P033

Zinc, Lead, and Arsenic Mode of Occurrence in the Mineral Waters of Primorye

(Results of Physical-Chemical Modeling)

A0081 Lev. M.Gramm-Osipov V.I.I1'ichev Pacific Oceanological Institute, FEB RAS

A0082 Aleksej. V. Savchenko V.I.I1'ichev Pacific Oceanological Institute, FEB RAS

A0083 Valentina N. Gramm-Osipova V.I.I1'ichev Pacific Oceanological Institute, FEB RAS

Chemical composition of mineral waters in Primorye has been studied

quite well. But it concerns only the total content of chemical

elements, while the speciation is unknown. In order to trace these

elements it is necessary to know their mode of occurrence in the

studied system. The authors were interested in the chemical processes

occurring at the contact of the subsurface water with the atmosphere.

To solve the above problem it was used the program complex of Selector

- C (Karpov, 1982). The authors created and solved the physical-

chemical models of the mineral waters of different pH types from 5.75

to 9.47 in the temperature interval from in situ to 25°C; it was also

modeled the interaction of the subsurface waters with the atmosphere.

The results of modeling are as follows:

1. pH of a closed system (there is no contact with the atmosphere)

decreases with the temperature growth.

2. In the waters where pH is below 9, the lead and zinc practically

occur in the form of PbHCO3+ and ZnHCO3+ . The predominant form of

arsenic in these waters is HAsO20.

3. The only spring where pH exceeds 9 (Amgu, pH=9.47) it was obtained

the following micro-components distribution: lead - not determined,

zinc - 81.4 % as ZnHCO3+ and 18.52 % as ZnHS+, arsenic is almost

all presented as H2AsO3- .

4. At the contact with the atmosphere, practically in all water types ,

excepting the Amgu Spring, it was observed pH increasing up to 8.9-

9.1. In all cases, it was iron hydroxide (III) which precipitated

from solution, and in some springs it was also boehmite and calcite.

On the contrary, at the contact with the atmosphere, the Amgu

Spring waters were acidified to pH=8.4, and also it was observed

the iron hydroxide (III)precipitation .

5. For all water types, at the contact with the atmosphere, the lead

and zinc speciation doesn't change, they occur in solution mainly

as the hydro-carbonate complexes. As to the arsenic, it is

oxidized to +5 and it is found mainly (97.8 %)as HAsO42- .