Arsenic Table toxicity

Rainbow trout (Oncorhynchus mykiss) fed diets containing up to 90 mg As+5/kg were slightly affected, but those given diets containing >120 mg As/kg (as As+3 or As+5) grew poorly, avoided food, and failed to metabolize food efficiently. No toxic effects were reported over 8 weeks of exposure to diets containing 1600 mg/kg, as methylated arsenicals (Table 28.4). Dietary disodium... 

Most of the compounds of arsenic are toxic when in contact with the skin, when inhaled, or when ingested. As with arsenics cousin phosphorus above it in group 15 of the periodic table, care must be taken when using arsenic. The compound arsenic trioxide (As O ), an excellent weed-killer, is also carcinogenic. Copper acetoarsenite, known as Paris green, is used to spray cotton for boll weevils. A poisonous dose of arsenic as small as 60 miUigrams can be detected within the body by using the Marsh test. 

Because of differences in the solvents and chemical agents in CAIS materials and recovered chemical munitions, the RRS and MMD use different neutralization chemistries and produce different liquid waste streams—collectively referred to in this study as neutralent wastes or neutralents. A summary of nonstockpile CWM that will be treated by the RRS and MMD, as well as the major constituents of their neutralent waste streams, is given in Table ES-1. According to the Army, the maximum permissible concentration for blister agents in a neutralent stream is 50 parts per million (ppm) (although in practice the actual concentration is more likely to be about 1 ppm). The maximum for nerve agents is 20 to 30 parts per billion (ppb). RRS neutralents may contain arsenic, a toxic heavy metal that must be captured and immobilized. 

To be useful as CVD precursors, a metallo-organic compound should be stable at room temperature so that its storage and transfer are not a problem. It should also decompose readily at low temperature, i.e., below 500°C. The compounds listed in Table 4.1 meet these conditions with the exception of the alkyls of arsenic and phosphorus, which decompose at higher temperatures. For that reason, the hydrides of arsenic and phosphorus are often preferred as CVD precursors (see Ch. 3). These hydrides however are extremely toxic and environmental considerations may restrict their use. 

Refining operations have two principal wastestreams, waste electrolyte and cathode and anode washwater. Spent electrolyte is normally recycled. A bleed stream is treated to reduce copper and impurity concentration. Varying degrees of treatment are necessary because of the differences in the anode copper. Anode impurities, including nickel, arsenic, and traces of antimony and bismuth, may be present in the effluent if the spent electrolyte bleed stream is discharged. Tables 3.14 and 3.15 present classical and toxic pollutant data for raw wastewater in this subcategory. 

Wastewater is generated in the primary zinc and primary cadmium recovery subcategories by acid plant blowdown, which results from sulfuric acid recovery, air pollution control, leaching, anode/ cathode washing, and contact cooling. The streams may contain significant concentrations of lead, arsenic, cadmium, and zinc. Tables 3.26 and 3.27 present classical and toxic pollutant data for the primary zinc and primary cadmium subcategories. 

Again, the waste treatment scenario with incineration has by far to the highest score for human toxicity. The scores for the other scenarios are more or less the same. The incineration of EoL PVC will lead to toxic emissions of metals (arsenic, lead, chromium, see Table 5) causing human health effects. However, the most important contribution to the human health effect is caused by the emission of mercury in the upchain processes of the production of mercury and sodium hydroxide. Sodium hydroxide is an auxiliary material in the waste incineration process. Mercury... 

Arsine is an extremely toxic, colorless gas used extensively in the semiconductor industry. Arsine also is used in mining and manufacturing processes involving arsenicals and in paints and herbicides containing arsenicals (Risk and Fuortes 1991). Annual production has been estimated at over 10,000 pounds and is likely increasing with greater use in the semiconductor industry (U.S. EPA 1980). The physical and chemical data for arsine are shown in Table 2-2. 

The process can be used to immobilize heavy metals such as Cd, Zn, Cu, Pb, Ni and Co. Cr(VI) can be reduced by some metal-reducing bacteria to the less toxic and less soluble form Cr(III). Arsenate [As(V)] can be reduced to the more mobile arsenite [As(III)] which precipitates as AS2S3, and is insoluble at low pH. Several laboratory-scale tests (batch and column) are currently available to study the feasibility of this process. However, only a few field tests have been performed to date. Two such tests have been conducted in Belgium, one at a non-ferrous industrial site, where the groundwater was contaminated with Cd, Zn, Ni and Co, and the other which was treated by injection of molasses in order to reduce chromium (VI) to chromium (III). A third demonstration in The Netherlands has been performed at a metal surface treatment site contaminated by Zn. The outcomes of a batch test of a groundwater heavily contaminated by Zn, Cd, Co and Ni are presented in Table 5. The initial sulphate concentration was 506mg/l. With the addition of acetate, a nearly... 

