Availability of toxic trace metals to the conceptus

1983 ◽  
Vol 28 (1-3) ◽  
pp. 433-442 ◽  
Author(s):  
Patricia L. Hackett ◽  
Bruce J. Kelman
Keyword(s):  
Trace Metals ◽  
Toxic Trace Metals

Identifying Sources of Sulfate Aerosols Reaching Whiteface Mountain, NY

1985 ◽  
Vol 43 ◽  
pp. 98-101
Author(s):  
James S. Webber
Keyword(s):  
Trace Metals ◽  
Acid Deposition ◽  
Surface Waters ◽  
Dry Deposition ◽  
Coal Combustion ◽  
Public Awareness ◽  
Sulfate Aerosols ◽  
Wet And Dry Deposition ◽  
Whiteface Mountain ◽  
Toxic Trace Metals

INTRODUCTION“Acid rain” and “acid deposition” are terms no longer confined to the lexicon of atmospheric scientists and 1imnologists. Public awareness of and concern over this phenomenon, particularly as it affects acid-sensitive regions of North America, have increased dramatically in the last five years. Temperate ecosystems are suffering from decreased pH caused by acid deposition. Human health may be directly affected by respirable sulfates and by the increased solubility of toxic trace metals in acidified waters. Even man's monuments are deteriorating as airborne acids etch metal and stone features.Sulfates account for about two thirds of airborne acids with wet and dry deposition contributing equally to acids reaching surface waters or ground. The industrial Midwest is widely assumed to be the source of most sulfates reaching the acid-sensitive Northeast since S02 emitted as a byproduct of coal combustion in the Midwest dwarfs S02 emitted from all sources in the Northeast.

scholarly journals Regional geochemical baseline concentration of potentially toxic trace metals in the mineralized Lom Basin, East Cameroon: a tool for contamination assessment

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Mumbfu Ernestine Mimba ◽  
Takeshi Ohba ◽  
Salomon César Nguemhe Fils ◽  
Melvin Tamnta Nforba ◽  
Nozomi Numanami ◽  
...  
Keyword(s):  
Trace Metals ◽  
Contamination Assessment ◽  
Geochemical Baseline ◽  
Baseline Concentration ◽  
Toxic Trace Metals

scholarly journals Early atmospheric contamination on the top of the Himalayas since the onset of the European Industrial Revolution

2020 ◽  
Vol 117 (8) ◽  
pp. 3967-3973 ◽  
Author(s):  
Paolo Gabrielli ◽  
Anna Wegner ◽  
M. Roxana Sierra-Hernández ◽  
Emilie Beaudon ◽  
Mary Davis ◽  
...  
Keyword(s):  
Trace Metals ◽  
Western Europe ◽  
Industrial Revolution ◽  
Ice Core ◽  
Toxic Metal ◽  
Enrichment Factors ◽  
High Elevation ◽  
Snow Accumulation ◽  
Metal Levels ◽  
Toxic Trace Metals

Because few ice core records from the Himalayas exist, understanding of the onset and timing of the human impact on the atmosphere of the “roof of the world” remains poorly constrained. We report a continuous 500-y trace metal ice core record from the Dasuopu glacier (7,200 m, central Himalayas), the highest drilling site on Earth. We show that an early contamination from toxic trace metals, particularly Cd, Cr, Mo, Ni, Sb, and Zn, emerged at high elevation in the Himalayas at the onset of the European Industrial Revolution (∼1780 AD). This was amplified by the intensification of the snow accumulation (+50% at Dasuopu) likely linked to the meridional displacement of the winter westerlies from 1810 until 1880 AD. During this period, the flux and crustal enrichment factors of the toxic trace metals were augmented by factors of 2 to 4 and 2 to 6, respectively. We suggest this contamination was the consequence of the long-range transport and wet deposition of fly ash from the combustion of coal (likely from Western Europe where it was almost entirely produced and used during the 19th century) with a possible contribution from the synchronous increase in biomass burning emissions from deforestation in the Northern Hemisphere. The snow accumulation decreased and dry winters were reestablished in Dasuopu after 1880 AD when lower than expected toxic metal levels were recorded. This indicates that contamination on the top of the Himalayas depended primarily on multidecadal changes in atmospheric circulation and secondarily on variations in emission sources during the last 200 y.

