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Federal Register f Vol. 45, No, 212 j Thursday. October 30. 1980 J Proposed Raffles 72031
<br /> the National Interim Primary Drinking level for chromium in drinking water, comments and after an adequate
<br /> Water standards are for total chromium. and have indicated explicitly that the supportive data base is available.
<br /> This is because pretreatment of standard is for hexavalent Chromium. C Incineration of Chrontium-Contoinh7g
<br /> drinking water by chlorination may (WHO,1970;NAS,1977;Sorg,1979 Wastes
<br /> result in oxidation of trivalent (describing Japan's drinking water
<br /> chromium.(Guidelines for Canadian standard for hexavalent chromium].] The Agency contemplates regulating
<br /> Water Quality,1978;Sorg,1979:U.& Since the underlying drinking water wastes which contain both tri-and
<br /> F?PA,1976.)Total chromium is thus the standard in fact reflects human health hexavalent chromium in one
<br /> appropriate parameter.(U.S.EPA,1976.1 and environmental dangers of circumstance,is namely when a
<br /> All chromium compounds also are hexavalent chromium, we feel justified chromium-bearing waste is incinerated
<br /> regulated as toxic under the Clean in retaining this standard when or destructively oxidized by a similar
<br /> Water Act(CWA).In part,this reflects regulating solely on the basis of process.Such control is necessary
<br /> The Congressional determination to list hexavalent chrome. because trivalent chromium oxidizes to
<br /> all chromium compounds as toxic We stress that under our proposal,all hexavalent chromium during
<br /> pollutants under CWA Section 307(a)(1). wastes are to be tested for the incineration.(U.S.Dept.of Interior,
<br /> :n addition, the Administrator has a characteristic of EP toxicity based on 1979).incinerated wastes containing
<br /> great deal of flexibility in making listing hexavalent chromium when the trivalent chromium thus should be
<br /> for delisting)determinations under amended characteristic is finalized.We regulated as if they contain hexavalent
<br /> CWA Section 307.He is to consider a wish particularly to clarify this point chromium,The Agency intends in the
<br /> series of enumerated factors, to assign because of other regulatory action taken near future to adopt appropriate
<br /> appropriate weight to each,and to today delisting certain chromium- regulations under Parts 261 and 266
<br /> arrive at a final determination by bearing wastes and granting temporary regulating these types of chromium-
<br /> balancing the different elements.The exclusions from hazardous waste status bearing wastes.Regulatory action is
<br /> identification process under RCRA is for other such wastes(published being deferred at the present time,
<br /> much less flexible and is to some extent elsewhere in Part XI of this issue). however,due to the need to implement
<br /> more stringent,in light of the All of these wastes will he subject to other parts of the hazardous waste
<br /> significantly more impactive the amended EP toxicity characteristic management program,and also because
<br /> consequences of a RCRA hazardous and generators of these wastes incineration of trivalent chromium-
<br /> waste determination.Thus, wastes are consequently will have to test their containing wastes does not appear to be
<br /> not to be identified as hazardous unless waste extracts for the presence of widespread,'limiting the possibility of
<br /> they are capable of posing a hexavalent chromium. environmental insult during this interim
<br /> .,substantial"hazard to human health or B.Proposed Analytical Method period,Furthermore, the Agency needs
<br /> the environment.In light of these Disti4vishing Between Tri- and more time to develop regulatory
<br /> differing statutory schemes,regulatory Hexavalent Chromium standards to apply to facilities
<br /> action affecting chromium-containingincinerating trivalent chromium-
<br /> wastes has no direct bearing on the The proposal to amend the EP toxicity containing wastes.For these reasons,
<br /> status of chromium as a toxic pollutant characteristic to apply only to we are not proposing any standards for
<br /> under CWA Section 307(a). hexavalent chromium requires that there incineration of trivalent chromium-
<br /> be an analytical method which containing wastes at this time.
<br /> U.Regulatory Action distinguishes between these two RPA is,however,anxious to obtain
<br /> valence states.EPA's Office of Research comments on this contemplated
<br /> A.Proposal To Amend the and Development has developed such a specifically
<br /> t Characteristic of EP Toxicityp � p approach.We ecificall solicit
<br /> procedure.The method(fully described comments to the following questions:
<br /> In order to reflect the differing in Appendix A to this preamble) is 1.When incineration of chromium-
<br /> environmental hazards posed by based on the separation of hexavalent containing wastes causes oxidation of
<br /> trivalent and hexavalent chromium- chromium from solution by the
<br /> containing wastes when disposed an coprecipitation of lead chromate with 'There also is one other situation where wastes
<br /> land, the Agency is proposing to amend lead sulfate at a pH of 3.5.The might be regulated based on total chromium.11te
<br /> the extraction procedure to apply to precipitate is resolubilized in nitric acid Agency still has some concern that trivalent
<br /> hexavalent chrome instead of to total and quantified by atomic absorption
<br /> chromium from waste disposal sites could oxidizmigrate
<br /> to public water systema whore it would be oxidized
<br /> chromium.We are not, however, spectroscopy.Since trivaient chromium during chlorination to the hexavuleni slate.We
<br /> proposing to change the maximum does not precipitate under such believe the likelihood of this occurring to be remote
<br /> concentration level of hexavalent conditions,the method offers a means of in light of the low migratory potential or irivelent
<br /> chromium in the EP extract,which determining the presence and chromium.However.should migration of trivalent
<br /> chromium from improper waste disposal occur in
<br /> would consequently remain at 5.0 mg/l, concentration of the hexavalent state in concentrations sufficient to interfere substantially
<br /> This level is based on the National admixture with the trivalent Form. with treatment of public water systems.or
<br /> Interim Primary Drinking Water Comments are solicited on the otherwise cause public health concerns,we view
<br /> Standard,which was established to application of this method to EP our Imminent hazard authority under Section 7003
<br /> of RCRA as suffirienl to enjoin further
<br /> reflect the known toxicity of the extracts, contamination.We are also prepared in this
<br /> hexavalent form.i(Sorg,1979.U.S.EPA. This method has been evaluated using circumatance to exercise our listing authority under
<br /> 1976.)s Other countries and effluents containing high concentrations Subtitle C to address the particular site creating the
<br /> organizations also have adopted this of organic material,samples where problem.
<br /> matrix Interferences have been 'Fur example,the tanning industry a principal
<br /> generator of trivalent chromium-hearing wastes.
<br /> 'The maximum concentration level of the FIR encountered with the more usual does not pregently incinerate any of its wdetes,
<br /> toxicily characterislic,of course•is established at chelation/extraction procedures.Further although a few individual tanneries and the
<br /> Iwo orders of magnitude above the Drinking Water evaluation presently is being conducted Tanners'Council in collaboration with the U.S.
<br /> Standard. Bureau of Mines are investigating the feasibility of
<br /> M1 with a wide variety of industrial wastes waste incineration.[U.S-Dept.orinI?rior.'1979.
<br /> As noted above•the standard also establishes a 1
<br /> margin of safely in light of oxidation of chramium as and EP extracts.The procedure will be several POTW's do.however.use the Zimpro
<br /> a result of drinking water treatmeA,(Sorg,1978). finally promulgated after review of process in incinerate tannery aiudges.
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