Microplastics’ (particles size ≤5 mm) sources and fate in marine bottom and beach sediments of the brackish are strongly polluted Baltic Sea have been investigated. Microplastics were extracted using sodium chloride (1.2 g cm−3). Their qualitative identification was conducted using micro-Fourier-transform infrared spectroscopy (μFT-IR). Concentration of microplastics varied from 25 particles kg−1 d.w. at the open sea beach to 53 particles kg−1 d.w. at beaches of strongly urbanized bay. In bottom sediments, microplastics concentration was visibly lower compared to beach sediments (0–27 particles kg−1 d.w.) and decreased from the shore to the open, deep-sea regions. The most frequent microplastics dimensions ranged from 0.1 to 2.0 mm, and transparent fibers were predominant. Polyester, which is a popular fabrics component, was the most common type of microplastic in both marine bottom (50%) and beach sediments (27%). Additionally, poly(vinyl acetate) used in shipbuilding as well as poly(ethylene-propylene) used for packaging were numerous in marine bottom (25% of all polymers) and beach sediments (18% of all polymers). Polymer density seems to be an important factor influencing microplastics circulation. Low density plastic debris probably recirculates between beach sediments and seawater in a greater extent than higher density debris. Therefore, their deposition is potentially limited and physical degradation is favored. Consequently, low density microplastics concentration may be underestimated using current methods due to too small size of the debris. This influences also the findings of qualitative research of microplastics which provide the basis for conclusions about the sources of microplastics in the marine environment.

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Sample thickness considerations for quantitative X-ray fluorescence analysis of the soft and skeletal tissues of the human bodytheoretical evaluation and experimental validation Magdalena Szczerbowska-Boruchowska* A good estimation of the matrix composition and the areal mass of the sample is critical for quantitative X-ray fluorescence (XRF) analysis. Integrated aspects of the XRF quantitative analysis of various human body organs are presented. Special emphasis is placed on the determination of the sample thicknesses at which the specimen can be regarded as thin, thick, or intermediate thickness depending on the element under consideration. Moreover, a method for a fully quantitative analysis allowing the determination of the masses per unit area of chemical elements in thin, thick, and intermediate thickness samples is discussed. It was found that for an incident beam of 17 keV energy, a 15 mm thick sample is of intermediate thickness for all elements between P and Ca and becomes thin from Fe for most human body tissues in a natural form. Dried samples of soft tissues excluding these of low water content can be regarded as thin for all elements from phosphorus to strontium. The use of thin sample approach in quantification of intermediate thickness specimen may result in about 30-45% discrepancy in areal mass (weight fraction) of phosphorus, 20-35% of sulfur, 15-25% of chlorine, 8-15% of potassium, and 5-10% of calcium. Theoretical evaluations presented in the work are verified experimentally. The analysis of human brain samples (white and gray matter) and bovine liver (National Institute of Standards and Technology standard reference materials 1577b) confirms high accuracy of the XRF quantification on the basis of the described procedures.

Amyotrophic Lateral Sclerosis (ALS) is an untreatable, neurodegenerative disease of motor neurons characterized by progressive muscle atrophy, limb paralysis, dysarthria, dysphagia, dyspnae and finally death. Large motor neurons in ventral horns of spinal cord and motor nuclei in brainstem, large pyramidal neurons of motor cortex and/or large myelinated axons of corticospinal tracts are affected. In recent synchrotron Fourier Transform Infrared microspectroscopy (sFTIR) studies of ALS CNS autopsy tissue, we discovered a small deposit of crystalline creatine, which has a crucial role in energy metabolism. We have now examined unfixed, snap frozen, post-autopsy tissue sections of motor cortex, brain stem, spinal cord, hippocampus and substantia nigra from six ALS and three non-degenerated cases with FTIR and micro-X-ray fluorescence (XRF). Heterogeneous pigmented deposits were discovered in spinal cord, brain stem and motor neuron cortex of two ALS cases. The FTIR signature of creatine has been identified in these deposits and in numerous large, non-pigmented deposits in four of the ALS cases. Comparable pigmentation and creatine deposits were not found in controls or in ALS hippocampus and substantia nigra. Ca, K, Fe, Cu and Zn, as determined by XRF, were not correlated with the pigmented deposits; however, there was a higher incidence of hot spots (Ca, Zn, Fe and Cu) in the ALS cases. The identity of the pigmented deposits remains unknown, although the absence of Fe argues against both erythrocytes and neuromelanin. We conclude that elevated creatine deposits may be indicators of dysfunctional oxidative processes in some ALS cases.

Synchrotron microbeam X‐ray fluorescence (µ‐SXRF) was applied for topographic and quantitative analysis of selected elements in human brain and spinal cord. The main goal of the study is a better understanding of the role of elements, mainly metals, in processes leading to degeneration and atrophy of nerve cells in cases of two neurodegenerative disorders, i.e. Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). The samples were taken during the autopsy from patients deceased with PD, ALS, and from a patient who died due to non‐neurological conditions. In measurements, a 5 × 2 µm2 X‐ray beam was applied for scanning the thin tissue slices. Two‐dimensional maps of elemental distribution were compared with histopathological sections. The results obtained showed that the spatial distribution of selected elements precisely corresponds to the microscopic views of scanned area of tissue. Moreover, differences in accumulation of selected elements in nerve cell bodies and areas representing white matter between patients affected by PD, ALS and the control case were noticed. The present investigation showed that the µ‐SXRF technique is suitable for elemental analysis at the single cell level in applications in neurological research. Copyright © 2003 John Wiley & Sons, Ltd.

X-ray absorption near edge structure spectroscopy was applied in order to investigate differences in iron chemical state between the nerve cells of substantia nigra (SN) representing Parkinson's disease (PD) and those of control cases. Autopsy samples were cut using a cryotome, and were not fixed and not embedded in paraffin. The comparison of the absorption spectra near the iron K-edge measured in melanized neurons from SN of PD and control samples did not show significant differences in iron oxidation state. Measurements of inorganic reference materials containing iron in the second and third oxidation states indicate that most of the iron in all the nerve cell bodies examined was oxidized and occurred as trivalent ferric iron (Fe 3+ ).

The central nervous system (CNS) is undoubtedly the most complex structure in the human body. Metal ions play an important role in the normal functioning of this organ. Disturbances of metal ion homeostasis may lead to serious diseases of CNS. On the other hand, the abnormal accumulation of selected elements may be a result of pathological processes. The application of different analytical techniques to the determination of the normal and pathological accumulation of trace elements in human CNS tissue has proved to be popular in recent years. A review of current analytical activity for human CNS tissue is presented. Special attention is paid to the remarkable opportunities provided by using synchrotron radiation in elemental analysis. The results of application of synchrotron radiation x‐ray fluorescence (SRXRF) as well as x‐ray absorption near‐edge structure (XANES) spectroscopy to investigate Parkinson's disease, amiotrophic lateral sclerosis and brain gliomas are shown. Topographic and quantitative analysis with the use of SRXRF allows the determination of minor and trace elements in thin tissue samples of human CNS at the single‐cell level. The comparison between these pathological cases and control group pointed out differences in elemental composition of the tissues. Moreover, application of XANES spectroscopy made it possible to determine oxidation states of Fe and S in Parkinson‐diseased tissue and brain gliomas. Copyright © 2007 John Wiley & Sons, Ltd.