Heavy Metals

Preface To The Series

The assessment of safe to use starts with the harvested plant material which has to comply with an official monograph. This may require absence of, or prescribed limits of, radioactive material, heavy metals, aflatoxin, pesticide residue, as well as the required level of active principle. This analytical control is costly and tends to exclude small batches of plant material. Large scale contracted mechanised cultivation with designated seed or plantlets is now preferable.

Elucidation of Environmental Factors that May have Caused the Decline in the Intermediate Hosts

Changes in pH associated with changes in the volume of water are more likely to be harmful. The pH values, which varied between 5.5 and 7.7 and 4.8 and 6.9 in the Teifi and Pysgotwr, respectively, were inversely correlated with water level or volume (Table 1). However, there is evidence that in times of heavy spate the pH values often declined to values even lower than those given in Table 1 (Wade, verbal communication). It is well established that under these conditions the mobilisation of heavy metals, such as aluminium, zinc, lead and copper into the labile, ionic form will be favoured (Hutchinson and Sprague, 1986 Howells etal. 1990). The results of analyses carried out on sediment cores in the River Teifi suggest that heavy metal toxicity may be involved in causing the decline in the distribution and abundance of intermediate hosts. Thus, according to the United States Environmental Protection Agency (US EPA) guidelines (Giesy and Hoke, 1990) for sediments the metal...

Results And Discussion

Table 2 represents the location, depth and concentration of arsenic and heavy metals Fe, Cu, Pb, Ni, Cr, Mn and Zn in ten sediment samples having arsenic concentrations higher than 10 mg kg in homogenized samples. Standard Reference Materials were analyzed for the validity of the result (Table 3). Regression analyses have been carried out between the arsenic and other heavy metals, e.g., Fe, Cu, Pb, Ni, Cr, Mn and Zn in 43 homogenized samples having arsenic concentrations above 10 mg kg. The linear regressions show good correlations between arsenic and iron (r2 0.95, P 0.001) and arsenic and lead (r2 0.92, P 0.001). Good correlations were seen in some individual boreholes, e.g., in the borehole of Mahisbathan village, Karimpur, Nadia district. Also, good correlations were observed between As and Cu (r2 0.808, P 0.001), As and Ni (r2 0.818, P 0.001), and As and Cr (r2 0.56, P 0.0086). The identical values of the As Fe ratio of the borehole sediment samples of eight consecutive layers...

Regulatory and Environmental Aspects

The USA, all ingredients used in feed, including silage ingredients, need to be listed in the official publication of the Association of American Feed Control Officials (AAFCO Manual), and registered with the states in which they are sold, as well as tonnage fees paid to the states. Any enzyme not listed in the AAFCO Manual requires an assessment of safety and efficacy by the Center of Veterinary Medicine at the Food and Drug Administration (FDA), who will then recommend listing in the Manual. In the EU, all enzymes require submission of a full dossier and specific approval by trade name. Although the regulations can vary from country to country, in general most require (Wohlleben et al., 1993 Chapman, 1996) (i) the use ofwell-char-acterized non-pathogenic non-toxigenic organisms (ii) good manufacturing practices (GMPs) involving well-documented, safe and reproducible fermentation and recovery processes in which only approved raw materials are used (iii) the absence of toxins or...

Choosing Appropriate Diet For Studies In Rodent Models

Although the content of these diets satisfies the established minimum requirements for most nutrients in mice and rats, the concentrations of individual nutrients may vary substantially. For example, the vitamin A and P-carotene content of different batches of the NIH-07 chow diet were found to vary over 6- and 20-fold, respectively (25). Natural ingredients may also exhibit marked variation in trace elements. For example, selenium found in corn and soybean meal from the Great Plains is typically 0.5-1.0 ppm. In contrast, corn and soy from the Ohio valley or Northeastern states may be

Reasons for some Parasites Causing Detrimental Effects

Fifthly, parasites can become more harmful to the host as a result of damage to the innate and adaptive arm of the immune system caused by detrimental changes in the environment. Examples are provided by low water temperature (Chubb, 1982 Hardie et al., 1994 LeMorvan et al., 1998 Bernstein et al., 1998), specific pollutants including heavy metals (Dunier, 1996) and ammonia (Hurvitz et al., 1997), general habitat degradation (Bakke and Harms, 1998)

