## 1 Introduction  
The scale of contaminant migration from sanitation systems highly depends on variable climatic conditions, range of geological formations and soilscapes [1]. Heavy metals are non-biodegradable and persist in the aqueous solution as toxic substances within the environment [2]. The release of heavy metal wastes towards water resources can cause many physical, chemical and biological modifications [3]. Accumulation of heavy metals in water sources cause threats to human life and the environment [2]. Heavy metal level determination in water resources is important, since most of them are harmful even at low concentrations [3]. Heavy metals can be a challenge in catchment water resources for an extended time, even when the source has been remediated [2]. In most rural and some urban areas in developing countries, people rely solely on untreated surface and groundwater sources for drinking purposes [1]. Monitoring, on a regular basis, of these water resources can sometimes be costly to meet the recommended guidelines for drinking water sources [1, 4, 5]. Heavy metal ions in solution tend to be difficult to remove with the use of traditional techniques [2, 6]. Frequently applied techniques for measuring heavy metal concentration, such as inductively coupled plasma optical emission spectrometry (ICP-OES), are time-consuming and expensive [2; 7; 8]. The analysis time, cost, laboratorial simplicity, need for chemical reagents, and sample amount per analysis can be essential in monitoring water contaminants [9]. The Fourier Transform Infrared (FT-IR) Spectroscopy has emerged to be very effective in analysis of any sample [9; 10; 11; 12]. Infrared spectroscopy has proven to have potential in the analysis and concentration of heavy metal contamination [2; 6; 8]. Application of the FT-IR techniques for the investigation of heavy metal elements has been significantly developed due to their flexibility and accuracy [7; 8; 13; 14]. Advances in the IR spectroscopy has led to the use of an interferometer and the Fourier-transform algorithm. The FT-IR spectroscopy operates through the interface of an IR beam with a sample. IR radiation excites the vibration of the coordination bond in metal complexes, the ionic bond in crystals and the covalent bonds between atoms. The product is an infrared spectrum that mirrors the complete chemical composition of the sample [9]. FT-IR is a non-destructive method normally used to distinguish the functional groups responsible for heavy metals adsorption [13; 14]. The applied FT-IR method can also be useful for characterization of heavy metals in ionic or sub-nanosized cluster form in a colloidal dispersed system and metals dispersed in solution [15]. The infrared position can give information for oxidation state, bonding and morphology of the dispersed clusters of heavy metal ions [16; 17]. To attain reproducible results, sample treatment procedures, IR measurement techniques and IR acquisition parameters must be controlled and calibrated rigidly [10]. Use of chemometric models such as Partial Least Square (PLS) and Principle Component Regression Analysis (PCA) relate the multiple spectral intensities from numerous calibration samples to the recognized analytes within samples by removing the random variation (noise) and retaining the principal components that capture the important variation [15; 18]. Nonetheless, the challenge on the choice of the optimal measurement procedure remains imprecise [7]. There is also a critical question on the dynamic issues of representativeness of samples for spectral analyses and relationship of the measurements in the laboratory after sample preparation or direct analysis. Moreover, other concerns relate to the choice of spectral methods, the influence of the difference of the material studied on the results, or the choice of chemometric techniques to create a calibration and prediction model [8; 19; 20].