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Broad issues on the State of the St. Lawrence
Progress report and future outlook for improving environmental monitoring
Emerging contaminants: possible repercussions on species and on human health
Day 2 (Wednesday, June 14, 2006, 2:45 p.m.)
Moderator: Isabelle Saulnier, Environment Canada
Panellists:
David Berryman, Développement Durable,
Environnement et Parcs Québec [Sustainable Development, Environment
and Parks Quebec]
Christian Gagnon, Environment Canada
Michel Lebeuf, Fisheries and Oceans Canada
Philip Spears, TOXEN (Environmental Toxicity Research
Centre), Université du Québec à Montréal
Panellist Presentations
David Berryman, Développement durable, Environnement et Parcs Québec
New names have been appearing in the world of pollutants for some time now: polybrominated diphenyl ethers (PBDEs), pharmaceuticals, hormones, surfactants, etc. These "emerging" substances are of current interest because they are a source of environmental concern. However, these are just some of the 100 000 or so substances currently in commercial use, with an other 500 to 1000 new substances being added to the list every year. In the face of such numbers, it is difficult not to imagine a deadlock. In trying to get around this impasse it is first necessary to carefully select the substances that should be monitored and to continue using biological indicators, which indicate the state of a given environment exposed to all of the substances present in it. With respect to selecting substances for specific monitoring, Mr. Berryman feels that, in terms of the standard criteria of bioaccumulation, persistence and toxicity, additional factors should be regional relevance and accountability. In the early years of this decade, the regional relevance criterion led the Ministère du Développement durable, de l’Environnement et des Parcs (Quebec Ministry of Sustainable Development, the Environment and Parks) to monitor ethoxylated nonyl phenols (ENPs), because these products were being used by two major industrial sectors in Quebec, textiles and pulp and paper. With regard to biological indicators, Mr. Berryman is of the opinion that the State of the St. Lawrence Monitoring Program, with its heavy reliance on this type of indicator, is on the right track. However, to report adequately on the status of the maritime portion of the St. Lawrence, fishery resource indicators should be added.
Christian Gagnon, Environment Canada
It is Environment Canada’s responsibility to classify the new substances produced each year (on the order of 1000). Most of the time, we have very little information on these substances, on their fate in the environment or on their impacts. It is important to be concerned about these new substances, but we must not forget other substances that have been in use for a long time and about which we also have very little information.
This can be discouraging for a scientist, but it must be acknowledged that great progress has been made in the past 20 years, with a lot of work done on polychlorinated biphenyls (PCBs) and mercury. There have been a number of new developments in the area of endocrine disruptors—hormone-mimicking substances—such as ENPs. Since 2000, a great deal of research has been done on the fate of endocrine disruptors in wastewater and drinking water.
Other recent research has dealt with pharmaceutical products whose provenance is not only industrial but domestic—related to the natural excretion of products ingested by human beings. It is therefore a source of contamination that is difficult to control and is inevitably found in the river. Other substances such as metabolites, antibiotics and nanotechnology products should also receive attention, given their potential environmental impact.
Michel Lebeuf, Fisheries and Oceans Canada
At Fisheries and Oceans Canada, there is no systematic temporal monitoring of contamination in the aquatic environment or in aquatic organisms being conducted. However, attempts are being made to determine the presence of metals and persistent organic compounds that may be toxic to aquatic organisms. We are seeking to find out what effect exposure to toxic substances has on organisms. In general, we use a project-by-project approach: if a species (such as the beluga whale) shows signs of problems, we assess whether contaminants may be the cause.
We are also studying the presence of new substances such as TCPMOH (tris[4-chlorophenyl]methanol) and TCPMe (tris[4-chlorophenyl]methane), which resemble dichlorodiphenylthrichloroethane (DDT) and which also accumulate in organisms. Research into PBDEs over the past five or six years has demonstrated that concentrations of these contaminants double every three years in beluga fat. Like PCBs, PBDEs accumulate in the food chain, and their concentrations amplify in organisms. These substances are not regulated, although the scientific community currently recognizes certain congeners as toxic. This is all the more disturbing because their concentrations in every environmental compartment are growing significantly.
Several other substances are worthy of special attention: polyfluorinated compounds, phthalate esters and triphenyltin (TPhT), but conventional persistent compounds still present in the environment, such as PCBs, must not be overlooked. The research spectrum should also be broadened, with focus not only on bioaccumulable substances, but also on organism exposure to unamplified substances, so as to assess the combined effects of all these substances on the environment and on organisms.
