Residual Effects from Occupational Mercury Exposure Include a Proposed Mercury Tremor Biomarker or “Fingerprint”

Abstract

The study investigated residual effects of high levels of occupational mercury exposure, 30 years after a cohort of women worked in public service dentistry. They had all used copper amalgam in a pellet form that required heating and handling, and silver amalgam before the encapsulated form was available. Mercury handling practices changed in the mid-1970 when the workforce was urine tested and mercury poisoning became apparent. The aim was to compare control group and exposed group scores on tasks from a neurobehavioural test battery; plus survey results from a composite health, work history and environmental influences survey. The findings showed that the exposed and control groups were equivalent not only on those variables that one would want to be matched (age, alcohol consumption), but also on many of the cognitive and psychomotor test scores. The present paper focuses on psychomotor skill and tremor patterns. Tremor patterns were seen as generating new evidence of long term effects of the historic mercury insult. Data also suggest that there may be a distinctive mercury “fingerprint”, in samples of sinusoidal waveforms that may have potential as a non-invasive sub-clinical biomarker for adverse effects of mercury exposure, in screening or workplace monitoring.