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A model for the tracking of inorganic chemical reactions is proposed. Designed to acquire, process, and solve a great number of inorganic reactions, this model will hopefully contribute to the development of powerful computer-aided chemistry teaching systems for use within or without the environment of a virtual laboratory. Using full representation of an inorganic reaction to allow the extraction of chemical knowledge, incomplete reactions (where species are absent) may be completed by adding the necessary species, and reactions may be solved and balanced. Various types of reaction are classified, and a layer-based model is defined for the solution of different reaction types, establishing the basis for the construction of a system which, based on a wide set of production rules, is capable of solving an incomplete inorganic chemical reaction.
Discrete-depth sampling of inorganic groundwater chemistry is essential for a variety of site characterization activities. Although the mobility and rapid sampling capabilities of direct-push techniques have led to their widespread use for evaluating the distribution of organic contaminants, complementary methods for the characterization of spatial variations in geochemical conditions have not been developed. In this study, a direct-push-based approach for high-resolution inorganic chemical profiling was developed at a site where sharp chemical contrasts and iron-reducing conditions had previously been observed. Existing multilevel samplers (MLSs) that span a fining-upward alluvial sequence were used for comparison with the direct-push profiling. Chemical profiles obtained with a conventional direct-push exposed-screen sampler differed from those obtained with an adjacent MLS because of sampler reactivity and mixing with water from previous sampling levels. The sampler was modified by replacing steel sampling components with stainless-steel and heat-treated parts, and adding an adapter that prevents mixing. Profiles obtained with the modified approach were in excellent agreement with those obtained from an adjacent MLS for all constituents and parameters monitored (Cl, NO(3), Fe, Mn, DO, ORP, specific conductance and pH). Interpretations of site redox conditions based on field-measured parameters were supported by laboratory analysis of dissolved Fe. The discrete-depth capability of this approach allows inorganic chemical variations to be described at a level of detail that has rarely been possible. When combined with the mobility afforded by direct-push rigs and on-site methods of chemical analysis, the new approach is well suited for a variety of interactive site-characterization endeavors.
A critical issue facing the turfgrass industry is the environmental fate and transport of organic and inorganic chemicals used on golf courses. The fate and distribution of those chemicals are strongly influenced by sorptive interactions with soil and sediment. In this study, the drainage and water supply piping material (used for construction of a prototype encapsulated golf green) was utilized to determine its potential sorption of three organic chemicals [2,4-dichloro-phenoxyacetic acid] (2,4-D), naphthalene and toluene and nitrate. Crushed piping material (small-to-large particle sizes) was evaluated. Isotherms were constructed using a batch equilibration technique. The results showed that the drainage/supply piping material at small particle sizes (<2.5 mm) has higher sorptive ability compared to soil (1.7 for 2,4-D and 13.4 for naphthalene). The K(F) value was 44, 253 and 70 for 2,4-D, naphthalene and toluene, respectively. K(oc) values were much higher than those of peat and soil at lower equilibrium concentrations. However, sorption decreased dramatically with increasing particle size (approaching zero at particle size 10 mm), due to reduction of surface areas and sorption sites. Sorption of NO(3)-N by the piping material was negligible. We concluded that sorption by intact drainage/supply piping material would not affect the recycling efficiency of pesticides and nutrients in the constructed encapsulated green. Conversely, drainage/supply piping material particles smaller than 2.5 mm in diameter can effectively be utilized as a filtering material.
Food tables documenting the concentration of various nutrients in individual foods do not provide satisfactory information on the contribution of essential inorganic trace elements by prepared meals. Only direct analysis of the actual food consumed during a 24-hour period can give an accurate estimate of the dietary intake. Employing the duplicate portion technique, we have analysed the concentration of a number of inorganic chemical elements in 882 dietary samples from various population groups in Sweden. The intake of several elements including potassium, magnesium, zinc, copper and selenium, in the normal mixed diets is low when compared with recommended dietary allowances (RDA). Vegetarian diets are richer in these elements than ordinary non-vegetarian diets. Plasma levels of trace elements are often poor indicators of body status. A clinical follow-up of a group of pensioners in Dalby, Sweden, for a period of 10-12 years has not indicated any specific signs or symptoms of trace element deficiencies. Vulnerable groups, namely, children, pregnant women, alcoholics and the elderly, may, however, be more susceptible than the population in general to marginal deficiencies resulting from normal everyday consumption of Western diets.
