| #D001 | | Mixing zone | A mixing zone is defined as an area of water contiguous to a point source or definable diffuse source where the water quality does not comply with one or more of the Provincial Water Quality Objectives. | high |
| #D002 | | Acute Toxicity | An adverse response, ranging from injury to death, following exposure of short duration relative to the normal lifespan of the organism. | high |
| #D003 | | Additive Effects | Toxic interactions of two or more substances on organisms producing a result such that the total effect approximately equals the sum of the individual effects. | high |
| #D004 | | Aesthetic | Dealing with those aspects of water that are perceived by the senses (e.g. taste or odour). | high |
| #D005 | | Assimilative Capacity | the limit of a waterbody to transform and/or incorporate substances (e.g. nutrients) by the ecosystem, such that the water quality does not degrade below a predetermined level. | high |
| #D006 | | Background Water Quality | The physical, chemical and/or biological conditions of a waterbody at a point upstream/up current of a polluting source. The establishment of background water quality may be based on historical data or on water quality in a similar, unaltered waterbody. | high |
| #D007 | | Ban | Prohibition of the use or release to the environment of specific substances judged to be particularly hazardous. Bans would normally be applied on a provincial or national basis. | high |
| #D008 | | Best Management Practices (BMPs) | Management procedures or structural practices designed to reduce the quantity of pollutants - e.g. contaminants, nutrients, sediments, animal wastes - washed by rain, snowmelt etc. from residential or farm lands into receiving waters, such as lakes, streams, rivers, and into groundwater. | high |
| #D009 | | Best Available Treatment Technology | can include, in order of preference - changes in production processes, chemical substitution, in-plant controls, best management practices, water conservation, waste treatment technologies, energy conservation. | high |
| #D010 | | Bioaccumulation | the process by which chemicals are amassed by organisms from water directly or through the consumption of food containing the chemicals. | high |
| #D011 | | Certificate of Approval (C of A) | A legal document issued, at a proponent’s request, by a Designated Director of the Ministry of Environment and Energy under the authority of the Ontario Water Resources Act. C of As may include effluent requirements and monitoring requirements. | high |
| #D012 | | Common Law | Law which relies for its authority on the decision of courts and is recorded in law reports as the decisions of judges along with the reasons for their decisions, as opposed to law established in a statute. | high |
| #D013 | | Compliance | A state achieved by adhering to the legislative and regulatory requirements of the Ontario Ministry of Environment and Energy. These requirements cover a wide range of activities, from the prevention, reduction and elimination of pollution, to the obtaining of approvals and licences, to the completion of routine paperwork and the filing of reports. | high |
| #D014 | | Contaminant | A substance which, once in the water, may pose a threat to the ecosystem and/or human health, as well as uses such as water supply, recreation, and aesthetic conditions. | high |
| #D015 | | Control Order | A document that requires the discharger to take specific action with an associated deadline. It is authorized by statute, binding upon the recipient, and directly enforceable by prosecution. | high |
| #D016 | | Conventional Pollutants | Traditional indicators of environmental quality including BOD, nutrients and solids.Materials defined as hazardous substances are not included in this category. | high |
| #D017 | | Effluent | the wastewater discharged to a receiving water body. | high |
| #D018 | | Effluent Limit | A legally enforceable effluent requirement. | high |
| #D019 | | Entrainment | The incidental capture of aquatic organisms in water being extracted (e.g. pumped) from a natural waterbody. | high |
| #D020 | | Flowing Well | a well in which the static water level is above ground level. | high |
| #D021 | | Hazardous Substances | chemicals that are persistent, bioaccumulative and extremely toxic. They including substances which, individually or in combination with other substances, can cause death, disease including cancer, behaviourial abnormalities, genetic mutations, physiological malfunctions and/or physical deformities. | high |
| #D022 | | Implementation Procedures | A set of activities required for the appropriate execution of a Water Management policy or guideline. | high |
| #D023 | | Irreversible Man-induced Conditions | An existing condition impairing water quality and/or uses caused by human activity. The actions are such that natural conditions cannot practically be restored. Examples might include removal of old-growth forest or urbanization. | high |
| #D024 | | Land Patent | A grant of land from the Crown under the Great Seal which may retain some interests in the land for the Crown. | high |
| #D025 | | Natural Background Water Quality | Chemical, physical and biological quality of a waterbody, if unaffected by human activity. | high |
| #D026 | | Non-indigenous | Not native or not belonging naturally to an area. | high |
| #D027 | | Non-point Source | A non-specific or diffuse source entering the aquatic environment. Commonly, any source that cannot be described as a point source. Usually, this type of source is not amenable to collection and, if necessary, treatment. | high |
| #D028 | | Objectives | Provincial Water Quality Objectives | high |
| #D029 | | Parameter | A measurable or quantifiable characteristic or feature of water quality. | high |
| #D030 | | Permit to Take Water | A permit issues by a designated Director of the Ministry of Environment and Energy, authorizing the taking of surface or ground water in excess of 50,000 litres per day as provided for under the Ontario Water Resources Act. | high |
| #D031 | | Permittee | The individual or group to whom a permit has been granted. | high |
| #D032 | | Persistence | Longevity in the environment usually expressed as half-life. | high |
| #D033 | | Persistent Pollutant | A substance with an environmental half-life in excess of 50 days. | high |
| #D034 | | Point source | A source of pollution that is discharged to the environment at a specific location. It is quantitatively and qualitatively definable. | high |
| #D035 | | Pollution Prevention | Any action which eliminates or reduces the creation of pollutants or waste at their source through measures such as substitution/reduction in use of a raw product, production redesign, process change, in-process recycling and/or improved maintenance and operating procedures. | high |
| #D036 | | Receiving Water | A waterbody to which a discharge is directed. | high |
| #D037 | | Remedial Actions | Actions undertaken to upgrade water quality and restore uses to a waterbody previously impaired. Initial actions are usually to eliminate or reduce the source(s) of the problem and can include physical intervention (e.g. dredging, artificial aeration, flow augmentation, etc.) | high |
| #D038 | | Riparian Rights | The common law rights of owners of property along a river or shore of other bodies or water. These rights include, stated generally, the right to make reasonable use of the water flowing past their land. | high |
| #D039 | | Streamflow Augmentation | The addition of water, often from reservoir storage or groundwater, to a river or stream to increase its base flow. | high |
| #D040 | | Sustainability | The utilization of a resource in a manner that the resource will be adequately protected for indefinite future use. | high |
| #D041 | | Surrogate | A convenient and/or practical substitute. | high |
| #D042 | | Toxic substance | A substance capable of producing an adverse response, ranging from injury to death, in a living organism. | high |
| #D043 | | Toxicity | An adverse response, ranging from injury to death, in a living organism. | high |
| #D044 | | Waste | any solid, liquid, gas, odour, heat, sound, vibration, radiation or combination of any of them resulting directly or indirectly from the activities of man which may: impair the quality of the natural environment for any use that can be made of it; cause injury or damage to property or to plant or animal life; cause harm or material discomfort to any person; adversely affect the health or impair the safety of any person; or render any property or plant or animal life unfit for use by man. | high |
| #D045 | | Water Conservation | Preservation of the quantity of available water through judicious use, reuse and minimal wastage. | high |
| #D046 | | Waste Assimilation | (See Assimilative capacity) | medium |
| #D047 | | Watershed | The area of land drained by a river/stream and its tributaries. | high |
| #D048 | | source protection | protecting the surface or ground water that supplies municipal drinking water systems | high |
| #D049 | | source protection plans | Source protection plans contain a series of locally developed policies that, as they are implemented, protect existing and future sources of municipal drinking water. | high |