The environmental factors affecting the archaeological buildings in Egypt, “IV deterioration by synergistic marine effects”

Abstract

AbstractThis paper investigates the marine effects that affect Qait Bey Fortress in Alexandria—Egypt. It presents the results of scientific studies and examinations to evaluate the deterioration conditions that affected archaeological buildings in themarine environment. In Alexandria, many monumental sites and stone buildings have suffered from many aggressive factors of deterioration (mechanical, chemical, and biological), which have caused great harmful appearances and threatened to eradicate them. These effects include the chemical actions resulting from seawater and marine aerosol and the mechanical actions of water waves. (Qait Bey Fortress), as a case study, was periodically investigated by many scientific techniques over five years to check its decay conditions and to define the most suitable conservation approaches and non-destructive methods for preservation. Different techniques and examinations were carried out to evaluate the current deterioration state of the fortress. For example, XRD analysis and PM investigation were used to study the mineralogical compositions, lithotype, and petrographic characteristics of the stone samples. SEM was used to investigate the morphological features of the same samples. AAS was also used for studying the chemical constituents of seawater samples. In addition, microbiological investigations were conducted to evaluate the colored hard crusts that affected the stone surfaces in the fortress. Our results proved that severe deterioration factors influenced the fortress by collaborating with chemical, mechanical, and biological mechanisms. These mechanisms caused several manifestations, such asabrasion and attrition, crystallizing of salt species, mortar desegregation, pitting and minerals’ honeycomb (Alveolar), color changes, in addition to theaccumulation of black and colored biogenic hard crusts composed of numerous tightly adjoining pits of several centimeters. Crusts, such as yellow to bluish green, resulted fromP. aeruginosaand granular appearance having brownish ting in the center resulted fromP. clacis. In addition, other pigmented features resulted fromBacillus firmusandBacillus atrophaeus. The presence of some black and dark color crusts was attributed to the growth of some fungal species, such asA. niger,A. phoenicis,Cladosporium cladosporioides, andAlternaria alternata.