Extraction procedure toxicity test

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. 

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. 

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. 

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. 

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. 

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. 

The in vitro bioassay for dioxins with cleaned sediment extracts (DR-CALUX) proved to comply with the QA/QC criteria needed to guarantee the reliability of data in an inter- and intralaboratory study (Besselink et al., 2004). The chemical stability of dioxins makes it possible to apply destructive clean-up procedures which remove all matrix factors. Sample extraction and cleanup for other in vitro bioassays for specific mechanisms of toxicity require further development to make sure that the chemicals of interest are not lost or unwanted chemicals included in the sediment extract to be tested. Table 4 summarizes possible bioassays that could be performed in addition to chemical analyses with the dredged sediment in a licensing system. 

It may be noted that Sr is one of the most toxic radionuclides formed in nuclear fission of 235U and 239Pu. It has been widely distributed by nuclear weapons testing and marginally increased by the Chernobyl accident. Analytical problems have been studied in detail1 as have attempts to find extraction procedures using crown and other polyethers, polyethyleneglycols, etc.2... 

Batch extraction of the particle fractions were performed using the U.S. EPA EP-toxicity test and a modified version developed in our laboratories. The 2 main differences in these tests are 1) the EP-toxicity test uses 0.5 N acetic acid to enhance leaching whereas the modified test uses 17.4 N glacial acetic acid and 2) the EP-toxicity test limits the amount of acid added to keep the pH at 5.0 + 0.5 to 40 ml so that the actual pH of the leaching medium may be well above pH 5.0 if additional acid is needed, whereas there was no limit as to how much 17.4 N acetic acid could be added to keep the pH at 5.0 + 0.5 in the modified test. The samples were placed on a shaker-table in a controlled temperature room (20 C) the pH was monitored and adjusted over a 24 hour period as specified in the EP-toxicity test procedure[ 9 ]. 

When positive biocompatibility results are reported, development discontinuation is not the only option. First it should be confirmed that no mistakes were made in the testing laboratory, including the testing of the proper article and formulation. In addition, it should be made certain that the article was properly manufactured, cleaned, stored, and tested (e.g., the extractant used, the testing conditions, and the procedure). Finally, reproducibility of positive biocompatibility results should be confirmed. In a certain situation where the possible benefits outweigh the risks, or when quality of life is a factor, a level of toxicity may be acceptable. 

Environmental contaminants are present as complex mixtures, so that if toxicity is found, procedures known as toxicity identification evaluation may be carried out. This procedure identifies toxic components by systematically treating the effluent, elutrate, or pore water to remove various fractions - hydro-phobic ( fat soluble ) chemicals, metals, acids, volatile compounds, etc. - and retesting the toxicity after each extraction. Loss of toxicity after an extraction implicates the chemical that was extracted. This is confirmed by chemical analysis and toxicity tests on... 

All pharmaceuticals and material for medical items are carefully screened and tested for extractables, as required by regulatory agencies. Suppliers are also responsible for developing extractable procedures and conducting toxicity studies to be shared with users in the industry and government. 

The leachabilities of toxic hazardous material were determined using the EPA extraction procedures (J). The leachabilities of certain metals (copper, nickel, potassium, and sodium) that are not considered toxic were also determined. Samples were stirred 24 h in water and filtered then the water-soluble concentrations were determined by atomic absorption. These metals form highly soluble sulfates that would be very susceptible to leaching and provide a test of the degree of ease of leaching within the phosphogypsum stacks. 

Comparison between foodstuffs and pharmaceuticals based on simulated extractive tests is inevitably difficult, because the site and mode of absorption may vary, because of the difference in the pre-storage period and the frequency of use, and the volume/weight of the product taken. With foodstuffs, the contact period between product and pack is usually shorter, but the quantity taken and frequency of use are greater, e.g. daily intake of margarine. Thus any EU extractive procedure may provide useful additional information for the pharmaceutical industry as part of stage 1 involving the screening of the material, but the simulants used may bear little relationship to the final pharmaceutical form. These tests are also more relevant to toxicity aspects rather than to irritancy. For food extractive tests see Appendix 8.6. 

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