Sunday, February 16, 2014

What is Toxic?

There is a heart wrenching story over at about one of the many chemical response stories that came to light after the Freedom spill in Charleston, WV. This is the type story that, as a chemical professional, I cringe at every time I hear people talk about the dangers of chemicals in the environment, because this is the type story that gets repeated every time that anti-chemical activists try to put unrealistic restrictions on the chemical industry.

The Problem

My heart goes out to this poor girl and her family, but no level of research by the makers of Crude MCHM would have identified this potential problem with their product. No amount of work by the water company would have removed enough of the Crude MCHM from the water to have made it safe for this girl to bathe in or drink. There are just too many variables in the human genome to make anything safe enough for everybody.

No body suggests that we eliminate peanuts from the world, but there is a significant portion of the population that peanut allergies are a potentially fatal reality that must be dealt with every day. I had to be fed soy milk as an infant because of an apparently temporary but potentially fatal allergy to diary milk, but there was no outcry to remove cows from the planet.

Thousands of industrial chemicals are made in this country every day. New blends of those chemicals are made on almost a daily basis in response to some new industrial problem. And for the vast majority of those chemicals there is little or no real toxicological testing done. Nobody is assuming that these chemicals are safe; we in the industry tell our employees and customers not to drink these chemicals, not to allow them to get on one’s skin, not to breathe the fumes. We know that these things are not inherently ‘safe’. If you take the appropriate precautions, well documented in the safety literature, then you should not suffer any consequences.

Water Treatment

Chemicals that are used to make our drinking water safe include some of the most dangerous industrial chemicals in use today, including the periodic bogeyman chlorine gas. The hazards associated with these chemicals are well understood. They are closely monitored and tightly regulated. However, because of epidemiological reviews we are finding new hazards associated with these chemicals that could never have been identified by even the most rigorous toxicological testing. As these new hazards are identified we modify treatment regimes, we change testing standards, and we make the process and product safer.

We do not attempt to remove all ‘chemicals’ from water; first off it is not physically possible since water is itself a chemical. Even when we have to have ‘pure’ water (something that is very expensive to produce) it still contains dissolved gasses that are technically contaminants. No, drinking water contains a wide variety and concentrations of chemicals that have been determined to be safe. And it almost certainly contains an even wider variety of chemicals in extremely low concentrations that we are not aware of.

What level of water treatment is needed is determined, in large part, by the level of contaminants in the source water and what the water is used for. Again, this is as much a political decision as it is a technical decision. There is a cost for any type of water treatment and that cost will be passed along to the consumers of the water. The politicians must determine what their constituents will pay for as much as what can be treated. No politician will long survive making a decision for more expensive treatment options than are reasonably needed to clean the water going into the distribution system.

Testing Water

Testing water for contaminants is very complicated science and politics. The science of analytical chemistry is advancing by leaps and bounds (as is most of science if you really care to know). New technologies are rolled out every year making it easier to detect chemicals at levels lower than anyone ever thought of testing at before. But, this new knowledge comes at a high cost.

Some of the advances come from applying old techniques in new ways or in new combinations. Much of this is relatively easy to apply if one keeps up with all of the new information being published. Unfortunately, the people doing the testing at water treatment facilities are not analytical chemists, professionals that routinely read analytical journals and attend conferences where they share information about new techniques and equipment. No, they are professional technicians, people that take great pains at conducting repetitive tests that are designed by others.

Which tests they conduct are determined by politicians, people that make decisions on technical matters while applying cost-benefit analysis to determine which chemicals must be identified and at what level of detection they must be reported.

No lab is capable of testing for everything. Most water treatment facilities only test for a very limited number of chemicals at a relatively high level of detection; these chemicals and limits are set by law. They are required to periodically send-off samples to better equipped labs to detect a wider range of chemicals at lower levels of concentration; again these are established by law.

