210,835 research outputs found

    Heavy metals and nitrogen in mosses: spatial patterns in 2010/2011 and long-term temporal trends in Europe

    Get PDF
    Naturally-occurring mosses have been sampled across Europe to monitor the deposition of heavy metals and nitrogen from the air. This survey has been repeated at five-yearly intervals since 1990 for heavy metals and since 2005 for nitrogen. In 2010/2011, mosses were collected at ca. 4,500 sites in 25 countries for heavy metals and ca. 2,400 sites in 15 countries for nitrogen. In general, the lowest concentrations in mosses were found in northern Europe for both heavy metals and nitrogen. The highest concentrations of heavy metals were often observed in south-eastern Europe, whereas the highest concentrations of nitrogen were found in parts of western and central Europe. Europe-wide the concentration of lead (77% decline), vanadium (57%), iron (52%) and cadmium (51%) has declined the most since 1990, whereas the concentration of copper has declined the least (11% decline). Since 1995, the concentration of arsenic and mercury has declined by 26% and 23% respectively. The nitrogen concentration in mosses has hardly changed since 2005

    Soil heavy metal contamination and acid deposition: experimental approach on two forest soils in Hunan, Southern China

    Get PDF
    In 1985, a tailing dam collapsed in Hunan province (southern China) leading to soil contamination by heavy metals from the tailings waste. Moreover, acid deposition becomes more and more serious in this area. In this context, two forest soils (a red soil and a yellow red soil, typically and commonly found in southern China) were collected from Hunan. The objectives are (i) to determine releases and changes in speciation fractions of heavy metals (especially Cd, Cu, and Zn) when the soils are contaminated with heavy metals and affected by simulated acid deposition, and (ii) to study effects of soil heavy metals and acid deposition on releases of soil Ca2+, Mg2+, and Al3+. The soil samples were soaked in the solutions of CdCl2, CuCl2, and ZnCl2 for 15 days to make contaminated soils containing 200 mg kg1 of Cd, Cu, and Zn. Then the contaminated soils and the original soils were extracted with five simulated acid deposition solutions (pH ranged from 5.6 to 3.0 and total dissolved salts increased). The experimental results indicate that acid deposition leads to great releases of soil heavy metals due to complicated soil chemical processes, mostly cation exchange and partly dissolution of minerals at pH lower than 4.2. These released heavy metals come mainly from soil exchangeable pools and other labile fractions. Releases of heavy metals are closely controlled by pH values or, in some cases, total cation contents in acid deposition; meanwhile, concentrations of heavy metals are negatively related to the relevant pH values in soil equilibrium solutions when pH values are in a range of 4.2–5.1. From the point of view of heavy metal releases, Zn is the most sensitive to acid deposition, followed by Cd and Cu. Compared with the original soils, the contaminated soils could probably release more base cations Ca2+ and Mg2+ and less Al3+. Greater amounts of Cd, Cu, Zn, and Al released from Soil B show that this soil is more sensitive to acid deposition, and we could expect serious environmental contamination in Soil B area if mining activities and acid deposition are not under control in the future

    Assessment of heavy metals in urban highway runoff from Ikorodu expressway Lagos, Nigeria

    Get PDF
    The distribution of heavy metals in the urban high way run off from Ikorodu expressway of Lagos was studied between March to May, 2004.The heavy metals studied include Pb, Cu, Cr, Zn and Cd. The levels of these selected heavy metals were determined using Atomic Absorption Spectrophotometer (Mscientific 200 Model). Trends in the heavy metal from the runoff showed significant variations between the months were values recorded in the month of April showed high values. Statistical analyses showed different mean levels of these heavy metals assessed at the five collecting points. The distribution shows Zn > Pb > Cu > Cr > Cd. Zn recorded the highest concentration levels between (53.4 ± 35.5 - 107.5 ± 80.4 μg/l), while Cd levels (ND - 6.00 μg/L) were the lowest. However, the results obtained falls within the permissible limits of FMENV effluents limits, FHWA and WHO standards of water for domestic use

