Tuesday, February 13, 2018

Iowa Proposes Rules To Create New General Wastewater Permits

The Iowa Department of Natural Resources (DNR) has proposed two general discharge permits to cover two types of common and generally low risk discharges. DNR plans to issue two new National Pollutant Discharge Elimination System (NPDES) general permits known as General Permit #8 (GP8) and General Permit #9 (GP9). GP8 allows for discharges of hydrostatic test water (water used to test the integrity of a pipe or tank), underground storage tank ballast water (water used to weight a tank to facilitate underground installation), and water associated with installation, repair, and replacement of potable water lines. GP9 allows for discharges from dewatering associated with construction and small residential geothermal heating and cooling systems. IDNR is proposing to include eligibility criteria and Best Management Practices. These will ensure that discharges will comply with water quality standards. Most permittees will be automatically authorized to discharge. Only a few higher-risk dischargers will need to submit a Notice of Intent. There is no fee for either permit. DNR is seeking public comment on proposed rules that will create two new general permits. DNR will hold three public hearings across the state in March:
  • Wednesday, Mar. 7, 4 p.m. at the Coralville, IA Public Library
  • Thursday, Mar. 8, 4 p.m. at the Harlan, IA Public Library
  • Wednesday, Mar. 14, 4 p.m. at the Urbandale, IA Public Library
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Saturday, February 10, 2018

Groundwater Health Limits For Trimethylbenzene

The Health Risk Assessment Unit at the Minnesota Department of Health has started a full review of three trimethylbenzene (TMB) isomers (1,2,3-trimethylbenzene; 1,2,4-trimethylbenzene; and 1,3,5-trimethylbenzene). TMB isomers are produced during petroleum refining and production of a component of gasoline. TMB isomers are also used in the production of solvents and are ingredients in paints, dyes, cleaning agents, and automotive fluids.

 The review will consider if the existing Health Risk Values (HRL) for the three trimethylbenzene compounds in groundwater are adequately protective. This review is particularly significant because trimethylbenzene compounds are commonly detected in soil and groundwater at petroleum release sites, such as leaking underground storage tank (LUST) sites.

 MDH previously developed water guidance for 1,2,4- and 1,3,5-trimethylbenzene. Re-evaluation of these contaminants in 2017 resulted in a recommendation for full review.

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