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Our Projects > Studies and Information About York's Rivers, Maine > Toxics & Sediments


Most environmental toxins in rivers are the result of historical or current land uses that involve toxic chemicals, or the result of air-borne contamination.  A newcomer to York might ask questions such as:  Are there any Superfund sites in the York River watershed? Other toxic discharges? Historical sites that might have contributed sediment contamination?

The short answer is that the York River is in fairly good shape.  There are no SuperFund sites or large industries currently polluting, and early industry does not seem to have left behind a legacy of heavily contaminated sediments, although there is some contamination.  The highest level of contamination is PAHs - poly-aromatic hydrocarbons.

Runoff from roadways and parking lots, as well as possible spills of marine fuels or oil, are likely the largest sources of toxic contamination to the York River.


  • Nothing is known about upstream sediment contamination, although there is also little disturbance to those sediments.

  • What is the toxic impact to the river from I-95 and other roadways?
Specific Studies

T1. York Harbor Sediment Studies. Army Corps of Engineers. 1994.

In conjunction with the dredging of York Harbor, the Army Corps of Engineers has sampled sediments from the areas to be dredged. This is required, so that care can be taken with contaminants during the dredging itself and for disposal. Although some contaminants have been found -- Poly-Aromatic Hydrocarbons (PAH's) and some metals -- the harbor sediments are clean enough that they have been allowed to go to ocean disposal off Cape Arundel.

Tests were taken in preparation for dredging in 1972, 1979/80, 1989, and 1994. Technology for testing has changed over this time; accordingly, the most sophisticated testing was done in 1994. The tests looked for pesticides, PCBs, PAHs, metals. Apparently did not test for butyltins (from marine paints); this is another potential source of contamination in the harbor.

The 1994 tests showed pesticides below detectable limits. Metals were detectable, but the Army Corps analysis did not indicate that the levels were high or of concern. Finally, PAHs were concentrated enough in two sampling locations to trigger the Army Corps to request further biological testing.

The 1994 biological tests looked at toxicity of sediments (2 samples from York Harbor, a "reference" sample from the disposal site off Cape Arundel, and a clean "control" sample from Manchester Harbor in Massachusetts. The tests concluded that the sediments were acceptable for ocean disposal, based on the survival rates of amphipods, marine clams, and marine worms.

As with any environmental parameters, interpretation is key. Some of these toxics occur naturally in small doses. Some do not. Some non-naturally occuring toxics are now found world-wide in small concentrations. In interpreting the data, you might ask: how might this level of contamination prevent our desired uses for the York River/Harbor; how significant are the levels of contamination; what could we do to prevent contamination; what should we do with the knowledge that the sediments are somewhat contaminated?

If further interpretation of these results are desired, possible resources include: the Army Corps of Engineers, Maine DEP, the Maine Coastal Program, or the Maine Toxics Action Coalition / Natural Resources Council of Maine.  Each of these organizations may have a different perspective on how much of any toxin is acceptable in the environment.

Contacts: Army Corps of Engineers: Phil Nimiskern 978-318-8660 or Ed O'Donnell. 978-318-8375. 1-800-343-4789. Portland DEP Office: Doug Burdick, 207-822-6322. Maine Toxics Action Coalition 1-800-287-3245.

Although these reports do not include sampling sites in the York River, they are useful as models for future study, and to put the Army Corps results into context, within Maine and nationally.

  • Toxic Pollution in Casco Bay. Casco Bay Estuary Project. 1996. Summarizes findings for Casco Bay, tested in the early 1990s for approximately 25 toxic pollutants including PCBs, dioxins, heavy metals, and pesticides. This report also puts the results into context: gives numbers for what is considered "high" on a national basis.
  • The Dirty History of Portland Harbor. Casco Bay Estuary Project. 1994. Traces sediment pollution to historical land uses, especially early factories and mills. Could be useful place to start for linking historic uses to possible contaminants.
Contact: Casco Bay Estuary Project, Katherine Groves.207-780-4820.

T3.  Federal Database Searches:  Current Industrial Use of Toxins. 1999.

Companies that use regulated toxic chemicals are required to report their use and discharges to the EPA.  Much of this data is available on-line through EPA's Surf Your Watershed.  A survey of this information reveals that the York River watershed does not have Superfund sites, nor are there known toxic discharges or waterwater treatment plants.  Of course, companies and homeowners are still using and discharging toxic chemicals such as pesticides, chlorine bleach, motor oil, and gasoline -- but there are no large single-point sources of pollution.

The data for the York River watershed is classified at the federal level along with the data for the Piscataqua watershed (which has many more discharges, both air and water).

Links:  Surf Your Watershed Data for the Piscataqua-Salmon Falls watershed (which in broad, federal cataloguing units, includes the York River).

T4.  Scorecard Database Search, Environmental Defense Fund.  1997.

Another Internet resource for use of toxics is the Scorecard website. You can search by zip code, to find out what companies are releasing toxics into the air or water.  A search on York County reveals relatively few polluters in the York area, and none in the York River watershed itself.

Links: Scorecard interface to the Toxics Release Inventory, as developed by the Environmental Defense Fund.


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