Scientific, medical experts come together to advocate for action, policy change

Significant scientific evidence links exposure to toxic environmental chemicals to neurodevelopmental disorders such as autism, attention deficits, hyperactivity and other learning and intellectual disabilities.

Project TENDR: Targeting Environmental Neurodevelopmental Risks, co-founded by Irva Hertz-Picciotto, the director of the UC Davis Environmental Health Sciences Core Center, issued a nationwide call to action to reduce exposures to chemicals and pollutants that contribute to neurodevelopmental disorders in children.

“By working with experts in research we can evaluate the science and work with health professional experts (like pediatricians, nurses, OBGYNs), advocates and community groups to make policy recommendations,” said Jacqueline Barkoski, a Ph.D. candidate in epidemiology at UC Davis, in an email interview.

The overall goal of the project is to increase general awareness about harmful chemicals and the lack of protective regulation. Many of the toxic chemicals can be found in our food, household cleaning and personal care products as well as in the air and water.

“[The way in which chemicals are regulated is] that the public has to prove harm rather than those who put the chemicals out there having to prove safety,” Hertz-Picciotto said in an email interview.

Many chemicals and pollutants contribute to children’s learning, intellectual and behavioral impairment. They include organophosphates (OP) found in pesticides, polybrominated diphenyl ethers (PBDE) found in flame retardants, combustion-related air pollutants like nitrogen dioxide, lead and mercury.

Specifically, PBDEs pose a threat to children’s brain capacities that are critical for thinking and success in school.

Although these chemicals are banned in some states due to health concerns, North America still has some of the highest detected levels in the world.

In the 1970s, these chemicals were found in manufactured furniture, TVs and other electronics. The risk of exposure comes from the fact that they are not chemically bound to the plastics and foam so they come out of these products into the air and dust of the household environment.

Replacing old couches or mattresses with products that are PBDE-free is one step toward reducing exposure of the flame retardants.

“Another way to prevent exposures is through cleaning up house dust because chemicals such as PBDEs, pesticides and lead can be found in house dust,” Barkoski said. “This will also help reduce exposures to young children who crawl on the floor and have a lot of hand to mouth actions.”

This unique project brings together stakeholders to address the issue of harmful environmental toxins affecting child neurodevelopment.

The Consensus Statement of the project, published in the Environmental Health Perspectives, describes the scientific approach to validating recommendations related to harmful chemicals and calls for policy change to reduce the high prevalence of neurological disorders developing in children.

Project TENDR has numerous organizations endorsing the Consensus Statement, including the American College of Obstetricians and Gynecologists, American Nurses Association, Child Neurology Society, National Hispanic Medical Association and Physicians for Social Responsibility.

“We are also in contact with several other large organizations who are considering endorsing either our original Consensus Statement or joining onto some of our upcoming recommendations related to specific chemicals,” Hertz-Picciotto said.

Recent progress includes the American Medical Association (AMA) passing a resolution to adopt Project TENDR recommendations on lead. No level of lead exposure is safe for a developing fetus or child and is known to cause harmful brain development.

Currently more than half a million children aged 1 to 5 years have a concentration greater than 5 μg/dL.

By utilizing the most current scientific literature on the topic, scientists hope to ensure that, by 2021, no child has a blood lead level greater than 5 μg/dL and, by 2030, no child has a blood lead level greater than 1 μg /dL.

Project TENDR members advocate for better policy regulations that governments, corporations and health care institutions should adopt to lower children’s risk of developing neurological disorders.

“This project is unique because it reflects the consensus of public health professionals. It allows experts to review science carefully and also go beyond the science to policy in order to reduce exposure and protect health,” said Asa Bradman, an associate professor of environmental health sciences at UC Berkeley.

Methods to reduce exposure to harmful chemicals can be utilized in the home and work environment. Choosing fruits and vegetables that have lower level of pesticides are safer choices of produce.

In addition, choosing personal care products with absence of phthalates and lead acetates can reduce exposure. Phthalates are often found in many fragrances and lead acetates are common in many hair dye kits.

Students interested in Project TENDR and children’s environmental health can obtain further information from the Environmental Health Sciences Center at UC Davis.

“We recently started a twitter account (@ProjectTENDR) and we post updates and materials we have developed and possibly in the future there will be more direct opportunities for UCD students to get involved with Project TENDR,” Barkoski said via email.

More information about how individuals and families can reduce exposure to harmful chemicals that impact brain development can be found on the Project TENDR website.

“We still have a long way to go, but I do have the sense that the tide is turning, with editorials appearing in medical journals and voicing similar ideas as those of Project TENDR,” Hertz-Picciotto said.

