Xem 1-20 trên 57 kết quả Soil toxicity
  • Soil contamination has severely increased over the last decades, mainly due to petroleum hydrocarbons, solvents, pesticides, lead and other heavy metals from industrial wastes and human activities. The critical point regarding contaminated soil monitoring is the intrinsic difficulty in defining fixed monitoring variables and indicators as the establishment of any a priori criterion and threshold for soil quality can be still considered subjective.

    pdf180p cucdai_1 19-10-2012 39 8   Download

  • Some of the POPs targeted by the Stockholm Convention are already virtually obsolete. Their toxic effects became obvious early on and they have been banned or severely restricted in many countries for years or even decades. Replacement chemicals and techniques are in place. The remaining challenge is to find any leftover stocks and prevent them from being used. Some developing countries may need financial support to dispose of these stocks and replace them with chemicals whose benefits outweigh their risks....

    pdf29p cao_can 02-01-2013 25 3   Download

  • The treatment of contaminated land to eliminate or reduce the presence of pollutants in the contaminated site has received (and will continue to receive) considerable attention from the practicing profession. Extensive research and development are still underway in respect to the delivery of more effective (and economic) means for site decontamination.

    pdf285p 951864273 11-05-2012 47 19   Download

  • This book provides an authoritative state-of-the-art biotreatment review for three key contaminant groups: chlorinated solvents, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Issues such as availability, toxicity, and treatability are discussed along with a summary of the latest bioremediation technologies. Special innovative research and development projects are presented for each contaminant group.

    pdf0p crazy_sms 10-05-2012 32 11   Download

  • The study conducted by Hiller et al. (2011) to investigate the concentrations, distributions, and hazards of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). PCBs are used mainly as coolant and electronic industries (capacitors, transformers), paints, sealants for wood, cutting and lubricating fluids, plasticizers, and as dielectric fluids. Therefore, at the former site of PCB manufacturing area in Slovakia, high concentrations of PCBs are detected in soils, sediments, humans, and wildlife (Kocan et al., 2001; Petrik et al., 2001; Hiller et al., 2011)....

    pdf53p lulanphuong 28-03-2012 47 7   Download

  • At the open burning sites, some metals were present at concentrations over one hundred times typical background levels for soils, including lead, a highly toxic metal. High levels of other toxic metals, including cadmium and antimony, were also present. Numerous classes of organic chemicals were also present in one or more of the samples, including many halogenated (chlorinated or brominated) chemicals. Many of the compounds identified are intentionally used in electronic devices.

    pdf22p cao_can 02-01-2013 26 5   Download

  • It has been demonstrated that most heavy metals that are in the fuels or raw materials used in cement kilns are effectively incorporated into the clinker, or contained by standard emissions control devices (WBCSD 2002; European Commission (EC) 2004; Vallet January 26, 2007). A study using the EPA’s toxicity characteristic leaching procedure to test the mobility of heavy metals in clinker when exposed to acidic conditions found that only cadmium (Cd) could be detected in the environment, and at levels below regulatory standards (5 ppm) (Shih 2005).

    pdf0p loixinloi 08-05-2013 19 4   Download

  • This lab will introduce students to a simple bioassay that will allow them to explore the effects that a chemical's concentration has on the level of toxicity. By relying on morphological examination of sponges hatching from gemmules that are smaller than a millimeter in diameter, this module will help students develop their microscopy skills. Our major aim, however, is to have students strengthen their ability to design and test their own hypotheses.

    pdf9p tainhacmienphi 19-02-2013 11 3   Download

  • Many of the traditionally sound cultural practices recommended for conventional agriculture are also employed in organic production. In fact, organic agriculture has been referred to as “good farming practice without using synthetic chemicals.”2 For example, planned crop rotations, which have multiple benefits in terms of soil building, plant health, pest management, and enhancing biodiversity, are required in annual organic cropping systems.

    pdf12p cao_can 02-01-2013 30 2   Download

  • The quality and design of a child’s physical environment can cause or prevent illness, disability and injury; therefore a high-quality environment is essential for children to achieve optimal health and development. While pediatricians are accustomed to thinking about health hazards from toxic exposures, much less attention has been given to the potential for adverse effects from “built environments” such as poor-quality housing and haphazard land-use, transportation, and community planning.

