Assessment of filter subsampling and extrapolation for quantifying microplastics in environmental samples using Raman spectroscopy.

A common method for characterizing microplastics (MPs) involves capturing the plastic particles on a filter after extraction and isolation from the sediment particles. Microplastics captured on the filter are then scanned with Raman spectroscopy for polymer identification and quantification. However, scanning the whole filter manually using Raman analysis is a labor-intensive and time-consuming process. This study investigates a subsampling method for Raman spectroscopic analysis of microplastics (operationally defined here as 45-1000 µm in size) present in sediments and isolated onto laboratory filters. The method was evaluated using spiked MPs in deionized water and two environmentally contaminated sediments. Based on statistical analyses, we found quantification of a sub-fraction of 12.5 % of the filter in a wedge form was optimal, efficient, and accurate for estimating the entire filter count. The extrapolation method was then used to assess microplastic contamination in sediments from different marine regions of the United States.

Characterization and regulation of microplastic pollution for protecting planetary and human health.

Microplastics are plastic particles <5 mm in diameter. Since the 1950s, there has been an exponential increase in the production of plastics. As of 2015, it is estimated that approximately 6300 million metric tons of plastic waste had been generated of which 79% has accumulated in landfills or the natural environment. Further, it is estimated that if current trends continue, roughly 12,000 million metric tons of plastic waste will accumulate by 2050. Plastics and microplastics are now found ubiquitously-in the air, water, and soil. Microplastics are small enough to enter the tissues of plants and animals and have been detected in human lungs, stools, placentas, and blood. Their presence in human tissues and the food chain is a cause for concern. While direct clinical evidence or epidemiological studies on the adverse effects of microplastic on human health are lacking, in vitro cellular and tissue studies and in vivo animal studies suggest potential adverse effects. With the ever-increasing presence of plastic waste in our environment, it is critical to understand their effects on our environment and on human health. The use of plastic additives, many of which have known toxic effects are also of concern. This review provides a brief overview of microplastics and the extent of the microplastic problem. There have been a few inroads in regulating plastics but currently these are insufficient to adequately mitigate plastic pollution. We also review recent advances in microplastic testing methodologies, which should support management and regulation of plastic wastes. Significant efforts to reduce, reuse, and recycle plastics are needed at the individual, community, national, and international levels to meet the challenge. In particular, significant reductions in plastic production must occur to curb the impacts of plastic on human and worldwide health, given the fact that plastic is not truly recyclable.

Analytical precision assessment for microplastic analyses.

The need for improved microplastic (MP) data accuracy has been widely reported, but MP precision issues have been investigated less thoroughly. This work demonstrates how initial and continuing assessments of a laboratory's analytical precision can be used for establishing laboratory repeatability for MP analyses. These precision estimates can be reported along with MP results to ensure their quality and compare them meaningfully to other data. Re-analyses of reference MP samples can be used to assess and compare precision between different laboratories. A multi-lab precision exercise was demonstrated using infrared (IR) standard test methods performed on reference samples consisting of low-concentration MP spikes in both clean water and wastewater matrices. Each lab repeated their IR analyses 7 times and calculated relative standard deviations (RSD) for each detected polymer type using a standardized template. All labs' MP methods yielded generally repeatable results, though RSDs were consistently higher for lower MP counts. The reported range of total MP counts per sample was 8-33 particles, and the observed RSDs were 0.1-0.6. These RSDs were the same or lower than the expected imprecision due to random (Poisson) counting error alone, suggesting that these automated methods did not contribute any additional variability, and had slightly better reproducibility than expected for independent recounts. The wastewater matrix exhibited numerous interfering particles but did not yield more variability than the clean water matrix. The low-count design is a worst case for precision but is appropriate for some real-world sample concentrations. In practice, labs could generate separate references for precision assessment at multiple MP ranges (e.g., high, medium, and low.) The RSDs obtained from this data can be used to generate QC charts, detect changes in analyst performance, compare to Poisson error to identify additional sources of imprecision, and determine target filtration and instrumental parameters for MP analyses.

Field-Portable Microplastic Sensing in Aqueous Environments: A Perspective on Emerging Techniques.

