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191.
To fulfill the purpose as a sink for trace elements, soils must not be overloaded with As and Cd. Therefore, it is necessary
to get knowledge of the sorption capacities of soils on a regional scale. The determination of these sorption capacities for
large areas is, however, impeded by the great expenditure of laboratory work involved. With data presented here retention
capacities for cadmium and arsenic from routinely determined soil parameters are estimated. In batch experiments the sorption
behaviour of 40 soils from the area of Freiberg/Saxony in Germany was examined. The obtained sorption isotherms from the laboratory
were fitted to the Freundlich equation (S = k*Cm). The two constants (k, m) of this equation were used for multiple linear regression to correlate the sorption capacity and
the soil parameters, namely clay content, pH value, total organic carbon, and dithionite extractable Fe contents. Due to long
lasting ore mining of Freiberg there exist high background levels in that area for the two surveyed elements As and Cd. Therefore,
this study offers two different mathematical procedures to take these contaminations into account. Thus the experimental data
were corrected before they were fitted to Freundlich and pedotransfer equations were determined. Using the transfer equation,
parameter k and m for cadmium sorption could be estimated with statistical certainties of 91% and 61% (adjusted R2), respectively, whereas the predictability for the arsenic sorption is not practicable because achieved R2 values are very low (17% and 7%).
This revised version was published online in June 2006 with corrections to the Cover Date.
This revised version was published online in June 2006 with corrections to the Cover Date.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
192.
An integrated modeling approach is used to link land use to river discharge, and then to survival of larval walleye that hatch
in northern Ohio streams draining into Lake Erie (USA). First, to link land use and river discharge, the parameters of a simple
hydrologic model are statistically related to watershed landscape attributes, including forest cover. One such relationship
allows estimation of the change in daily river discharge that could result from a reduction in basin-scale forest cover. Second,
to represent the river discharge-larval survival link, we reexamine a dataset from Mion and others to propose a relationship
between daily flow velocity, water temperature, and walleye larval survival. Together, these linked models provide estimates
of the reduction in larval survival due to reduction in forest cover, along with the uncertainty of those estimates. For the
Grand River watershed, decreasing forest cover from 45.2 to 30% is projected to reduce average larval survival by about 45%.
In the adjacent Chagrin River, dropping cover from 62.5 to 30% reduces survival by almost 60%. The greater rate of reduction
of survival in the Chagrin River as forest levels fall is explained by a relatively greater increase in storm flows for the
Chagrin, due to more frequently saturated soils. Therefore, forest preservation in the Chagrin River watershed is projected
to be more effective in preserving walleye larval tributary habitat. 相似文献