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We sought to develop a longer and more robust history of pollution in the Hudson River by studying LWB1-8, a high sedimentation rate core (~1 cm/yr) retrieved near Yonkers, NY. The sediment has been affected both by industrial pollution and natural disasters such as distant volcanic eruptions. In order to study this core, we analyzed its elemental composition in a variety of ways. Previous data from ITRAX scanning of the core years ago was lined up with new elemental analyses done with an XRF machine in order to pick which layers may be the most likely to contain volcanic ash. If ash particles were deemed likely in these layers, samples were run through a Franz, or magnetic materials were separated out using a Nb magnet. Then, particles of potential ash were picked out by hand. These ash candidates were then run through an SEM machine to provide a more in-depth elemental analysis of the particles as well as obtain high-resolution photos of them. Peaks in uncalibrated Ni, Ti, and SI (peaks in counts) from the ITRAK can be used to locate the depths of prospective volcanic ash layers. Ni peaks were especially good at identifying which layers may contain volcanic ash. .We found at least four layers containing volcanic ash , but there is still uncertainty about their source volcanoes. Many of the volcanic ash particles have very high Fe and very low K contents. These likely come from explosive Icelandic eruptions like those of Hekla. Other ashes have very low Fe, higher K and higher Si. These ashes likely come from volcanic arcs located at high latitudes, such as the Cascade and Aleutian arcs. This experiment has shown that it is possible to find volcanic ash in Hudson River cores. However, the number of ash particles we have retrieved so far is very small, from one to nine per age horizon. We do best at finding ash below 100 cm, where there is little industrial pollution. In future, we need to refine our methods of segregating ash from industrial debris. We must also analyze our ash particles on a microprobe and an ICPMS to determine their source volcanoes. Only then can we convert our measurements of metals versus depth into a pollution history. 

Our study examines how volcanic ash layers affect Earth's environment and climate, focusing on carbon, cadmium, and sulfur changes in deep-sea sediment from the Toba super eruption 74,000 years ago. This eruption, the largest of the Quaternary period, released 2,800 cubic kilometers of material and sulfur dioxide, which formed sulfate aerosols, potentially causing a volcanic winter. In sediment core RC14-37, we found a 15 cm thick Toba ash layer at 100-115 cm depth, with the highest ash concentration at 102-104 cm, significantly diluting the sulfur signal from 102-106 cm and masking the sulfur peak. Elevated sulfur levels just below the top of the ash layer suggest rapid deposition after most ash settled, with levels decreasing towards the base, indicating additional atmospheric sulfur. We used X-ray fluorescence (XRF) to measure sulfur and cadmium content. High cadmium levels in the ash layers suggest increased marine productivity. The SiO2 content in the ash ranged from 66% to 78%. Given that Toba ash contains 12 ppm sulfur, our corrected sulfur content (1700-3100 ppm) suggests most sulfur came from atmospheric sulfate aerosols. These results indicate increased biological productivity and sulfur in the ash layers, providing insights into the eruption's ecological impacts.