In the past few weeks, I have been doing some literature research on environmental factor exposure, such as the effects of drinking water contamination by heavy metals (e.g. Arsenic, hexavalent Chromium, Uranium). Central Oklahoma is known to be one of the hot spots for the heavy metal contamination in groundwater, which is a source for the public water supplies. After discussing with epidemiologists, we thought that the topic might be a relevant issue to pursue from the standpoint of scientists working on mechanisms of carcinogenesis and cancer prevention.
Incidentally, there is a rising concern by the public on the safety of the drinking water. I saw a few local newspaper articles and facebook posts.
To do biomedical research in a professional setting, we need to define question, hypothesis, methods, and overall scope that leads to useful results (and get the research funded).
Research involved in environmental factors is somewhat tricky.
It is easy to accept that when the contaminants come in high dose, they would cause severe or acute damage. Like in the Flint water case.
But how about the opposite, "low-dose long-term"? That is the case for most environmental factor studies.
In practice, biomedical effects of such "low-dose long-term" exposure are very difficult to assess.There is a controversy in biology if "low-dose long-term" effects even exist.
There is a "threshold model" that states that the effects of an environmental factor below a certain threshold is null and negligible. Another model (linear effect model) states that even if the dose is small, there is an effect, which leads to a concern that the effect may act accumulative, or may show additive or synergistic effect on the system at the molecule, cell, organ, or body-level.
In scientific studies, whether the effects exist or not is determined individually, factor-by-factor. Intuitively, the recipient's status (e.g., age [old, young, etc], reproductive status [active/inactive, pregnant, etc], genetic background) should affect. But testing for all has not been done. It's a lot of work, and there are many incomplete parts in medical science.
The incomplete parts, the "we don't know" answer, can be taken by some as a source of (often irrational) fear. [On the other hand, others can argue that negative effects don't exist, because there is no evidence. Logically it is false, but it is common argument nonetheless.]
I want to clarify here that I am not interested in fear mongering and conspiracy theories.
I think local engineers are doing fine job. They are doing their best to keep the contaminants below exposure standards set by the government. They test the contaminants and/or water pH (heavy metals cannot come out if the pH is within a certain range). If necessary, they shut down the contaminated wells.
In a small dose, negative effects by contaminants can be countered by your "good" habits. For example, a main effect of Arsenic is generation of Reactive Oxygen Species (ROS) [oxidative stress] in the body.High Arsenic can lead to high ROS and damage, such as chromosome breakage, which can lead to cancer.
Good news is that some anti-oxidants (green tea, glutathione, etc) can counter the oxidative stress-inducing effect of Arsenic, at least in animal models. The cup of tea you just had might have negated the Arsenic's effect. Good for you.
Although I am not interested in fear mongering and conspiracy theories, sometimes, scientists have to address fear by the public. I want to do something about the issue.
After the literature research, I am shifting my lab research interest to assessments of the biomarkers on the people's side (well, eventually). Not all smokers develop cancer. Likewise, not all recipients of the same environmental factor show the visible/significant effects. It will be a valid approach to establish methods to identify severely affected high-risk individuals out of un(or less) affected people. I want to establish methods to find "A needle in the haystack", so to speak, like cholesterol for cardiovascular health, or blood sugar for diabetics. I am writing a grant proposal for that.
It has been an interesting set of research. It led to an idea for a grant proposal. After all, it's about the tap water I use to make my breakfast tea or to feed my cat. I have my own vested interest (sort of) in it.
In the meantime, I use filter pitcher and prayers. I drink green tea, too ;) .