    pdf28p connhobinh 10-12-2012 6 1   Download

  • Vascular dysfunction may also reduce oxygen delivery to gingival tissue. Pocket oxygen tension was reported to be significantly lower in smokers than non-smokers providing support for the negative effects of smoking on vascular system (Hanioka et al. 2000). Evidence from both human and experimental studies suggests that smoking has a long-term chronic effect, and its effect is not simply a vasoconstriction.

    pdf51p pt_1669 26-03-2012 83 49   Download

  • Despite the tremendous progress that has been achieved in water pollution, almost 40% of the U.S. waters that have been assessed by states do not meet water quality goals. About 20,000 water bodies are impacted by siltation, nutrients, bacteria, oxygen depletion substances, metals, habitat alterations, pesticides, and toxic organic chemicals. With pollution from point sources being dramatically reduced, nonpoint source pollution is the major cause of most water that does not meet water quality goals.

    pdf331p crazy_sms 10-05-2012 72 18   Download

  • Metabolism of pesticides denotes that any foreign substance that enters in the living system and how it will be changed into non-toxic and thrown out due to the enzymatic activity and other mode of action. When chemical toxins applied to nonliving substance (soil and water) that will lose the toxic principles by degradation process due to the action of biotic and abiotic factors. The time to nullify the toxicity is of prime importance and it vary depending upon the chemical molecule and environmental conditions.

    pdf386p conquynho32 18-09-2012 27 13   Download

  • Mechanisms of salt tolerance in halophytes: can crop plants resistance to salinity be improved? High concentrations of sodium are toxic to most plant species, making soil salinity a major abiotic stress in plant productivity world wide. Many crop species, which countless people rely for survival, are negatively affected.

    pdf11p nguyenngocsonctu 24-11-2010 86 12   Download

  • Though alternative methods of controlling insects, rodents, insect pests, pathogens, microbes and weeds have been developed, pesticides could not be replaced. The prosperous role of pesticides in the management of insect pests and diseases is indisputable. However, its nature of non selective toxicity towards other organisms and deposition in the environment warrants the legislation of usage. Pesticide use raises a number of environmental concerns.

    pdf232p conquynho32 18-09-2012 22 12   Download

  • Forty undergraduate students from three different faculties were recruited for the study. Using official IELTS Test results obtained by the students at the beginning of their study in Australia and towards the end, as well as interviews with most of the students, the study investigated patterns of improvement, as well as lack of improvement among the 40 students. While most of the students in the study did achieve a higher score in the IELTS Test taken towards the end of their study in Australia, only a small number were able to achieve an Overall score of 7.0, with at least...

    pdf162p dambaotaikhoan 04-05-2013 26 11   Download

  • Candidate no:000124971 Mechanisms of salt tolerance in halophytes: can crop plants resistance to salinity be improved? Jennifer Seaman High concentrations of sodium are toxic to most plant species, making soil salinity a major abiotic stress in plant productivity world wide. Many crop species, which countless people rely for survival, are negatively affected.

    pdf11p nguyenngocsonctu 21-11-2010 57 9   Download

  • Introduction: Diazine and triazine herbicides are being widely used in the world. These herbicides inhibit the electron-transport system in the higher plants and thus suppress the photosynthesis, resulting in the herbicidal action. These compounds are also important as pollutants for crops, soil and groundwater [1, 2]. The attention is usually directed toward chronic toxicities of the herbicides [3].

    pdf8p bigbaby87 01-09-2010 43 7   Download

  • Introduction: As one of azide salts, lead azide is well known, because it is used as a detonator for air bags of automobiles. Recently, sodium azide has been frequently used for suicides and homicidal attempts. In this chapter, therefore, analytical methods are described only for sodium azide. Sodium azidea is being well used as an antiseptic (preservative)b in biochemical researches and as a material for synthesis of organic compounds.

    pdf8p bigbaby87 01-09-2010 50 7   Download

  • The US Environment Protection Agency defines arsenic as a persistent, bio-accumulative, and toxic chemical having the ability to accumulate in the air, soil, and water. In 1961, the pollution of arsenic was first discovered in Taiwan, and later in Belgium, Netherland, Germany, Italy, Hungary, Portugal, The Philippines, Ghana, USA, Chile, Mexico, Argentina, and Thailand. In 1992, the toxicity of arsenic was found as a disaster in West Bengal, India.

    pdf14p sinhtobo111 25-04-2011 33 7   Download

Đồng bộ tài khoản