Environmental effect and genetic influence: a regional cancer predisposition survey in the Zonguldak region of Northwest Turkey

The Cretaceous-Eocene volcano-sedimentary units of the Zonguldak region of the western Black Sea consist of subalkaline andesite and tuff, and sandstone dominated by smectite, kaolinite, accessory chlorite, illite, mordenite, and analcime associated with feldspar, quartz, opal-CT, amphibole, and calcite. Kaolinization, chloritization, sericitization, albitization, Fe–Ti-oxidation, and the presence of zeolite, epidote, and illite in andesitic rocks and tuffaceous materials developed as a result of the degradation of a glass shards matrix, enclosed feldspar, and clinopyroxene-type phenocrysts, due to alteration processes. The association of feldspar and glass with smectite and kaolinite, and the suborientation of feldspar-edged, subparallel kaolinite plates to fracture axes may exhibit an authigenic smectite or kaolinite. Increased alteration degree upward in which Al, Fe, and Ti are gained, and Si, Na, K, and Ca are depleted, is due to the alteration following possible diagenesis and hydrothermal activities. Micromorphologically, fibrous mordenite in the altered units and the presence of needle-type chrysotile in the residential buildings in which cancer cases lived were detected. In addition, the segregation pattern of cancer susceptibility in the region strongly suggested an environmental effect and a genetic influence on the increased cancer incidence in the region. The most likely diagnosis was Li-Fraumeni syndrome, which is one of the hereditary cancer predisposition syndromes; however, no mutations were observed in the p53 gene, which is the major cause of Li-Fraumeni syndrome. The micromorphology observed in the altered units in which cancer cases were detected may have a role in the expression of an unidentified gene, but does not explain alone the occurrence of cancer as a primary cause in the region.     

Assessment of geo-environmental problems of the Zonguldak province (NW Turkey)

The Zonguldak province is a coastal settlement area that has been suffering from serious natural and human-induced environmental problems sourced by its geology and geomorphology. Since the province locates at the heart of a coal-producing basin, the geo-environmental problems related to mining activities such as esthetic degradation, disposal of mining wastes and subsidence of the abandoned coal galleries are badly affecting every day life in Zonguldak province. Disposal of municipal wastes is also a big problem since only one municipality out of 32 has a sanitary disposal area. The rest of the municipalities dispose their solid wastes to rivers or to the sea. The province has also some health problems, which are pointed out in the literature, related to coal mining and geologic environment. These are cytogenetic damage in peripheral lymphocytes and pheumoconiosis (most commonly seen at coal workers), goiter and cancer. Landslides are the most important hazards in the area since 13% of the total surface of the Zonguldak is affected by landslides. In this study, considering the hazard potential special attention is given to deep landslides and using the stepwise forward conditional logistic regression technique, the landslide susceptibility map for the Zonguldak province is produced. The results showed that the most important independent variables governing the landslides are slope gradient, volcanic, and sedimentary rocks of Eocene and clastic and carbonate units of Cretaceous. The landslide map is used as a base map for the production of geo-hazard reconnaissance map on which areas subjected to other important geo-hazards (flood, earthquake and subsidence) are also shown to provide guidance for both existing settlement areas to take the necessary preventive measures and for new developing settlement areas to avoid the problematic areas.