Written by: Shivani Kamal — science@theaggie.org

Home remodeling project in San Francisco leads to study of a mummified child

In a strange twist of events, a seemingly normal home remodeling project turned into an archaeological excavation led by archaeologist and UC Davis anthropology professor Jelmer Eerkens when the mummified daughter of an elite historical San Francisco family was uncovered. The California Aggie dug deeper to learn more about the findings.

The mummy, later identified as Edith Howard Cook, from the affluent Cook family, was exhumed almost 150 years post-mortem and offered UC Davis researchers and their teams a source of archaeological analysis.

Angela Evoy, an archaeometry lab technician, was especially excited about the news that a mummy had been found.

“I was very excited because it’s not something that you come across very often,” Evoy said. “And you know, you hear about mummies, you think of Egypt. So [to] find out that there was a mummy in San Francisco, it’s pretty amazing, it’s pretty phenomenal that it was preserved.”

The research team submitted the mummy’s hair samples for various lab analyses, including carbon, sulfur, nitrogen and hydrogen testing.

“Hair is nice because it grows over time,” Eerkens said. “We have about one year’s worth of hair growth […] Based on dental corruption patterns, we estimated [the girl] was about 2.5 years old — we had information about the girl that was preserved in her hair from about 1.5 to about 2.5 years before she died. Given new analytical techniques, we can use really small pieces of hair […] we cut it into small sections and we do analyses on each of those different sections. It gives us sort of a picture of what the girl was eating and where she was during the last year of her life.“

During analysis, the research team found that the nitrogen isotopes that would normally come from one’s diet started being sourced from her own body, indicating starvation. This led to the belief that the girl most likely died from malnourishment, possibly brought on by an infectious disease. However, the sulfur isotopes, normally used to indicate the presence of medicine in the body, showed no signs of any medication given to the child before she died.

The process of submitting the samples for analysis was the most tedious step in the process, as the team had to submit around 630 samples for analysis.

“There are always roadblocks when it comes to dealing with samples that are that tiny,” said Bryna Hull, an archaeology Ph.D. student and former archaeometry lab technician. “So even with the [hair], we occasionally had issues with static. Not only do we have to worry about getting it out of the vial, but sometimes when you go to remove it, it will start climbing around in the vial due to static electricity.”  

With the process being so frustrating, it was no wonder that there was a large number of team members working on it.

“People are involved in it together,” Evoy said. “We got to do some really cool stuff here, but there’s a lot of other people who put in a lot of work to make it happen. It’s a huge project. The people in San Francisco who originally initiated this project and the people who are doing the DNA analysis […] and also the people at the stable isotope facility get left out of a lot because they’re sort of more in the background, but they run all of our samples for us through their inductively coupled plasma mass spectrometer (ICP-MS), which gives us their data. Without them, we wouldn’t have anything.”

The most unexpected result from the research was actually being able to find the child’s identity. Evoy said that it made her take a step back and think about the person behind the skeleton.

“It’s really exciting because sometimes when you’re working with archaeological collections, you can tend to forget that it’s a human being,” Evoy said. “You’re working with a person, somebody’s loved one, somebody really cared about this. You’re so hyper-focused on just getting your sample to cooperate or get some data [that when] they give you a name, and then you have a picture, and then you see family members, you realize that this is a person and that people actually care […] It sort of brings it all home and in this way, doing a sort of historical project, you get to find out a little bit more than you probably would within an archaeological collection that’s really old where there are no living descendants.”

Written by: Kriti Varghese — science@theaggie.org

New planetary object rocks canonical Earth-moon theory

The giant-impact hypothesis is the most popular in explaining the moon’s origins and  matches up with the prominent theories of the solar system’s formation. But there are still many mysteries that have yet to be solved — and the research team of a Harvard graduate student and a UC Davis professor may have figured out part of the mystery.

Simon Lock, a graduate student at Harvard University, has suggested a piece of the puzzle in his article about the discovery of a new planetary object: the synestia.

The term “synestia” is derived from the prefix “syn-”, meaning “together”, and “Hestia”, the Greek goddess of the hearth and architecture. After the initial press release, the internet dubbed this object a “hot vaporized space donut”.

However, Sarah T. Stewart, an earth and planetary sciences professor at UC Davis and the co-author of Lock’s paper, doesn’t think that the description of “space donut” is entirely accurate. Stewart was a professor at Harvard for 11 years and continued to work with Lock even after her move to Davis in 2014.

A synestia is a biconcave disk, comparable to the shape of a red blood cell, and is mainly vaporized rock. When two planet-sized rotating objects collide with high enough temperature and angular momentum to pass the corotational limit, a synestia is formed.

