david diaspora

Bucharest - September 2010

University of Bucharest, ROMANIA

Iulia Gabriela David, Vasile David, Iulia Gabriela David, Vasile David, Department of Analytical Chemistry, Faculty of Chemistry

Marius Matache, Marius Matache, Centre for Environmental Research and Impact Studies


essential elementsessential elements Fe, Se, Cu, Zn Fe, Se, Cu, Zn

toxic metals toxic metals Pb, Cd, Hg, AsPb, Cd, Hg, As


Obtain &preserverepresentative

sample

Transform the sample to an analyzable form

Calculate the result

(Input)

(Black box)

(Output)


Ialomita River Prut River

Seasonal variations in trace metals concentrations

Quantification of xenobiotics bioaccumulation

in wetland food chains

aimaim

techniquetechnique

ICP-AES ASV

(filtration)


-springs from the Southern Carpathians collecting its waters from

hydrographical basin surface area of 10350 km2 (4.4% of the

total area of Romania).

-length of the main collector – Ialomiţa – is 417 km, and of the total

rivers network is 3131 km (4.6 % of the total length of the hydro-

graphic network of the country).

The Ialomiţa gathers the waters of 145 water flows


Sampling sessions: Sampling sessions: APRIL –

period of high snow melting in the mountain zones- AUGUST periods of reduced flow and high temperature of the water- NOVEMBER period of high precipitation

Sampling sites:Sampling sites:7 places along Ialomita Riverfrom the axis of maximum turbulence of the river, from the water-sediment interface

Sample preservation:Sample preservation:- in Teflon bottles- concentrated HNO3 added to avoid analytes losses


Hydrographical basin of the Ialomiţa river with indications of the sampling points.

1 Pietroşiţa– upstream of any pollution source-natural background 2 Pucioasa– downstream from the Pucioasa reservoir lock→contribution

of 2 economic operators – the cement factory+light sources factory Fieni.3 Ciolpani – characterises the region Pucioasa reservoir lock and DN 1 Bucharest– Ploieşti, possible pollution

sources: Pucioasa city, thermo-electric power station Doiceşti, Târgovişte city with the special steel aggregate works4 Dridu – downstream from the Dridu reservoir lock– characterises region of agricultural activities; 5 Albeşti – Urziceni town, live-stock farms Căzăneşti, contribution of

the Prahova river;6 Bucu –Slobozia twon with

chemical fertilizers aggregate works, 7 Vlădeni –Ţăndărei town

Doiecesti

Targoviste


Modell for the disturbance of ecological balance in wetlands (CCMESI, 2008)

Bioaccumulation of heavy metals and/or pescticides along food chains

Domestic, industrial and agricultural waste waters; organic substances; nutrients

Excessive exploitation of fisheries resources

Toxic atmospheric inputs: NOX, SX, heavy metals

Uncontrolled hunting;Poaching

Uncontrolled deforestation

Excess of nutrients for fisheries


Sampling sessions: Sampling sessions: Spring - april 2009Summer - july 2009

Sampling:Sampling:6 sampling places along the Romanian side of Prut River from the axis of maximum turbulence of the river, from the water-sediment interface

Sample preservation:Sample preservation:- in Teflon bottles- concentrated HNO3 added to avoid analytes losses

1. Upstream of the Maţa-Rădeanu complex water quality at the entrance of the Prut river into

the Lower Prut Floodplain Natural Park2. Downstream of the Rogojeni village influence

of some pollution sources: Maţa-Rădeanu complex, Pochina lake, Cacia and Leahu pools, Broscarului and Teleajen lakes and the localities Vădeni and Rogojeni

3. Downstream of Vlădeşti and Măicaşu lakesimpact of the two lakes, of Şovârca pool and

localities Oancea, Slobozia-Oancea and Vlădeşti

4.Downstream of Vlăşcuţa lake influence of lakes

Brăneşti, Vlăşcuţa, and of Manta lake on the left side of Prut (Moldova Rep), and localities Brăneşti and Măstăcani

5.Downstream of Beleu, at Tuluceşti covers a region including the loop Cotul Hiului and some

localities on the left river side and Beleu lake6.Upstream of Prut’s run into the Danube finalsampling point----- influence of Brateş lake, of

agricultural fields-gives an image of pollutants concentrations

transferred by Prut into the Danube Bucharest - September 2010


SCHEMATIC OF AN ICP-AESpectrometer

Nebuliser

Ar

excited atoms

hDetector

Polychromator

(Ar+sample aerosole)

(T=8000Kh=12 cm)

(cooling, 12 L/min)

(0.8 L/min)

(1 L/min)

Sample(0.002 l/min)

(Frequency 27.12 MHz Power adjustable 800 -1,600 W)

(165–210 nm;210-580 nm)

Plasma torch


-low detection limits for over 70 elements (ppb)

[e.g. 10 ppb for Pb; 50 ppb for As]

-PDA detectors enable simultaneous multielemental analysis

-enables automatisation high sample throughput :

1-3 minutes for a complete analysis of 30 elements

- high Ar consumption-expensive instrumentation


-HMDE-MFE-Bare C, Au, etc.

10-4 -10-5 Hg+2 for co-metal deposition.

A cathodic or reducingpotential is applied for afixed time interval reducing Mn+

Potential is scannedin anodic or oxidizingdirection to strip out Mo


•Sensitive and reproducible (RSD<5%) method for

trace metal ion analysis in aqueous media.

Accuracy is proportionate to the way of sample calibration:<5% when calibrated directly via the method of standard

additions. 10% when a calibration curve is built before measuring20% - 40% when operating uncalibrated

•Concentration limits of detection for many metals are in

the low ppb to high ppt range (S/N=3)

ppm - instantaneous ppb < 30 seconds or less ppt - several minutes

compares favorably with AAS or ICP analysis.

