PROJECT RESULTS

1. Identification of the elements present in the selected waters by semi-qualitative methods

2. Development and validation of the quantitative method for the determination of heavy metal concentrations in water

3. Drawing up web page

1. Identification of the elements present in the selected waters by semi-qualitative methods

Inductively coupled plasma mass spectrometry (ICP-MS) is an analytical technique used for elemental determinations. In this study, the Perkin Elmer Elan DRC (e) ICP-MS instrument was used; it provides analytical methods allowing a rapid, simultaneous determination of the concentration of nearly all the elements in the Periodic Table. Though this method is a semiquantitative one, it is still a very useful tool for the rapid quantification of elements within various samples. 

Water samples were taken from the treatment plant Gilãu (raw, filtered), from the point of entry in Cluj-Napoca (Şapca Verde) and from the different points of the distribution (Faculty of Chemistry, Faculty of Environmental Sciences, Institute of Public Health). Also, the waters from Sălaj County were collected from six locations (Crasna and Vârşolt lakes, Hororatu Crasnei, Jibou, input/output water treatment station Zalău).

Several groups of elements were established, classified by the range concentrations: light elements Na, Mg, Ca (with concentrations between 1900 and 7000 µg/l), elements whose concentration is between 10 and 500 µg/l (Al, Ti, Fe, Cu, Zn, Sr, Ba), elements whose concentration is between 0.1 and 10 µg/l (Co, Ni, As, Mo, Pb), rare-earth metals (at concentrations below 0.1 µg/l.

2. Development and validation of the quantitative method for the  determination of heavy metal concentrations in  water

The minimum detection limit is the lowest concentration or quantity of analyte which can be measured with reasonable statistical certainty. The limit of detection ranged between   0.5-5 ppt for the studied metals ensures the limit of quantification required for quantitative determinations of the concentrations of these elements in waters. Good linearity (correlation factor 0.998≥R≥0.9999) for most elements recommends the method described for determination at trace and ultra-trace level. Maximum limit of measurement is limited by the requirement that the total amount of solid dissolved in the sample solution must not exceed 0.2%.

The uncertainty estimation takes into account the uncertainty influence in determining the parameters of the calibration curve; values determined lies between (0.09-3.7) μg/l, depending of concentration domain.

Reproducibility was tested by two European interlaboratory tests (LGC Standards Proficiency Testing Distribution. The score Z was <1.

Method validation is the basis of the validation report laboratory measurements by ICP-MS metals – RENAR accredited laboratory for method:”Determination of trace metals in water by ICP-MS”.