Proposed Updates to DEQ-7 Consolidation of corrections and submissions for 2008 and 2009

Description of changes Re-write of introduction to expand explanation of risk factors and human health advisories as well as provide an explanation of the new magnitude/frequency/duration criteria Re-write of introduction to expand explanation of risk factors and human health advisories as well as provide an explanation of the new magnitude/frequency/duration criteria Addition of pesticides found in groundwater: 20 new compounds and three metabolites Addition of pesticides found in groundwater: 20 new compounds and three metabolites EPA National Water Quality Criteria: Seven revisions to existing toxicology limits, five new compounds from the priority pollutant list and nine new compounds from the non priority pollutant list EPA National Water Quality Criteria: Seven revisions to existing toxicology limits, five new compounds from the priority pollutant list and nine new compounds from the non priority pollutant list Correction to existing standards for typos and incorrect synonyms: thirteen corrections Correction to existing standards for typos and incorrect synonyms: thirteen corrections Alteration of footnotes to reflect incorporation of frequency and duration for to all standards, as well as separating comments specific to either Human Health or Aquatic Life standards. Alteration of footnotes to reflect incorporation of frequency and duration for to all standards, as well as separating comments specific to either Human Health or Aquatic Life standards. Alteration of format ( 8.5x14 landscape to 8.5x11 portrait), and modification of cell contents to allow electronic searches of the entire database, within any field Alteration of format ( 8.5x14 landscape to 8.5x11 portrait), and modification of cell contents to allow electronic searches of the entire database, within any field

Alterations to Introduction Added a detailed explanation of the implementation of frequency and duration criteria to the standards. Added a detailed explanation of the implementation of frequency and duration criteria to the standards. Expanded the explanation of terms section to give more detailed descriptions of classifications (carcinogen, toxin, etc.) Expanded the explanation of terms section to give more detailed descriptions of classifications (carcinogen, toxin, etc.) Added a more detailed explanation of the differences between aquatic life and human health standards Added a more detailed explanation of the differences between aquatic life and human health standards

Pesticides All of the following pesticides were detected by the monitoring program, as managed by the Montana Department of Agriculture. It is DEQ’s responsibility to establish interim numerical standards as authorized under All of the following pesticides were detected by the monitoring program, as managed by the Montana Department of Agriculture. It is DEQ’s responsibility to establish interim numerical standards as authorized under DEQ has sought the support of the regional EPA Toxicologist in making determinations as to the classification of the compounds (toxic or carcinogenic) and the selection of the appropriate cancer slope indices, where appropriate. DEQ has sought the support of the regional EPA Toxicologist in making determinations as to the classification of the compounds (toxic or carcinogenic) and the selection of the appropriate cancer slope indices, where appropriate.

Pesticide list Aminopyralid Aminopyralid Azinophos-methyl Azinophos-methyl Difenoconazole Difenoconazole Ethion Ethion Ethofumasate Ethofumasate Fenbuconazole Fenbuconazole Imazalil Imazalil Imazethapyr Imazethapyr Mecoprop (MCPP) Mecoprop (MCPP) Proprioconazole Proprioconazole Prosulfuron Prosulfuron Sulfosulfuron Sulfosulfuron Tebuconazole Tebuconazole Triclopyr Triclopyr Dimethenamid Dimethenamid Dimethenamid OA Dimethenamid OA Flucarbazone Flucarbazone Flucarbazone sulfonamide Flucarbazone sulfonamide Imazapic Imazapic Pyrasulfotole Pyrasulfotole Azinophos-methyl oxon Azinophos-methyl oxon

List of new compounds to be added or altered from the National Water Quality Criteria for priority pollutants New criteria New criteria Chlorodibromomethane Chlorodibromomethane 2-methyl-4,6-Dinitrophenol 2-methyl-4,6-Dinitrophenol Bis(2-ethylhexyl)Phthalate Bis(2-ethylhexyl)Phthalate 2-chloronapthalene 2-chloronapthalene Nitrobenzene Nitrobenzene Revised numeric limits Revised numeric limits Alpha-BHC (HH) Gamma-BHC (AL) Dinitrophenol-2,4 (HH) Heptachlor (HH, AL) Methylene Chloride (HH) Methyl Bromide (HH) Bis(2-chloroisopropyl)ether (HH) Acrolein (AL)

List of new compounds to be added from the National Water Quality Criteria for non-priority pollutants Ether, Bis(chloromethyl) Ether, Bis(chloromethyl) Nitrosamines Nitrosamines Dinitrophenols Dinitrophenols Nitrosodibutylamine,N Nitrosodibutylamine,N Nitrosodiethylamine,N Nitrosodiethylamine,N Nitrosopyrrolidene Nitrosopyrrolidene Demeton (Aquatic life) Demeton (Aquatic life) Barium Barium

List of compounds attributed to the Drinking Water Standards (MCL’s) Bromate (New) Bromate (New) Chlorite (New) Chlorite (New) Haloacetic acids (New) Haloacetic acids (New)

Corrections to the 2008 version of DEQ-7 Numerical errors Numerical errors Alpha emitters (HH numeric error) Alpha emitters (HH numeric error) Dichloroethene,1,1,- (HH numeric error) Dichloroethene,1,1,- (HH numeric error) Dinitrotolulene,2,4- (HH numeric error) Dinitrotolulene,2,4- (HH numeric error) Endosulfan (HH numeric error) Endosulfan (HH numeric error) Radon 222 (HH numeric error) Radon 222 (HH numeric error) Trichlorobenzene,1,1,2- (GW numeric error) Trichlorobenzene,1,1,2- (GW numeric error) Heptachlor (AL numeric error) Heptachlor (AL numeric error) Improper synonyms Improper synonyms Iron Selenium Manganese Copper Nonylphenol p,p-dichlorodiphenyl trichloroethane (DDT) Improper attribution Improper attribution Lead Radon 222 Alpha emitters Beta emitters Dichloroethene,1,1-

Significant Alterations to footnotes Footnote 3 identifies an averaging period (one hour average) and exceedance frequency (once in any three year period, on average) for acute aquatic life standards Footnote 3 identifies an averaging period (one hour average) and exceedance frequency (once in any three year period, on average) for acute aquatic life standards Footnote 4 identifies the averaging period (96 hour average concentration) and adds an exceedance frequency (once in any three year period, on average) for chronic aquatic life standards Footnote 4 identifies the averaging period (96 hour average concentration) and adds an exceedance frequency (once in any three year period, on average) for chronic aquatic life standards These changes would improve the consistency of Montana’s standards with EPA 304(a) criteria and fit better with how Permitting utilizes the standard to develop permits. These changes would improve the consistency of Montana’s standards with EPA 304(a) criteria and fit better with how Permitting utilizes the standard to develop permits.