Properties of New York/New Jersey Harbor Sediments

Sediments found in waterways around the world may contain toxic compounds of anthropogeilic origin that can harm the environment and human health. As a result, it is often necessary to remove them and find disposal methods that are environmentally and economically acceptable. Here, we report on results obtained in an experimental program to characterize the nature of the sediment contamination. The objective was to gain a better understanding of the properties of the sediments to develop better methods for understanding the fate and transport of the contaminants and for improving methods for their removal from the sediments. Our investigations made use of x-ray facilities at the Brookhaven National Synchrotron Light Source (NSLS) and the European Synchrotron Radiation Facility (ESRF) at Grenoble, France. The experiments included: measurements of the microstructure of the sediments using computed microtomography, x-ray absorption, and fluorescence microscopy with resolutions as low as 0.2 micrometers to obtain information on the relationships of organic and mineral components of the sediments and on the distribution of contaminants on the surfaces of the sediment grains, investigation of functional groups of chemical compounds using x-ray absorption near-edge spectroscopy (XANES) and Fourier Transform Infrared Spectroscopy (FTIR). Scanning electron microscopy (SEM) and electron probe measurements were made to ascertain the morphology of the sediment surfaces and the distribution of metals on individual sediment grains

Characterization of sulfur in New York/New Jersey waterway sediment

Sulfur plays an important role in the biogeochemical cycle of trace elements and in the diagenetic reactions in sediments/soils. Due to very low solubility of sulfide compounds, metal sulfides are a big concern in the coastal and marine environment. In this study, we investigated sulfur compounds and speciation in contaminated sediments from the wateways of New York and New Jersey in the region of New York City, USA. Measurements were made on particles from the National Institute of Standards and Technology Standard Reference Material (SRM) 1944 (a composite from 6 locations) and from a mud flat on the Passaic River in New Jersey, USA. The experimental measurements were made at the ID21 X-ray Microscopy beamline at the European Synchrotron Radiation Facility (ESRF), France. Maps of the Si, P, and S distributions were made with a sub-$\mu$m beam on individual sediment particles. In order to chemically specify sulfur, X-ray absorption near-edge spectroscopy (XANES) measurements were taken from selected areas (regions-of-interest) within these maps

Characterization of Sulfur in New York/New Jersey Waterway Sediment

Sulfur plays an important role in the biogeochemical cycle of trace elements and in the diagenetic reactions in sediments/soils. Due to very low solubility of sulfide compounds, metal sulfides are a big concern in the coastal and marine environment. In this study, we investigated sulfur compounds and speciation in contaminated sediments from the waterways of New York and New Jersey in the region of New York City, USA. Measurements were made on particles from the National Institute of Standards and Technology Standard Reference Material (SRM) 1944 (a composite from 6 locations) and from a mud flat on the Passaic River in New Jersey, USA. The experimental measurements were made at the ID21 X-ray Microscopy beamline at the European Synchrotron Radiation Facility (ESRF), France. Maps of the Si, P, and S distributions were made with a sub-μm beam on individual sediment particles. In order to chemically specify sulfur, X-ray absorption near-edge spectroscopy (XANES) measurements were taken from selected areas (regions-of-interest) within these maps

Phase contrast X-ray microscopy at 4 keV photon energy with 60 nm resolution

X-ray microscopy in the multi-keV photon energy range offers unique possibilities to study relatively thick samples with high spatial resolution. When employing a high N. A. condenser zone plate for sample illumination in combination with a high resolution micro zone plate objective tens, a spatial resolution of currently 60 nm is achieved. We report here on phase contrast X-ray microscopy at 4 keV photon energy on copper interconnect structures, buried in silicon dioxide. While the amplitude contrast in those samples is only 7%, negative as well as positive phase contrast were demonstrated using 2.2 $\mu$m and 0.7 $\mu$m high Nickel phase rings with a contrast of 30% and 39%, respectively

