The Proof of the Pudding - Pollution Impacts on Human Health

Photo by CARC.

The question on everyone’s mind when discussing pollutants is “How will this affect my health?” Researchers studying Arctic contaminants have found that question difficult to answer. Northern Perspectives editor Clive Tesar interviewed the co-chairs of the AMAP Human Health Committee, Andy Gilman of Canada, and Jens Hansen of Denmark.

Are we now seeing impacts on human health from pollutants in the Arctic?

Gilman -- Yes, I think we are now seeing impacts on human health. Primarily those impacts are related to alterations in the body’s immune system, that’s the system that is used to fight disease. That has been reduced or lowered so our ability to fight disease is less.

And although we haven’t proven it yet, I think we can expect to find slight impairments in the development of children as a result of some of the exposures that we see. That information will be arriving shortly, but we don’t have it yet, that’s from a study that is being conducted in northern Quebec.

Hansen -- I could add that there’s also a concern for the effect of pollutants on reproduction. We don’t know at the moment for sure if that’s true, but we’re starting for instance in Greenland to look into that question.

Which people are most at risk?

Hansen -- The traditional food is the most important source of pollutants in the Arctic. The level of pollutants in the food is related to the food web system. Those people having their food from the highest level of the food web are the highest exposed. That means the Inuit population in Greenland and in eastern Canada who have the sea mammal as priority food.

Gilman -- It does depend which contaminant is being evaluated and what the human health group is doing is to try to look at all contaminants together. Certainly, for PCBs in Greenland and the eastern Canadian Arctic, they would appear to come primarily from the blubber of marine mammals. Mercury levels come more from the muscle, the meat, so mercury levels are reasonably high in parts of Greenland and parts of the eastern Canadian Arctic, and have been high in places such as the Faeroe Islands.

Is what we’re finding in certain areas partly a function of where we’re looking?

Gilman -- I would say now we have pretty good coverage in human blood levels from all across the Arctic. The only portion we don’t have results back from now is eastern Russia. So all the way from Alaska, right the way across Canada, Greenland, Iceland, the Scandinavian countries, the Faeroe Islands we have very good information. So I think we have good coverage, I think it’s probably not a function of where we’re looking so I think we have a very good idea geographically of the contaminant picture.

You had asked who was most likely to be affected by contaminants, and certainly the most at risk groups are going to be those most highly exposed groups, and also within that, the major concern would be for pregnant women because of the impact these chemicals can have on the foetus, and on children as they’re growing up. So a sort of a subset of those contamination experiences, it’s that part of the population that it seems critical to protect.

Hansen -- There is one additional element in this question. It is true that food is the main source, but it has been shown during the latest AMAP phase that lifestyle factors such as smoking influence the amount of pollutants in the body, not because tobacco contains the pollutants, but the smoking by itself influences the way the body deals with contaminants.

Which substances to date have been identified as the most problematic?

Gilman -- I think we have two groups, in general what are called the organochlorines, in particular the PCBs, we have found them in the highest concentrations and I think at the moment they are the highest concern. Another contaminant is mercury. In certain areas it is at a level that would give rise to concern, from a public health point of view.

One of the issues with respect to these two groups of contaminants is the direction in which we are going globally in terms of exposure. At this conference, one of the messages that has been fairly strong is that we are looking at continued emissions of mercury from various parts of the world that are going to lead more than likely to more Arctic pollution rather than less. So I think there’s quite a strong imperative for us to move forward aggressively on curtailing those emissions worldwide, and that is an issue that is being addressed by the United Nations Environment Programme now.

For PCBs, I think we’ve learned that the emissions to the Arctic are continuing, however, they are not rising. We may be beginning to see some declines in some of the wildlife species that have been measured. We can not tell whether levels are going down in human populations yet because the monitoring of human populations is not long enough. That will be one of the priorities if the AMAP continues, to get another data point to see whether or not we’re starting to see those concentrations declining in human populations.

What action do you expect to flow from some of the data you’ve been seeing?

Gilman -- The key action is in getting continued support for ratification of both the United Nations Economic Commission for Europe protocol on POPs and metals, mercury is in that protocol, and also the Stockholm Convention. If there was still any doubt in anybody’s mind, there ought not be after looking at the infor mation that has been provided at this conference. We simply have to move forward aggressively on stopping the use of these compounds and reducing emissions of these metals.

Participants in Rovaniemi AMAP symposium. Photo by CARC.

Hansen -- I totally agree with Dr. Gilman that international action is absolutely necessary, but also local action. We have to develop strategies for advice to local populations, how to avoid the highest contaminated food, and that must be done on a local, regional basis by the health authorities, but we provide the scientific background. That’s the only way to take into account local customs, cultures, and the way of life.

What information gaps remain in terms of Arctic contaminants and public health?

Hansen -- We need to establish time trends. We have only measured for short periods and that does not say anything about the decline or stability of levels of persistent organic pollutants. For mercury, we don’t have any certain indication of time trends, only for lead. There has been a significant decrease of lead in the blood concentrations in the Arctic, parallel to the reduction of lead in gasoline, so that is a story that tells us that international actions do work.

