Defining Emerging Chemical Contaminants
Today, governments and process authorities throughout the world are focusing
efforts on determining the toxicological implications of human exposure to both
known and newly identified chemical contaminants, developing standards for methods and levels of detection, identifying prevention and management strategies for
industry, and establishing appropriate regulatory or legislative mandates as necessary.
But what are we really talking about? The U.S. Geological Survey (USGS) defines
emerging chemical contaminants as “any synthetic or naturally occurring chemical or
any microorganism that is not commonly monitored in the environment but has the
potential to enter the environment and cause known or suspected adverse ecological
and(or) human health effects.”
In defining an emerging chemical as “unregulated, recently discovered and potentially of concern to human health and the environment,” known chemicals that have
posed problems historically can also be included in the discussion of emerging
chemicals. These chemicals, such as
benzene or pesticides, can reemerge
after years of dormancy as issues to
industry. Although these aren’t new
chemicals, they are problems that have
existed historically and that are revisited with a current population.
As alluded to in the USGS definition, emerging chemicals become known as potential issues through a variety of
ways. First, with advances in analytical detection, industry is able to analyze more
chemicals to much lower concentrations, resulting in a seemingly unending array of
identified compounds that, since now known, must be addressed. We know that
chemical contaminants that pose a risk range from pesticides, veterinary drugs, myco-toxins, banned food dyes, industrial chemicals (e.g., acrylamide, perchlorate, benzene), radionuclides, environmental and heavy metals (e.g., arsenic, cadmium, lead,
mercury, methylmercury) and persistent organic pollutants (e.g., polybrominated
diphenyl ethers, dioxins, polycyclic aromatic hydrocarbons). The ability to detect
and measure more chemicals at extremely low levels in environmental, food or water
matrices not only adds to the shopping list of potential threats but adds to the complexities of deciphering whether a chemical measured at parts-per-billion or trillion
(ppb/ppt) levels rather than a parts-per-million (ppm) level has, in reality, more of a
health implication for consumers.
Another less objective reason that some chemical contaminants become known as
potential issues to the business involves how the public perceives the safety or
wholesomeness of a product, whether the issue raised has real health implications or
not. If a product contains some level of arsenic, it may not matter to the consumer
that it is well below a threshold limit or is scientifically shown to be of little significance because the compound has a back history associated with adverse health
effects. The reality is that in many cases the public perception of a product drives
how a product is designed or redesigned even more than scientific fact or evidence
to the contrary. Food companies will need to factor this “real problem vs. phantom
issue” consideration into their risk assessment strategies.
other industries include agricultural
residues; additives/colorants/flavors;
impurities; manufacturing processes;
source water; and packaging. Many
industries are beginning to look at various chemical threats to their sector’s
businesses, including heavy metals in
dyes or other kinds of plasticizers or
hydrocarbons found in source water or
packaging materials. Although these
chemicals are used in very small quantities because their applications cross
myriad manufacturing sectors, they can
be detected via biomonitoring at waste-
“The number of chemical contaminants with
public health implications has risen
exponentially since the first CDC report in 2001.”
Sources of Emerging Chemicals
Today, more work is being done in the US and the EU involving the chemical
analysis of human tissues, blood and breast milk. As researchers find chemical
residues in these clinical samples, the question becomes, where are they coming from
and what is the toxicological significance? In other words, when a compound is tested in a laboratory and it is found that it has high toxicity, persists or is not readily
degradable, how does that translate to health implications outside of the lab environment?
In general, the areas currently receiving the greatest emphasis by the food and
water treatment plants or through
product evaluations.
Impurities are another big issue
under the emerging chemicals umbrella. These represent a “grey zone” not
only in terms of identifying the source
of an emerging issue but whether a specific impurity carries with it attendant
health implications. This goes to the
heart of knowing the composition of a
product because although the manufacturer may know what materials were
put into the product (i.e., the black-and-white components), the company
is not necessarily looking for what else
is in the product, hence the problem
of the “grey zone.” Additionally, a
food product manufacturer doesn’t
necessarily know how much of an
impurity is in that grey zone, what category or level of impurity it represents,
or even whether it has some desirable
attributes.
Since many nongovernmental
organizations (NGOs) and regulators
overseeing the implementation of
California’s Prop 65 requirements are
targeting “impurities” right now, many
companies are taking a closer look to
see how much they actually know
about materials used in their products
or in the processing of their products.
Similarly, we are beginning to see a lot
of material safety data sheets (MSDSs)
