## 2 Application of Membranes in Contamination Situations
### Contamination of the Soil Environment
This is due to their very good mechanical properties, resistance to chemical and biological degradation, and suitability for operation in various conditions, e.g., in areas with high or low temperatures. The influence of temperature and soil properties on the penetration process of petroleum hydrocarbons through three different types of geomembranes (HDPE, low density polyethylene LDPE, PVC) was investigated for both laboratory samples and samples after three years of use in the area of low temperatures. The diffusion parameters of the geomembranes were measured at 7 and 14 \({}^{\circ}\)C, and the data were combined with previously published test results at 23 \({}^{\circ}\)C. PVC geomembranes were also tested at 2 \({}^{\circ}\)C. It was found that all the measured parameters decreased with the temperature. Moreover, exposure of LDPE and PVC to cyclic freezing and thawing did not affect the values of diffusion parameters. The diffusion parameters of the HDPE geomembrane collected from the research site at the Resolution Island landfill (an island in the Labrador Sea, located on the south-eastern shore of Baffin Island), after three years of use, were compared with the unaged and unexposed HDPE geomembrane from the same manufacturer, confirm their comparability. On this basis, it was found that the cold climate and cyclic freezing and thawing in the field did not negatively impact the diffusion parameters of the geomembrane. Thus, the research results fully confirmed the usefulness of such protection as a diffusion barrier in the landfill [55]. Geomembranes can be also subjected to elevated temperatures both due to their use in various areas and due to exothermic degradation processes taking place in landfills. Elevated temperatures may reduce the life or effectiveness of geomembranes by accelerating the loss of antioxidants in the geomembranes and degradation of the polymer [56; 57]. A case history is provided to illustrate the potential effects of elevated temperatures and time-temperature history on the HDPE geomembrane and associated reduction in service life or performance. Based on laboratory studies and a case study of an aluminum waste landfill, it was found that the usefulness of the geomembrane may be reduced to decades when temperatures reach 60-80 \({}^{\circ}\)C, due to degradation processes related to the loss of antioxidants. The destruction and degradation of membranes may cause unsealing and release of pollutants into the environment [58]. Therefore, the type and nature of membranes should be properly selected depending on the environmental conditions and the purpose of the reclamation (Table 2). Geomembranes may also be subjected to mechanical damage causing leaks from landfills or other protected places. Minimizing leakage through the geomembrane is very important for environmental protection and water management, and is essential in many industrial applications [66]. Each geomembrane laid, and especially the large-size one, should be tested to avoid any undetected damage. Geomembrane lined containment rooms are designed to contain fluids. It is often difficult to detect leaks that arise, and on occasions, it may take years or decades to detect groundwater contamination. An effective method of leak detection is the electrical leak location (ELL) technology. All ELL methods follow the basic principle of introducing an electric potential through the geomembrane by applying a current source to a power source above the geomembrane and returning the current below it. If there is a break in the geomembrane, then an electric current will flow from the source to the return through the break. It should be added that ELL methods can be divided into two different categories, i.e., exposed geomembrane methods and covered geomembrane methods [67]. The biggest advantage of the covered geomembrane methods is that the measurements are made after the covering material has been laid. This makes it possible to detect the largest leaks.