A global assessment of natural sources of atmospheric trace metals
TL;DR: For most of the toxic metals, the natural fluxes are small compared with emissions from industrial activities, implying that mankind has become the key agent in the global atmospheric cycle of trace metals and metalloids as mentioned in this paper.
Abstract: A PROPER inventory of atmospheric emissions from natural sources is basic to our understanding of the atmospheric cycle of the trace metals (and metalloids), and is also needed for assessing the extent of regional and global pollution by toxic metals1. It is generally presumed that the principal natural sources of trace metals in the atmosphere are wind-borne soil particles, volcanoes, seasalt spray and wild forest fires2–6. Recent studies have shown, however, that particulate organic matter is the dominant component of atmospheric aerosols in non-urban areas7–10 and that over 60% of the airborne trace metals in forested regions can be attributed to aerosols of biogenic origin11,12. Here I estimate that biogenic sources can account for 30–50% of the global baseline emissions of trace metals. For most of the toxic metals, the natural fluxes are small compared with emissions from industrial activities, implying that mankind has become the key agent in the global atmospheric cycle of trace metals and metalloids.
Citations
More filters
TL;DR: This review provides an analysis of arsenic, cadmium, chromium, lead, and mercury's environmental occurrence, production and use, potential for human exposure, and molecular mechanisms of toxicity, genotoxicity, and carcinogenicity.
Abstract: Heavy metals are naturally occurring elements that have a high atomic weight and a density at least five times greater than that of water. Their multiple industrial, domestic, agricultural, medical, and technological applications have led to their wide distribution in the environment, raising concerns over their potential effects on human health and the environment. Their toxicity depends on several factors including the dose, route of exposure, and chemical species, as well as the age, gender, genetics, and nutritional status of exposed individuals. Because of their high degree of toxicity, arsenic, cadmium, chromium, lead, and mercury rank among the priority metals that are of public health significance. These metallic elements are considered systemic toxicants that are known to induce multiple organ damage, even at lower levels of exposure. They are also classified as human carcinogens (known or probable) according to the US Environmental Protection Agency and the International Agency for Research on Cancer. This review provides an analysis of their environmental occurrence, production and use, potential for human exposure, and molecular mechanisms of toxicity, genotoxicity, and carcinogenicity.
4,407 citations
TL;DR: In this article, the range of heavy metals, their occurrence and toxicity for plants, and their effects on the ecosystem is discussed, where the authors focus mainly on zinc, cadmium, copper, mercury, chromium, lead, arsenic, cobalt, nickel, manganese and iron.
Abstract: Metal contamination issues are becoming increasingly common in India and elsewhere, with many documented cases of metal toxicity in mining industries, foundries, smelters, coal-burning power plants and agriculture. Heavy metals, such as cadmium, copper, lead, chromium and mercury are major environmental pollutants, particularly in areas with high anthropogenic pressure. Heavy metal accumulation in soils is of concern in agricultural production due to the adverse effects on food safety and marketability, crop growth due to phytotoxicity, and environmental health of soil organisms. The influence of plants and their metabolic activities affects the geological and biological redistribution of heavy metals through pollution of the air, water and soil. This article details the range of heavy metals, their occurrence and toxicity for plants. Metal toxicity has high impact and relevance to plants and consequently it affects the ecosystem, where the plants form an integral component. Plants growing in metal-polluted sites exhibit altered metabolism, growth reduction, lower biomass production and metal accumulation. Various physiological and biochemical processes in plants are affected by metals. The contemporary investigations into toxicity and tolerance in metal-stressed plants are prompted by the growing metal pollution in the environment. A few metals, including copper, manganese, cobalt, zinc and chromium are, however, essential to plant metabolism in trace amounts. It is only when metals are present in bioavailable forms and at excessive levels, they have the potential to become toxic to plants. This review focuses mainly on zinc, cadmium, copper, mercury, chromium, lead, arsenic, cobalt, nickel, manganese and iron.
2,898 citations
TL;DR: In this paper, a broad overview and synthesis of current knowledge and understanding pertaining to all major aspects of mercury in the atmosphere is presented, including physical, chemical, and toxicological properties of this element.
1,668 citations
TL;DR: In this paper, the authors assess current data in this area, develop global scale estimates of the atmospheric fluxes of trace elements, mineral aerosol, nitrogen species, and synthetic organic compounds to the ocean; and compare the atmospheric input rates of these substances to their input via rivers.