Microplastics (MPs) have been found in aqueous environments ranging from rural ponds and lakes to the deep ocean. Despite the ubiquity of MPs, our ability to characterize MPs in the environment is limited by the lack of technologies for rapidly and accurately identifying and quantifying MPs. Although standards exist for MP sample collection and preparation, methods of MP analysis vary considerably and produce data with a broad range of data content and quality. The need for extensive analysis-specific sample preparation in current technology approaches has hindered the emergence of a single technique which can operate on aqueous samples in the field, rather than on dried laboratory preparations. In this perspective, we consider MP measurement technologies with a focus on both their eventual field-deployability and their respective data products (e.g., MP particle count, size, and/or polymer type). We present preliminary demonstrations of several prospective MP measurement techniques, with an eye towards developing a solution or solutions that can transition from the laboratory to the field. Specifically, experimental results are presented from multiple prototype systems that measure various physical properties of MPs: pyrolysis-differential mobility spectroscopy, short-wave infrared imaging, aqueous Nile Red labeling and counting, acoustophoresis, ultrasound, impedance spectroscopy, and dielectrophoresis.

Nondestructive Extraction and Identification of Microplastics from Freshwater Sport Fish Stomachs.

Microplastics were extracted from freshwater sport fish stomachs containing substantial biomass and identified using optical microscopy, scanning electron microscopy plus energy-dispersive X-ray spectroscopy (SEM/EDS), and Fourier transform infrared (FTIR) micro-spectroscopy with automated spectral mapping. An extraction method is presented that uses a negatively pressurized sieve stack and purified water to preserve plastic surface characteristics and any adsorbed persistent organic pollutants (POPs). This nondestructive extraction method for large predators' stomachs enables multiple trophic-level studies from one fish sampling event and provides other dietary and behavioral data. FTIR-identified microplastics 50-1500 µm, including polyethylene (two with plastic additive POPs), styrene acrylonitrile, polystyrene, and nylon and polyethylene terephthalate fibers 10-50 µm wide. SEM/EDS revealed characteristic surface weathering on the plastic surfaces. The nylon fibers appear to be from human fishing activities, suggesting options for management. Some particles visually identified as potential plastics were revealed by micro-spectroscopy to be mineralized, natural polyamide proteins, or nonplastic shell pieces. A low-cost, reflective sample preparation method with stable particle mounting was developed to enable automated mapping, improved FTIR throughput, and lower detection size limit. This study yielded 37 intact prey items set aside for future analyses.

Cognitive impairment and Charles Bonnet syndrome: a prospective study.

OBJECTIVES: Charles Bonnet syndrome (CBS) is a common cause of visual hallucinations in older people. The relationship between CBS and cognitive impairment is unclear, but anecdotal reports exist of dementia emerging in patients diagnosed with CBS. This work set out to determine if there is an increased incidence of dementia, and increased severity of cognitive impairment, in people with CBS compared to controls from the same clinical setting. METHOD: People over 65 attending low-vision and glaucoma clinics, and a cohort of age-matched controls, underwent a psychiatric assessment. The cohorts were followed up after one year. RESULTS: Mild cognitive impairment was present in 2/12 CBS participants and 2/10 controls. Partial insight was seen in nine CBS participants. Two participants with CBS, and no controls, developed dementia at follow-up. No significant differences in performance on the ACE-R were found between the groups. Both participants who developed dementia had partial insight and hallucinations of familiar figures at diagnosis of CBS, and one had mild cognitive impairment. CONCLUSIONS: Reassurance that CBS is universally benign may be misplaced. Some people given this diagnosis go on to develop dementia. Cognitive testing at the point of diagnosis was unable to identify those at risk of this outcome. Partial insight, the presence of Mild Cognitive Impairment, and hallucinations of familiar figures at diagnosis of CBS may confer an increased risk of subsequent dementia diagnosis. Copyright © 2017 John Wiley & Sons, Ltd.

Polybrominated diphenyl ethers (PBDEs) in fish tissue may be an indicator of plastic contamination in marine habitats.

