Abstract
Concentrations of Cd, Cu, Pb and Zn in sediments of Egypt Bay in Hancock County, Maine, are elevated above background levels. The source of the contamination is Cu mining that occurred in the uplands adjacent to Egypt Stream between 1877 and 1885. Egypt Stream is a tributary to Egypt Bay. Egypt Bay is part of the Taunton Bay estuary system. The Hagan Mine was one of the mines extracting metals from the sulfide deposits in Downeast Maine north of Penobscot Bay. Metal concentrations were determined using ICP-AES after sample digestion with nitric acid. Soil collected from the coarse textured mine tailings pile contained elevated concentrations of Cd, Cu, Pb and Zn, but the majority of the surface soils at the Hagan Mine site were not contaminated. Estuary sediments from the surface to 100 cm depth were collected in four locations within Egypt Bay. Below 40 cm, metal concentrations in sediments were similar to those in uncontaminated upland soils. Metal concentrations in the estuary sediments between the surface and 26 cm were above background levels. According to 210Pb dating, the sediment at 26-34 cm depth was likely to have been deposited at the time the historic mines were in operation. Concentrations of Cd, Cu, Pb, and Zn in sediment from the 32-34 cm depth interval are similar to concentrations in the upland soil sample from the mine tailings pile. Elevated Pb concentrations in sediments from the surface to 24 cm are from atmospheric Pb deposition from anthropogenic sources. Sediment in the top 10 cm of the estuary has been mixed both by the polychaete worm Nereis virens and by those harvesting the worms for sale as fish bait.
| Original language | English |
|---|---|
| Pages (from-to) | 169-179 |
| Number of pages | 11 |
| Journal | Estuarine, Coastal and Shelf Science |
| Volume | 70 |
| Issue number | 1-2 |
| DOIs | |
| State | Published - Oct 2006 |
Funding
We appreciate the careful work of Bruce Hoskins and others at the University of Maine Plant and Soil Analysis Laboratory. We thank UM recent graduates Emily Berry (2005) and John Boucher (2004) for help with fieldwork and Patricia Rouleau (2005) for assistance with creating the maps. Christopher Flannagan was responsible for the collection and sub-sampling of the cores used for 210 Pb dating, and assisted us by sharing data and observations from his research on the soils of the Taunton Bay estuary. The historical research completed by H.D. Gallison and reported in the 1935 University of Maine MS thesis “Boom days in Hancock County or a history of mining in the towns of Hancock and Sullivan, Maine” was a valuable source of information pertaining to the study site. Dr Daniel Belknap facilitated this research by loaning his vibracore equipment. Dr William Halteman provided valuable suggestions for data analysis methods. Dr Ivan Fernandez, Dr Sharon Tisher and Dr William Glanz and two unnamed reviewers provided editorial review on previous versions of this manuscript. A grant from the University of Maine Faculty Equipment Fund enabled us to purchase the pontoon boat from which the estuary sediments were sampled. The USDA CREES NRI Grant ME0-2003-01799 and USDA CREES Hatch Fund ME-08822 made this research possible.
Keywords
- Pb dating
- bioturbation
- erosion
- heavy metals
- mining
- sediment
- soils