The Standard – October 2013

The United States Environmental Protection Agency is proposing to add a nonylphenol category to the list of toxic chemicals subject to reporting under section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA) of 1986 and section 6607 of the Pollution Prevention Act (PPA) of 1990. Any company that manufactμres, processes or uses nonylphenol-containing compounds will be subject to this reporting. It is expected that nonylphenol compounds will continue to see increased scrutiny.

The objectives of human exposure assessment to environmental chemicals are to quantify the magnitude, duration, frequency and routes of exposure, and to characterize and enumerate the exposed population. There are several ways to do human exposure assessment. The first is the external dose measurement process followed by modeling to predict the individual internal dose. This method usually involves the collection of questionnaire data and a measurement or estimation of concentrations of the chemical(s) in various environmental media such as air, water, soil, dust, food, consumer products, etc. This is followed by assumptions of media contact or intake routes that yield a level of applied dose. Predicting levels of toxicants in people using environmental media monitoring is very difficult and involves many assumptions such as: individual lung, intestine and skin absorption coefficients; genetic factors; personal habits; lifestyle factors; nutritional status; and many others.

Polychlorinated naphthalenes (also known as PCNs or simply CNs) comprise a class of compounds of up to 75 congeners containing from one to eight chlorine atoms per naphthalene molecule. PCNs are structurally similar to PCBs, sharing chemical and physical properties. PCNs are hydrophobic, have high thermal and chemical stability, resist weathering in the environment and have low flammability risks, as well as low to medium volatility.

A recent ad campaign for Preen, a weed preventer comprised of ~1.5% trifluralin (2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine or α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) caught our attention in a market where glyphosate is a dominant herbicide. Trifluralin is a pre-emergent dinitroaniline herbicide that was first approved for use by the US EPA in the early 1960s, and has been assigned CAS Number: 1582-09-8.