Clogging the wheels of Cancer (0) comments
By Ik Anyanwu | Friday, July 18 2008 | Faculty
  
 With more incidences of cancer being recorded in Nigeria and globally there has been an increase in research focused on exposing cancer causing agents (carcinogens). Polynuclear Aromatic Hydrocarbons (commonly known as PAHs) have been identified as one of the most potent of carcinogens, mainly because of its abundance in our environment.
Dr. Chimezie Anyakora, head of the research team on the environmental impact of PAHs, gives us direct answers as to the importance of these studies at this time and what relevance it holds for the future.
We would like you to tell us what PAHs are?
Polynuclear Aromatic Hydrocarbons (PAHs) are a major class of environmentally hazardous organic compounds. They are ubiquitous environmental contaminants found in air, water and soil, and are always found as a mixture of individual compounds. They comprise the largest class of chemical compound known to be cancer-causing agents. Many human activities result in PAH formation such as industrial processes, tobacco smoke, oil spills, coal combustion, vehicle emissions, waste incineration and biomass burning. PAHs enter the body through a variety of ways, for example, when they are breathed in air that contains them or by swallowing food, water, soil or dust particles that contain PAHs. Also skin contact with soil or with products like crude oil containing high levels of PAHs is a source of contamination.
What is the focus of your team’s research and why is it especially important today?
Basically our research focus is on developing analytical methodologies for the analysis of PAHs and their metabolites in the environment and the body fluids of exposed subjects. I think this research area is extremely important since it is in line with global trend on making our environment safer and cleaner. More important is the fact Nigeria is a crude oil producing country and so her scientists should be among the best in the world in this field. If Nigerian scientists do not pull their weight in this area of research it will be a clear sign of lack focus. I believe we are doing a great job for our country and the world.
How much impact has PAH made in terms of its link with cancer?
The carcinogenicity was established some decades ago, in fact they were listed as priority pollutants by the United States and the European Community several years ago. Research on this topic has for some time focused on the analysis and detection of these compounds in contaminated samples. Nigeria, like many crude oil producing countries, has increased levels of these compounds in the environment. Petroleum products contribute a lot to PAH contamination, for example Oil spills in various parts of the globe and in the Niger Delta region of Nigeria.
Is this phenomenon related to a particular type of cancer, or can it be linked to all types?
All types of Cancers have been linked to PAH contamination. A study in Spain, correlated gastric cancer risk to consumption of a local wine sealed with a tar like substance obtained through boiling and distilling fir and pinewood, which contains PAHs. In another study from Xuan Wei, located in Yunnan province in China, mortality rate from lung cancer was found to be five times the Chinese national average especially among women. This was correlated to the use of ‘smoky’ coal as fuel which contains high level of PAHs. In my recent book titled: Environmental Impact of Polynuclear Aromatic Hydrocarbons, there is a contribution by Dr. Delia Cavallo, of the National Institute of Occupational Safety and Prevention in Italy, where varied cases of cancer across the world as a result of PAH contamination were recorded.
What are you working on now?
We have been screening some occupationally exposed subjects for PAHs and their metabolites. In the past 2 years we have been able to screen a number of subjects which include mechanics, fuel station attendants. We have analyzed their blood and urine samples for these compounds. We are also developing a fingerprinting methodology to determine source specific information. As PAHs in the environment have multiple sources, it is good to know and apportion blame properly to the right source of contamination.
What do the results of screening indicate, so far?
As expected the exposure rate is quite high among people of certain profession. The good news is that those who are less exposed have much less. But the gap between having the metabolite in the blood and having cancer is quite wide; it is just an indication of the risk. Basically PAHs cause cancer by binding to the DNA thereby causing a series of disruptive effect that end up in tumour initiation. But the body has a DNA repair mechanism, capable of reverting this effect. The ability for this repair varies a great deal from person to person. That is why when two people are exposed equally, one may get cancer while the other does not, as you notice in smokers.
Let's have your opinion, How soon do you think a definitive solution will be provided?
It depends on what you mean by definitive solution. It is an environmental problem which is managed by education. The environment has to be taken care of so that we leave it better than we met it, giving the future generation a better life. Many countries have done very well by putting in place legislatures to protect the environment. What is left is to enforce those legislatures. This is what is lacking in most developing countries and I think that is where the solution lies.
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