[CUSTOM SOLUTION] Honors Forensic Science

Honors Forensic ScienceNameHair Analysis for Heavy MetalsGeneral BackgroundDetection of Heavy Metals in Hair SamplesHeavy metal toxins such as arsenic and thallium commonly enters the body through ingestion. These toxins pass through the stomach and are absorbed by the blood stream. Once in the bloodstream, the toxins travel to all parts of the body. Heavy metals have a high affinity to bind to the amino acid cysteineFigure 1: Cysteine, an essential amino acid.Keratin, the major structural protein in hair, contains many cysteine molecules, and therefore, is one of the main accumulation sites of these heavy metals.Image result for keratinFigure 2: Keratin, the major structural protein in hair.In simpler terms, heavy metal toxins like arsenic and thallium are “trapped” inside the keratin inside the strands of hair. Therefore, hair analysis is a great way to determine the presence of heavy metals in a person’s system.Image result for contamination in hair strandsFigure 3: Toxins trapped in the bloodstream are carried to the scalp. When at the scalp, the toxins are bound to the keratin, through the composite cysteine molecules, which makes up the structural integrity of a strand of hair. As the hair follicle grows, the trapped toxins are suspended in the individual strand of hair where they can then be detected through forensic toxicology analysis.Hair grows at approximately 1.3 cm /month . Hair keratin that is produced today will not protrude through the scalp for one week. This indicates that if a hair sample tests positive for toxins directly at root, the exposure occurred just one week prior. If the presence of heavy metal toxin does not appear until 1 inch away from the scalp, the exposure occurred 2 months prior, and so on.How to Analyze a Hair Sample1. A hair sample is collected for analysis. Approximately 1 gram of hair is needed for analysis (this is about 2000-5000 strands of hair!). Hair found at the back of the head offers the best results for analysis. Why do you think the hair found here offers the best results? (take your best guess)2. In the lab, the individual strands of hair are split and analyzed under a microscope. The microscopic analysis ensures there is a contaminant present in the hair and is in need of further elemental testing.3. The overall chemical makeup of the hair is then identified using mass-spectrometry to determine the elemental analysis inside of the strands of hair.ProcedureUsing the patient’s symptoms and the chemical makeup of the toxic metals found in a hair sample, it is up to you to determine how the patient died.A male, aged 40, went to the hospital complaining of abdominal pains and muscle cramps, accompanied by overwhelming nausea and vomiting. While at the hospital, his health began to decline rapidly. His hands began to turn brown and scaly and his fingers and toes felt like they were always on fire. After a couple days, his body shut down resulting in a coma after he fell into cardiac arrest. The blood supply to his brain eventually stopped and his family decided that it was time to pull the plug.The hospital toxicologist knew they needed to perform an autopsy to determine that exact cause of death, although he already had an idea in mind. The toxicologist has suspicions that the patient was poisoned and sent samples of the patient’s hair to the lab for analysis.Below are the results the lab determined to in the chemical makeup of the patient’s hair sample:Lab Questions1. What major symptoms did the patient exhibit that made the toxicologist believe the patient was suffering from a poisoning?2. The reference interval is the maximum amount of heavy metal exposure a person can have in their system before symptoms of acute poisonings begin to appear. Analyze the table above and indicate which heavy metal toxins are above the maximum in the patient’s system (there is more than 1).3. Of the heavy metal toxins found in the patient’s system, what heavy metal toxin do you believe is the reason for the death of the patient? Why?After the patient passed away from the poisoning, the forensics team began their search to figure out the cause of the poisoning. Was it an accidental exposure? Was it deliberately done? The forensics team traced the patient’s whereabouts in the weeks leading up to the onset of the symptoms of a poisoning to determine the cause. The patient was an employee for the World Health Organization. At his job, he was responsible for traveling to different communities and gathering water samples for routine analysis to ensure the water quality was within quality range. At one particular site, the quality of water appeared to be contaminated with heavy metals that were well above standard amounts. A new drilling project recently began very close to the water source resulting in a runoff of the metals naturally found in the soil. The patient accidentally fell into this water source while collecting his routine analysis samples, ingesting some of the water.4. How did the patient get high levels of toxins into his system resulting in his death? Was the poisoning an accident or did someone deliberately try to poison him?

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