Extraction procedure toxicity

There are four lists of hazardous wastes in the regulations wastes from nonspecific sources (F list), wastes from specific sources (K list), acutely toxic wastes (P list), and toxic wastes (U list) there are also the four characteristics mentioned before ignitability, corrosivity, reactivity, and extraction procedure toxicity. Certain waste materials are excluded from regulation under the RCRA. The various definitions and situations that allow waste to be exempted can be confusing and difficult to interpret. One such case is the interpretation of the mixture and derived-from rules. According to the mixture rule, mixtures of solid waste and listed hazardous wastes are, by definition, considered hazardous. Similarly, the derived-from rule defines solid waste resulting from the management of hazardous waste to be hazardous (40 CFR 261.3a and 40 CFR 261.1c). 

Both Congress and EPA have a number of studies and efforts underway which may ultimately impact disposal of pesticide waste. Among these are reevaluation of the small generator exclusion limit, expansion of Extraction Procedure toxicity characteristic to include additional organic chemicals, revamping of Section 261. 33 (commercial chemical products which are hazardous waste when discarded or intended to be discarded) to both bring mixtures of active ingredients under the definition and also to establish concentration thresholds for the wastes, and a prohibition on land disposal of certain wastes. At this time I would like to briefly touch on each of these areas. 

If a medical office has photoprocessing waste, typically from x-ray processes, which leaches silver in a concentration of 5 mg/L or more, or has a dental waste which leaches mercury in a concentration of 0.2 mg/L or more, this medical office is a generator of hazardous waste, of which concentrations are determined by an extraction procedure toxicity test. 

It should be noted that ink and paint wastes may contain certain metals that make the waste FP Toxic. For more information, the readers are referred to the MSDS, to talk to the manufacturer or an environmental consultant, or have a certified laboratory conduct an Extraction Procedure Toxicity Test on the waste in question. 

Under the Resource Conservation and Recovery Act (RCRA), EPA was charged with identifying wastes which pose a hazard to human health and the environment when improperly managed. In fulfilling this mandate, EPA identified a number of characteristics which, if exhibited by a waste, would indicate that the waste is hazardous. These characteristics include ignitability, corrosivity, reactivity, and Extraction Procedure Toxicity. 

The last characteristic, the Extraction Procedure Toxicity Characteristic (EPRC), identifies hazardous waste by evaluating the potential of a waste to release toxic constituents to the ground water. The Toxicity Characteristic entails use of a leaching test to measure the tendency of a waste to leach, coupled with extract concentrations above which the waste is defined to be a regulated, or hazardous, waste. 

Determining Whether a Solid Waste is Hazardous for Subtitle C Purposes A person who handles a solid waste not within one of the regulatory exclusions must look to 261.30-33 and 261.20-24 to determine whether that waste is hazardous and hence subject to the full panoply of Subtitle C regulations. Sections 261.30-33 contain EPA s hazardous waste lists 261.21-24 identify four characteristics (ignitibility, corrosivity, reactivity, and Extraction Procedure toxicity) that make a waste hazardous regardless of whether it is included on a hazardous waste list. 

They exhibit EP (extraction procedure) toxicity. Wastes are EP-toxic if an extract from the waste is tested and found to contain high concentrations of heavy metals (mercury, lead, cadmium) or specific pesticides that could be released into the groundwater. 

The behavior of elements (toxicity, bioavailability, and distribution) in the environment depends strongly on their chemical forms and type of binding and cannot be reliably predicted on the basis of the total concentration. In order to assess the mobility and reactivity of heavy metal (HM) species in solid samples (soils and sediments), batch sequential extraction procedures are used. HM are fractionated into operationally defined forms under the action of selective leaching reagents. 

The ability to identify and quantify cyanobacterial toxins in animal and human clinical material following (suspected) intoxications or illnesses associated with contact with toxic cyanobacteria is an increasing requirement. The recoveries of anatoxin-a from animal stomach material and of microcystins from sheep rumen contents are relatively straightforward. However, the recovery of microcystin from liver and tissue samples cannot be expected to be complete without the application of proteolytic digestion and extraction procedures. This is likely because microcystins bind covalently to a cysteine residue in protein phosphatase. Unless an effective procedure is applied for the extraction of covalently bound microcystins (and nodiilarins), then a negative result in analysis cannot be taken to indicate the absence of toxins in clinical specimens. Furthermore, any positive result may be an underestimate of the true amount of microcystin in the material and would only represent free toxin, not bound to the protein phosphatases. Optimized procedures for the extraction of bound microcystins and nodiilarins from organ and tissue samples are needed. 

Physical and chemical tests of the final product may need to address two concerns (1) whether the solidified waste exhibits any RCRA defined toxicity characteristics or could be delisted and (2) the potential long term fate of treated materials in the disposal environment. Three tests are available which address the first concern. These are the Extraction Procedure (EP Tox) (40 CFR 261, Appendix II, 1980) and the Toxicity Characteristic Leaching Procedure (TCLP) (40 CFR 261, Appendix II, 1986), and the Multiple Extraction Procedure Test (40 CFR 261, Appendix II, January 1989). It is important to note that these tests are not indicators of expected leachate quality but of potentials. A solidified product which cannot pass the appropriate test (EP Tox or TCLP) would be subject to classification as a hazardous waste. 

