With respect to water quality benchmarks, symptoms unfortunately, different terminology is being used across jurisdictions in Canada and around the world, often with conflicting definitions and interpretations. Terminology may even differ within the same country. Terms like guideline, criterion, standard, objective, limit, threshold, trigger value, and benchmark are all used inconsistently, and sometimes interchangeably. What is a “guideline” in one jurisdiction, is a “criterion” in another, and a “standard” in a third. However, in many but not all jurisdictions, the term “water quality guideline” (e.g., Canada [national], Autralia, New Zealand, etc.) or “water quality criterion” (e.g., USA) is given to a voluntary guidance value, “water quality standard” is used for a legally-enforceable benchmark (e.g., Canada, USA), while the term “water quality objective” is applied when technological or socio-economic aspects are incorporated (e.g., Canada [national]). However, there are many exceptions, for example within Canada, the Province of Ontario had published its “Provincial Water Quality Objectives”, which are science-based and equivalent in legal standing to the national “Canadian Water Quality Guidelines”, i.e., voluntary guidance benchmarks. Other jurisdictions may identify legally-enforceable values as “water quality criteria”. International harmonization in terminology would be ideal and practical, but is also likely unobtainable.
Various Forms of Water Quality Benchmarks
A water quality benchmark is generally a threshold level(s) and guidance value(s) which aims to approximate the level where there are no observable effects (or accepted effects) to aquatic life. Such a benchmark can either be quite simple (e.g., a single value), or be more complex (e.g., a range or values), or quite extensive (e.g., equations, tables, or matrices). It can be a numeric value(s), a narrative statement, or a combination of both. The former option is used mostly for chemical substances, while the latter is used often for environmental parameters (such as pH, temperature, turbidity, water hardness, etc.).
Generic / National versus Local / Site-Specific Water Quality Benchmarks
It is recognised that the concentration of a substance in the ambient environment is the result of natural factors, human actions, or a combination of both, and that these concentrations change over time and space. Both the natural and anthropogenically caused variations in concentrations over time can be quick (i.e., over hours or days) or slow (i.e., seasonal, decades, centuries), and spatial differences can occur abruptly over very short distances (intercept of two different surface geologies, upstream versus downstream of a significant point source at a river, etc.) or gradual over large areas (along a river with diffuse sources, estuaries, near shore versus open ocean). With respect to naturally occurring substances, it is important to distinguish between the portion of the concentration that is due only to natural causes (i.e., the natural background concentration) and the portion of the concentration that is due, at least in part, to anthropogenic causes (sometimes referred to as the ambient concentration). However, quantifying these two portions reliably is often challenging. A water quality benchmark designed to apply over a large geographic area (e.g., a national water quality benchmark) is derived considering all acceptable and applicable toxicological data from a variety of toxicological studies (i.e., including organisms from different aquatic ecosystems and regions, and experimental exposure conditions resembling different geological backgrounds). As the natural background concentration of naturally occurring substances is a very site-specific matter, it often cannot be adequately addressed by such a (national) benchmark. It regularly happens that the recommended national benchmark value for such a substance falls below the natural background concentration (or outside of natural conditions) of a particular site of interest. This happens for example with many national benchmarks for metals when applied to mineral-rich areas (as in the vicinity of mining sites). This fact does not invalidate the national benchmark or its derivation process, but it shows the need to understand this derivation process and to know how to properly apply benchmark values. It generally leads to the derivation of site-relevant values (i.e., site-specific water quality benchmarks) to better reflect the adapted local ecosystem.
This approach to develop a site-specific water quality benchmark is based on the assumption that the biological community present at a site has adapted to the local conditions, including a naturally elevated level of the substance of concern. It does, however, not imply that the adapted community may be able to adjust to an additional, anthropogenically created exposure to this substance without showing negative effects. This can only be determined with appropriately designed site-specific toxicity studies and can generally not be deduced from generic, non-site-specific studies.
Role of Water Quality Benchmarks
A water quality benchmark can fulfill several roles. For example, it can be a tool to evaluate and interpret environmental monitoring data. In this, it becomes an assessment tool to determine the specific or overall ecosystem health, and can be an integral part of any reporting on the state of the environment pertinent to the jurisdiction in question. An example for this use of water quality benchmarks is the Canadian Water Quality Index, a communication and education tool that summarizes a number of water quality variables into a single measure [i.e., score] of overall water quality. A water quality benchmark can also be a legal tool, and serve as the basis for environmental protection and prosecution. Furthermore, they can be starting points to create industrial and municipal release and effluent limits. But under no circumstances should water quality benchmarks be considered as “pollute-up-to permits”.
Register here for the upcoming Training Course:
"Developing and Evaluating Water Quality Benchmarks
... ... anyone who wants to know details about the
use, implementation, and development
of Water Quality Benchmarks to protect aquatic life in Canada ... .... ....
Environmental experts (managers (non-scientists), and scientists) handling ambient water quality issues in Canada. The training course is designed to provide familiarity with water quality benchmarks in general terms (i.e., “management-level”), as well as in-depth knowledge of generic and site-specific water quality benchmarks for the protection of aquatic life in Canada (esp. the CCME CWQG-PAL). The course is for environmental managers and scientists involved in the decision-making and handling of water quality issues in Canada, the development and derivation of water quality benchmarks, and/or the evaluation of proponent-derived site-specific water quality benchmarks.
A four-day intensive training course on water quality benchmarks for the protection of aquatic life, designed to give an overall understanding of WQBs-PAL in Canada, provide an in-depth knowledge on available derivation techniques (both for generic, as well as site-specific benchmarks), and enable to critically assess and evaluate a WQB document.
PowerPoint presentations and interactive teaching techniques will be used throughout the course, as well as a fictitious site-specific water quality benchmark as a training tool. You will be encouraged to participate from the basis of your own experiences and insights. Participant number will be limited to approximately 15 attendees in order to allow for interactions, discussions, and questions.
In addition to learning and skills development, the training course will provide a valuable opportunity for those involved in water quality benchmark work in Canada to meet, share experiences, and make new contacts.
Cost: CAN $ 800.00 plus HST; i.e. total of $ 904.00 per participant
Note: The CAN $ 800.00 registration fee (plus HST; $104; i.e. total of $904) per participant covers the four-day training course, course material, lunches, and refreshments.