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Magnetometry as a Tool to Estimate the Pollution of Marine Environment Around Small Shipwrecks (Gulf of Gdańsk) – Preliminary Results

Gwizdała M., Jeleńska M., Łęczyński L.

Acta Geophysica

2016

Vol. 64, no. 5

1691--1702

Magnetic properties of deposits around the shipwrecks (“Munin” and “Abille”) in the Gulf of Gdańsk were investigated. Values of magnetic susceptibility (χ) are relatively low; however, they reveal significant differences between investigated sites. The values of χ around “Abille” wreck were 5-8×10-8 m3 /kg. Around “Munin” wreck results were more diversified reaching value of χ between 3.07×10-8m3 /kg and 12.92×10-8 m3 /kg. The spatial variability of χ coincided with near-bottom water currents distribution in the Gulf of Gdańsk. Magnetic minerals were identified by thermomagnetic analysis. Around “Abille” wreck we have found magnetite with small amount of maghemite or hematite. The “Munin” sediments include only one magnetic phase; in several samples it is magnetite, in the others – maghemite. Day–Dunlop plot shows that “Abille” set is shifted towards lower magnetization ratio and higher coercivity ratio. The correlation between the distribution of χ and hydrodynamic condition around shipwrecks allows to determine the direction of contaminant transport.

Magnetic signature of indoor air pollution: household dust study

Górka-Kostrubiec B., Jeleńska M., Król E.

Acta Geophysica

2014

Vol. 62, no. 6

1478--1503

The combination of magnetic and geochemical methods was used to determine the mineralogy, grain size and domain structure of magnetic particles in indoor dust collected in 195 sites in Warsaw, Poland. Data show an asymmetric distribution of magnetic susceptibility (χ) in the wide range of 20-1514 × 10-8 m³ kg–1. Comparison of magnetic parameters shows that the internal dust contains outside pollution characteristic for air and soil. More than 90% of indoor dust samples were characterized by roughly uniform magnetic mineralogy, typical for fine grained magnetite (diameter of 0.2-5 μm), and grain size between pseudo-singledomain and small multi-domain with small contribution of superparamagnetic particles (~10%). Samples with χ larger than 220 × 10–8 m³ kg–1 contain mainly magnetite and an anthropogenic metallic Fe with TC > 700°C. The indoor dust contains, characteristic for the urban areas, spherical magnetic particles originated from fossil fuel combustion processes and mixture of irregular angular iron-oxides grains containing other elements, including Na, Ca, Al, Si, K, S, Mn, Cl, and Mg.