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Historical Isoscapes for Servicemember Identification
Historical Isoscapes for Servicemember Identification Historical Isoscapes for Servicemember Identification
Geochemical forensics supporting POW/MIA accounting

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ABOUT THE PROJECT

Isoscapes

Small differences in the average weight of common elements occur naturally in the environment.

Forensics

Isotope signatures are locked into our bones, teeth, and hair as they grow, reflecting the environment we live in.

POW/MIA

When remains of service members are returned to the USA, this information can help establish their identity.

You can help

By filling a bottle or sending an eggshell, you can help us read these isotope signatures and make IDs.

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Isoscapes

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Everything and everyone is made up of atoms of many elements. These elements - for example, carbon and hydrogen - are the building blocks of our bodies, and can be found in all body tissues. Your hair, bones, and teeth contain abundant carbon and hydrogen, and even low levels of other, rarer, elements like strontium and lead.

Did you know, though, that not all hydrogen atoms are the same? Minor differences in the nucleus cause natural variation in the weight of different atoms of the same element, and these different 'flavors' of an element are called isotopes.

We tend to think of isotopes as associated with bombs, nuclear energy, or radiation, and indeed some are. Most isotopes, however, are not radioactive or dangerous. They are a naturally occuring part of the environment, and have been since the Earth was formed. Lake Monona, Wisconsin, for example, contains about 112 million tons of water. That water contains a little more than 12 million tons of the element hydrogen. Of that, about 5 thousand tons is not the normal, common version of hydrogen but rather the rare isotope hydrogen-2.

Although rare isotopes occur everywhere in nature, their abundance is not the same in all locations. Natural processes sort isotopes and create predictable patterns in their distribution. Water in lakes at high latitudes, for example, has less hydrogen-2 than does water in lakes nearer the equator. We use isotopic measurements of samples collected at different locations together with statistical mapping methods to produce estimates of isotope variation across the USA and other parts of the world. The resulting maps are called 'isoscapes', or isotopic landscapes.

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Forensic Applications

Saltair Sally

Our bodies grow and replace tissue continuously throughout our lifetimes. As this happens, new tissues are formed from the elements and isotopes taken into our bodies from the local environment. Our food, the water we drink, and even the air we breathe all contribute to the isotopic composition of our bodies. Because the isotopic composition of these elemental sources varies among locations, isotopes in our body are a bit like a biological passport, registering a change each time we move from one location to another.

Many body tissues preserve isotope signatures obtained when they were initially formed for years to decades. The hard enamel coating our teeth, for example, is chemically stable throughout our lifetime, and its isotopic composition reflects the location and environment we lived in during our childhood, when these teeth first formed. Hair, which grows continuously, is more akin to a tape recorder, with each new segment of growth locking in body isotopic signatures as it is growing.

The ability to reconstruct the geographic origin or movements of individuals based on isotope compositions of their body tissues is now used by many law enforcement agencies as an investigative tool. In 2012, police in Utah solved a 12-year-old cold case when isotope measurements of human remains helped point their investigation toward missing people who had traveled to the Pacific Northwest prior to their death. Just this year, isotope evidence contributed to the identification of remains discovered in North Carolina in 1998.

DNA and Isotopes

Isotope forensic evidence is different from fingerprints or DNA: it does not provide a unique identification of an individual or location. Instead, it indicates general areas that are more or less likely to be places where an individual has lived in the past. However, isotopes have one key advantage that makes them a great addition to the forensic scientist's toolkit: isotope data can be useful even in no reference sample is available. Fingerprints must be matched to a fingerprint taken from the same individual. DNA samples generally need to be compared to samples from close relatives to make a positive match. For isotopes, however, we can use isoscapes to help us interpret data from forensic samples. This means that even if scientists have never sampled a relative, or even someone living in the same town or county, they can assess whether an individual may have lived there.

This makes isotopes and DNA a great pair, and in fact this is how IDs were made in both cold cases mentioned above. DNA provides very specific identification information, but requires the right reference samples. Without guidance on where to look for potential relatives, the collection of reference data can take a huge amount of time and resources and represent a bottleneck in many cases. Isotope data can help to guide this process, highlighting the most likely locations where an individual might have lived and helping investigators prioritize the collection of DNA reference samples.

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POW/MIA Accounting

Missing

More than 82 thousand American armed service members from post-WW I actions remain un-accounted for. Obtaining, identifying, and repatriating the remains of those who perished oversees remains a focus for the families of missing service members, the US military and many non-governmental groups that have taken on this mission.

