Soil, Groundwater and Sediment Quality Criteria in Ontario:

A History of their Development from the 1970s to December 2009

Technical Report

Prepared for:  Environmental Commissioner of Ontario

Prepared by: B. Edwards, Consultant, Scarborough, Ontario

Date: January 2010

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1.0 Introduction

The quality of our soil, groundwater and sediment has become an important contributing factor in determining where we locate our homes, schools, hospitals, offices, wells, industrial facilities, playgrounds and marinas; and where farmers plant crops and graze livestock. We have recognized that soil, groundwater and sediment are valuable resources that, once degraded, can affect our quality of life, health and economy, and the health of our ecosystems. Beginning in earnest in the 1970s, the Ontario government has developed legislation and policies that have reduced and sometimes eliminated discharges of substances that can degrade these resources; and that have guided management of degraded soil, groundwater and sediment. The development of quality criteria has played a critical role in the progress that we have achieved.

Our cities and rural areas are littered with thousands of properties, called “brownfields,” which were abandoned after polluters dumped their wastes onto them. Many of our ports and marinas, particularly on the Great Lakes, have also been dumping grounds for wastes. Today, undeveloped land is scarce, particularly in urbanized southern Ontario, and our tolerance for polluting activities continues to decline. The pressure to remediate brownfields and our ports and marinas, and to have comprehensive legislation and policies to guide the process is increasing.

Over the last four decades, the Ontario government has committed considerable time and resources developing quality criteria for soil, groundwater and sediment. These criteria are now used by owners, industry, developers and governments in determining if a site is contaminated; what activities are allowed on the site; and if a site should be remediated and to what standard. This report provides an overview of the key policy decisions and legislation that have guided the development of quality criteria for non-hazardous soil, groundwater and sediment from the early 1970s to December 2009.   

This report includes four appendices.

• Appendix 1: Definitions.
• Appendix 2: Summaries of Selected Policy Documents. This appendix contains additional information about some of the documents described in the main part of the report. In addition, it has summaries of some of the documents identified in Appendix 3.
• Appendix 3: Chronology. This appendix contains a detailed chronology of relevant proposals and decisions and identifies documents that have guided the development of quality criteria. This appendix also includes information on where copies of some of these documents can be found.
• Appendix 4: Past ECO Articles Related to the Management of Soil and Sediment.

2.0 Background

Since colonial days Ontarians have moved soil and sediment from one location to another for the purpose of constructing and maintaining buildings, roads and railways; creating and remediating land for agricultural, residential, business and recreational purposes; controlling erosion and preventing floods; and creating, maintaining and remediating harbours and canals. Much of Toronto’s downtown was built on excavated soil and Great Lakes shipping has been dependent on harbours being dredged regularly. Excavated soil has also been deposited in landfills, sometimes as daily cover, and used to remediate aggregate sites.

The Ontario government, particularly the Ministry of the Environment (MOE) and its predecessors, has been actively involved with issues related to soil and sediment quality since the early 1970s. At first, the focus was on determining chemical concentrations in soil for the purpose of investigating phytotoxicity in terrestrial plants, such as fruit and vegetable crops; and in sediment for the purpose of disposing of it in open water. However, our concerns about contaminated soil and sediment grew as our understanding improved of how even trace amounts of contaminants can affect the environment and human and animal health.

The health of the Great Lakes became a particular concern of the American and Canadian governments with the realization that contaminants from industrial discharges, sewage effluent, agriculture and other sources were degrading sediment and water quality in the lakes, threatening commercial fisheries, drinking water supplies, aquatic ecosystems, recreational opportunities and the economies of the states and provinces that bordered the lakes. These concerns led to the signing of the Great Lakes Water Quality Agreement by both countries in 1972 and an amended agreement in 1978.

Meanwhile, increasing amounts of soil and sediment were being excavated and dredged, and deposited without appropriate regard for the health of the receiving lands and waters, or of the people and animals and ecosystems that rely on them. In addition, thousands of properties were not being re-developed due to concerns about historical contamination. Today, the focus of quality criteria has expanded beyond phytotoxicity to include carcinogenicity, lethality, bioaccumulation, dermal exposure and vapour migration; and beyond plant receptors to include other types of receptors, such as children, workers, adults, benthic organisms, mammals, birds, fish and grazing animals. In addition, the focus now includes the potential impact of contaminated soil on potable and non-potable groundwater.

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(Source: http://www.eco.on.ca/)