Report Name: Phase III, Environmental Site Investigation, Former New Haven Water Company Property, Hamden, Connecticut (Volumes I through V)

Date: December 2002

By: Leggette, Brashears & Graham, Inc.

Prepared for: South Central Connecticut Regional Water Authority

Status of the Report: Comment on this report by the State Department of Environmental Protection will be released in March 2004. A public presentation of a work plan to complete investigation of the former South Central Connecticut Regional Water Authority properties will be made in April 2004.

Note: This is a summary of a report that was done for the Hamden Middle School site. The summary is only a brief explanation of the full report. Read the full report.

What Is This Report About?

This report describes the results of soil and groundwater testing on properties in the Newhall Street neighborhood that were formerly owned by the New Haven Water Company. The properties include the Hamden Middle School and athletic field, a portion of the Newhall Community Center, and two residential properties. The New Haven Water Company became part of the South Central Connecticut Regional Water Authority (RWA).

In July 2001, the Connecticut Department of Environmental Protection (DEP) ordered the RWA and three other potentially responsible parties to investigate and remediate (clean up) possible harmful substances (contamination) in the Newhall neighborhood. While the DEP order was being appealed by all of the parties, the RWA voluntarily conducted testing on these former New Haven Water Company properties. This summary report calls these properties the “RWA site”. The New Haven Water Company owned these properties during much of the time they were used as a dump site. Dumping of garbage and industrial waste at the RWA site took place from approximately 1925 until at least 1970, and additional fill including construction debris and soil was used to fill the back of the site until the 1980s.

What Was The Purpose of the Study?

This study is called a “Phase III” and the purpose of the Phase III is to fully define the nature and extent of the contamination at the RWA site. Testing was done to find out (define) what types of chemicals and other contaminants are in the soil and groundwater underneath the RWA site. The testing was also done to determine where the contamination is located and what levels of contamination are present.

How Did They Test The Soil And Water?

Soil and groundwater samples were taken from throughout the RWA site between July and November 2002. Soil samples were taken from 70 soil borings and eight excavated test pits. Twenty-four monitoring wells were installed so that groundwater samples could be collected from them. In total, 105 soil samples were analyzed from the soil sampling locations and 32 groundwater samples were analyzed from the well locations.

What Contaminants Were Tested For?

The soil and groundwater samples were tested for the following substances:

• Pesticides
• Metals (lead, arsenic, antimony, copper, mercury, cadmium, nickel, and zinc)
• Cyanide
• Polychlorinated biphenyls (PCBs)
• Volatile Organic Compounds (VOCs)
• Semi-Volatile Organic Compounds (SVOCs, includes the group of compounds called polycyclic aromatic hydrocarbons [PAHs])
• Extractable Total Petroleum Hydrocarbons (ETPH)

Groundwater samples were also tested for herbicides and other chemicals typically found in groundwater near landfills. An additional test was done on some of the soil samples, called a Synthetic Precipitation Leaching Procedure (SPLP). The SPLP test was done for lead, arsenic, and other metals when high levels (concentrations) of those substances were found in soil samples. The SPLP test indicates whether metals might move from soil into groundwater (such as when it rains) and possibly cause groundwater pollution.

The concentrations of the contaminants found in the soil and groundwater samples were compared to state standards. These standards identify the concentrations that could be potentially harmful to people who come into contact with them or to groundwater. The standards were developed to protect people’s health and the environment.

The concentrations of substances found in the soil samples were compared to the following state standards:

• Residential Direct Exposure Criteria (RDEC): The RDEC sets a contaminant concentration level in soils for many different substances. This standard is applied in residential areas (such as the Newhall Street neighborhood). Contaminant concentrations below the RDEC level are considered not harmful. Concentrations at or above the RDEC require further investigation to determine the potential risk to people’s health.
  
• GA Pollutant Mobility Criteria (GAPMC): This standard relates to the ability of soil contaminants to pollute groundwater. “GA” refers to groundwater classified as “A” or “AA”, the highest standards for water quality in the state. The groundwater below the RWA site is classified as “AA”, so the GAPMC standard was used. (A different standard would apply to areas with different groundwater classifications.) Soil contaminants with concentrations at or above the GAPMC could result in polluted groundwater and require further investigation to determine the potential risk to the environment.

The concentration of substances found in the groundwater samples was compared to:

• Groundwater Protection Criteria (GWPC): The GWPC sets a concentration level for many different substances in groundwater underlying GA classified land areas, such as the RWA site. Contaminant concentrations below the GWPC level are considered not harmful. Concentrations at or above this level require further investigation to determine the potential risk to the quality of groundwater.
  
• Surface Water Protection Criteria (SWPC): The SWPC sets a concentration level for different contaminants found in groundwater that flows into a surface water body such as a stream or pond. Contaminant concentrations below the SWPC level are considered not harmful to surface water bodies and fish and other organisms that live in the water. Concentrations at or above this level require further investigation to determine the potential risk to water quality and the animals that live in the water.
  
• Residential Volatilization Criteria (RVC): The RVC sets concentration levels for volatile chemicals that have a tendency to evaporate from water into the air (such as gasoline and degreasing solvents). If the chemicals evaporate from groundwater into air beneath a building or house, the chemicals could accumulate in closed in spaces and be harmful to people’s health. Contaminant concentrations below the RVC are considered not harmful to people. Concentrations at or above this level require further investigation to determine the potential risk to air quality and people’s health.

What Was Found?

The study found contaminants at levels higher than the state standards in both the soil and the groundwater. The main findings were:

• Pesticides were found in some of the soil samples, but concentrations did not exceed state standards. No pesticides were detected in groundwater.
  
• Lead, arsenic, mercury, copper, and antimony were found in the soil at levels above state standards. This contamination occurred all over the site.
  
• The SPLP tests on contaminated soil found lead, arsenic, antimony, cadmium, mercury, nickel and zinc at levels higher than the state standards for groundwater protection.
  
• Extractable total petroleum hydrocarbons were found in soils throughout the site at levels above state standards.
  
• Semi-Volatile Organic Compounds (SVOCs) were found in soils throughout the Middle School grounds at levels above state standards. Several different chemicals within the large group of SVOCs were identified.
  
• PCBs were found in one soil sample at levels above state standards.
  
• Lead, barium, ETPH, SVOCs, and Volatile Organic Compounds (VOCs) were found in groundwater at levels higher than state standards. Several different chemicals within the large group of SVOCs and VOCs were identified.
  
• No herbicides or PCBs were found in any of the groundwater samples.

Additional findings included:

• Testing of the Middle School athletic field noted a top layer of sand, silt and gravel, 2 to 4 feet deep over the fill material. The report says that this “cap” successfully prevents human contact with the underlying (contaminated) soil.
  
• Fill material was noted to be up to 22 feet thick in places.
  
• Groundwater appears to move from east to the south and southwest. That would be the direction that pollutants are carried in the groundwater.