The corotational limit refers to the point when the disk’s energy and mass can still be taken back into the planet and rotate as a single body. However, beyond this limit, the planet physically cannot be a normal spheroidal planet.

“Collisions between planets are incredibly energetic,” Lock said. “Two planet-sized bodies are coming together and colliding at tens of kilometers per second. So, many times the speed of sound. That dumps a lot of energy into both impacting bodies. Impacts in near-Earth mass bodies tend to vaporize a few to 10 percent of the body and melt the rest.”

A rotating object is explained easiest with the analogy of an ice skater moving their arms in or out to change the rate of spin, while conserving angular momentum.

Another example is an amusement park swing ride. As the rider is lifted into the air and accelerates, the rider spins at an angle, and they are pushed out at a larger radius than when the ride is stopped. If there was no chain to limit the angle, the rider would “expand” farther.

This is how a synestia works: its mass expands to its outer edges by moving slowly outward, creating the disk-like shape.

“These bodies were rotating faster than the corotational limit, so, even if you tried, you could not squish all of their mass and angular momentum into one body,” Lock said. “You have to have some part of the body in what’s called the disk-like region.”

After the object’s mass spreads out into this biconcave shape, it cannot be compacted into a “normal” planet’s shape until it slows or cools down.

“Eventually, what happens is you lose enough energy from the synestia that you fall below the corotational limit, and the whole thing can collapse down to a single body,” Lock said. “That process for the Earth itself takes around 100 years or so. It cools, in geological terms, reasonably fast, down to a more corotating object. Other objects may last longer than that.”

The formation of the Earth and the moon is highly debated because of its irregularity. According to Stewart, the moon is expected to be chemically different than the Earth based on physics models, but it’s not. Their isotopes, or “chemical fingerprints,” are basically identical, which is not clearly explained by any hypothesis thus far.

“[Lock and Stewart’s work] allows a lot more mixing between the material which will eventually make up the moon and the earth, and could explain why they’re so similar,” said Jay Melosh, an earth, atmospheric, and planetary sciences professor at Purdue University. “Ideally, and this is surely what Lock and Stewart hope, this will be regarded as the solution to the formation of the moon.”

Lock and Stewart’s work is built upon years of investigation and research from other sources as well as their own observations. Both stated the synestia resulted from a completely different perspective of looking at planet formation, one which has not been thought about before.

“These synestias are objects that are always moving,” Stewart said. “That’s different from the way we think about planetary objects. We don’t think about their mass changing, or in this case, losing this mass to what would then become moons. That was our eureka moment. It was almost three years ago.”

That “eureka moment” led Stewart and Lock to play around with calculations, working to find out what the structure was and why no one had seen it before. According to Lock, Stewart was looking at the data from her models and thought it didn’t look right alongside the canonical model. In hindsight, Lock said that the canonical model and preconceptions of what a post-impact planet is supposed to look like limited them, as well as other researchers.

“It was that moment, from changing our world view and having to reform our opinions and having to rethink all of the things we thought we knew, which was a really exciting thing,” Lock said. “Stewart likes to call it the eureka moment, and I like to agree.”

The current moon formation model dates back to the ‘70s and continues to be a highly-debated topic as technological advances are made.

“10 years ago, we thought we had [the moon’s formation] nailed,” Melosh said. “And then the geochemists got better at measuring isotopes and it turned out that the isotopic composition of elements on the moon is, essentially, identical to the earth, and that did not agree with most of the scenarios of impact that we could think of.”

Both Lock and Stewart have expressed their excitement about the discovery of a new object and the implications it has for hypotheses on the moon formation.

“I expect it will take some number of years to shake it all out and define the new normal,” Stewart said. “We’re hoping we’ve found the right path to the new textbook answer because we think the current textbook answer is not quite right. How long it takes until we call it a consensus answer is yet to be seen.”

Among Stewart’s future research plans are the evolution of the Earth’s surface and the magma ocean. Lock wants to take the synestia and learn if non-terrestrial planets, like a super-Earth or a Jupiter-sized planet, could form one in their lifetime.

“There are still things about our universe that we don’t understand,” Lock said. “There’s just infinite fascination in our universe. We’re in the 21st century, and still there are whole new concepts that have never been thought about. There’s an endless possibility to the things we can see in our universe and have yet to be discovered.”

Lock and Stewart’s next paper is currently in review and will cover their explanation of the moon’s formation using the research on the synestia.

More information about the synestia and moon formation can be found on Professor Stewart’s website and Simon Lock’s website.

Written by: Jack Carrillo Concordia — science@theaggie.org