Inorganic substances constitute by far the greatest proportion of chemical contaminants in drinking water. They are present in greatest quantity as a consequence of natural processes but several important contaminants are present as a result of man's activities. Some of the most important even come from the plumbing material through which water is passed. Inorganic contaminants are the most important determinands of acceptability to the consumer, affecting taste, colour and scale deposition on pipes and fittings. They are also demonstrably the most important for health, having both beneficial and adverse effects which have been shown in human populations. This is a brief review of some of the most important inorganic constituents of drinking water covering major elements such as hardness and nitrate and more minor constituents in terms of quantity, such as arsenic, selenium and lead.
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Inorganic constituents of the leaves of several kinds of plants growing on different soil types were investigated using energy-dispersive X-ray fluorescence spectrometry. The results can be summarized as follows: (1) Each plant exhibited a characteristic metals profile, even if they were grown on similar soil types. (2) As we would expect, the metals profile of the plant leaves depends on the inorganic constitution of the soil on which it is grown. However, the degree of the influence of the soil types on the metals profile of the plant differs according to the kind of inorganic element: Ca and Cu are almost independent of the soil types, but the Ti and Fe content is dependent upon the soil types. (3) Sr content of plant leaves is closely related to the ratio of Sr to Ca of the soil on which the plants are grown. (4) This information should be helpful in identifying the producing district or original plant of a crude drug by its metals profile.
Inorganic constituents of many Cinnamomi Cortices (64 samples; almost all obtained commercially on the Osaka market) were investigated using energy-dispersive X-ray fluorescence spectrometry. The results can be summarized as follows: (1) The Cinnamomi Cortex contains K, Ca, and Fe (except for Japanese cinnamon) at lower levels than those of orchard leaves, while Mn and Sr are present at high levels. (2) A feature of the metals profile of Cinnamomi Cortex is high Mn-content. Especially, Chinese cinnamon (originated from Cinnamomum cassia) contains at extremely high levels, 300-900 ppm, whereas Mn concentrations of Java and Japanese cinnamons range from 100 to 300 ppm, and those of Ceylon cinnamon ranged from 50 to 150 ppm. (3) The contents of Mn and Rb depend on the kind of Cinnamomi Cortex, making identification possible.
The estimation of chemical concentrations in wildlife foods, such as plant foliage, is often performed for risk assessments at contaminated sites. Regression models and uptake factors for use in estimating the uptake of inorganic elements from soil by above-ground plant tissues were derived in this study. These included models for arsenic, cadmium, copper, lead, mercury, nickel. selenium, and zinc. Models were developed using published data from soil contaminated in the field and were validated using measured concentrations from two contaminated sites. Single-variable regression models of log-transformed concentrations in plants versus log-transformed concentrations in soil are generally recommended over simple uptake factors for use in estimating plant uptake of inorganic contaminants in ecological risk assessments. Multiple regression models with soil concentration and pH as the variables are also recommended for estimating the uptake of four chemicals (cadmium, mercury, selenium, and zinc) by plants. Models for use in screening risk assessments, i.e., the upper 95% prediction limits on the regressions, are recommended to provide conservative estimates of uptake of inorganic chemicals by plants.
There are innumerable strains of microbes (bacteria, yeast and fungi) that degrade or transform chemicals and compounds into simpler, safer or less toxic substances. These bioprocesses have been used for centuries in the treatment of municipal wastes, in wine, cheese and bread making, and in bioleaching and metal recovery processes. Recent literature shows that microorganisms can be also used as effective sorbents for solid phase extraction procedures. This review reveals that fundamental nonanalytical studies on the parameters and conditions of biosorption processes and on metal-biomass interactions often result in efficient analytical procedures and biotechnological applications. Some selected examples illustrate the latest developments in the biosorption of metals by microbial biomass, which have opened the door to the application of microorganisms to analyte preconcentration, matrix separation and speciation analysis.
A model for the completion and balancing of inconsistent inorganic reactions is presented. A series of fuzzy parameters is proposed. These parameters are considered within a knowledge frame representing inorganic reactions via a semantic/functional network and, through the calculation of possibility measures, allow the completion and solution of such reactions by considering new inorganic species to be added to the reaction. Species to be added are formulated on the basis of atoms present and/or absent in the reaction, along with valence, system features, and a series of flags that determines the cardinality of the possible solution set. Incorporation of the proposed model into an inorganic chemistry formulation system would contribute to the development of powerful computer-assisted learning systems, given the extent of information extracted from a reaction.