Fluorescence X-ray microscopy on hydrated tributyltin-clay mineral suspensions

Using the scanning transmission X-ray microscope at ID21 beamline of the ESRF in fluorescence mode, we mapped tin at a bulk concentration of 1000 $\mu$g(Sn)/ml within hydrated tributyltin (TBT)-clay mineral (Kaolinite) dispersion with sub-300 nm spatial resolution. Using the $L$ absorption edges of tin at 3929, 4156 and 4465 eV fluorescence radiation was excited in tin atoms with incident photon energies of 4 and 4.5 keV. When using 4 keV radiation, only tin fluorescence is excited. For 4.5 keV X rays, both the fluorescence of tin and calcium (which is present in the solid phase) can be measured. Methodologically, we were interested in assessing and proving the possibilities and limitations of fluorescence mapping using the $L$ absorption edges of tin, where the fluorescence yield is significantly lower compared to other elements with their $K$ edges in the same energy range. Scientifically, organotin-clay mineral interactions are of environmental concern because this factor influences significantly the distribution of toxic TBT in the aquatic System. On one hand, the half-life of TBT deposited to the sediment phase increases, and consequently the time of its bioavailability. On the other hand, the adsorption process is reversible, which means that contaminated sediments can act as a source of pollution. The adsorption and desorption effects can be studied directly with high spatial resolution and brought into connection to the surface properties of the clay mineral under study as well as to other experimental parameters, like pH or salinity

Spectromicroscopy of soil colloids

A soil with a high organic content, a calcaric phaeozem, has been imaged in a hydrated state using the Stony Brook scanning transmission X-ray microscope at the NSLS, Brookhaven, USA. This experiment has been performed at the carbon K absorption edge to determine the distribution of organic matter within this soil. Spectromicroscopic methods using the known spectra of humics are helping to distinguish between different kinds of carbon in the sample. In addition, a marsh soil from Northern Germany has been analyzed at the sulfur $K$-absorption edge with the scanning X-ray microscope at the ESRF (ID 21), Grenoble, France. This soil contains a variety of sulfur containing components, which are attached to the soil colloids. A major source of these components is the microbial activity. In this soil it is possible to identify spectroscopically amino acids like methionin and cysteine and proteins, which are built up from those molecules, and inorganic components like sulfates and sulfides

Design, fabrication, and analysis of chirped multilayer mirrors for reflection of extreme-ultraviolet attosecond pulses

Wonisch A, Neuhäusler U, Kabachnik NM, et al. Design, fabrication, and analysis of chirped multilayer mirrors for reflection of extreme-ultraviolet attosecond pulses. APPLIED OPTICS. 2006;45(17):4147-4156.Chirped Mo/Si multilayer coatings have been designed, fabricated, and characterized for use in extreme-ultraviolet attosecond experiments. By numerically simulating the reflection of the attosecond pulse from a multilayer mirror during the optimization procedure based on a genetic algorithm, we obtain optimized layer designs. We show that normal incidence chirped multilayer mirrors capable of reflecting pulses of approximately 100 attoseconds (as) duration can be designed by enhancing the reflectivity bandwidth and optimizing the phase-shift behavior. The chirped multilayer coatings have been fabricated by electron-beam evaporation in an ultrahigh vacuum in combination with ion-beam polishing of the interfaces and in situ reflectivity measurement for layer thickness control. To analyze the aperiodic layer structure by hard-x-ray reflectometry, we have developed an automatic fitting procedure that allows us to determine the individual layer thicknesses with an error of less than 0.05 nm. The fabricated chirped mirror may be used for production of 150-160 as pulses. (c) 2006 Optical Society of America

Microanalysis of NY/NJ Harbor Sediments using Synchrotron X-Ray Beams

Sediments found in the New York/New Jersey Harbor are widely contaminated with organic and inorganic compounds of anthropogenic origin. As a result, the environmental health of the Harbor has deteriorated and the efficient operation of the Port compromised by difficulties in disposing of sediments resulting from maintenance and improvements of navigational channels. Knowledge of the properties of the sediments on a micro-scale is useful in understanding the transport of contaminants through the environment, for developing effective methods for sediment decontamination, and for subsequent beneficial use of the cleaned sediments. We have investigated several properties of these sediments using synchrotron radiation techniques. These include computed microtomography using absorption and fluorescence contrast mechanisms, x-ray microscopy, microbeam x-ray fluorescence, and Fourier Transform Infrared Spectroscopy (FTIR) for measurements of microstructure, distribution of metals on individual sediment particles, and chemical forms of the contaminants on a micrometer scale. Typical results obtained with these techniques are presented