Occurrence of microplastics in municipal sewage treatment plants: a review

Municipal sewage treatment plants (STPs) are thought to be important point sources of microplastics in freshwater systems and many peer-reviewed articles have been published on this issue since mid-2010s. In this review, we summarize existing literature on the occurrence of microplastics in STPs and experimental methods used for isolation and identification of microplastics. The number concentrations of microplastics in STP influents were 15.1-640 L⁻¹, whereas those in the STP effluents were highly variable and ranged from not detectable to 65 L⁻¹. For most of cases, conventional STPs are removing microplastics very effectively. Fragments and fibers are dominant shapes of microplastics. Thermoplastics (polyethylene and polypropylene) and polyester are the predominant materials recovered. Although further research is needed, size distribution of microplastics in STPs is likely to follow a power law, implying that different studies using different size cutoffs may be compared after establishing a power law relationship.

Occurrence of microplastics in municipal sewage treatment plants: a review

Municipal sewage treatment plants (STPs) are thought to be important point sources of microplastics in freshwater systems and many peer-reviewed articles have been published on this issue since mid-2010s. In this review, we summarize existing literature on the occurrence of microplastics in STPs and experimental methods used for isolation and identification of microplastics. The number concentrations of microplastics in STP influents were 15.1-640 L⁻¹, whereas those in the STP effluents were highly variable and ranged from not detectable to 65 L⁻¹. For most of cases, conventional STPs are removing microplastics very effectively. Fragments and fibers are dominant shapes of microplastics. Thermoplastics (polyethylene and polypropylene) and polyester are the predominant materials recovered. Although further research is needed, size distribution of microplastics in STPs is likely to follow a power law, implying that different studies using different size cutoffs may be compared after establishing a power law relationship.

Primary Spinal Cord Melanoma in Thoracic Spine with Leptomeningeal Dissemination and Presenting Hydrocephalus

Primary spinal cord melanoma is a rare central nervous system malignant tumor. Usually it resembles an intradural extramedullary (IDEM) nerve sheath tumor or melanoma. We experienced a patient with upper thoracic primary IDEM spinal cord melanoma who was diagnosed to be with hydrocephalus and without intracranial lesions. Initial symptoms of the patient were related to the hydrocephalus and the primary spinal cord melanoma was diagnosed eight months later. At the first operation, complete resection was impossible and the patient refused additional radiotherapy or chemotherapy. At 22 months after surgery, the patient revisited our institution with recurrent both leg weakness. Leptomeningeal dissemination was present in the whole spinal cord and only partial resection of tumor was performed. The symptoms slightly improved after surgery. Primary spinal cord melanoma is extremely rare but complete resection and additional radiotherapy or chemotherapy can prolong the disease free interval. Hydrocephalus or signs of increased intracranial pressure may be the diagnostic clue of spinal cord malignancy and progression.

Posterior C2-C3 Fixation for Unstable Hangman's Fracture

OBJECTIVE: This is a retrospective review of 13 unstable Hangman's fractures who underwent posterior C2-3 fixation to describe clinical outcomes with a literature review. METHODS: Thirteen patients for unstable Hangman's fracture were enrolled between July 2007 and June 2010 were included in this study. The medical records of all patients were reviewed. Concurrently, clinical outcomes were evaluated using Neck Disability Index (NDI) scores and Visual Analogue Scale (VAS) scores during preoperative and postoperative follow up period. Plain radiographs were obtained on postoperative 1day, 1week, and then at 1, 2, 6, and 12 months. CT was done at postoperative 12 months in all patients for evaluation of bone fusion. The mean period of clinical follow-up was 17 months. RESULTS: Mean age were 43 years old. Bone fusion was recognized in all cases at the final follow-up. The average preoperative VAS score for neck pain was 8.3+/-1.1, while the final follow-up VAS score was 2.07+/-0.8 (p<0.001). The average immediate postoperative NDI was 84% points and final NDI was 22% points (p<0.001). There were one case of infection and 1 case of screw loosening. CONCLUSION: In the treatment of the patients with unstable Hangman's fracture, posterior C2-C3 fusions is effective and curative treatments to achieve cervical spinal stability.