Engineered Nanomaterials as Emerging Contaminants in Water - Nanotechnologies for Water Environment Applications - page 565

Wastewater systems will likely be one very important point source of engineered
NMs into the environment (Figure 16.5). Consumer products containing NMs will enter
the sewer system based upon the observations that personal care products,
pharmaceuticals, pesticides, etc are all present in raw sewage, treated effluent and
processed biosolids (e.g., (Kolpin et al., 2002)). Over 75% of the US population, and
most industries, is served by centralized wastewater systems, and as such represent a
significant potential flux of NMs from consumer products into the environment. If
NMs are removed during wastewater treatment, they will end up in biosolids which are
land applied, incinerated or landfilled, and lead to very different environmental
exposures from the presence of NMs in wastewater effluents discharged to surface
waters. Incinerated or landfilled biosolids containing NMs may provide a means of
limiting their release into the environment. Identifying and quantifying sources and
routes of NM fluxes into the environment are critical.

Land Application
of Biosolids

Land Application
of Biosolids

Society Society

Wastewater
Treatment plant

Wastewater
Treatment plant

Wastewater
Treatment plant

Wastewater
Treatment plant

Wastewater
Treatment plant

Drinking Water
Treatment Plant

Drinking Water
Treatment Plant

Drinking Water
Treatment Plant

Society Society Society

Stormwater Runoff Stormwater Runoff

Figure 16.5 Schematic illustration of important aquatic resources and potential routes of
exposure from NMs.

As NMs enter the environment society will have to evaluate their relative
ecosystem and human health risk assessment. In order to quantify risk and evaluate
management options the traditional risk assessment paradigm can be applied (Figure
16.6). Information summarized above and in the literature is the first step in
synthesizing data and information that help define the problem. For example, copper or
cadmium based NMs appear to pose greater adverse effects on aquatic organisms than
other metal oxide NMs (e.g., (Powers et al., 2006; Griffit et al., 2007) ) , thus it is