Lead, zinc, cadmium hyperaccumulation and growth stimulation in Arabis paniculata Franch

2009 ◽  
Vol 66 (1) ◽  
pp. 126-134 ◽  
Author(s):  
Ye-Tao Tang ◽  
Rong-Liang Qiu ◽  
Xiao-Wen Zeng ◽  
Rong-Rong Ying ◽  
Fang-Ming Yu ◽  
...  
Keyword(s):  
Growth Stimulation ◽  
Zinc Cadmium ◽  
Lead Zinc ◽  
Cadmium Hyperaccumulation

Part I. Friction of metals - Influence of oxide films on metallic friction

1952 ◽  
Vol 212 (1111) ◽  
pp. 450-452 ◽  
Keyword(s):  
Surface Damage ◽  
Metallic Contact ◽  
Degree Of Protection ◽  
Number Of Factors ◽  
Gold Silver ◽  
Zinc Cadmium ◽  
Natural Oxide ◽  
Lead Zinc ◽  
Relative Hardness ◽  
Metallic Friction

The mechanism of metallic friction, in air, has been investigated for loads ranging from 0.003 to 10000 g. The metals studied include platinum, gold, silver, copper, tin, lead, zinc, cadmium, magnesium, aluminium and chromium. The earlier work of Whitehead has been extended and simultaneous measurements made of the frictional force and the electrical resistance between the sliding surfaces. The results show that with most metals the natural oxide layer is sufficient to prevent metallic contact at very small loads. The degree of protection depends on a number of factors, such as the surface roughness, the thickness of the oxide film and in particular on the relative hardness of the oxide and the metal substrate. When sliding occurs solely on the oxide layers the friction is not necessarily less than that observed when appreciable metallic contact occurs. The surface damage is, however, greatly diminished on account of the reduced metallic interaction.

scholarly journals Physico-chemical properties and heavy metal contents of a tropical estuarine ecosystem, Nigeria

2018 ◽  
Vol 5 (11) ◽  
pp. 781-797
Author(s):  
Paul Chinedu Echi ◽  
Daberechi Ndudim Okpechi ◽  
Janet Azu Urum ◽  
Izuchukwu Samson Arukwe
Keyword(s):  
Heavy Metal ◽  
Chemical Properties ◽  
Oxygen Demand ◽  
International Standards ◽  
Anthropogenic Pressure ◽  
Estuarine Ecosystem ◽  
Metal Concentrations ◽  
Metal Contents ◽  
Zinc Cadmium ◽  
Lead Zinc

Ibaka Estuarine in Mbo, Nigeria, has little or no information on its basic properties, therefore its water samples were studied from March to June 2018 in three different stations and compared with International Standards to evaluate its physic-chemical properties as well as heavy metal contents. The physic-chemical properties studied include pH, salinity (g/L), EC (μs/cm), turbidity (NTU), total suspended solids (mg/L), total dissolved solids (mg/L), dissolved oxygen (mg/L), BOD5 (mg/L), and chemical oxygen demand (mg/L). In addition, some metal concentrations of manganese, iron, copper, lead, zinc, cadmium, chloride and magnesium were determined by atomic absorption spectroscopy (AAS). The range of metal concentrations manganese (0.08-0.12 mg/L), copper (0.05-0.09 mg/L), lead (0.01-0.03 mg/L), iron (1.86-4.66 mg/L), zinc (0.68-1.16 mg/L), cadmium (0.04-0.08 mg/L), chloride (675.0-791.25 mg/L), magnesium (10.66-14.30 mg/L). The study infers that anthropogenic pressure plays damaging role to its properties in addition to general health implication of high values for Fe, Zn, Cd, Cl and Mg which exceeded international standard.

Metal contamination of natural surface soils from long-range atmospheric transport: Existing and missing knowledge

2006 ◽  
Vol 14 (3) ◽  
pp. 169-186 ◽  
Author(s):  
Eiliv Steinnes ◽  
Andrew J Friedland
Keyword(s):  
Organic Matter ◽  
Long Range ◽  
Atmospheric Transport ◽  
Long Range Transport ◽  
Surface Soils ◽  
Air Masses ◽  
Range Transport ◽  
Zinc Cadmium ◽  
Lead Zinc ◽  
Temporal And Spatial

This review focuses on the long-range atmospheric transport of metals to organic-rich surface soils (mostly 50–90% organic matter) in the temperate, coniferous, and boreal zones of North America and Europe. From various air-pollution related measurements (air, precipitation, moss, peat cores) Pb and Zn are known to be transported long distances in the air in large amounts. Arsenic, Cd, Hg, Sb, and Se are also typical representatives of long-range transported air masses, and there is evidence that Ag, Bi, In, Mo, Tl, and W belong to this group of elements. Through the use of “environmental archives” such as ice and peat cores it has become evident that long-range transport of pollutants and associated contamination of natural surfaces is not just a recent phenomenon. There is compelling evidence for widespread enrichment of surface soil horizons in Pb from long-range transport, and many studies support enrichment of Zn. Mercury is also generally elevated by anthropogenic emissions over natural levels in organic-rich surface soils, whereas results for Cd are less conclusive. There is evidence that As, Se, Ag, Mo, In, Sb, W, Tl, and Bi all are subject to some enrichment in organic-rich surface soils from long-range atmospheric transport, but studies are still few for most of these elements. With the exception of Pb, little is known about residence times of the elements in the organic-rich surface horizon, and more research is needed on this topic. Further studies are desirable on the temporal and spatial trends in supply of the above elements, which are poorly known in large parts of the northern temperate zone.Key words: natural soils, metals, long-range atmospheric transport, organic matter, lead, zinc, cadmium, mercury.

