Soil Chemical Analysis

A eview of the literature revealed that bioaccumulation of silver in soil is rather low, even if the soil is amended with silver-containing sewage sludge. Plants grown on tailings of silver mines were found to have silver primarily in the root systems. In marine and freshwater systems, the highest reported bioconcentration factors (BCFs) were observed in algae (>105), probably because of adsorption of the dissolved silver (<0.45 μm fraction) to the cell surface. In herbivorous organisms (e.g., zooplankton and bivalves), the BCF was lower by about two orders of magnitude. Low amounts of silver were assimilated from food with no substantial biomagnification. In carnivores (e.g., fish), the BCF was also lower by one order of magnitude with no indication of biomagnification. Toxicity of silver occurs mainly in the aqueous phase and depends on the concentration of active, free Ag+ ions. Accordingly, many processes and water characteristics reduce silver toxicity by stopping the formation of free Ag+, binding Ag+, or preventing binding of Ag+ to the reactive surfaces of organisms. The solubility of a silver compound, and the presence of complexing agents (e.g., thiosulfate or chloride), dissolved organic carbon, and competing ions are important. In soil, sewage sludge, and sediments, in which silver sulfide predominates, the toxicity of silver, even at high total concentrations, is very low. The highly soluble silver thiosulfate complex has low toxicity, which can be attributed to the silver complexed by thiosulfate. Silver nitrate is one of the most toxic silver compounds. The toxic potential of silver chloride complexes in seawater is and will be an important issue for investigation. Aquatic chronic tests, long-term tests, and tests including sensitive life stages show lower toxicity thresholds (˜1 μg Ag+/L). The organisms viewed as most sensitive to silver are small aquatic invertebrates, particularly embryonic and larval stages.

https://setac.onlinelibrary.wiley.com/doi/epdf/10.1002/etc.5620180112

Bioaccumulation and toxicity of silver compounds: A review

The increasing utilization of heavy metals in modern industries leads to an increase in the environmental burden. Nickel represents a good example of a metal whose use is widening in modern technologies. As the result of accelerated consumption of nickel-containing products nickel compounds are released to the environment at all stages of production and utilization. Their accumulation in the environment may represent a serious hazard to human health. Among the known health related effects of nickel are skin allergies, lung fibrosis, variable degrees of kidney and cardiovascular system poisoning and stimulation of neoplastic transformation. The mechanism of the latter effect is not known and is the subject of detailed investigation. This review provides an analysis of the current state in the field.

Nickel essentiality, toxicity, and carcinogenicity.

Aqueous geochemistry of chromium: A review

Geochemistry of Major and Trace Elements in Sediments of the Ria de Vigo (NW Spain): an Assessment of Metal Pollution ☆

Aquatic chemistry is becoming both a rewarding and substantial area of inquiry and is drawing many prominent scientists to its fold. Its literature has changed from a compilation of compositional tables to studies of the chemical reactions occurring within the aquatic environments. But more than this is the recognition that human society in part is determining the nature of aquatic systems. Since rivers deliver to the world ocean most of its dissolved and particulate components, the interactions of these two sets of waters determine the vitality of our coastal waters. This significant vol ume provides not only an introduction to the dynamics of aquatic chem istries but also identifies those materials that jeopardize the resources of both the marine and fluvial domains. Its very title provides its emphasis but clearly not its breadth in considering natural processes. The book will be of great value to those environmental scientists who are dedicated to keeping the resources of the hydrosphere renewable. As the size of the world population becomes larger in the near future and as the uses of materials and energy show parallel increases, the rivers and oceans must be considered as a resource to accept some of the wastes of society. The ability of these waters and the sediments below them to accommodate wastes must be assessed continually. The key questions relate to the capacities of aqueous systems to carry one or more pollutants."

Metal pollution in the aquatic environment

The tracing of pollution sources by means of water analysis frequently gives rise to difficulties which may usually be ascribed to sampling procedure and the physical-chemical condition pertaining to the investigated species rather than to the accuracy and precision of analytic techniques. Determination of heavy metal concentrations in surface water samples collected from rivers at short intervals reveals fluctuations of several orders of magnitude. These may be partially explained by variations resulting from water discharge and the predominance of certain source areas leading to irregular effluent emissions. This phenomenon has been discussed in Chap. C. Exchange processes between interstitial and surface water effect fluctuations along the river course. These processes are influenced by pH and Eh conditions, the type and quantity of complexing agents, their biologic activity and by salinity and temperature. Therefore, in addition to having limited experimental data available, the extremely complex system of influencing factors generally makes it impossible to arrive at any definite conclusion regarding the source of pollution.

Metal Pollution Assessment from Sediment Analysis

The role of heavy metals in aquatic organisms has been treated in earlier literature reviews (e.g., Doudoroff and Katz, 1953) with emphasis on the toxicity of the individual metals. Only since mercury and cadmium poisoning in Japan (ref. Chap. B) has the accent been shifted towards investigations dealing with the influence of heavy metals on the metabolism of aquatic organisms and the ability of the latter to accumulate both essential and non-essential metals.

Heavy Metals in Aquatic Organisms

According to rough estimates 875 km3 of water evaporate daily from the oceans. After condensation, approx. 100 km3 of this total is transported from the oceans to the continents by wind action where is becomes deposited as rain, snow, mist or dew together with approx. 160 km3 of condensate from continental sources. The most important part of this cycle occurs during transport from land to sea via ground and river waters: these 100 km3 per day constitute the source of our available freshwater supply. However, freshwater from drainage runoff fluctuates greatly according to region. The Amazon and Orinoco Rivers, for example, carry nearly one-quarter of the total surface waters practically unused to the sea, while in other parts of the world water shortages due to climatic and geologic conditions or factors such as overpopulation, concentration of industries, etc., may prevail. Of groundwater reserves, which constitute 0.6% of the total global water reserves, little more than one-tenth to one-fifth can be exonomically exploited. Thus, at the utmost, only one-third of the total fresh water reserves can be utilized at the present stage of development; of this, only a limited amount is potable due to the heavy salt load from natural or industrial sources.

Metal Concentrations in River, Lake, and Ocean Waters

The heavy pollution of many inland waterways, with respect to the amount as well as to the variety of the contaminants, has put the water supply utilities in an increasingly difficult situation. It has basically been shown that “every type of fresh water recovery from surface waters is accompanied by problems that increase overproportionally to the actual pollutant load of the used water” (Haberer, 1975). Special problems arise when water is scarce even though the pollution intensity may be relatively low; such a situation is found mainly in arid areas.

Gottfried T. W. Wittmann

Papers

Metal pollution in the aquatic environment

Metal Pollution Assessment from Sediment Analysis

Heavy Metals in Aquatic Organisms

Metal Concentrations in River, Lake, and Ocean Waters

Trace Metals in Water Purification Processes