scholarly journals Evaluation of Heavy Metals Profile in Different Brands of Infant Food Nutrition

2019 ◽  
pp. 1-9
Author(s):  
Ogochukwu Augustina Onuorah ◽  
Rufus Sha'ato ◽  
Fina Okeke ◽  
Adekola Omololu Atanda ◽  
Agbele Idowu Elijah ◽  
...  
Keyword(s):  
Trace Metals ◽  
Infant Formula ◽  
Daily Intake ◽  
World Health ◽  
Infant Food ◽  
Formula Milk ◽  
Infant Formulae ◽  
Infant Formula Milk ◽  
Significant Difference ◽  
Toxic Trace Metals

The concentrations of five essential metals in six selected (NAN, Cowbell, MY BOY, CERELAC, FRISO GOLD and NUTREND) infant formulae sold in Makurdi metropolis, were determined using Atomic Absorption Spectrophotometer. Data collected were subjected to Analysis of Variance using SPSS 24 statistical software package. Significant differences in means were separated using Duncan Multiple Range Test. There was significant difference in the levels of the trace metals in the different brands of infant formula milk. The results of the toxic trace metals show that Cr has the highest concentration of 6.175 ±0.001 mg/kg (Cowbell), when compared to other toxic trace metals analyzed. Milk based infant formula showed copper concentration ranged from 2.55±0.001– 6.357±0.001mg/kg, which was higher than the provisional tolerable daily intake of copper that is 3 mg/kg. Chromium, Copper, Manganese and lead were detected in the six brands of infant formula milk but they were below the limits set by World Health Organization (WHO). However, the intake levels of Cd in this study from these concentrations were below the WHO limits. These results validate and in some cases counter earlier reports on the composition of infant formula found in our local markets. Therefore, the concentrations of the studied elements were within the safe limits recommended by National Industrial Standard and the Institute of Medicine for foods but higher concentrations of trace metals in some brands of infant formulae above the recommended limit pose a risk of bioaccumulation.

scholarly journals Use of Paleoflood Deposits to Determine the Contribution of Anthropogenic Trace Metals to Alluvial Sediments in the Hyperarid Rio Loa Basin, Chile

Geosciences ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 244 ◽  
Author(s):  
Jerry R. Miller ◽  
Danvey Walsh ◽  
Lionel F. Villarroel
Keyword(s):  
Trace Metals ◽  
Organic Matter Content ◽  
Enrichment Factors ◽  
Matter Content ◽  
Anthropogenic Sources ◽  
Biogeochemical Processes ◽  
Riverine Ecosystems ◽  
Local Background ◽  
Toxic Trace Metals ◽  
Source Materials

Toxic trace metals are a common and significant contaminant in riverine ecosystems, and are derived from both natural and anthropogenic sources. Determining the contributions of metals from these sources has proven difficult, in part, because physical and biogeochemical processes alter the nature (e.g., grain size, mineral composition, organic matter content) of the source materials as they are transported through the drainage network. This study examined the use of paleoflood deposits located along the hyperarid Rio Salado, a tributary to the Rio Loa of northern Chile, to construct local background functions and enrichment factors (LEFs) to differentiate between natural and anthropogenic metal sources. Significant variations in metal content occurred between river reaches and flood deposits of a given reach; these variations were primarily related to changes in sediment source that may reflect differences in El Niño and La Niña precipitation patterns. Three conservative elements (Al, Fe, Co) were examined to construct background functions for seven trace metals. Cobalt yielded the most effective background functions for As, Cd, Ni, Pb, and Zn; Fe was selected for Cr, and Al for Cu. The resulting LEFs approximated 1, illustrating that paleoflood deposits produced effective background functions, and could be applied to downstream sites contaminated by mining activity.

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