Another gap is that we need to know more about the biochemical effects at the present level of contaminants and the present mixture of contaminants, because there are interactions between different chemicals. They can potentiate the effects or they can counteract the effects so what we need to study is the actual mixture, how does that function in the human body. So we need to develop these programmes much more and have them implemented more widely in the Arctic area.

Gilman -- I think we still have some sampling that needs to be done in some parts of the Arctic especially eastern Russia.

We have not yet taken a look at all at some of the newly identified contaminants, and that’s an issue for us because there are publications out now indicating that polybrominated diphenyl ethers have been found accumulating very rapidly in animal tissues and in some blood samples that have been stored over time. The perfluoro octane sulfonate or PFOS is another one that has been found in wildlife, we have not looked for that in human tissues. Short-chain chlorinated paraffins are another group. Most of these chemicals appear to have similar kinds of properties to other ones that are there and we just don’t know anything about those in human tissues, so that’s an area that requires more work.

We probably have more work to do looking at infectious and non-infectious diseases because these chemicals can affect immune systems. Then we may be seeing more of the infectious diseases appearing in Arctic populations and we need to gather that database.

At this point, it is impossible to evaluate the combined effects of all contaminants and other factors that influence human health in the Arctic. AMAP's Human Health Program is designed to gather information from a number of different areas to make better assessments of combined effects in the future. AMAP, p. 91, "Arctic Pollution 2002"

We also need to look at some of the changes in non- infectious diseases that may be occurring as a result of changes in diet, because people are fearful of consuming a diet that contains contaminants. So things like switching diet so that obesity becomes a problem, or diabetes begins to occur, or more cardio-vascular disease begins to occur, those are things that need to be monitored.

There are a number of things that need to be done, but they’re certainly not actions or bits of research that have to be filled in before we can draw the conclusion that international action must press forward to eliminate these kinds of compounds. This is refining our understanding so that the sort of advice that can be provided locally to populations is better advice. These findings are not going to have a direct impact on whether or not we do or don’t take action on POPs and metals. I think that action has been taken; we need to press on with that.

In terms of filling those information gaps to provide local advice, how soon can that be given?

Gilman -- I think that advice already has been given in some locations and has led to significant change. For instance, in the Faeroe Islands starting about five years ago the advice was for people to eat less pilot whale, and as a result mercury levels have declined dramatically. The PCB levels haven’t declined because the blubber of pilot whales contains the PCB rather than the meat, and it was the reduction in the meat consumption that occurred, so PCB levels didn’t drop but mercury levels did drop. So we know that interventions can be successful, however they need to be developed with local communities and local public health officials taking into account social and cultural interactions.

Hansen -- Intervention is easier in some areas than in others. Dr. Gilman mentioned the Faeroe Islands. Pilot whale is only a small part of the diet there, otherwise it’s a typical western diet. But in several areas of Siberia, people still depend about 100% on traditional food, and other food items are not available. In such an area, intervention is much more difficult. That’s a reason strategies must be absolutely regional.

As Arctic scientists you focus on the Arctic of course because that’s your job, but how does the data compare with populations outside the Arctic? Are people in the Arctic more specifically at risk from these pollutants than people in temperate Europe or southern Canada?

Another Perspective on Arctic health. While most presenters at the AMAP symposium stressed risks from pollutants, Arild Vaktskjold with the University of Tromso in Norway wanted to ensure that people put those threats in perspective. She says her studies show that, "Lifestyle factors are a larger pregnancy health problem than most environmental contaminants." Vaktskjold says that smoking and drinking among pregnant Arctic women are more prevalent than ever. She believes that higher prices for alcohol and tobacco and information programmes warning of the risks have both failed to change the behaviour of pregnant women. Vaktskjold believes there is only one way to make a dent in the numbers of pregnant women drinking and smoking, "We need to make it socially unacceptable to smoke and drink during pregnancy."

Gilman -- In my opinion, because contaminant concentrations are higher in parts of the Arctic, eastern Canada, Greenland in particular, depending on the contaminant, parts of Russia, I think intuitively those people are at higher risk because they’re exposed to higher levels of contaminants. Balanced against that is the fact that the quality of the diet in those regions is also extremely important. The traditional diet is a very high quality diet that is very good at preventing a number of serious diseases related to heart health and diabetes, so there are those competing influences.

Certainly, levels of these contaminants that we find in the Arctic can be found in every blood sample throughout Canada and throughout Europe, however, the levels are lower. Twenty years ago, levels of DDT in populations in the Great Lakes region were probably 10-15 times higher than they currently are in the Arctic. So the situation has changed in southern regions of Arctic countries, and the residual problem now is remaining in the Arctic because of the cold environment and the movement of chemicals northward into the Arctic.

I think the risks currently are higher in parts of the Arctic than they are in the rest of the Arctic countries if we’re talking about these kinds of contaminants, the persistent organic pollutants and mercury. For airborne contaminants that are not persistent—things like particulates, sulphates, nitrous oxides, smog-related contaminants—certainly exposures are much worse in southern regions than northern regions, most of the time. So there’s a real difficulty in saying ‘this is the right answer’ because it depends on which contaminant, which effect, which population, which part of the population, and which lifestyle they have.