Abstract: Over the past decade it has become apparent that the atmosphere is a significant pathway for the transport of many natural and pollutant materials from the continents to the ocean. The atmospheric input of many of these species can have an impact (either positive or negative) on biological processes in the sea and on marine chemical cycling. For example, there is now evidence that the atmosphere may be an important transport path for such essential nutrients as iron and nitrogen in some regions. In this report we assess current data in this area, develop global scale estimates of the atmospheric fluxes of trace elements, mineral aerosol, nitrogen species, and synthetic organic compounds to the ocean; and compare the atmospheric input rates of these substances to their input via rivers. Trace elements considered were Pb, Cd, Zn, Cu, Ni, As, Hg, Sn, Al, Fe, Si, and P. Oxidized and reduced forms of nitrogen were considered, including nitrate and ammonium ions and the gaseous species NO, NO2, HNO3, and NH3. Synthetic organic compounds considered included polychlorinated biphenyls (PCBs), hexachlorocyclohexanes (HCHs), DDTs, chlordane, dieldrin, and hexachlorobenzenes (HCBs). Making this assessment was difficult because there are very few actual measurements of deposition rates of these substances to the ocean. However, there are considerably more data on the atmospheric concentrations of these species in aerosol and gaseous form. Mean concentration data for 10° × 10° ocean areas were determined from the available concentration data or from extrapolation of these data into other regions. These concentration distributions were then combined with appropriate exchange coefficients and precipitation fields to obtain the global wet and dry deposition fluxes. Careful consideration was given to atmospheric transport processes as well as to removal mechanisms and the physical and physicochemical properties of aerosols and gases. Only annual values were calculated. On a global scale atmospheric inputs are generally equal to or greater than riverine inputs, and for most species atmospheric input to the ocean is significantly greater in the northern hemisphere than in the southern hemisphere. For dissolved trace metals in seawater, global atmospheric input dominates riverine input for Pb, Cd, and Zn, and the two transport paths are roughly equal for Cu, Ni, As, and Fe. Fluxes and basin-wide deposition of trace metals are generally a factor of 5-10 higher in the North Atlantic and North Pacific regions than in the South Atlantic and South Pacific. Global input of oxidized and reduced nitrogen species are roughly equal to each other, although the major fraction of oxidized nitrogen enters the ocean in the northern hemisphere, primarily as a result of pollution sources. Reduced nitrogen species are much more uniformly distributed, suggesting that the ocean itself may be a significant source. The global atmospheric input of such synthetic organic species as HCH,PCBs, DDT, and HCB completely dominates their input via rivers.
1,651 citations
01 Jan 2007
Abstract: Some heavy metals have bio-importance as trace elements but, the biotoxic effects of many of them in human biochemistry are of great concern. Hence, there is the need for proper understanding of the conditions, such as the concentrations and oxidation states, which make them harmful, and how biotoxicity occurs. It is also important to know their sources, leaching processes, chemical conversions and their modes of deposition to pollute the environment, which essentially supports lives. Literature sources point to the fact that these metals are released into the environment by both natural and anthropogenic sources, especially mining and industrial activities, and automobile exhausts (for lead). They leach into underground waters, moving along water pathways and eventually depositing in the aquifer, or are washed away by run-off into surface waters thereby resulting in water and subsequently soil pollution. Poisoning and toxicity in animals occur frequently through exchange and co-ordination mechanisms. When ingested, they combine with the body’s biomolecules, like proteins and enzymes to form stable biotoxic compounds, thereby mutilating their structures and hindering them from the bioreactions of their functions. This paper reviews certain heavy metals and their biotoxic effects on man and the mechanisms of their biochemical activities.
Keywords: Biochemical, biotoxic, environment, heavy metals, pollution.
1,596 citations
References
More filters
Book•
09 Oct 2011
TL;DR: Erratum to: Aminocarboxylic Acids to: Iminodiacetic Acid Derivatives to: Peptides to: Aliphatic Amines to: Protonation Values for other Ligands.
Abstract: Aminocarboxylic Acids.- Iminodiacetic Acid Derivatives.- Peptides.- Anilinecarboxylic Acids.- Pyrrolecarboxylic Acid.- Pyrazlinecarboxylic Acid.- Pyridinecarboxylic Acids.- Aliphatic Amines.- Azoles.- Azines.- Aminophosphonic Acids.- Carboxylic Acids.- Phosphorus Acids.- Phenols.- Carbonyl Ligands.- Alcohols.- Polyethers.- Thioethers.- Thiols.- Phosphines.- Hydroxamic Acids.- Oximes.- Amides.- Inorganic Ligands.- Protonation Values for other Ligands.- Ligands Considered But Not Included.- Erratum to: Aminocarboxylic Acids.- Erratum to: Iminodiacetic Acid Derivatives.- Erratum to: Peptides.- Erratum to: Aliphatic Amines.- Erratum to: Azoles.- Erratum to: Azines.- Erratum to: Carboxylic Acids.- Erratum to: Phosphorus Acids.- Erratum to: Phenols.- Erratum to: Carbonyl Ligands.- Erratum to: Alcohols.- Erratum to: Polyethers.- Erratum to: Thioethers.- Erratum to: Hydroxamic Acids.- Erratum to: Oximes.- Erratum to: Amides.- Erratum to: Inorganic Ligands.- Erratum to: Protonation Values for other Ligands.- Erratum to: Bibliography.
6,389 citations
TL;DR: Calculated loading rates of trace metals into the three environmental compartments demonstrate that human activities now have major impacts on the global and regional cycles of most of the trace elements.
Abstract: Calculated loading rates of trace metals into the three environmental compartments demonstrate that human activities now have major impacts on the global and regional cycles of most of the trace elements. There is significant contamination of freshwater resources and an accelerating accumulation of toxic metals in the human food chain.
4,097 citations
Book•
01 Jan 1979
TL;DR: In this paper, the authors propose a method to solve the problem of how to find the shortest path between two points of interest in a set of images. Index Reference Record created on 2004-09-07, modified on 2016-08-08
Abstract: Note: Bibliogr. : p. 275-317. Index Reference Record created on 2004-09-07, modified on 2016-08-08
2,256 citations
TL;DR: The worldwide inventories of the natural and anthropogenic sources and emissions of airborne cadmium, copper, lead, nickel and zinc are presented here.
Abstract: FEW (if any) recent studies on the atmospheric cycle of trace metals have considered the flux of the metals into the atmosphere on a global scale. Information on worldwide emissions is needed to assess the transboundary movement of pollutant metals and to validate models of the global atmospheric circulation patterns. The worldwide inventories of the natural and anthropogenic sources and emissions of airborne cadmium, copper, lead, nickel and zinc are presented here. The data summarised here are taken from very detailed studies published elsehwere1–5.
775 citations