Soil functional assessments

There are two standardised procedures for measuring the functional activity of the soil microbial community. These provide an indication of the size and activity of 

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In PAH solubilization tests with soil, batch-test soil-aqueous samples with nonionic surfactant and 14C-PAH were rotated on a tube rotator periodically to maintain the soil in suspension during equilibration. The samples were centrifuged, and aliquots were expressed through preconditioned 0.22- xm Teflon filters to reduce soil-derived colloidal substances. The extent of PAH solubilization in nonionic surfactant solution without soil was assessed in batch tests as a function of surfactant dose to confirm the value of PAH aqueous solubility (S) and to determine the values of Scmc and MSR. Nonionic surfactant sorption onto soil was evaluated for sub-CMC (or sub-CAC) aqueous-phase concentrations by surface-tension measurements. Supra-CMC sorption of nonionic surfactant to determine or supra-CAC isotherm was assessed either with azo dye solubilization and spectrophotometric analysis, or by measurement of chemical oxygen demand, from which the amount of surfactant in bulk solution could be inferred (10). 

Accepting that the absence of an international guideline should not be a barrier to the use of developing methods, further useful methods can be identified. Some, such as the bait lamina (Tome, 1990a) and earthworm lysosomal membrane stability assay (Weeks and Svendsen, 1996), are now well established in the scientific literature and appear particularly suited to assessing exposure and effects. Some of the biomarker techniques, such as ChE inhibition, metallothio-nein induction and possibly immune function assessment, can be used to provide valuable information regarding the nature of the chemicals present and the exposure of soil species. 

A miniaturized MB spectrometer MIMOS II was developed for the robotic exploration of Mars, where it provided fundamental information about mineralogical composition and alteration processes, helped to classify rocks and soils, aided geologic mapping, was instrumental in assessing habitability of past and present environments, and identified potential construction resources for future human explorers. The applicability of the instrument as a process monitor for oxygen production and prospecting tool for lunar ISRU has been demonstrated. The characterization of air pollution sources and the study of mixed-valence materials as a function of depth in soil are examples of terrestrial in situ applications. MIMOS lla with additional XRF capability will open up new applications. 

The introduction of estrogens and progestogens into the environment is a function of the way several factors are combined. The manufactured quantity and the dosage applied (amount, frequency, and duration) combined with the excretion efficiency of the compound and its metabolites, the capability of adsorption and desorption on soil, and the metabolic decomposition in sewage treatment are examples of necessary factors to assess environmental exposure. In general the fate and effect of a substance in the environment is dependent on the distribution into the different natural systems, such as air, water, and solids (soil, particles, sediment, and biota). Information on the physical and chemical properties (Ku, Kd, and Kim vapor pressure) of a compound may help determine whether it is likely to concentrate in the aquatic, terrestrial, or atmospheric... 

Rutgers, M. (2000). Site-specific ecological risks a basic approach to the function-specific assessment of soil pollution, ISBN 9073270448, Wageningen, The Netherlands. 

The major sources of PCBs, globally, are found in northern latitudes. Breivik et al. [144,145] published a complete assessment of global historical usage of PCBs and, using a mass balance approach, predicted emissions of PCBs to the air as a function of their use and climate factors (primarily temperature). They identified major sources of PCBs as directly contaminated soils, fires, open use, use in capacitors, use in closed systems, disposal to landfills, waste incineration, and PCB destruction. They found that use... 

Studies on sorption of triazines by individual soil constituents and by model sorbents have been very helpful in evaluating sorption mechanisms and in assessing the potential contribution of various constituents to triazine sorption by soils. However, intimate associations between organic substances, silicate clays, and oxyhydroxide materials modify the sorptive properties of the individual constituents. Associations between soil constituents influence soil properties - such as pH, specific surface area, and functional group availability - which in turn influence triazine sorption behavior. For instance, atrazine and simazine sorption behavior is different for synthetic mixtures of model soil... 

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