Fish As Sentinel Organisms

The sites of action of toxicants are numerous, and there is no single protocol that can be proposed to test for all toxicants, or even for all toxicants in a particular class of chemicals. For example, the heavy metals exert their effects via different pathways, and the biological effects of the polychlorinated biphenyl (PCB) family are known to differ, depending on structure of the specific PCB congener. Some congeners act on the nucleus of cells, where they interact with the aryl hydrocarbon receptor. This leads to the increased expression of some genes, including those that code for the synthesis of cytochrome P450 detoxifying enzymes. In contrast, although other congeners do not elicit a P450 response, they do effect changes in thyroid hormone metabolism (Porterfield, 1994 Brouwer et al., 1998 Leatherland 1998 Porterfield and Hendry, 1998). It is beyond the scope of this chapter to deal with the specific mechanisms of toxicity, but in general, toxicants bring about biological...

Efficacy and Safety of CAM

Severe hepatotoxicity from some herbal products. However, in general, there are no major safety concerns with the common forms of therapy (herbs and nutritional supplements) used by GI patients. Potential risks include allergic reactions, contamination or mislabeling of herbal products, nutritional deficiencies resulting from restrictive diets, and neck and spine injury resulting from spinal manipulation. However, physicians and patients should be aware that some therapies are associated with the risk of serious side effects due to the therapy's chemical constituents (eg, hepatic veno-occlusive disease from herbs such as comfrey that contain pyrrolizidine alkaloids), contamination with heavy metals (reported with some medicines prepared in Asia), and the potential risk for toxicity to the fetus.

Causes Of Parenchymatous Acute Renal Failure

Acute tubular necrosis Hemodynamic cardiovascular surgery,* sepsis,* prerenal causes* Toxic antimicrobials,* iodide contrast agents,* anesthesics, immunosuppressive or antineoplastic agents,* Chinese herbs, Opiaceous, Extasis, mercurials, organic solvents, venoms, heavy metals, mannitol, radiation Intratubular deposits acute uric acid nephropathy, myeloma, severe hypercalcemia,

In Situ Chemical Fixation

Variations of ISF processes have been applied to heavy metals in cationic form (e.g., Cd2+, Cr3+, Pb2+), which reduced the toxicity and or water solubility of the contaminant. Arsenic forms a number of relatively insoluble compounds with solubility products on the order of 10 10 to 10 51. Research shows that arsenic compounds formed with ferric (Fe3+) and ferrous (Fe2+) iron and calcium (Ca2+) salts tend to be highly insoluble and relatively stable (J.R. Howell in Hartsfield, 1999).

Autoantibodies in Experimental Models of Autoimmunity

The second type of model also involves the manipulation of normal, non-autoimmune animals to produce an autoimmune response. In these cases the triggering event is the introduction into the animal of exogenous material that, unlike the case of direct immunization, may appear to bear little relationship to the ensuing autoimmune response. These mediators - which may include drugs, biologicals, and environmental agents such as hormones and microbes -and their role in inducing autoimmunity are discussed by Per Hultman in Chapter 22. An excellent example of this type of model is the autoimmunity induced by heavy metals 10 . Administration of mercury by several different routes and in several different forms (most notably, subcutaneous injection of mercuric chloride) produces in mice an autoantibody response that targets the nucleolus 12 . The principal autoantigen involved is the 34-kDa protein fibrillar-in 58, 59 , a protein component of the box C D snoRNP particles. Mercury induces this...

Helminth Parasites and other Aquatic Organisms as Pollution Bioindicators

Table 30 shows that all the scores for Station 1 in the Teifi bog area are lower than at other stations further downstream. However, the scores for Station 1 although relatively low are still indicative of good water quality whereas those for the other stations are exceptionally high, particularly those where the BMWP and average score per taxon (ASPT) scores exceed 200 and 6.0, respectively. There are two possible explanations for the relatively low biotic indices for the bog area site. Firstly, they may be attributable to the toxic effects of heavy metals, including zinc and lead, which have been shown to be present at higher concentrations in the sediments in the bog area than further downstream. Secondly, the lower values in the bog area may be the result of lower habitat diversity compared with the downstream sites. Despite the fact that the scores for Station 1 are within acceptable Environment Agency standards the lower indices and the higher levels of heavy metals in the...

