~ lelio.' Figure 2 Lower Nepon se t River PCBs - PowerPoint PPT Presentation

Lower Neponset River Site Boston/Milton, MA February 2020 *644037* SEMS Doc ID 644037

Topics for Discussion  Introduction  MassDEP – Request for EPA Involvement  Area of Interest  National Priorities List (NPL)  Overview of Superfund Process  Timeline of Activities  Outreach

~ '.A."l:•.a ~ ■ • ■ ■ lelio.' Figure 2 Lower Nepon se t River PCBs Boston/Milton, Massachusetts E:PARcg1on I Superfund TedirK.al ru~ and Aespomc- Teem (ST ART) IV Ccn,..act Na. E.P~IS-01 ....... TOI-01. JU16 -0009 .. .... 3April2011 18 Ap- il 2019 L EGE:ND Upper N e- RM!< M el.her Brook to Charms lioslOn & Holingsworth Dam Area 0.2 0.4 Miles .. ,

tudies/Evaluations  Extensive USGS sampling – 2002-2006  MassDEP work _ Oversight/evaluation of various studies and remediation of Mother Brook.  EPA ◦ Limited sampling to confirm previous results November 2017 and September 2018 ◦ Preliminary Assessment – August 2018 ◦ Site Inspection – April 2019 ◦ Hazard Ranking System Package - TBD

Fig ur e 10 20 18 START Sed i ment Sample Loo, tion s and T Olal PCBs (C ongener) Results M ap Lower Nepoo set River PCBs Boston/Milton , Massachusetts EMAegiar,I Supt,fund Tcd1 n ul ~ 111d R~Tea111(START)rl Camlci No. E P.Sl.1 5.0 1 TO l -01 -1 &..(Ni.((XJg u .... lApil017 u .... 14 F ebrwry 201!1 LE G EN D Appro x. S.1 e Bcuv:bry \\'al t er Bater OamAtea Br~ed CNmel heJ. Slue !-Ws A~Ma Tiest on & Hclling!w:xth Dan/vu F ai rmomtiMoht' B root Area Mocher Brook 10 ChJries l,l,pe,Nepon,et- BelCJ11VBadg rom d 8 - - 0 0. 25 0.5 Mi les ve lm.igiry: [SRI. ._am1, USDA F !.A. ~ only . A tx , GeoE:,t.Gtlmlff""l}lwo!, ,d, IGP m T'1JOE Ma1IPllh AUofiff du: ST ART , Me!GIS, Mii.XP PCB Concentrations in Sediment

What is the National Priorities List (N PL)?  National list of sites that EPA determines require further detailed investigation, and potential cleanup action in accordance with CERCLA*.  Investigations at NPL sites determine whether long-term threats to human health & environment exist.  Where needed, comprehensive strategy to address threats is implemented. *CERCLA = Comprehensive Environmental Response, Compensation and Liability Act (Often referred to as Superfund)

Why Add A it To NPL?  Sites on NPL subject of detailed investigation, and cleanup where warranted.  Only sites on the NPL are eligible to receive federal Superfund resources for comprehensive cleanup.  Federal resources can include monetary support, as well as expertise/staffing.  Absent the use of federal resources, comprehensive cleanup strategies may not be able to be pursued.

How is a it Add d to the NPL?  Sites added to NPL through federal rulemaking.  Requires letter of concurrence from Governor.  Site is first proposed to the NPL.  60-day public comment period.  Site finalized to NPL, upon consideration of public comments received.

The Superfund Process: Discovery and Cleanup for a Long- erm Site valuate site 's con min · n 4iht,i :: and determine cl n p '/ n de n p program. Discover n w • Choo a nup P n.

Low r N pons t Riv r Pos ibl Tim lin for NPL  Develop a Hazard Ranking System (HRS) package.  Propose site to NPL – Fall 2020/Winter 2021 (tentative).  60 day public comment period.  Finalize site to NPL – 2021 (dependent on public comments).  Letter of concurrence from Governor – likely Summer 2020.

Outreach  Meetings held to date: ◦ City of Boston/Town of Milton  March 2017  April 2017 (Boston only)  Milton Conservation Commission public mtg April 2017  November 2019 ◦ Federal legislative delegation briefing – Dec. 2019 ◦ State legislative delegation briefing – Feb. 2020 ◦ Boston City Council member briefing – Feb. 2020  Planned meetings: ◦ EPA sponsored public informational meeting Mattapan – Feb. 24, 2020 ◦ EPA/MassDEP presentation at Milton BOS meeting – ◦ Feb. 26, 2020