Assessment of Iron, Lead, Zinc, Cadmium and Chromium in Green Vegetables Irrigated with Domestic Waste Water

2016 ◽  
Vol 6 (4) ◽  
pp. 448-456 ◽  
Author(s):  
Humayun Ajaz ◽  
A.J. Shiekh ◽  
M. Umar ◽  
F. Rabbani ◽  
H. Mubeen ◽  
...  
Keyword(s):  
Waste Water ◽  
Domestic Waste ◽  
Zinc Cadmium ◽  
Lead Zinc

scholarly journals Evaluate the Rate of Pollution in Soil using Simulink Environment

2019 ◽  
Vol 32 (1) ◽  
pp. 135 ◽  
Author(s):  
Luma N.M.Tawfiq ◽  
Mohammed A. Hasan
Keyword(s):  
Heavy Metals ◽  
Differential Equations ◽  
Mathematical Models ◽  
Contamination Sources ◽  
Simulink Model ◽  
Cobalt Nickel ◽  
Zinc Cadmium ◽  
Lead Zinc ◽  
Contamination Levels ◽  
Copper Lead

       In this paper we design a Simulink model which can be evaluate the concentration of Copper, Lead, Zinc, Cadmium, Cobalt, Nickel, Crum and Iron. So, this model would be a method to determine the contamination levels of these metals with the potential for this contamination sources with their impact. The aim of using Simulink environment is to solve differential equations individually and as given data in parallel with analytical mathematics trends. In general, mathematical models of the spread heavy metals in soil are modeled and solve to predict the behavior of the system under different conditions.

Contamination and Wildlife Communities in Stormwater Detention Ponds in Guelph and the Greater Toronto Area, Ontario, 1997 and 1998 Part II — Contamination and Biological Effects of Contamination

2000 ◽  
Vol 35 (3) ◽  
pp. 437-474 ◽  
Author(s):  
Christine A. Bishop ◽  
John Struger ◽  
Leonard J. Shirose ◽  
Lesley Dunn ◽  
G. Douglas Campbell
Keyword(s):  
Natural Wetland ◽  
Detention Ponds ◽  
Total Pahs ◽  
Stormwater Ponds ◽  
Greater Toronto Area ◽  
Quality Guidelines ◽  
Zinc Cadmium ◽  
Lead Zinc ◽  
Stormwater Pond ◽  
Copper Lead

Abstract Due to concerns that wildlife may be attracted to Stormwater detention ponds and would be exposed to contaminants accumulating in these ponds, a field study of 15 Stormwater ponds and one natural wetland in Guelph and the Greater Toronto Area, Ontario, was performed in 1997 and 1998. At 9 of 16 sites, copper levels in water exceeded the Canadian Water Quality Guidelines (CWQGs) for the protection of aquatic life. Canadian Water Quality Guidelines were also exceeded by average water concentrations for lead at four sites, for zinc at three sites, for chromium at seven sites, and turbidity at ten sites. At the natural wetland, only turbidity levels exceeded the CWQGs. Sediments from all ponds contained concentrations of at least one contaminant that exceeded the “lowest effects level” (LED of the Guidelines for the Protection and Management of Aquatic Sediment in Ontario. Stormwater pond sediments contained concentrations exceeding provincial sediment quality guidelines at the LEL for polychlorinated biphenyls (PCBs), gamma-hexachlorocyclohexane (g-bhc), total Kjeldahl nitrogen (TKN) and total phosphorus (TP), turbidity, oil and grease, total PAHs, chromium, zinc, cadmium, copper, lead, nickel and arsenic. Concentrations of g-bhc, TKN, TP, cadmium, copper, lead, zinc and arsenic in the sediment of the natural wetland also exceeded the LEL. Sediments at one site exceeded the provincial guideline at the severe effect level for chromium. Concentrations of lead, zinc, cadmium and total PAHs in sediments were correlated with the age of the ponds. Concentrations of organochlorine pesticides and PCBs were low (<0.08 µg/g wet weight) in pump-kinseed (Lepomis gibbosus) collected from two ponds in Guelph. Red-winged blackbird [Agelaius phoeniceus) eggs from two ponds in Toronto contained up to 1130 ng/g pp’DDE and up to 670 ng/g total PCBs. Those concentrations were much higher than in a reference site, but an order of magnitude below concentrations associated with health effects in songbirds. Among four Stormwater ponds and one natural wetland in Guelph, there was statistically lower hatching success of northern leopard frogs (Rana pipiens) eggs, and larvae took longer to metamorphose into frogs at two Stormwater ponds. Statistically fewer tadpoles survived to metamorphosis at one Stormwater pond. We conclude that Stormwater ponds do not offer clean ecosystems for wildlife and the monitoring of contamination and its effects within Stormwater ponds is necessary.

Sign in / Sign up

Export Citation Format

Share Document