Adding a new chemical to the list of chemicals to be tested for is as much a political decision as it is a technical decision. First off, since testing has a cost associated with it (and that cost is variable depending on what testing technique is used), a determination must be made that there is a reasonable probability of the chemical being detected. That determination is a combination of the possibility of the chemical being in the source water for the facility, the detection limit of the tests being considered, and the amount of that chemical that might pose a safety risk in the drinking water.

Once a test is identified for a chemical that might be in the source water, a cost-benefit analysis must be done. If new, expensive equipment must be added to the lab; equipment that will require additional training and maintenance support and the chance of finding the chemical is low or the acceptable contaminant level is very high then the political decision will almost certainly be made not to implement the test in-house. For example, it appears that the water treatment facility in Charleston, WV is still relying on an outside lab to test for Crude MCHM.

What to Test For

Current federal regulations for drinking water treatment facilities require them to do a source water assessment to determine what chemicals to test for. Once a treatment authority understands what chemicals are routinely found in their source water, they determine what type of water treatment is required to ensure that those chemicals reach the distribution side of their system at safe levels. They also establish a testing regime that ensures that their facility continues to operate in a manner that meets those standards. Some of that testing will be done on site, and some will be done off site with a testing frequency that meets established standards for that type of treatment facility.

Currently, those regulations do not require a facility to take into account industrial chemicals that could possibly get into the source water in the event of a spill at a facility adjacent to the source water. This was a political decision (almost certainly an unconscious decision, or at least one that was not based upon public discussions) based upon the assumption that these facilities would have measures in place to prevent these industrial chemicals making their way into the source water.

It is now readily apparent that the source water assessment should include industrial chemicals that could reasonably (again a political term) be expected to make their way into source water for a treatment facility. That does not mean, however, that a treatment facility must be able to remove every industrial chemical that might make its way into the source water. Again, a political cost-benefit analysis must be conducted, looking at the cost of a system that could remove a chemical that has a low probability of making its way into the source water.

If the decision is made to design a facility that cannot remove that potential contaminant, then steps must be taken to ensure that the chemical does not make its way into the treatment facility. What those steps would be will depend on the chemical involved, the amount that might make its way into the source water, and how far upstream that potential chemical source is from the intake of the drinking water treatment facility.

A key component of that prevention scheme must include actions taken by the owner of the facility that houses the chemical in question. Toxic chemicals that cannot be removed by a downstream treatment facility will require higher standards of spill protection and spill notification than other chemicals at the facility. A regulatory scheme must be in place to ensure that those standards are employed and maintained.

What is Toxic?

Again, this gets back to the question of what is toxic. Anyone with any experience in the chemical industry knows that all chemicals (including water) are toxic at some level. We also know that toxicity varies substantially in the population. What is toxic for the little girl in the Mother Jones article is substantially different than that for the average healthy adult male. Establishing levels of toxicity is as much a political decision as it is a technical decision.

Again, it comes down to cost. Relatively simple toxicity testing with rats (for example) is still costly. Most chemicals that the public is not expected to come into contact with does not even require that level of testing. We can look at the chemical structure and compare that structure to other chemicals with better known toxicity profiles and determine the probability that the chemical is toxic. As long as those comparisons are done properly and the decisions are made with liberal bias towards safety, this is more than adequate for determining how those chemicals are handled in an industrial environment.

Chemicals that might reasonably be expected to contaminate source water for a drinking water treatment plant require a higher standard. For chemicals that are readily removed by a water treatment system, something that is typically easier to determine than toxicity, there should be a minimal level of toxicity testing completed to establish safe limits. More extensive testing should be required for those chemicals that the treatment facility cannot remove from the water.

Finally, epidemiological testing must be done to refine the toxicology testing. We can only truly determine what is an acceptable level of toxicity by exposing a large population to a chemical. No one will, or should, authorize such large scale testing in advance of a spill. But, once there is such a population exposure, it is only prudent to study that population to make a more accurate determination of what is actually toxic both for the chemical of exposure and related chemicals.

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