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Figure A-1. Regional map of the Sudbury River area


Figure A-2. Nyanza Chemical Site Map

Figure A-3a. Local Map of Nyanza Chemical Site Area

Figure A-3b. Enlargement of the enclosed area shown in figure A-3a.

Figure A-4. Boundary marking the area impacted by ambient air emissions during dye manufacturing processes at the Nyanza site


The following tables were not available in electronic format for conversion to HTML at the time of preparation of this document. To obtain a hard copy of the document, please contact:

Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation
Attn: Chief, Program Evaluation, Records, and Information Services Branch
1600 Clifton Road NE
Atlanta, Georgia 30333

Footnotes for Tables

  1. Units:

    mg/kg = milligrams per kilogram
    µg/m3 = micrograms per meter cubed
    ng/m3 = nanograms per meter cubed
    ppm = parts per million
    ppb = parts per billion

  2. Monitoring occurred over a 20-year period. The levels reported here encompass the maximum levels detected and may not represent the current conditions. For example, the maximum mercury level in fish was detected in the early 1970's. Since that time, a gradual decrease in mercury levels in fish has been observed. In addition, the maximum organic contamination in on-site soils was observed during the vault investigation. Much of this contaminated soil was incinerated during an emergency removal action.
  3. Chemical Compounds:

    1,2-DCB = 1,2-dichlorobenzene
    1,3-DCB = 1,3-dichlorobenzene
    1,4-DCB = 1,4-dichlorobenzene
    1,2,4-TCB = 1,2,4-trichlorobenzene
    trans-1,2-DCE = trans-1,2-dichloroethylene
    TCE = trichloroethylene
  4. 1,2-DCE was reported as either trans-1,2-DCE or total 1,2-DCE. When trans-1,2-DCE and cis-1,2-DCE were both monitored, the majority of 1,2-DCE detected was comprised of trans-1,2-DCE.
  5. The lack of a number indicates that monitoring for a this compound did not occur at this location/media or, if monitored, that no compound was observed above the detection limit. ND indicates not detected.
  6. Off-site Locations:

    Trolley Brook Wetlands - the portion of the Trolley Brook Wetlands located east of Trolley Brook.

    Northeast wetlands - the wetlands located 2,500 feet northeast of the site, where the outfall of the Chemical Brook culvert is located and including the Raceway until its confluence with the Sudbury River.

    Chemical Brook - the portion of Chemical Brook located from its confluence with the Trolley Brook to the culvert intake. The location of the intake changed with time, as it was extended toward the site.

    Mill Pond - the impoundment of the Sudbury River located north of the site and created from the Myrtle Street dam. Data were also considered for locations upstream of the pond.

    MDC Reservoirs - the data considered for this location originated from the Sudbury River downstream of the Raceway confluence and from the MDC Reservoirs #1 and #2.

    Sud. R. ds MDC Res. - all portions of the Sudbury River located downstream of the MDC Reservoir system, and includes the Saxonville Dam, Heard Pond, the confluence with the Assabet River, etc.

    Sudbury Reservoir - this reservoir is located on the northern branch of the Sudbury River and converges with the southern branch, which passes near the Nyanza Chemical site, at the MDC Reservoirs #3 and #1.

    Heard Pond - although not an impoundment of the Sudbury River, it is within the Sudbury River's floodplain. At times of high water/flooding, the Sudbury River will overflow into the Heard Pond.

    Basement - residential basements located north and northeast of the site and/or a church basement located in downtown Ashland.

    Residential - a home located adjacent to the site on the northeast side.

    Other - samples obtained from off-site monitoring well borings or from nearby 21E sites.

    North/northeast - locations north and northeast of the site, and roughly bounded by the Sudbury River and Main Street.

    Southeast - the portion of the Trolley Brook Wetlands located off-site due east-southeast of the site.

    * Ground water monitoring for non-TCL organic compounds (i.e., benzidine, 1-naphthylamine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, p-cresidine, and o-anisidine) was conducted in 1990. These compounds were targeted because they were purchased by Nyanza, Inc. in large quantities and are known to be toxic.

    The maximum levels of these compounds detected in the on-site and off-site monitoring wells are provided below. The monitoring data are limited and many of the data were rejected during data validation.


    Concentrations (µg/l)
      On-site Off-site
    benzidine 240 19
    1-naphthylamine 1,100 50
    3,3'-dimethoxybenzidine 330  


    280 8




    170 40

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