Objectives:

1. Development of preparation method for soil and sediments samples
2. Development and validation of the quantitative method for the determination of heavy metals in soil
3. Elaboration of quantitative method for the determination of TOC, DOC, THM in drinking waters
4. Determination of heavy metal and REE concentration in soil and sediments from the surrounding zones of the raw water accumulations
5. Participation to interlaboratory testing for the determination of metals in water, soil  
6. Determinations of heavy metal and REE in water samples. Experimental data accumulation
7. Results dissemination:


1. Development of preparation method for soil and sediments samples

    Our studies were aimed at developing more efficient methods of extracting (US EPA Methods - www.epa.gov) organic compounds from complex matrices for multi-element analysis by inductively coupled plasma mass spectrometry. Extraction of the solid samples was done with concentrated mineral acids (HF conc., HNO3 conc., HCl conc.) with the digestion system/ microwave mineralization, type Mars 5. Extraction of soil samples was done in special reaction vessels, Teflon, XP-1500 Plus, with a volume of 100 ml.  
    Microwave digestion process of the sample took place after a temperature and pressure well defined program depending on the nature of sample. To establish the optimum extraction method has been developed several different methods of extraction with concentrated mixture acids. A reliable extraction method is providing an extraction efficiency of least 90% of the desirable element. The best results for microwave digestion with mixture of acids was the procedure HNO3:HF:HCl = 3:1:0,7, v/v/v. Microwave acid digestion method  reduces the risk of external contamination, small amounts of reagents and provides accurate of analytical method.
    In conclusion, the result of the extraction procedure is an essential part in defining the procedure for measuring the environmental analysis.

2. Development and validation of the quantitative method for the determination of heavy metals in soil

    All the determinations were carried out by inductively coupled plasma quadrupole mass spectrometry (ICP-Q-MS). A PerkinElmer ELAN DRC (e) instrument was used.

    Ultra-pure de-ionized water (18 MΩcm-1) from a Milli-Q analytical reagent-grade water purification system (Millipore) and ultra-pure HNO3 60% (Lot –No B0157318 Merck) were used. In order to validate the method for determining the concentration of metals, NCS ZC 73006 Certified Reference Material was used.  For digestion of this reference material, an acid mixture (3 ml HNO3 ultrapure 60%, 2 ml HF 40%) was used. Calibration standard solutions and internal standards were prepared by successive dilution of a high purity ICP-multielement calibration standard (10g/l from twenty-nine element ICPMS standard, item N9300233, Matrix: 5% HNO3, PerkinElmer Life and Analytical Sciences).
Several parameters have been taken into account and evaluated for the validation of the analytical methods for quantitative determination of metals in soils, namely:
    - linearity domain: using calibration solutions calibration curves: y = ax + b, were determined, where y is the signal intensity and x is the know concentration of the given analyte in the calibration solution. The linearity of the calibration curve was considered acceptable when the correlation factor R>0.999  
    - the minimum detection limit: is the lowest concentration or quantity of analyte which can be measured with reasonable statistical certainty. To determine the limit of detection 3SD, a method developed by PerkinElmer was used (the limit of detection ranged between 0.0001-0.034 mg/kg for studied metals)
    - the limit of quantification is the lowest concentration that can be quantitatively determined with an acceptable level of repeatability accuracy. The quantification limit is generally considered to be approximately ten times the minimum detection limit
    - the maximum measurement limit is conditioned by the dynamics of the spectrometer detectors and limited by the requirement that the total amount of the dissolved solid must not exceed 0.2% in the sample solution (unless clogging of the nebulizer nozzles would lead to instabilities and loss of sensitivity). To test the maximum measurement limit, two samples of 1.5 and 2 mg/l As, Cd, Hg, Pb, Ni, Se, Cr, Be were prepared.
    - repeatability was obtained measuring the same sample, with the same method, in the same laboratory, with the same equipment, by the same operator, in short intervals of time. Intermediate repeatability was obtained measuring the same sample, with the same sample, in the same laboratory, but by different operators and in different days. Standard deviation was found to lie between 1-6%.
    All the possible sources of uncertainty have to be carefully identified and taken into account. While measuring the concentrations by ICP-MS with external standard, fluctuations in the measurement of ionic currents occurring as a result of the electrical noise in the detector, instabilities in plasma discharge, instabilities of the electrical parameters of the analyzer, lead to uncertainties in the determination of the parameters of the calibration line. Possible errors in the preparation of the calibration solutions increase these uncertainties. The uncertainty estimation takes into account the uncertainty influence in determining the parameters of the calibration curve; highest value was to Mn (19.60 mg/kg to a concentration of 793 mg/kg).

