Effects of Multicomponent Hydrocarbon Feed on Hydrocarbon Adsorption–Desorption and Oxidation Light-Off Behavior on a Pd/BEA Hydrocarbon Trap

In order to determine how water flowpath controls stream chemistry, we studied both soil and stream water during spring snowmelt, 1985. Soil solution concentrations of base cations were relatively constant over time indicating that cation exchange was controlling cation concentrations. Similarly SO4 adsorption-desorption or precipitation-dissolution reactions with the matrix were controlling its concentrations. On the other hand, NO3 appeared to be controlled by uptake by plants or microorganisms or by denitrification since their concentrations in the soil fell abruptly as snowmelt proceeded. Dissolved Al and pH varied vertically in the soil profile and their pattern in the stream indicated clearly the importance of water flowpath on stream chemistry. Although Al increased as pH decreased, the relationship does not appear to be controlled by gibbsite. The best fit of calculated dissolved inorganic Al was obtained using AlOHSO4 with a solubility less than that of pure crystalline jurbanite.

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Methodology of Research in Micropollutants – Heavy Metals

Water Science & Technology ◽

10.2166/wst.1982.0037 ◽

1982 ◽

Vol 14 (12) ◽

pp. 107-125 ◽

Cited By ~ 15

Author(s):

Roland Wollast

Keyword(s):

Heavy Metals ◽

Mathematical Models ◽

Aqueous Phase ◽

Suspended Matter ◽

Solid Phase ◽

Aquatic Organisms ◽

Biological Processes ◽

Particulate Phase ◽

Sources Of Pollution ◽

Adsorption Desorption

A comparison of the concentration of dissolved and of particulate heavy metals in the aquatic system indicates that these elements are strongly enriched in the suspended matter. The transfer between the aqueous phase and the solid phase may be due to dissolution-precipitation reactions, adsorption-desorption processes or biological processes. When these processes are identified, it is further possible to develop mathematical models which describe the behaviour of these elements. The enrichment of heavy metals in the particulate phase suspended or deposited and in aquatic organisms constitutes a powerful tool in order to evaluate sources of pollution.

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Trace Metal Soil Quality Criteria to Protect Ground Water

Water Science & Technology ◽

10.2166/wst.1992.0728 ◽

1992 ◽

Vol 26 (9-11) ◽

pp. 2327-2329

Author(s):

J. Lee ◽

B. Chen ◽

H. E. Allen ◽

C. P. Huang ◽

D. L. Sparks ◽

...

Keyword(s):

Drinking Water ◽

Quality Criteria ◽

Maximum Level ◽

Inorganic Materials ◽

Decision Making Process ◽

Water Quality Standards ◽

Solution Ph ◽

Drinking Water Standard ◽

Cadmium And Lead ◽

Adsorption Desorption

A major problem in site remediation is frequently the lack of appropriate standards for pollutants in soil. Lack of standards for an exposure route can result in subjective judgments regarding the extent of remediation needed. These problems are particularly important when considering the potential for groundwater contamination by inorganic materials. The partitioning of trace metals is highly dependent on the nature of the soil and on the solution pH. The maximum level of metal in soil for which the equilibrium soluble metal does not exceed the drinking water standard can be computed, at any pH, from the measured partition coefficient for any metal and soil. The sorption of cadmium and lead onto major types of New Jersey soil has been determined as a function of pH. As the pH decreased, the amount of adsorbed metal decreased. As is conventionally done, we have transformed these data into sorption coefficients (Kd) which are a function of pH. To apply such data in the decision making process, it is necessary to use the Kd and appropriate conditions of soil/groundwater in the environment. The calculation determines the maximum concentration of metal which will not result in exceedence of water quality standards. Thesecriteria can be used as a soil standard which will be protective of groundwater quality. We developed adsorption/desorption relationships in the form of a mathematical model and computed the maximum level of metal in soil for which the equilibrium soluble metal will not exceed the drinking water standards.

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