Contaminants of emerging concern

For a compound to be recognized as an emerging contaminant it has to meet at least two requirements:

1. Somewhere in the world people are hampered by the effect(s) of the compound.
2. There is an established relationship between the positive and negative effect(s) of the compound.

These contaminants were not previously detected by systems which analyze water quality, or they were found in much smaller concentrations. They are of emerging concern because we do not yet fully understand the risk they pose to human or environmental health.

There have always been, and will likely always be emerging contaminants in our water supplies, because the list is ever-evolving and many compounds that are intensely regulated now due to their harmful nature were in food, water, and the environment casually in the past.

• In the 1950s asbestos was not considered a hampering to personal and environmental health at all. Asbestos was investigated for the first time in 1977 by the National Research Council, and they had completed limited research which suggested the adverse health effects of consuming asbestos fibers in drinking water.[7] Today it has passed the status of concern and entered territory of clear causal relationships with negative health impacts and strict regulation, but it took the compound a long time to move from being a miracle material for construction to its present status of harmful contaminant.
• As recently as the 1970s there was a serious issue with the water treatment infrastructure of some states, notably in Southern California with water sourced from the Bay Delta. Water was being disinfected for domestic use through chlorine treatment, which was effective for killing microbial contaminants and bacteria, but in some cases, it reacted with runoff chemicals and organic matter to form trihalomethanes. Research done in the subsequent years began to suggest the carcinogenic and harmful nature of this category of compounds, but the burden fell to the water treatment plant and providers to clean the water, not the federal government. It took many years to get hard regulation of these chemicals passed federally, in fact, the Maximum Contaminant Level for THMs was lowered again in 2001 as more research continues to become available.

Emerging contaminants are most often addressed as a hampering in issues concerning water quality. The release of harmful compounds into the environment which find their way into municipal food, water, and homes have a negative externality on social welfare. These contaminants have the capability to travel far from the point-source of their pollution into the environment and accumulate over time to become harmful because they have been left unregulated by federal agencies. These harmful compounds cause damage to environmental and human health, and they are difficult to trace therefore it is challenging to establish who should foot the bill for the damage done by ECs. Because these contaminants were not detected or regulated in the past, existing treatment plants are ill-equipped to remove them from domestic water.[8] There are sites with waste that would take hundreds of years to clean up and prevent further seepage and contamination into the water table and surrounding biosphere. In the United States, the environmental regulatory agencies on the federal level are primarily responsible for determining standards and statutes which guide policy and control in the state to prevent citizens and the environment from being exposed to harmful compounds. Emerging Contaminants are examples of instances in which regulation did not do what it was supposed to, and communities have been left vulnerable to the adverse health effects of ECs. Many states have assessed what can be done about emerging contaminants and currently view it as a serious issue, but only eight states have specific risk management programs addressing emerging contaminants.[9]

For some emerging contaminants, the EPA has suggested that the best control for them is through advancing technology at treatment plants[10]. One suggestion is "enhanced coagulation" in which the treatment entity would work to optimize filtration by removing precursors to contamination through treatment. In the case of THMs, this meant lowering the pH, increasing the feed rate of coagulants, and encouraging domestic systems to operate with activated carbon filters and apparatuses that can perform reverse osmosis. Although these methods are effective, they are costly, and there have been many instances of treatment plants being resistant to pay for the removal of pollution, especially if it wasn't created in the water treatment process as many EC's occur from runoff, past pollution sources, and personal care products. It is also difficult to incentivize states to have their own policies surrounding contamination because it can be burdensome for states to pay for screening and prevention processes. There is also an element of environmental injustice, in that lower income communities with less purchasing and political power cannot buy their own system for filtration, and are regularly exposed to harmful compounds in drinking water and food.

• Water pollution