9 - Perchlorate

Abstract

This chapter presents information on the chemistry, sources of perchlorate, analytical techniques, and available forensic techniques to distinguish between naturally occurring and anthropogenic origins. Perchlorate is a contaminant whose presence in the environment and origin is of considerable environmental interest. Perchlorate is an emerging chemical of concern due to its presence in many drinking-water aquifers throughout the United States and its potentially deleterious toxicological properties. Perchlorate's toxicological properties at low concentrations have also only recently been examined in detail. The primary toxicological issue is associated with its inhibition of the thyroid gland. The thyroid gland is deprived of iodide and becomes inactive relative to maintaining a healthy hormonal balance in the human body. This hormonal imbalance can lead to thyroid cancer. The emergence of perchlorate as a contaminant of environmental and toxicological interest has resulted in the development of techniques to distinguish between naturally occurring and anthropogenic sources. As the presence of perchlorate in additional industrial and military sources expands, greater opportunities are available to use surrogate chemicals associated with perchlorate to distinguish co-mingled sources of anthropogenic sources of perchlorate. The need to incorporate techniques to distinguish between naturally occurring and anthropogenic sources are therefore of paramount importance in any forensic investigations dealing with the source of age and of a perchlorate release into the environment.