We found significant differences in mercury fluxes measured with a dynamic surface mercury flux chamber made of Teflon versus one made of polycarbonate. While both materials responded reasonably well when virgin materials were used, the polycarbonate chamber was found to exhibit significant chamber blanks under light after it was exposed to surface mercury fluxes of >100 ng/m2/h. Most significantly, the polycarbonate chamber blocked all wavelengths of light below approximately 320 nm. Given that ultraviolet radiation plays an important role in soil mercury flux, the polycarbonate chamber was found to significantly underestimate observed fluxes from background soil in both high light conditions (by 1-4-fold) and under diffuse, low light conditions (by approximately 10-fold). These results suggest that Teflon produces fewer analytical artifacts in the surface emission of mercury measured with a flux chamber than polycarbonate.

Rationale: Surfer's myelopathy is a rare atraumatic spinal cord injury most frequently experienced by novice surfers. Patients often experience back pain, followed by motor, sensory, bowel, and bladder involvement. Here, we report a case of surfer's myelopathy.Patient concerns: The patient presented with acute low back pain associated with lower limb weakness, sensory loss, urinary retention, and perineal paraesthesia 1 hour after her first surf lesson.Diagnosis: On arrival at the emergency department, she was noted to have flaccid paralysis with flickers in both lower limbs, reduced sensation in the midthoracic region, reduced anal tone, and saddle anesthesia. Magnetic resonance imaging of the spine revealed evidence of restricted diffusion from T6 to the level of the conus. Extensive investigations, including cerebrospinal fluid analysis, vasculitides/paraneoplastic screening, and further imaging, were unremarkable. She was diagnosed with complete T7 spinal cord injury secondary to surfer's myelopathy.Interventions: She subsequently received methylprednisolone and was transferred to the spinal injury unit for rehabilitation. As she experienced persistent neuropathic pain at the level of the injury, she received input from the local pain team. One month after the injury, the patient developed swelling of the right thigh associated with reduced internal and external rotation of the right hip, impacting rehabilitation. The patient was diagnosed with heterotopic ossification following a triple-phase bone scan. She then received intravenous zolendronic acid, which had a good effect.Outcomes: Four months after the initial presentation, she was discharged to the community. Despite no improvement in her neurological status, she was independent of transfers and mobility with a wheelchair. In addition, she managed her neurogenic bowel and bladder independently with intermittent self-catheterization and a transanal irrigation system. At 6 months, she engaged well with returning to drive program and vocational rehabilitation.Lessons: Neurological recovery from surfer's myelopathy has been shown to vary from complete recovery to minimal recovery. With a spinal-specific rehabilitation program, this patient remains independent of her activities of daily living. Surfer's myelopathy often occurs in inexperienced surfers; therefore, it is crucial to provide education to surfers and instructors.