Distribution and transport of microplastic and fine particulate organic matter in urban streams.

Plastic litter is accumulating in ecosystems worldwide. Rivers are a major source of plastic litter to oceans. However, rivers also retain and transform plastic pollution. While methods for calculating particle transport dynamics in rivers are well established, they are infrequently used to quantify the transport and retention of microplastics (i.e., particles < 5 mm) in flowing waters. Measurements of microplastic movement in rivers are needed for a greater understanding of the fate of plastic litter at watershed and global scales, and to inform pollution prevention strategies. Our objectives were to (1) quantify the abundance of microplastics within different river habitats and (2) adapt organic matter "spiraling" metrics to measure microplastic transport concurrent with fine particulate organic matter (FPOM). We quantified microplastic and FPOM abundance across urban river habitats (i.e., surface water, water column, benthos), and calculated downstream particle velocity, index of retention, turnover rate, and spiraling length for both particle types. Microplastic standing stock was assessed using a habitat-specific approach, and estimates were scaled up to encompass the study reach. Spatial distribution of particles demonstrated that microplastics and FPOM were retained together, likely by hydrodynamic forces that facilitate particle sinking or resuspension. Microplastic particles had a higher downstream particle velocity and lower index of retention relative to FPOM, suggesting that microplastics were retained to a lesser degree than FPOM in the study reaches. Microplastics also showed lower turnover rates and longer spiraling lengths relative to FPOM, attributed to the slow rates of plastic degradation. Thus, rivers are less retentive of microplastics than FPOM, although both particles are retained in similar locations. Because microplastics are resistant to degradation, individual particles can be transported longer distances prior to mineralization than FPOM, making it likely that microplastic particles will encounter larger bodies of water and interact with various aquatic biota in the process. These empirical assessments of particle transport will be valuable for understanding the fate and transformation of microplastic particles in freshwater resources and ultimately contribute to the refinement of global plastic budgets.

Citizen science datasets reveal drivers of spatial and temporal variation for anthropogenic litter on Great Lakes beaches.

Accumulation of anthropogenic litter (AL) on marine beaches and its ecological effects have been a major focus of research. Recent studies suggest AL is also abundant in freshwater environments, but much less research has been conducted in freshwaters relative to oceans. The Adopt-a-BeachTM (AAB) program, administered by the Alliance for the Great Lakes, organizes volunteers to act as citizen scientists by collecting and maintaining data on AL abundance on Great Lakes beaches. Initial assessments of the AAB records quantified sources and abundance of AL on Lake Michigan beaches, and showed that plastic AL was >75% of AL on beaches across all five Great Lakes. However, AAB records have not yet been used to examine patterns of AL density and composition among beaches of all different substrate types (e.g., parks, rocky, sandy), across land-use categories (e.g., rural, suburban, urban), or among seasons (i.e., spring, summer, and fall). We found that most AL on beaches are consumer goods that most likely originate from beach visitors and nearby urban environments, rather than activities such as shipping, fishing, or illegal dumping. We also demonstrated that urban beaches and those with sand rather than rocks had higher AL density relative to other sites. Finally, we found that AL abundance is lowest during the summer, between the US holidays of Memorial Day (last Monday in May) and Labor Day (first Monday in September) at the urban beaches, while other beaches showed no seasonality. This research is a model for utilizing datasets collected by volunteers involved in citizen science programs, and will contribute to AL management by offering priorities for AL types and locations to maximize AL reduction.

TMJ arthroscopy in patients with Ehlers Danlos syndrome: case series.

OBJECTIVE: The purpose of this report was to assess the outcome of temporomandibular joint (TMJ) arthroscopy in patients with temporomandibular disorders (TMDs) associated with Ehlers Danlos syndrome (EDS). STUDY DESIGN: This retrospective case series describes 18 patients with EDS who underwent arthroscopy for temporomandibular disorders. The patients' demographics were recorded, along with preoperative TMJ symptoms, Wilkes classification, mouth opening, and the presence of systemic involvement. The incidence of early and late postoperative complications and the final outcome were noted. RESULTS: All of the patients were females, with EDS Type III, and had a mean age of 34 years. A high proportion of the patients had joints other than the TMJ affected. Five patients were classified as stage II according to the Wilkes classification, 9 patients were stage III, 3 patients were stage IV, and only 1 patient was diagnosed with stage V Wilkes before intervention. Arthroscopy, followed by arthrocentesis and balloon dilatation of the affected TMJs was performed and intra-articular morphine injections were given to all patients. The main pre- and early postoperative complaint was pain, but this resolved in most cases. Improvement of mouth opening was noted from 23.4 +/- 4.2 to 27.8 +/- 5.1 mm after arthroscopy. Patients were followed for an average of 62 months and all were asymptomatic at their last review appointment. CONCLUSION: For patients where conservative measures of treating TMD are not effective, arthroscopy is a minimally invasive surgical procedure that has been shown to result in a satisfactory outcome, with no need to resort to open joint surgery. This case series is limited by its size and further research on surgical intervention on EDS patients with temporomandibular disorders is recommended.