Rotoevaporated Arsenicrich Water Residues From Contaminated Handtubewells

After studying arsenic along with other heavy metals in borehole sediment samples from arsenic-affected districts of West Bengal, it was felt necessary to study the heavy metals in the arsenic-rich underground water from hand tubewells of the affected districts. In this work, the water samples (each 10 l) were roto-evaporated and finally the solid mass obtained was dried on silica gel in a vacuum desiccator. Twenty-two well water samples having an arsenic concentration in the range of 200-2480 g l from eighteen affected blocks, were roto-evaporated to dryness. While studying the borehole sediment samples we observed good correlations in linear regression between As and Fe, Pb, Mn and Zn. Regression analyses were further carried out between the arsenic and other heavy metals for all the 22 water samples which were evaporated to dryness. The linear regression shows good correlations also between As and Fe, Pb, Mn and Zn (Table 9). The similar correlations between arsenic and heavy...

Series Preface

Quality measurements are essential for demonstrating the comparability of data obtained worldwide and they form the basis for correct decisions related to management of water resources, monitoring issues, biological quality, etc. Besides the necessary quality control tools developed for various types of physical, chemical and biological measurements, there is a strong need for education and training related to water quality measurements. This need has been recognized by the European Commission, which has funded a series of training courses on this topic that cover aspects such as monitoring and measurement of lake recipients, measurement of heavy metals and organic compounds in drinking and surface water, use of biotic indexes, and methods of analysing algae, protozoa and helminths. In addition, a series of research and development projects have been or are being developed.

Risk Factors for MSA

Only two case-control studies have been reported for MSA. The first examined family history and specific occupational exposures. This noted significant odds ratios for organic solvents (2.4), metallic dusts (14.8), pesticides (5.8), and plastic monomers and additives (5.3) (27). Anecdotal case reports have also suggested pesticides (28), heavy metals (28), and organic solvents (28,29).

Figure 101

Chronic exposure to drugs, occupational hazards, or environmental toxins can lead to chronic interstitial renal diseases. The following are the major causes of chronic interstitial renal diseases occupational exposure to heavy metals abuse of over-the-counter analgesics misuse of germanium chronic intake of mesalazine for intestinal disorders, lithium for depression, and cyclosporine in renal and nonre-nal diseases and environmental or iatrogenic exposure to fungus or plant nephrotoxins (ochratoxins, aristolochic acids).

EM Reagents

Heavy metals, osmium tetroxide, and Lowicryl can be purchased from EM 1. Heavy metals used for EM, such as osmium tetroxide, uranyl acetate, and lead citrate, are biohazards. These should be handled with gloves and disposed as directed by the local administrator handling hazardous wastes.

Methodology

A large number of borehole sediment samples were analyzed for arsenic and other heavy metals using atomic absorption spectrometer (Perkin Elmer Model 3100 and Varian AAS Model Spectra AA-20), both GFAAS and FI-HG-AAS, X-ray fluorescence, and ICP-AES. Sediment samples were examined and analyzed by binocular microscope, petrological microscope, X-ray powder diffractometer, electron probe micro-analyzer (EPMA), laser microprobe mass analyzer (LAMMA), and scanning electron microscope (SEM). Details of the procedures of sample preparation and instrumentation have been described in our earlier publications (Chatteqee et al., 1992, 1995 Das et al., 1996 Roy Chowdhury, 1999).

Figure 622

Arrows indicate the characteristic intranuclear inclusions. Exposure to a variety of heavy metals results in development of chronic TIN. Of these metals, the more common and clinically important implicated agent is lead. Major sources of Other heavy metals associated with TIN are cadmium, silicon, copper, bismuth, and barium. Sufficient experimental evidence and some weak epidemiologic evidence suggest a possible role of organic solvents in the development of chronic TIN.

