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Tag: Sharon H.

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Green Screen: D.C. Environmental Film Festival

Attendees of the 23rd Environmental Film Festival in the Nation’s Capital have traveled the world this past week, from the banks of the Anacostia to the harsh icescape of Antarctica, following pressing environmental issues and reveling in impressive cinematography. And the best part is, the adventure continues until March 29th.

The theme of this year’s festival is “Climate Connections,” but the screenings have covered a broad swathe of both local and global issues from sustainable agriculture to the pollution legacy of the fashion industry. Many of the films have highlighted environmental health issues, but several water-centric films told particularly poignant stories.  On Sunday, the festival held a “Women and Water” event in celebration of World Water Day, which featured films by women filmmakers. The first segment of the session featured stories of pollution and restoration that took place right in CHEJ’s backyard – in the Anacostia and Potomac rivers that run through Washington, D.C.

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Image from Stone Soup Films

‘The Anacostia River: Making Connections’ discussed the rampant discharge of industrial pollutants and trash into the Anacostia, which has threatened the river’s vitality and posed health risks to those who build community on its banks and eat fish from its waters. The film also documented heroic efforts to clean up the Anacostia, restoring it for generations to come. Watch the film here.

In ‘Potomac: The River Runs Through Us,’ researchers and advocates discussed the dependence of the nation’s capital on the waters of the Potomac River, where emerging contaminants like endocrine disruptors may be rearing their toxic heads. In its second half, ‘Women and Water’ expanded its scope from local to global. ‘Riverblue,’ a sobering work-in-progress film, shone light on the fashion industry’s pollution of rivers in India and Bangladesh, where workers must cope with both unsafe working conditions and an environment ravaged by the refuse of tanneries and garment factories.

The festival has curated over 160 films, many of which are showing for free at venues across the D.C. area for the rest of the week. The remaining schedule includes several films that highlight pollution and environmental health issues. Tomorrow (Tuesday), ‘Are Vah!’ tells the story of  of a French power company aspiring to build the largest nuclear plant in the world in a vital fishing and mango production zone of India. On Wednesday, ‘E-Waste Tragedy’ covers the environmental and health implications of toxic electronic waste, while ‘Landfill Harmonic’ discusses poverty and waste pollution in Paraguay. On Thursday, Our Canyon Lands will address pollution resulting from mining development in Utah.

For a full schedule of events, visit the film festival website.

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Staying Safe (Probably): Risk, Hazard and Chemical Regulation

‘Risk’ and ‘hazard.’

These two words are often used interchangeably, but they have distinct meanings in the context of chemical safety assessment. When we say a particular chemical is ‘hazardous,’ we are noting its mere potential to cause negative health or environmental effects. On the other hand, ‘risk’ describes the probability that these negative effects will actually occur under specific circumstances. In order to generate a measurable risk, some exposure to the hazard in question must occur.


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Both a hazard and an exposure are necessary for a risk to exist.


If you have followed my last several posts, you’ve probably caught on to the idea that attempting to declare a chemical ‘safe’ or ‘unsafe’ is an exercise in futility. To comprehensively determine risk, we must know not only the detailed structure and function of a chemical, but also understand the intricacies of its interactions with the environment and the human body. Current chemical regulation in the United States operates within a risk-based framework. We establish standards and criteria for acceptable levels of hazardous compounds in products, in the environment and in our bodies; we enact bans and restrictions on chemicals in order to limit our exposures. These regulations are the product of risk assessments, which report not only the hazardous properties of chemicals but also the likelihood of human exposure.

My recent post on BPA illustrates the complexity of risk assessment. Though BPA has demonstrated hazardous potential, the levels to which humans are exposed to the compound, and therefore the actual risks of its use, are uncertain. Exposure may seem like a simple factor to evaluate, but our understanding of exposure is continually evolving, particularly with consideration for the special vulnerability of developing babies and children.  The ban on BPA in baby bottles reflects this emerging awareness of long-term effects of chemical exposures. However, the replacement of BPA with BPS illustrates the shortcomings of an approach that controls risk by limiting exposure to specific high-profile hazardous compounds.

The replacement of BPA, a known hazard, with BPS – an untested and unregulated compound with a nearly identical structure – may be considered an example of what scientists and regulators refer to as “regrettable substitution.” Regrettable substitution occurs when we eliminate one hazardous chemical from consumer products, only to replace it with a similar or even more hazardous alternative. Our risk-based chemical regulation enables us to remove demonstrably dangerous chemicals from consumer products, but also leaves profound loopholes for new chemicals, untested and unregulated, to enter the market in their stead, as long as risk assessments have not proven them dangerous. In a 2010 post on his Environmental Defense Fund blog, Dr. Richard Denison refers to this process as playing “whack-a-mole” with chemicals. No sooner have we knocked one hazardous chemical back into its hole, than a replacement rears its likely-hazardous head…until we generate evidence of its actual risk and seek to replace it with another unknown quantity.

Is this game of “whack-a-chemical” inevitable, or do more precautionary approaches exist? In Europe, regulators are striving for a balance between risk assessment and the more protective approach of hazard classification. While risk assessment relies on scientific studies to determine the risks of chemicals under different exposure scenarios, hazard classification groups chemicals based on their inherent hazard potential. It is this potential to cause harm that guides regulation, not demonstrated adverse effects.  A hazard classification regulatory scheme might have prevented BPS from entering the market, since its structural similarities to BPA make it a likely health hazard.

Hazard classification is essentially a more precautionary approach to chemical regulations. And when we operate in a framework of precaution rather than risk, the regulatory question itself changes. “A precautionary approach asks how much harm can be avoided rather than asking how much is acceptable,” write Dr. Ted Schettler and coauthors in a 2002 essay on the role of the Precautionary Principle in regulation and policymaking.