At present, there are two large industrial plants recovering oil from the lower Athabasca oil sands area and there are plans for several more mines in the area. There are environmental concerns for aquatic life in areas downstream of current and future oil sands activities. To assess and predict potential impacts of industrial activities, it is important to separate impacts from those produced by naturally occurring oil sands deposit. Studies were therefore conducted to determine whether the water quality of tributaries to the Athabasca River, which have not been impacted by anthropogenic activities, is affected by inorganic constituents resulting from flowing through reaches with natural oilsands deposit. Three tributaries, Steepbank River, Mackay River, and Ells River at upstream and downstream locations on each stream were investigated during four surveys from 1998 to 2000. In addition to some physical parameters such as pH, conductance and hardness and the major ions (calcium, magnesium, sodium, potassium, bicarbonate, chloride, sulfate, and silicates), seventeen trace metals were investigated. Some of these metals, especially iron and manganese, were of high concentrations and in some instances, particularly in a survey conducted during the spring freshets in April 1999, exceeded guidelines for the protection of aquatic life. The observed concentrations of metals seem to be of natural origin and can be used as base-line data for future assessment of anthropogenic activities in the oil sand region.
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The Atlantic Forest with its exuberant vegetation of high level of biodiversity is classified as one hotspot of the world. Chemical composition of leaves from native trees and underlying soils was evaluated by INAA. The predominant species Euterpe edulis, Bathysa meridionalis, Hyeronima alchorneoides, Marlierea tomentosa, Gomidesia flagellaris, and Gomidesia spectabilis belonging to the diverse plant families were studied. Euterpe edulis, the most abundant understory specie, presented the lowest element concentrations except for Zn. Some variation in chemical composition was noted, however, the chemical specificity of tree species can be more predominant than the soil variability for the obtained leaf concentrations. Factor values obtained through the Monte-Carlo assisted factor analysis were used for species discrimination, The results indicate that chemical investigation of native trees is a quite promising tool for biodiversity studies in the Atlantic Forest.
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Leaves of nine different plant species (terrestrial moss: Hylocomium splendens and Pleurozium schreberi, blueberry: Vaccinium myrtillus, cowberry: Vaccinium vitis-idaea, crowberry: Empetrum nigrum, birch: Betula pubescens, willow: Salix spp., pine: Pinus sylvestris, and spruce: Picea abies) have been collected from up to nine catchments (size 14-50 km2) spread over a 1,500,000 km2 area in northern Europe. Additional soil samples were taken from the O-horizon and the C-horizon at each plant sample site. All samples were analysed for 38 elements (Ag, Al, As, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Sb, Sc, Se, Si, Sn, Sr, Th, Tl, U, V, Y, Zn, and Zr) by ICP-MS, ICP-AES or CV-AAS (Hg) techniques. One of the 9 catchments was located directly adjacent (5-10 km S) to the nickel smelter and refinery at Monchegorsk, Kola Peninsula, Russia. The high levels of pollution at this site are reflected in the chemical composition of all plant leaves. However, it appears that each plant enriches (or excludes) different elements. Elements emitted at trace levels, such as Ag, As and Bi, are relatively much more enriched in most plants than the major pollutants Ni, Cu and Co. The very high levels of SO2 emissions are generally not reflected by increases in plant total S-content. Several important macro-(P) and micro-nutrients (Mn, Mg, and Zn) are depleted in most plant leaves collected near Monchegorsk.
Inhaled low molecular weight chemicals (LMWC) encountered in the work-place can induce airways disease. Most LMWC are irritants and if exposure levels are high enough or if there is extended exposure, can cause inflammation of the eyes, respiratory tract, and alveolar membrane without class specific antibody production or involvement of cellular mechanisms. Reflex or inflammatory bronchoconstriction may result. At lower concentrations, some of these LMWC are haptenic and induce respiratory symptoms by immune mechanisms. Dose and duration of exposure, as well as physiochemical properties of the agent and host factors, influence the effect that a given agent may have on an individual. It is important to distinguish between irritant and hypersensitivity responses for diagnostic purposes and for subsequent patient management. However, long term effects of sub-lethal exposure to primary irritants, such as SO2 or chemicals which are irritants at high concentrations but can also induce antibody formation, such as the isocyanates and acid anhydrides, are not clear.