Extraction procedures must be adjusted when separated anthocyanins will be tested in biological studies. We have found that the types of acids used for anthocyanin extraction as well as their residual concentrations in the final extract may affect the results obtained from biological tests. The growth inhibitory effect of anthocyanins on HT29 (human colonic cancer) cells may be overestimated if the residual acid in the extract exerts a toxic effect on the cells. Acetic acid residues in anthocyanin extracts showed less toxicity to HT29 cells than hydrochloric acid when samples were prepared under the same extraction procedure and subjected to the same tests on HT29 cells. In addition, the procedure to remove acids affected the acid residual concentration as well in final anthocyanin extracts, with lyophilization being more successful than rotary evaporation. 

The risk assessment has also concluded that a level of 200 mg/kg for lead in the soil will be a protective level for expected site exposures along with an excess cancer risk level for TCE-contaminated soil (56 pg/L). Based on investigations of activities at the site, the TCE-contaminated soil has not been determined to be a listed RCRA hazardous waste, as the cleaning solution records indicate the solution contained less than 10% TCE. However, the lead-contaminated soil is an RCRA hazardous waste by characteristic in this instance due to extraction procedure (EP) toxicity. None of the waste is believed to have been disposed at the site after November 19, 1980 (the effective date for most of the RCRA treatment, storage, and disposal requirements). 

A waste is toxic under 40 CFR Part 261 if the extract from a sample of the waste exceeds specified limits for any one of eight elements and five pesticides (arsenic, barium, cadmium, chromium, lead, mercury, selenium, silver, endrin, methoxychlor, toxaphene, 2,4-D and 2,4,5-TP Silvex using extraction procedure (EP) toxicity test methods. Note that this narrow definition of toxicity relates to whether a waste is defined as hazardous for regulatory purposes in the context of this chapter, toxicity has a broader meaning because most deep-well-injected wastes have properties that can be toxic to living organisms. 

Some of the disadvantages of the Stille reaction, e. g. the low reactivity of some substrates, separation difficulties in chromatography, and the toxicity of tin compounds, have been ameliorated by recent efforts to improve the procedure. Curran has, in a series of papers, reported the development of the concept of fluorous chemistry, in which the special solubility properties of perfluorinated or partly fluorinated reagents and solvents are put to good use [45]. In short, fluorinated solvents are well known for their insolubility in standard organic solvents or water. If a compound contains a sufficient number of fluorine atoms it will partition to the fluorous phase, if such a phase is present. An extraction procedure would thus give rise to a three-phase solution enabling ready separation of fluorinated from nonfluorinated compounds. 

Davidson CM, Duncan AL, Littlejohn D, Garden LM. A critical evaluation of the three-stage BCR sequential extraction procedure to assess the potential mobility and toxicity of heavy metals in industrially-contaminated land. Anal. Chim. Acta 1998 363 45-55. 

Pablos, M.V. Fernandez, C. Garcia-Hortiguela, R Valdovinos, C. Tarazona, J.V. 1999, Comparison of different extraction procedures for organic-fraction toxicity testing of urban sewages. Toxicol. Environ. Chem. 70 115-127. 

Finally, toxicity (defined in terms of a standard extraction procedure followed by chemical analysis for specific substances) is a characteristic of all chemicals, whether petroleum or nonpetroleum in origin. Toxic wastes are harmful or fatal when ingested or absorbed, and when such wastes are disposed of on land, the chemicals may drain (leach) from the waste and pollute groundwater. Leaching of such chemicals from contaminated soil may be particularly evident when the area is exposed to acid rain. The acidic nature of the water may impart mobility to the waste by changing the chemical character of the waste or the character of the minerals to which the waste species are adsorbed. 

The first step to be taken by a generator of waste is to determine whether that waste is hazardous. Waste may be hazardous by being listed in the regulations, or by meeting any of four characteristics ignitability, corrosivity, reactivity, and extraction procedure (EP) toxicity. 

Kataoka (1997) describes a method for the analysis of 21 protein amino acids and 33 nonprotein amino acids with NPD detection. One disadvantage of this method is the use of diazomethane, which is explosive and toxic (Kataoka, 1997). A method for homocysteine with GC-FID analysis uses a one-step derivatization with ethyl chloroformate and an extraction procedure (Husek et al., 2003). 

The use of Zn-Cr(III) alloy plating has almost replaced the use of Cr(VI) in the electroplating industry due to its excellent corrosion resistance and its lower toxicity. Recently, a solvent extraction procedure for separating and selectively recovering the two metals, zinc and chromium, from electroplating wastewaters has been demonstrated [10]. 

Pesticides are very much a part of the definition of hazardous wastes (Table 11). In fact, the toxicity characteristic of hazardous waste as defined by RCRA (referred to as extraction procedure or EP toxicity) is based on threshold concentrations of eight metals and six pesticides in an extract of the waste (Table II-A). Sixteen of the specific hazardous waste streams listed by... 

Relationship of Fractions to Other Toxins. Our initial extractions of tHe toxic fractions are tHe same as that of Tachibana, ( ) and others. Thus, the isolation of GT-la and GT-lb correspond exactly to the initial steps in the isolation of ciguatoxin by Scheuer ( ). The isolation of GT-2b and GT-2c and their similar action on the ileum preparation, causes us to conclude that they are either a more polar form of GT-1 or a modification of GT-1 accomplished during the extraction procedures. GT-3, it appears, would most likely correspond to a carry over of a maitotoxin-1ike fraction from the initial ether-water separation. Without any chemical confirmation, however, these are only tentative identifications. Indeed, toxins extracted from Caribbean isolates of toxicus, could be quite different from those extracted from Pacific isolates. 

EP-toxicity Refers to toxicity derived using the Environmental Protection Agency s extraction procedures... 

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