Lead In Natural Waters Research Articles

Determination of Trace Amount of Lead in Natural Water by Isotope Dilution-Inductively Coupled Plasma Mass Spectrometry.

Isotope dilution-inductively coupled plasma mass spectrometry (ID-ICP-MS) was applied to the determination of lead in natural water, and its precision was compared to that of the conventional calibration method. Trace amount of lead in natural water was preconcentrated using a chelating resin of Chelex 100 before ID-ICP-MS, where the preconcentration factor of 50 was obtained. The concentrations of lead were 26.1 pg/g and 266 pg/g for the certified river reference materials (JAC 0031) and the pond water sample, respectively, with the RSD less than 1%.

Voltammetric determination of lead with a chemically modified carbon paste electrode with diphenylthiocarbazone

A carbon paste electrode modified with dithizone (diphenylthiocarbazone) was employed for quantification of lead from aqueous solutions. Lead(II) was chemically deposited on the chemically modified electrode (CME) by complexation with the modifier, and the electrode was transferred to an electrochemical cell for pulse voltammetric anodic stripping. The response depends on the concentration of lead in the bulk solution as well as the parameters involved in both the preconcentration and the measurement steps. For a 6-min preconcentration time, the calibration graph is linear from 20.7 ng ml −1 to 207.2 ng ml −1 and from 207.2 ng ml −1 to 518.0 ng ml −1. The detection limit (DL, 3σ) was about 16.7 ng ml −1 and the response could be reproduced with a 5.8% relative standard deviation at the concentration level of 31.1 ng ml −1. Interferences by metal ions which compete for complexation with the modifier on the CME surface could be eliminated by using masking reagents. Strong complexing agents, such as sulphide, interfere. The method was used for the determination of lead in natural waters.

Determination of lead in natural waters using flow injection with on-line preconcentration and flame AAS detection

A rapid and sensitive method has been developed for the determination of lead in water samples by flame atomic absorption spectrometry using on-line preconcentration on a microcolumn packed with silica gel treated with a mixture of Aliquat 336 and nitroso-R-salt. The lead is retained at pH 5.5. The preconcentrated lead is directly eluted from the column to the nebulizer-burner system using 150 μL of 0.1 mol/L hydrochloric acid. The optimum preconcentration conditions are given and the retention efficiency achieved is higher than 80%. The enrichment factor is 37 and 100 for sample volumes of 5 and 30 mL, respectively. The limits of detection are 10.0, 6.0 and 4.0 ng/mL when 5, 10 and 30 mL of water is preconcentrated.

Small crack growth in mutiaxial fatigue: Reddy, S.C. and Fatemi, A. Proc. Conf. Advances in Fatigue Lifetime Predictive Techniques, San Francisco, California, USA, 24 Apr. 1990 276–298

The development of 3D printing in recent years opens up a vast array of possibilities in the field of flow analysis. In the present study, a new 3D-printed flow system has been developed for the selective spectrophotometric determination of lead in natural waters. This system was composed of three 3D-printed units (sample treatment, mixing coil and detection) that might have been assembled without any tubing to form a complete flow system. Lead was determined in a two-step procedure. A preconcentration of lead was first carried out on TrisKem Pb Resin located in a 3D-printed column reservoir closed by a tapped screw. This resin showed a high extraction selectivity for lead over many tested potential interfering metals. In a second step, lead was eluted by ammonium oxalate in presence of 4-(2-pyridylazo)-resorcinol (PAR), and spectrophotometrically detected at 520 nm. The optimized flow system has exhibited a linear response from 3 to 120 µg L−1. Detection limit, coefficient of variation and sampling rate were evaluated at 2.7 µg L−1, 5.4% (n=6) and 4 sample h−1, respectively. This flow system stands out by its fully 3D design, portability and simplicity for low cost analysis of lead in natural waters.

DISCUSSION1

The sequential development of trace metal clean techniques has resulted in a systematic decrease in reported lead concentrations in the ocean. Similar decreases have been observed in reports of lead concentrations in fresh water. This was illustrated by the changes in reported baseline concentrations of lead in Lake Huron. However, even the latest (1980) of those concentrations (19 ng/L) appears to be erroneously high based on recent measurements of lead concentrations in the Great Lakes. Lead concentrations in surface waters in the center of Lake Ontario are < 2 ng/L or one order of magnitude lower than the reported baseline concentration of Lake Huron in 1980. Corresponding concentrations of lead in surface waters of Lake Huron should be equal to or less than those in Lake Ontario. Anthropogenic lead fluxes to Lake Huron (621 metric tons per year) and Lake Ontario (592 metric tons per year) are comparable, while the assimilative capacity of Lake Huron is two-fold greater than that of Lake Ontario. Moreover, the atmospheric flux of industrial lead aerosols to surface waters in Lake Huron is approximately one half of the flux in Lake Ontario. Therefore, if removal rates are similar in these two lakes, the authors expectmore » the baseline concentration of lead in Lake Huron to be {le} 2 ng/L or one order of magnitude lower than the 1980 baseline concentration. Concentrations in remote fresh water systems in North America, where inputs of industrial lead aerosols are orders of magnitude lower should also be < 2 ng/L. The preceding measurements and projected concentrations of lead in fresh water systems in North America are of note in light of some recent reports on the decrease of lead in natural waters within the US. Those reports are questionable, in spite of other reports of decreasing lead concentrations in the Mississippi River and North Atlantic.« less

Determination of cadmium and lead in natural waters

Determination of cadmium and lead in natural waters

The use of anodic stripping voltammetry for determination of the concentration and forms of existence of lead in natural waters

The application of anodic stripping voltammetry to the determination of the lead distribution in natural waters was studied. The optimum procedure has been developed and applied to samples of river waters. It was concluded that the method is applicable for the purpose, but may be difficult to apply in the presence of larger amounts of organic impurities. Probable effects of these impurities on the determination were discussed and a possibility of their detection outlined.

Determination of cadmium, copper and lead in natural waters after anion-exchange separation

A method is described for the determination of cadmium, copper and lead in samples of natural non-saline waters. After acidification with hydrobromic acid, the water sample is filtered and, following the addition of ascorbic acid, passed through a column of the strongly basic anion-exchange resin Dowex 1-X8 (bromide form). On this exchanger cadmium(II). copper(I) and lead(II) are adsorbed as anionic bromide complexes. After elution of these elements with 1 M nitric acid, the determinations by atomic absorption spectrometry are carried out in a medium consisting of 90% ( v v ) methanol and 10% ( v v ) 1.5 M hydrobromic acid. The procedure was used for the routine determination of cadmium, copper and lead in water samples collected in Austria.