Soil metal pollutant levels

Table 11.2. Metal pollutant levels in soil (from author s own files) ...

LA-ICP-MS is well suited for monitoring element distribution in annual rings of trees. Annual ring profiles in pine and birch from the Norwegian-Russian border and from northwest Russia measured by LA-ICP-MS as a rapid and sensitive method show the pollution history (especially of the heavy metal content) of the area. No correlation was found between the pollution levels of the soils and the observed metal content in the annual rings by Garbe-Schoenberg et al.20... 

The metals of most concern are the heavy metals, especially cadmium, lead, and mercury. Although it is a metalloid with characteristics of both metals and nonmetals, arsenic is commonly classified as a heavy metal for a discussion of its toxicity. Though not particularly toxic, zinc is abundant and may reach toxic levels in some cases. For example, zinc accumulates in sewage sludge and crop productivity has been lowered on land fertilized with sludge because of zinc accumulation. Copper may be toxic to plants. Aluminum, a natural constituent of soil, may be leached from soil by polluted acidic rainwater and reach levels that are toxic to plants. Other metals that may be of concern because of their toxicides include chromium, cobalt, iron, nickel, and vanadium. Radium, a radioactive alpha particle-emitting metal, can be very toxic at even very low levels in water or food. 

Marigomez I, Kortabitarte M, Dussart GBJ. 1998. Tissue-level biomarkers in sentinel slugs as cost-effective tools to assess metal pollution in soils. Arch Environ Contam Toxicol 34 167-176. 

Beveridge, A. and W. P. Pickering. 1980. Influence of humate-solute interactions on aqueous heavy metal ion levels. Water, Air, Soil Pollut. 14.T71. 

Of the six heavy metals discussed in this chapter, Pb has been studied extensively with respect to the environmental effects. Clair Patterson, the father of environmental Pb studies, in one of his many major publications concerning the global Pb cycle (Patterson and Settle, 1987), noted that during pre-industrial times Pb in the troposphere originated from soil dusts and volcanic gases. In modern times (1950-1980) the proportion of natural Pb in the atmosphere is overwhelmed by the industrial sources of smelter emissions and automobile exhausts. Lead air pollution levels measured near our Nation s roadways decreased 97% between 1976 and 1995 due to the consequence of the Clean Air Act that eliminated leaded gasoline which interfered with the performance of catalytic converters. 

Farrah H. and Pickering W. F. (1977) Influence of clay-solute interactions an aqueous heavy metal ion levels. Water Air Soil Pollut. 8, 189-197. 

Chapter 9 gave an equation that predicted the rate of advance, vm, of metal pollutants, M, through a water-saturated soil column if the velocity of water flow, v, through the column was known. This same equation could in principle predict the movement of low levels of an organic pollutant, assuming that sorption is reversible ... 

As we know feathers reflect better levels of emission, while internal tissues reflect a pool of elements accessible for animals in the environment through consumption and drinking. This difference, which explains the lack of a decrease of lead content in magpie livers from the Znl and Zn2 areas between 1989 and 1993, is well-mirrored in the feather studies and proved by routine air monitoring. Although pollution levels diminished distinctly in this period, amounts of heavy metals in soil (the main abiotic element that stores many harmful elements) and the amounts made further accessible by food to animals, remained at the same level or even slightly increased so the studies of liver (and also other internal tissues) have registered no reduction of pollution. 

R. M. McKenzie, The adsorption of lead and other heavy metals on oxides of manganese and iron, Aust. J. Soil Res. 18 61 (1980). H. Kerndorf and M. Schnitzer, Sorption of metals on humic acid, Geochim. Cosmochim. Acta 44 1701 (1980). D. G. Kinniburgh, M. L. Jackson, and J. K. Syers, Adsorption of alkaline earth, transition, and heavy metal cations by hydrous oxide gels of iron and aluminium, Soil Sci. Soc. Am. J. 40 796 (1976). H. Farrah and W. F. Pickering, Influence of clay-solute interactions on aqueous heavy metal ion levels, Water, Air and Soil Pollution 8 189 (1977). 

A possible source of soil contamination results from recycling industrial wastes for fertilizer. According to data compiled by the Environmental Working Group (EWG) during the 1990s, approximately 25 million kg per year of potentially toxic wastes were used to prepare fertilizers that contained elevated levels of arsenic, cadmium, lead, radioactive materials, and dioxins. A potential source of heavy metal pollution in fertilizers is ash from furnaces used to recycle steel, commonly processed to provide zinc in zinc-deficient soils. 

The suggestion frequentiy is made that substitution of organic fertilizers, namely manures and composts, for chemical fertilizers would be of ecological benefit. The reaUty is, however, that the supply and logistics of such materials could never be adequate for the present-day level of agriculture. Furthermore, iatensive appHcation of such materials to the soil would itself present ecological problems, such as mn-off pollution and steady buildup of toxic heavy metals. 

Humans may also be indirectly affected through exposure to increased levels of toxic metals in drinking water and food. Increased levels of toxic metal are a consequence of direct deposition of pollutants into water sources, increased leaching of metal from soils and lake sediments, and increased corrosion of water pipes. 

We must also consider the consequences of forty years of ecosystem pollution loading. Compared with soil analyses of heavy metal concentrations made in 1965, cadmium, copper, lead and zinc levels are now elevated 24) to the point where laboratory studies have shown that red spruce root and shoot growth is reduced, growth of obligatory mycorrhizal fungi is repressed and... 

Heavy metals and to some extent their derivatives are among the indestructible pollutants that are neither subject to bacterial attack nor other breakdown or degradation processes and are thus permanent additions to the environment.12 14 Accordingly, their concentrations most often exceed the permissible levels normally found in the environment soil, water ways, and sediments, ending up in the food chains. Following these events, heavy metals and/or their derivatives accumulate in the plant and animal life where they profoundly disrupt biological processes, causing various... 

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