    The cupric complexes of glycine and of alanine

    Get PDF
    The following report is the first of a projected series of studies of the physical chemistry of the compounds of the heavy metals, particularly of copper and of iron, with substances of biological importance. These studies are invited by the accumulation in recent years of examples of the importance of the heavy metals in biological chemistry

    THE INFLUENCE OF MERCURY POLLUTION ON THE GROWTH OF BIO-INDICATOR PLANTS

    Get PDF
    Heavy metals are found naturally in the earth, and become concentrated as a result of human caused activities. Common sources are from mining and industrial wastes, vehicle emissions, lead- acid batteries, fertilisers, paints, treated woods, aging water supply infrastructure, and microplastics floating in the world's oceans. Heavy metals enter plant, animal and human tissues via air inhalation, diet and manual handling. Most of these chemicals including mercury, lead, cadmium and their compounds are among the most common and highly toxic substances capable of accumulation in living organisms. Heavy metals with excessive exposure to environmental objects behave like ecotoxicants that negatively affect not only individual organisms, but also the ecosystem as a whole

    Influence of salts of heavy metals on the structure of epiphyseal cartilage

    Get PDF
    Among the known unfavorable influences on the skeletal bone, there is reaction on epiphyseal cartilage of bones under the influence of salts of heavy metals in the organism. To study the morphological changes of epiphyseal cartilage of skeletal bones using salts of heavy metals (chrome, zinc and lead). When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/552

    The Adsorbsi Cuper (II) by Sulfonated Sawdust

    Full text link
    The existence of heavy metals is one of the major problems in the world. Increasing concentration of heavy metals because toxic in the soil, air, and water. Many methods have been developed to decrease concentration of heavy metals from water, for example by precipitation, evaporation, electrochemical and resin's consumption. However, the method is not effective because it requires high cost to operate. Therefore, the research for that materials are cheap and available. Biomaterial is one of the are used to reduce heavy metals from water (biosorption), for example sawdust. In this research, sawdust that used as adsorbent ion copper (II) must be modified by adding a sulfonate group by sulfonation process. The parameters tested are the activation time (sulfonation) and contact time. The optimum conditions of adsorption of Copper (II) by sulfonated sawdust in a single solution occurred at the sulfonation time 120 minutes and adsorption's contact time 60 minutes, the efficiency adsorption is 99.27%. From that conditions, the sulfonated sawdust is tested on the adsorption of Copper (II) in electroplating wastewater. The efficiency adsorption of Copper (II) in electroplating wastewater is 39.03%. This is occured because of the competition uptake's metals in the electroplating wastewater

    INVESTIGATION OF PHYTOINDICATION EFFECTS DUE TO CADMIUM CONTAMINATION

    Get PDF
    Heavy metals are one of the most dangerous contaminants in the natural environment that cause toxic effects in the cells of plants and animals. They are not decomposed in the environment but consequently accumulated in the tissues of living organisms. Penetrating, for example, plants, heavy metals can adversely affect the metabolic processes, which ultimately leads to a reduction in yield and poses a threat of contamination by toxicants to the further food chain

    Heavy metals partioning in three French forest soils by sequential extraction procedure

    Get PDF
    To know the concentration of heavy metal associated to chemical compounds is important to evaluate the environmental risks on soils, particularly regarding ion bioavailability. The relative mobility and strength of binding of heavy metals to the soil components can be studied using a sequential extraction procedure which provides a meaningful comparison between different soil profiles. The heavy metals partitioning bas been identified in three different french forest soils : one cambic podzol, one calcaric cambisol and one mollic andosol, using a new sequential extraction method. Results show that metal fractionation is metal and site specific. The water leaching phase does not contain any metals. The proportion of heavy metal leached in the exchangeable and the acid — soplhuabslee is significant for Cd. The residual phase is important for Cr, Pb, and to a lesser extend for Ni. The organic matter fraction is dominant for Zn and Cu. Thus, the considered heavy metals are mainly bounded to iron oxides, to the organic matter and to the mineral residue. The order of heavy metals availability in the three soils would be : Zn>Cd>Cu>Pb>NiL&egatd;C r.i sotopes in some extracts of the extraction procedure corroborate the anthropogenic inputs for two soils. These both infomations allow to trace the origin, the mobility and the distribution of Pb in the soil
    corecore