The word bismuth is derived from the German word Weissmuth, or white substance. It is the heaviest stable element of the periodic table. Even though it carries the status of heavy metal, this metal is rated as relatively nontoxic and noncarcinogenic, unlike its neighboring elements (in the periodic table) like arsenic, antimony, lead, and tin, which are highly toxic. This nontoxicity arises from the insolubility of its salts in neutral aqueous solutions such as biological fluids, which... 

A number of objections have been raised to the use of the term. In the first place, the list of so-called heavy metals usually includes some elements that are not even metals, such as the semimetals arsenic and antimony. Also, some of the "heavy metals" are not really very "heavy" by almost any standard. Beryllium, for example, has an atomic mass of about 9, and aluminum, an atomic mass of about 27. Yet both are often classified as "heavy metals." For these reasons, some authorities now prefer the term toxic metals to the more traditional term heavy metals. Either term can refer to elements in both their free and combined states. The table on pages 120-121 provides an overview of the sources and health effects of some heavy metals,... 

As this table suggests, the environmental hazard posed by heavy metals varies significantly. Some of the elements listed in that chart are among the most hazardous substances released to the environment. The EPA has classified four of the heavy metals—arsenic, lead, mercury, and cadmium—among the top 25 most hazardous chemicals present in the environment in the United States. (Of the remaining substances on that list 18 are toxic organic chemicals one is another heavy metal, chromium one is white phosphorus and the last is creosote produced from coal tar.)... 

Concomitants Concomitants can be considered impurities present in naturally occurring, nonsynthesized raw materials. They may either present toxic effects, as with arsenic, or be as harmless as chloride ions. An overview of usual concomitants and their limits cited in pharmacopeial compendia are listed in Table 7. 

Swedish law requires that major retailers make an assessment of potential health and environmental hazards when deciding on which products to stock and sell. As a guide to which chemicals should be avoided, KEMI has published a list of especially hazardous chemicals ( OBS-listan ). The hazard profiles of the KEMI-listed substances differ widely, from decidedly toxic compounds, like arsenic salts and benzene, to practically innocuous substances, such as metallic zinc and many zinc compounds. (Like any other chemical, including table salt, zinc and its compounds should, of course, not be dumped in rivers in large quantities, but they are perfectly safe in most other contexts.)... 

Metals frequently occurring in the state s waste streams include cadmium, chromium, lead, arsenic, zinc, copper, barium, nickel, antimony, beryllium, mercury, vanadium, cobalt, silver, and selenium. These metals are toxic to humans and other organisms, are persistent in the environment, and can bioaccumulate in food chains. They are typically used by businesses in many industrial categories, as shown in Table 2.1-1. 

The Clean Air Act of 1990 has made trace metal content in fuels and wastes the final ash-related compositional characteristic of significance. Considerable attention is paid (ca 1993) to emissions of such metals as arsenic, cadmium, chromium, lead, mercury, silver, and zinc. The concentration of these metals in both grate ash and flyash is of significance as a result of federal and state requirements of particular importance is the mobility of metals. This mobility, and the consequent toxicity of the ash product, is determined by the Toxic Characteristic Leaching Procedure (tclp) test. Tables 8—10 present trace metal contents for wood wastes and agricultural wastes, municipal waste, and refuse-derived fuel, respectively. In Table 8, the specific concentration of various components in the RDF governs the expected average concentration of trace metals. 

It can be seen from Table 7.4 that the population dietary exposure to total arsenic for UK consumers has remained fairly constant. The dietary exposures for mean and 97.5th percentile adult UK consumers in 1997 were 0.12 mg/day and 0.42 mg/day respectively. Although these exposures are similar or greater than the JECFA Provisional Tolerable Daily Intake (PTDI) for inorganic arsenic of 0.002 mg/kg bodyweight, which is equivalent to 0.12 mg/day for a 60 kg person, these are estimated for total arsenic. As has been stated before, most of the arsenic in the diet is from fish and most of the arsenic in fish is in the less toxic organic forms. 

Of the elements in the Periodic Table more than two thirds are metals. Although many of these metals are toxic, only some metals are major environmental pollutants, because of their widespread use. U S. EPA has classified 13 metals as priority pollutants aluminum, antimony, arsenic, beryllium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, and zinc. The Resource Conservation and Recovery Act has fisted eight metals whose mobility in the soil is measured to determine the characteristic of toxic wastes. These metals include arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver—all but one from the above list of priority pollutant metals. 

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