How can we better incorporate the Precautionary Principle into the chemical regulation process in the US? This question has been at the epicenter of the debate on reforming the Toxic Substances Control Act (TSCA), which I will cover next time on Backyard Talk.

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When ‘Safer’ isn’t Safe: BPA and BPS

Two weeks ago on Backyard Talk, I wrote about BPA, a major plastic component that has been linked to number of health impacts, particularly endocrine disruption. The jury is still out on BPA; the European Food Safety Authority has declared that BPA does not pose a health risk at normal exposure levels, while recent studies have emerged showing that BPA affects stem cells and may impact reproductive health later in life. In the face of all this scientific uncertainty, it’s lucky that we have access to BPA-free products. Or is it?

I have a few new water bottles from Christmas sitting in my cabinet, stamped with a leaf design and a guarantee that their plastic is BPA-free. Our eco- and health-conscious readers probably have similar items in their homes. BPA-free products have proliferated since the U.S. Food and Drug Administration banned the sale of baby bottles containing BPA in 2012. Unfortunately, studies over the past few years have shown that even BPA-free products release estrogenic compounds, some of which can even be more potent than those released by BPA-containing products.

One common replacement for BPA, or bisphenol A, is BPS, or bisphenol S, which has been shown to disrupt cell functioning at very tiny concentrations. It’s no surprise that the compounds might have similar effects, because they are close in structure as well as in name. A brief organic chemistry interlude:




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Image from the blog ‘Science Minus Details.




To the right is an image of BPA side-by-side with a particular estrogen, estradiol.

This image highlights the structural similarities between BPA and estradiol, which enable BPA to mimic the hormone and cause disruptions to the endocrine system.

Below is the structure of BPS:




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BPS molecule









Though the two molecules are not identical, BPS contains the essential ring structure, called a ‘phenol’ group, which is highlighted in both BPA and estradiol. Structural similarity between BPA and BPS is what enables them to play a similar role in conferring hardness to plastics. It also enables them to interact with cells in similar ways. According to Scientific American, BPS is thought to be more resistant than BPA to escaping from plastics when they are heated. However, studies have demonstrated that it is prevalent in human urine, and that even small amounts can cause changes to cells.

We are caught between a rock and a hard place when it comes to developing safe, or safer, alternatives to chemicals that have been linked to adverse health or environmental impacts. When replacing chemicals in products, we often first look to chemicals that share properties with the ones we are seeking to eliminate. As in the case of BPA, however, these similarities that preserve the function of a product can also preserve its toxic effects. When health risks are demonstrated for a given compound, is it prudent to bring in a replacement, even if this new player has not been vetted by scientific studies? Should we settle for lesser risk and continue working towards an even safer ideal? What does ‘safe’ mean, anyway? Tune in next time!

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Citizen Science: Tracking The Air We Breathe

Smartphone apps and portable gadgets have made it possible for individuals to get up-to-the-minute information on their own vital signs and activity levels. What if we could just as easily monitor environmental impacts on our health, tracking real-time data on pollution exposures? Development of portable sensing devices is making this individualized approach to air quality monitoring a possibility for people worldwide, and is fueling citizen science initiatives to more comprehensively track pollution on a global scale.

The Air Quality Egg, the Smart Citizen Kit, and the DustDuino are just a few examples of this new type of gadget, which can measure levels of particulate matter and other pollutants like nitrogen dioxide and carbon monoxide. Nature has dubbed these devices “Sensors for the People.”  Data from these devices may be able to fill in the gaps left by official monitoring networks, whose sensors are, according to Nature, “sophisticated but sparsely distributed.”

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Graphic from Nature.com

While data from official monitoring networks is important from a regulatory standpoint, it holds little relevance for individuals’ health. In fact, fixed sensors are generally inadequate for predicting environmental exposures, because people pass through so many different microenvironments throughout their days. A study at Columbia University fitted students with portable sensors and found that the majority of their exposure to airborne metals came from riding on the subway, rather than from breathing the air in their homes. Data from portable sensors can provide more pertinent information on individual exposures in the home, in transit, and in the workplace than the values obtained at the nearest monitoring station.

According to Nature, these approaches are “part of an effort to democratize air-quality monitoring so that it no longer remains solely in the domain of governments and academic researchers.” This may be a powerful shift in monitoring, particularly for areas facing both air pollution and a lack of readily-available data . Wired recently reported on David Lu, a UC Berkeley student from Shanghai who has collaborated with other students to develop a sensor and launch a startup for monitoring air quality in China, where reports have surfaced that some governments are blocking pollution data from being publicly available.

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Clarity Sensor (Image from Wired)

These portable sensors allow people to collect air quality data on their own personal environments, but data can also be aggregated to create more accurate pollution maps. That is the next phase of Lu and his fellow students’ project; essentially, they will be crowdsourcing data from China and other highly polluted areas to make air pollution mapping easier.

While research is taking off at some institutions and public enthusiasm is growing, the atmospheric science community has had a more tempered response to these devices. “Monitoring air-pollution levels is far more involved than the manufacturers and suppliers of cheap sensors suggest,” Ben Barratt, a British Air Quality Scientist said to Nature, citing differences in temperature and humidity as some of the complicating factors that make it difficult to cross-compare results between devices. Part of the reason why there are few official monitoring sites is because they take a lot of maintenance and care to ensure the data is accurate.

Though the data generated from these sensors does not currently hold up under sufficient scientific scrutiny for use in a regulatory context, citizen sensing projects are still in their early stages, and future technical developments may give crowdsourced pollution readings more clout. In the meantime, citizen scientists are developing the frameworks necessary for widespread monitoring of one of the biggest environmental health threats of our time.

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