In addition to emerging substances, it is important not to forget DDT, PCBs, mercury, dioxins and other contaminants of traditional, historic concern. Though they are much more closely regulated now, these contaminants are still found in biological processing chains. The past mistake was to monitor one or two contaminants, whereas, in reality, organisms are subject to an integrated type of contaminant exposure. However, detecting, sampling and analyzing all of these substances in order to arrive at a clearer understanding of their cumulative effects is a complex process. Past clashes between environmentalists and industry have given way to a more open dialogue, and the industrial sector is more sensitive to environmental concerns.
There is a lack of documented information from which to develop criteria for the protection of aquatic life. Most often, those involved must resort to extrapolation, which may lead to errors, while the combined effects of multiple substances are not considered. More research into these synergistic effects is most definitely required because organisms can sometimes be subject to low concentrations of multiple concentrations simultaneously, which can become problematic.
There is also a need for improved coordination between environmental analyses (analyses of water and sediments, for example) and analyses conducted on organisms. It is important that communications between chemists and biologists improve.
Lastly, substances that act as endocrine disruptors should be a priority for monitoring, because of the very broad-based potential for biochemical, genetic and biological effects on organisms. An integrated approach must therefore be favoured for the continuation of studies. In conclusion, it should be noted that a great deal of work remains to develop tools that can detect subtle effects on organisms and produce a clearer picture of the situation.
Many of the public’s questions had to do with legislation in effect to regulate the use of contaminants. Essentially, this means the Canadian Environmental Protection Act, 1999, which governs the regulation of these substances. For example, PCBs and organochlorine pesticides have been banned, and other contaminants such as nonyl phenols must be reduced by 97% by 2009. A great deal of work remains to be done in the area of assessing and developing criteria for new substances, since very little information is available on the persistence of their degradation products.
For the 1000 new compounds produced every year, the Government of Canada requires a minimum of information. There are occasional omissions for certain substances, however, and their toxicity, persistence and bioaccumulation must be assessed by extrapolation, based on their chemical structure or similarity to other contaminants. The green light is given on the basis of a calculated risk and, unfortunately, it is not possible to limit industrial technology development. There are also gaps in the area of assessing combined effects—all the more so since the effects of substances can combine with other environmental effects (hypoxia, climate change).
Other questions dealt with the presence in potable water of contaminants such as pharmaceutical products or metals. Some substances must be monitored, but not necessarily all of them. There must be an awareness that the detection levels of these substances are not necessarily equivalent to the levels at which human beings are affected. It is also important to keep in mind that substances present in drinking water are water-soluble and therefore not the same as the substances monitored in organisms, which are fat-soluble and bioaccumulable. Moreover, on a more positive note, it appears that treatments such as ozonation can destroy a large portion of the contaminants present in drinking water. For example, ozonation can destroy approximately 75 to 80% of the nonyl phenols present in water.
Some participants think that, owing to the alarming number of new substances that come out every year—added to existing substances that are problematic for the environment—the precautionary principle should be adopted, and should particularly encompass increased awareness on the part of industry. The number of industries complying with such rules could then serve as an indicator, similar to ISO certifications, for example.
As regards public education, it would be worthwhile to develop educational tools to help consumers make informed choices. However, this is a difficult task, insofar as little information is as yet available on the environmental effects of numerous substances, including their effects on human beings. However, the Health Canada Web site contains a list of substances known to have harmful effects on human health.
The discussions concluded with the selection of tools as a function of the high cost of analyses. Some people wondered if consideration had been given to less costly approaches to the monitoring of toxic substances, particularly the use of passive samplers. Unfortunately, although this type of tool is very user-friendly and practical, it is not as specific, accurate or sensitive as conventional laboratory analyses; a combination of tools, however, could prove to be a more interesting approach. Lastly, recognized toxic substances are currently being monitored under the the State of the St. Lawrence Monitoring Program. The monitoring of emerging substances in the St. Lawrence is both a considerable challenge and a growing concern to users and decision makers alike. Knowledge gained about new substances, in complement to current monitoring activities, must be considered as part of an integrated approach to monitoring water contamination in the St. Lawrence.
Date modified: 2008/05/01 – Important Notices
