The spatial patterns of water management practices are reflected in the strontium isotope ratios of human hair

TIPPLE, BRETT; VALENZUELA, LUCIANO O; EHLERINGER, JAMES R

San Francisco

Encuentro; AGU Fall Meeting; 2012

American Geophysical Union

Element concentrations and isotopes of human tissues are commonly used to understand how emissions and processes within urban ecosystems affect health. Thus, it is important to understand how these elements are incorporated and flow through the urban environment and are ultimately incorporated into human tissues. Here, we designed an experiment to identify the relative importance of strontium (Sr) sources (bedrock, dust, food, and water) to hair Sr isotope ratios (87Sr/86Sr). To understand the contribution of Sr to human hair, we collected hair from individuals living in Salt Lake City, Utah. In addition to sample location, we compiled information regarding age, sex, ethnicity, and dietary habits. We found a significant association between 87Sr/86Sr value of hair and collection location. There were no significant relationships between 87Sr/86Sr value of hair and age, ethnicity, or sex. We had not predicted a relationship between 87Sr/86Sr values and collection location, because of the close proximities of sites to one another (all within an 8-km radius). We found that tap water 87Sr/86Sr values across the Salt Lake Valley varied with water management practice and this variation corresponded to hair 87Sr/86Sr value. These data suggest an additional geographically controlled source of Sr may be an important contributor to the 87Sr/86Sr value of hair. These findings suggest that local water is an important source of Sr in human hair and that hair is a sensitive temporal carrier of this environmental information. These observations have important implications to future studies of humans with regard to urban ecology, human health, forensic sciences, and anthropology.