the items exceeded the most stringent standards of 75 ppm, for products that touch the skin.  Levels must be undetectable, or less than 20 ppm for children under 3 years, and can be as high as 300 ppm for products like outerwear that do not come into direct contact with the skin.  Some of the highest levels were found in men's no-iron shirts.

EPA is in the process of developing emission standards for pressed wood products.  See http://yosemite.epa.gov/opa/admpress.nsf/e77fdd4f5afd88a3852576b3005a604f/1428c8203841ad17852577c100560350!OpenDocument.

The August 2010 GAO report can be found at http://www.gao.gov/products/GAO-10-875.