An investigation of the effects of commercially available herbicides on local building materials

Abstract

Herbicides are widely used, both locally and internationally, on all types of cultural heritage. They have become an integral part of vegetation management in the conservation of heritage. Currently, a limited amount of knowledge is available on the effects of herbicides in conservation practices, especially locally. Due to the growing use of herbicides in cultural heritage, the need was felt for scientific research to investigate the effects of these products on local building materials, with particular reference to Globigerina and Coralline Limestone. The current dissertation focuses on surface effects, especially as regards colour and texture changes, and internal effects, especially as regards water and vapour movement, caused by herbicide applications to the local limestone. Testing carried out included: visual observations: colour and texture, weight of samples, drying index, static contact angle, water absorption by capillarity and immersion and water vapour permeability. Results have shown that herbicide applications do generally affect the overall visual characteristics of the treated stone, causing changes in colour and texture. Tests that investigated behaviour with water have highlighted a change In moisture movement, as well as water repellence with a particular herbicide. This study will hopefully shed new light on the effects of using herbicides in cultural heritage, making professionals and operatives in the field aware of the damage that can result from their application.