•Simultaneous metal ions analysis.

No interference between: Pb, Cd, Cu and Hg Zn, Pb, Cd and Hg Zn and Cu at low concentrations

(higher concentrations + Ga3+ )Interferences:

Tl - with Cd, Pb Bi - with Cu (at conc > 50 times)

Aplications to saline solutions: unlike Graphite AA techniques, salinity does not impact the accuracy or performance of the metals measurement


CuPb

Zn

Cd

Ga


Sample pretreatment•In General: no electrode rotation or sample de-oxygenation. •Clean samples: only addition of a supporting electrolyte. •Biological, Soil, Seawater and Dirty-Water:

• filtration• wet acid digestion (+ UV digestion).

•Cost of ultra-sensitive instrumentation. A quarter of the cost of AA systems A tenth of the cost of ICP systems Use one electrode to measure up to five metals Robust electrodes can make thousands of measurements; can use disposabel electrodes (PGE) Small, field devices – cheap !!!


•Selectivity & sensitivity can be improved by electrode surface modification e.g.:-Bi deposition on GCE (DL=1.4×10-10 mol/L Pb²+; 0.03 μg/L)

[C. E. Cardoso et.al. Anal. Sci., 23, 1065, 2007]

-Heparin modified GCE (DL= 3×10-10 mol/L Pb²+; 0.06 μg/L) [N.-B. Li, J.-P. Duan, G.-N. Chen, Chin. J. Chem., 22, 553, 2004]

-Polyethacridine film modified GCE (PFM-GCE)

Ethacridine lactate (Rivanol)

Film preparation: -5 CV cycles (0-1,5 V vs AgAgCl); v=100 mV/s - ABS (pH=5.00) + 10-2 M ethacridine lactateSurface cleaning: - 5 minutes in 0,1 M HNO3 at 0.100 VMetal ions determination Technique: -AS-DPV Medium: - 0.1 M HNO3 Accumulation:Eac= -1.2 V vs g/AgCl

tac= 120 s (C <10-7 mol/L Cd²+ )

ResultsResultsBare GCE MF-GCE PFM-GCE

LR= 5 10-7 – 10-5 mol/L 2.2 10-8 – 10-6 mol/L 10-8 -10-5 mol/L Cd²+

DL= 5 10-8 mol/L Cd²+ 8 10-9 mol/L Cd²+ 5 10-9 mol/L Cd²+

http://upload.wikimedia.org/wikipedia/commons/e/e3/Ethacridinlactat.svg


Variation of Zn and Mo concentration in water samples from the Ialomiţa River


Technique:

Differential Pulse Anodic Stripping Voltammetry (DP-ASV)

Working electrode:

Mercury film deposited on a glassy carbon electrode (MF-GCE)Optimum conditions: tac = 120 s, Eac= -1,1 V; v = 20 mV/s, Pulse amplitude = 50 mV; Sampling width = 20 ms; Pulse width = 40 ms; Pulse periode = 300 s

Concentration evaluation method: Standard addition

Analyte: Cu(II), Pb(II), Cd(II) from Prut River water samples

and mollusks


DP-anodic stripping voltammograms recorded in HNO3 0,1 M on

MF-GCE for sample 6 collected upstream of Prut’s run in theDanube: (6b-5)=water sample 6; (6b-6)= water sample 6 + 0,1 mL standard solution; (6b-7)= water sample 6 + 0,2 mL standard solution containing Cu(II) = Cd(II)= Pb(II)= 8 10-3 g/L.


Me(II)sample

Cu(II) (g/L) Pb(II) (g/L) Cd(II) (g/L)

apriljuly

apriljuly

apriljuly

pr1 3.20 10-61.30 10-5 3.00 10-6

<LOD 2.10 10-5<LOD

pr2 6.74 10-51.60 10-5 5.66 10-7

2.60 10-4 1.61 10-5<LOD

pr3 1.93 10-54.10 10-5 1,83 10-5

1.80 10-5 3.30 10-51.20 10-4

pr4 3.88 10-5<LOD <LOD <LOD 1.48 10-4

<LOD

pr5 9.20 10-69.50 10-6 <LOD <LOD 5.15 10-5

<LOD

pr6 6.70 10-62.50 10-5 8.60 10-6

<LOD 1.09 10-4<LOD

Heavy metals concentration in Prut River Water Samples


SeparationSeparation Shell Soft part

Washing

Weighing

Adding 5 ml HNO3 (65%) 5 ml HCl (35-37%) 5 ml HClO4

Heating to dryness

Adding 5 ml HNO3 (65%) 5 ml HCl (35-37%)

Heating

Filtering

Diluting with MilliQ H2O to the mark of a 25 ml volumetric flask

Lymnaea stagnalis, (sample X 5 collected on 29.07.2009, at sampling point 6, where Prut runs into Danube).


-1.50E-02

-1.00E-02

-5.00E-03

0.00E+00

-1000 -800 -600 -400 -200 0

i (A

)

E (mV)

X4

X41

X42

DP-anodic stripping voltammograms recorded in HNO3 0,1 M on

MF-GCE for dissoluted mollusk sample X4 (Lymnaea stagnalis) collected upstream of Prut’s run in the Danube: (X4)=dissoluted mollusk sample; (X41)= dissoluted mollusk sample + 0,1 mL standard solution; (X42)= dissoluted mollusk sample + 0,2 mL standard solution containing Cu(II) = Cd(II)= Pb(II)= 8 10-3 g/L.


Acknowledgement

Financial support is acknowledged from the

PN-II- project BIOXEN 32111-2008.

david diaspora

Education

university of bucharest

ialomia river

sampling places

sampling sessions

sampling points

total length

dridu reservoir lock

total area of romania