3. Elaboration of quantitative method for the determination of THM in drinking waters

      In a large number of Water Treatment Plants (WTPs) from a wide range of countries, chlorine is one of the most popular disinfectant agents used for disinfection purposes owing to its increased efficiency in removing microbes. Unfortunately behind positive effects of disinfection practices, has been observed that uses of chlorine have resulted also in formation of potential toxic and carcinogenic chlorination by-products such as trihalomethanes (chloroform, dichlorobromomethane, dibromochloromethane, bromoform).
    In this study, different analytical techniques were developed and applied for the analysis of trihalomethanes in drinking water. Their analyses were performed with gas chromatograph (GC). Mass spectrometer (MS) and electron capture detector (ECD) were used as detectors for trihalomethanes detection from water samples. Performance of different extraction techniques such as liquid-liquid extraction (LLE), headspace extraction (HS) and headspace-solid phase microextraction (HS-SPME) were evaluated, optimizing: volume ratio of sample, extraction temperature and incubation time to HS; the addition of salts, magnetic stirring, desorption time and fiber selection to HS-SPME, solvent selection to LLE. Analytical parameters such as linearity, repeatability and limit of detection were also evaluated. Lower detection limits were obtained for all THMs compounds with ECD detection than in case of mass spectrometry detection, 0.02–0.07 µg/l and 0.1–0.5 µg/l, respectively. Linearity range in both detection cases were between 0.5 µg/l up to 250 µg/l.
    The results of THMs from the water samples collected from Gilău and Zalău WTPs and their corresponding distribution systems showed that the most predominant trihalomethane compounds was chloroform, which was within the Romanian drinking water quality standard of 100 µg/l.

4. Determination of heavy metal and REE concentration in soil and sediments from the surrounding zones of the raw water accumulations.

    The soils like water and air is an environmental factor with important impact on health. The soil quality depends on the formation and protection of water sources, both the surface water and especially the ground water.  
    The concern regarding the possible ecological effect of the increasing accumulation metallic contaminants in the environment is growing. For this reason, the investigation of heavy metals in sediments is essential since even slight changes in their concentration above the acceptable level (whether due to the natural or anthropogenic factors) can results in serious environmental harms and subsequent problems. Sediment samples have the ability to reflect the water quality and can be used for the assessment of river pollution particularly trace elements.
Soil and sediments samples from raw water accumulation from the surrounding areas of Cluj were characterized (collected in 2009, 2010). Trace metal (such as: Hg, Ag, Cd, Pb, As, Co, Zn, Cr, V, Mn, Cu) were quantitatively determined in a large range of concentration, between: 0.001-2500 µg/l. There have been found:
    - close values of Hg, Ag, Cd concentrations in different location (except for higher values of Cd and Hg in soil sample taken from Someşul Rece). The concentrations obtained in some areas exceed the permitted limits by regulations (Cd - 1 mg/kg, Hg -0.1 mg/kg), but the values don’t fall below the limit of sensitive alert. The results obtained For Ag were within normal limits.
    - Co concentrations close enough from different areas, under the permissible limits (except Tarniţa and Someşul Rece - where there were obtained values close to the alert limits).
    - As concentrations are above the limit allowed at the confluence area: Someşul Rece lake /Someşul Cald lake, reaching to a value corresponding to a stage of intervention.
    - The highest concentrations of Cr and V were reported in samples taken from Someşul Cald
    - Samples from the Gilău dam are more concentrated in Mn (in the sensitive threshold concentration), Cu (in the interventional area), Zn (sensitivity alert threshold), and Pb (alert threshold sensitivity)
    - Comparative quantitative characterization of soils and sediments’ samples from the same geographic areas has highlighted a bigger accumulation of rare metals in sediments than in soils.
    - Comparative characterization of the waters/sediments from the same collecting areas have highlighted that the sediments accumulate a bigger quantity of toxic and rare metals.

5. Participation to interlaboratory testing for the determination of metals in water, soil
 
    Interlaboratory testing was initiated (INCDTIM Cluj-Napoca, Cluj-Napoca ICIA, and ICSI Rm.Vâlcea). Two standard solutions were analyzed by different concentrations of water and digested solution of a soil reference material. The results showed that the results fall in the range of uncertainty given for the proposed methods.

6. Determinations of heavy metal and REE in water samples. Experimental data accumulation

    Water samples were taken from lakes/rivers that feed Cluj County: Beliş, Tarniţa, Someş Cald, Someş Rece, and Gilău.  
Water samples from different areas close to raw water accumulations from Cluj and Salaj were characterized.  Heavy metals around 0.001-25 µg/l were quantitatively determined.
    The results obtained from samples from different areas and different periods (months, years) from Cluj have highlighted small toxic metal concentrations such as: As, Cd, U, Pb, Co - under the allowed limits; Al concentrations ranging between 5-20 µg/l  and Zn - between  under the allowed limit.  A concentration of Mn has been noticed (around tail of Tarniţa lake), of Al (near the end of the Gilău lake), and Ni (Someşul Cald). Toxic metals concentrations in the water samples from Salaj are under the limits imposed by regulations.
    In all analyzed water samples, the selenium was in concentrations below the limits of detection method (<0.001µg/l).
Water samples from waters treatment stations (Gilău-Cluj entry and Cluj distribution areas), collected in 2009-2010 were characterized on the basis of toxic metals. The values obtained were within the following ranges: 0.1-0.6 µg/l (As); 0.03-0.7 µg/l (Pb); 0.007-0.2 µg/l (U); <0.001 (Cd).
In order to determine the concentration of rare earths a standard multielement was used (Multi-element Calibration standard  (2:10 mg/l –Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Sc, Tb, Th, Tm, Y, Yb – PerkinElmer (Atomic Spectroscopy Standard).
The rare metals concentrations in water ranged between 0.001-0.5 µg/l (excepting Sc: -0.5- 5 µg/l)  

7. Results dissemination:

• Conference participation

• Upgrading the web page