Source: CIM Magazine
Author: Kylie Williams
Hair to replace needles in lead monitoring
A toxicology laboratory near Victoria, British Columbia, has developed a novel hair screening tool to measure metal levels in the body with a single hair. A six-month pilot study involving 100 volunteers at Teck Resources’ zinc and lead smelting and refining complex in Trail, which concluded last month, determined that hair analysis is a sensitive and effective tool to screen for elevated blood lead levels – as well as being quicker and less painful.
“Our goal is to reduce the need for needles,” said Jennie Christensen, CEO and founder of TrichAnalytics. Christensen, a toxicologist, led the study. “We can use hair lead levels as a proxy for what is happening in the blood. We can use any growing hair, as long as the root is intact.”
With sample collection as easy as using tweezers to extract three to five hairs and place them in an envelope, the non-invasive method was welcomed by those smelter workers who are anxious about blood tests using needles.
“As part of Teck’s values and policy, we work to identify and manage occupational health exposures for the protection of longer-term health,” said Corrine Balcaen, Teck’s director of occupational health and hygiene. “We’ve been pleased to support this pilot project, which has the potential to reduce or replace blood sampling for occupational exposure and make it easier and more comfortable for our employees.”
The method could have community applications too, such as blood lead level monitoring of children and families close to industrial sites. Teck partners with the City of Trail and B.C.’s interior health authority on the Trail Area Health and Environment Committee (THEC) to monitor lead levels in children in the surrounding community, which currently collects samples via regular voluntary blood tests.
Trail has historically had high blood lead levels. In 1989, children aged six to 36 months in Trail were registering an average of 13.5 micrograms per decilitre. That is now down to four micrograms per decilitre in 2017, the lowest result to date, according to a THEC release from February. Currently, the Canadian standard for intervention is if blood lead levels are 10 micrograms per decilitre or higher, though the Centers for Disease Control and Prevention in the United States recommends testing for those with five micrograms per decilitre.
At the TrichAnalytics laboratory, once Christensen and her team have received the hair samples, they use Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) to analyze a three-millimetre section of the sample near the root, just below the skin, to eliminate contamination from the environment.
“We designed a statistical algorithm to help us find the sweet spot where blood and hair lead levels match,” said Christensen. “We’re the only lab that is doing it commercially.”
Monitoring industrial lead exposure is critical because at lower concentrations, it can impact the nervous system, resulting in weakened limbs, anemia and increased blood pressure. At high concentration, lead exposure will severely damage the brain and kidneys. In the past, said Christensen, hair samples have been used mainly for nutritional testing, but not for occupational health monitoring as it was viewed as inaccurate and unreliable because of contamination.
The pilot used lessons learned about contamination from the death of seaman John Hartnell during the ill-fated Franklin Expedition in 1845. For a previous study, Christensen was given access to a 170-year-old fingernail belonging to Hartnell. Using x-ray fluorescence, Christensen and her co-authors mapped the distribution of certain elements on the outer surface and underside of the nail, honing a technique to account for contamination in growing tissue and questioning the role of lead in his death.
“The lesson we took from the Franklin study to the occupational health realm was how contamination affects results and how to get around it,” said Christensen, who published her study of the role of lead poisoning during the Franklin Expedition using fingernail analysis in the Journal of Archeological Science in December 2017. “We’re using the protected piece of the hair – protected by the scalp and follicle – so environmental contamination is less of an issue, and coloured, treated, or damaged hair can also be used.”
Christensen’s pilot study was run in parallel with Teck’s regular on-site blood monitoring program. More than 70 per cent of the participants said they would be content with a hair test compared to only nine per cent who preferred a blood test. In the future, the non-invasive hair test could be used to monitor blood lead levels by proxy so, when a certain hair lead level is reached, it triggers a blood test.
TrichAnalytics received funding, in-kind support and access to Trail workers from Teck for the pilot study, and a contribution from the National Research Council of Canada’s Industrial Research Assistance Program. The response to the trial was positive and discussions are underway to expand the program at Trail and beyond, said Christensen.
“We’re looking for forward-thinking companies that are looking to change the way they monitor,” said Christensen, who hopes that with the ease and speed of collecting a single hair sample, the method may evolve into a preventive tool for mines, smelters, refineries, battery manufacturing and recycling plants, and welding facilities, and for the communities surrounding them.
“Instead of a [semi-annual] or annual blood test, we can test hair more regular, perhaps monthly, and see the trend creeping up over time,” said Christensen. “We can do something about it sooner.”