Multi O- and S-isotopes as tracers of black crusts formation under volcanic and non-volcanic atmospheric conditions in Sicily (Italy)

The deterioration of monument or building stone materials is mostly due to the growth of black crusts that cause blackening and disaggregation of the exposed surface. This study reports on new oxygen (δ¹⁷O, δ¹⁸O and Δ¹⁷O) and sulphur (δ³³S, δ³⁴S, δ³⁶S, Δ³³S and Δ³⁶S) isotopic analyses of black crust sulphates formed on building stones in Sicily (Southern Italy). The measurements are used to identify the possible influence of volcanic emissions on black crust formation. Black crusts were mostly sampled on carbonate stone substrate in different locations subject to various sulphur emission sources (marine, anthropogenic and volcanic). Unlike atmospheric sulphate aerosols that mostly exhibit Δ³³S > 0‰, here most of the analysed black crust sulphates show negative Δ³³S. This confirms that black crust sulphates do not result from deposition of sulphate aerosols or of rainwater but mostly from the oxidation of dry deposited SO₂ onto the stone substrate. The δ³⁴S and δ¹⁸O values indicate that most of black crust sulphate originates from anthropogenic activities. Δ¹⁷O values are found to be related to the sampling location. The largest ¹⁷O-anomalies (up to ~4‰) are measured in black crust from areas highly influenced by volcanic emissions, which demonstrates the strong involvement of ozone in the formation of black crusts in volcanically influenced environments.

[The pathogenesis of rapidly destructive coxarthrosis]

Using clinical, radiological and histologic examinations, 41 cases with the rapidly destructive coxarthrosis (RDC) were studied. (a) The radiological findings of RDC were classified into the following three types; type I suddenly started from the normal hip joint and terminated in the upper outer subluxation with destruction of the head and acetabulum resulting in narrowing of the joint space; type II was clinically very similar to type I. The joint was destructed but remained in the primary acetabulum; type III developed into sudden destruction of the joint during ordinary course of secondary RDC. (b) The histological findings of RDC were classified into those involving avascular necrosis and those involving osteoarthritis. (c) 65% of cases of radiological Type I showed avascular necrosis, 33% in Type II, and 12.5% in Type III. (d) The clinical examinations revealed that most cases have some immunological abnormality. The present study, therefore, indicates that the most common pathogenesis of RDC has a basic condition of avascular necrosis in the femoral head in the elderly, in addition, the accompanying rapid destruction appears to be related to an immunological abnormality.