The accumulation of plastic debris in pelagic habitats of the subtropical gyres is a global phenomenon of growing concern, particularly with regard to wildlife. When animals ingest plastic debris that is associated with chemical contaminants, they are at risk of bioaccumulating hazardous pollutants. We examined the relationship between the bioaccumulation of hazardous chemicals in myctophid fish associated with plastic debris and plastic contamination in remote and previously unmonitored pelagic habitats in the South Atlantic Ocean. Using a published model, we defined three sampling zones where accumulated densities of plastic debris were predicted to differ. Contrary to model predictions, we found variable levels of plastic debris density across all stations within the sampling zones. Mesopelagic lanternfishes, sampled from each station and analyzed for bisphenol A (BPA), alkylphenols, alkylphenol ethoxylates, polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), exhibited variability in contaminant levels, but this variability was not related to plastic debris density for most of the targeted compounds with the exception of PBDEs. We found that myctophid sampled at stations with greater plastic densities did have significantly larger concentrations of BDE#s 183 -209 in their tissues suggesting that higher brominated congeners of PBDEs, added to plastics as flame-retardants, are indicative of plastic contamination in the marine environment. Our results provide data on a previously unsampled pelagic gyre and highlight the challenges associated with characterizing plastic debris accumulation and associated risks to wildlife.

Bright light therapy for agitation in dementia: a randomized controlled trial.

BACKGROUND: Agitation is common in people with dementia, is distressing to patients and stressful to their carers. Drugs used to treat the condition have the potential to cause particularly severe side effects in older people with dementia and have been associated with an increased death rate. Alternatives to drug treatment for agitation should be sought. The study aimed to assess the effects of bright light therapy on agitation and sleep in people with dementia. METHODS: A single center randomized controlled trial of bright light therapy versus standard light was carried out. The study was completed prior to the mandatory registration of randomized controls on the clinical trials registry database and, owing to delays in writing up, retrospective registration was not completed. RESULTS: There was limited evidence of reduction in agitation in people on active treatment, sleep was improved and a suggestion of greater efficacy in the winter months. CONCLUSIONS: Bright light therapy is a potential alternative to drug treatment in people with dementia who are agitated.

The impact of neuropsychiatric symptoms of dementia on distress in family and professional caregivers in Singapore.

BACKGROUND: Behavioral and psychological symptoms of dementia (BPSD) are a source of distress and burden for caregivers. This study attempts to determine the neuropsychiatric symptoms, demographic characteristics, and referral patterns of outpatients with dementia compared with patients admitted to the acute psychogeriatric wards of Woodbridge Hospital. We also assessed the impact of neuropsychiatric symptoms on distress in family and professional caregivers. METHOD: Eighty-five consecutive patients with a first-time diagnosis of dementia were recruited. They were assessed using the Neuropsychiatric Inventory Caregiver Distress Scale (NPI-D). The professional caregiver distress questions were rephrased to assess the "occupational disruptiveness" of behaviors in the nursing home version (NPI-NH). RESULTS: Neuropsychiatric symptoms were common and were positively correlated with caregiver distress. Family caregivers were significantly more distressed than professional caregivers over the delusion, agitation, depression and aberrant motor domains, although the severity of the behavioral disturbances reported was not higher in the sample. The median NPI scores for the agitation and disinhibition domains were significantly higher in the inpatient group, contrasting with a higher score for the depression domain among the outpatient group. CONCLUSIONS: This study highlights the prevalence of neuropsychiatric symptoms in dementia and illustrates the strong correlation between the severity of behavioral disturbances and caregiver distress.

The use of light therapy to lower agitation in people with dementia.

Agitation and sleep disturbance are problematic for people with dementia and their carers, and have been linked to disrupted circadian rhythms caused by a lack of exposure to light. Bright light therapy (BLT) offers a powerful and cost-effective alternative to pharmacological options, and can be easily incorporated into care routines. This article describes practical issues faced when implementing light therapy in a nursing home setting, and attempts to address existing perceptions about its effectiveness.

Optical and Magnetic Spectra of Bis-N-Propylsalicylaldiminato Copper ( II ).

The electronic and electron spin resonance spectra of bis-N-propylsalicylaldiminato copper (II) have been measured. The measurements show that the g-tensor has some rhombic character with g z = 2.225, g x = 2.064, and g y = 2.038. Four d-d transitions were observed in the electronic spectrum at 14,800, 16,800, 19,800, and 22,000 cm-1. A consistent set of assignments has been made based on the polarization data of the bands. These results are compared to the results from other similar molecules.