Discovering and obtaining remains is usually only the first step in the process of accounting for missing service members. Depending on the context of the recovery, positive identification of the individual or individuals recovered can be a major challenge. Forensic scientists use a wide range of contextual clues and records to work toward an identification. In addition to these traditional methods, forensic DNA techniques have led to huge advances in the ability to identify long-missing persons. DNA-based identification requires matching with samples from close relatives, however, and in many cases the search for potential relatives, acquisition of reference samples, and testing represents a major bottleneck in the identification process.

Isotope forensics can assist in this process by guiding and streamlining the search for DNA reference samples. Consider a typical 11-man crew of a B-24 Liberator bomber. If unidentified remains are recovered from a crash site, DNA identification may require finding, obtaining and analyzing reference samples from relatives of up to 11 crew members, assuming the identity of the plane and the crew can be established by other means. This type of un-focused search places a large burden on over-taxed forensic DNA labs and can slow the identification process.

Isotope analysis offers the potential to dramatically reduce this workload and associated delays by focusing the search. Analysis of the isotope composition of teeth from the recovered remains, for example, might indicate that the individual spent his childhood in the southern Great Plains states of Texas and/or Oklahoma. If only two of the 11 crew fit this profile, a simple isotope test will have reduced the DNA testing effort by more than 80%, meaning more cases can be processed to obtain positive identifications faster.

Missing

The key to succesfully adding isotope testing to servicemember accounting process is isoscape mapping. Although researchers have learned a lot about isotope distributions, reliable, high-quality maps showing the isotope values found in food and water across the USA don't yet exist. In addition, isoscapes for POW/MIA accounting need to represent isotope values expected for servicemembers living many decades to a century ago, not today. The HIS_ID project will be developing these isoscape maps, using a combination of isotope sampling and GIS-based modeling to reconstruct historic patterns of isotope variation across the USA at key times relevant to the POW/MIA accounting mission.

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Help Us

The HIS_ID team is working hard to gather the samples and information needed to develop historical isoscapes supporting the POW/MIA accounting mission. We have a lot of ground to cover, though, and could use your help!

A big part of this effort is collecting high-quality, known-origin environmental samples from across the USA. These samples will be measured to determine their stable isotope composition, and will be the foundation on which our isoscape maps are built. We live in a large country, and it's neither efficient nor cost-effective for our team to personally visit and collect samples everywhere they are needed. We are hoping you can help.

Our team has identified several types of samples that will be especially useful, and at different points in our project we will be focusing on collecting these materials. Our intial effort is focusing on groundwater from private and public wells, which provides more than half of the drinking water used in the USA. As the project moves forward we will also be collecting tap water from homes and businesses and eggshells from locally-raised hens.

Are you able and willing to collect one or more of these types of samples from your home or community and share them with our team? Have a look at the details in the section below and see if we need samples from your area. Your samples will contribute to a growing database of isotope information that will allow us to build and improve isoscapes supporting servicemember identification, advancing the mission of accounting for all members of the US armed forces lost in action.

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THE TEAM

Gabe

Prof. Gabriel Bowen

Principal Investigator

Gabe is Professor of Geology & Geophysics at the University of Utah and has 20 years of experience applying isotope data to environmental and forensic problems.

Sagarika

Sagarika Banerjee

Technician

Sagarika brings expertise in sample collection, preparation, and isotope analysis to the HIS_ID project.

Scott

Dr. Scott Allen

Postdoctoral Researcher

Scott's expertise includes spatial analysis and modeling of isotopes in hydrological research.

Jessica

Dr. Jessica Guo

Postdoctoral Researcher

Jessica has a background in ecology and Bayesian statistical methods useful in developing and interpreting isoscapes.

OUR WORK

Check out the HIS_ID project team's current efforts, and learn how you can help

Groundwater

Groundwater

Tap Water

Tap Water

Eggs

Eggshells

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Sampling Trips

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Groundwater

More than half of the drinking water consumed in the USA comes from underground aquifers. As a result, isotope values of human body tissues in many parts of the country are strongly controlled by isotope values of groundwater. Good isoscape maps of US groundwaters don't currently exist. The HIS_ID team will create these maps, and you can help.

The map below shows the current distribution of groundwater samples in our database. Do you live in an area we haven't sampled, and have a well at your home? If so, helping out is as easy as filling a small bottle with water from your home and sending it to us. The isotope composition of your water will be analyzed in our lab and added to our database within 2-3 weeks. You can check back on the map and see when your contribution has been added! We do not keep or distribute any personally identifying information that would associate you with the sample.

If you're interested in contributing please contact us.

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Tap Water

Coming soon

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Egg Shells

Coming soon

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Isotope Sampling

Follow along as our team travels across the country collecting samples for isotope analysis.

Southern States, March 2019

CONTACT US

Salt Lake City, USA

Phone: 801-585-7925

Email: gabe.bowen@utah.edu

If you are interested in providing samples in support of the HIS_ID project please let us know where you are located and which of our sample types you could collect.