Figure 634

In a geographic area bordering the Danube River as it traverses Romania, Bulgaria, and the former Yugoslavia. The cause of Balkan nephropathy is unknown however, it has been attributed to genetic factors, heavy metals, trace elements, and infectious agents. The disease evolves in emigrants from endemic regions, suggesting a role for inheritance or the perpetuation of injury sustained before emigration.

Quality Control

Present (69, 70), along with scoring the embryos at key times and determining blastocyst cell number. The most common system used by our laboratory for QC is outlined in Protocol 3.1. The stage at which the embryos are cultured has an impact on development. Embryos collected at the pronucleate stage do not tend to fair as well in culture as those collected at the two-cell stage. Reports that mouse embryos can develop in culture in medium prepared using tap water (71, 72) should be interpreted carefully after taking into account the types of media used and the supplementation of medium with protein. Silverman et al. (72) used Ham's F-10. This medium contains amino acids, which can chelate any possible toxins present in the tap water, such as heavy metals. George et al. (71) included high levels of BSA in their zygote cultures to the blastocyst stage. Furthermore, all studies used blastocyst development as the sole criterion for assessing embryo development. Blastocyst development is a...

Figure 613

The principal manifestations of TIN are those of tubular dysfunction. Because of the focal nature of the lesions that occur and the segmental nature of normal tubular function, the pattern of tubular dysfunction that results varies, depending on the major site of injury. The extent of damage determines the severity of tubular dysfunction. The hallmarks of glomerular disease (such as salt retention, edema, hypertension, proteinuria, and hema-turia) are characteristically absent in the early phases of chronic TIN. The type of insult determines the segmental location of injury. For example, agents secreted by the organic pathway in the pars recta (heavy metals) or reabsorbed in the proximal tubule (light chain proteins) cause predominantly proximal tubular lesions. Depositional disorders (amyloidosis and hyperglobulinemic states) cause predominantly distal tubular lesions. Insulting agents that are affected by the urine concentrating mechanism (analgesics and uric acid) or medullary...

Toxicants

Various pollutants and heavy metals have been shown to cause changes in the morphology of the gill in fishes. It is neither within the scope of this paper, nor is it an objective here, to describe in detail the responses of the respiratory and cardiovascular systems to all studied toxicants. However, we describe here some of those effects, emphasizing those responses which are common to a range of different toxicants. Qualitative descriptions of changes in the fish gill in response to toxicant exposure are numerous. In general, the tissue reaction to being exposed to many environmental toxicants resembles an inflammatory response (Fig. 10.10). Fish exposed to heavy metals, detergents, and nitro-phenols show a separation between the epithelial cells and the underlying pillar cell system, which can lead to a collapse of the structural integrity of the secondary lamellae (Skidmore and Tovell, 1972 Fig. 10.10). In response to zinc exposure, for example, Skidmore and Tovell (1972), in...

Whats the Evidence

During most of his distinguished career, Dean Hamer, the scientist who took on the question, has worked at the National Cancer Institute in Bethesda, Maryland. For almost 20 years he studied the ways in which genes are expressed, what turns them on and what turns them off. Even by scientific standards, his work was esoteric. He spent a decade investigating the regulation of a single gene that makes a protein which binds to toxic heavy metals such as cadmium when they get in cells. By studying what makes the protein abundant when the toxins are present, but barely detectable when they are not, he was exploring the much deeper question of how genes are regulated.

Autoimmunity

The most perplexing and challenging aspect of autoimmunity and autoanti-body elicitation is the identification of the events involved in the initiation of the response. Although these early events are poorly understood for most autoimmune diseases, it is thought that an exogenous trigger can provide the first step in the initiation of some autoimmune responses. The best evidence for this comes from drug- and chemical-induced autoimmunity, which has been described in both human disease and animal models of autoimmunity 7 . However, even in exogenously induced autoimmunity, many of the events between the administration of a chemical or drug and the appearance of autoantibodies remain to be unveiled. Induction of autoantibodies by exogenous agents can take several weeks to many months. Drug-induced systemic autoimmunity in humans can take prolonged periods of time to develop and can be provoked by a large number of chemically unrelated drugs 7 . The autoantibody response, however,...