Environmental Risks of Nanomaterials - Nanotechnologies for Water Environment Applications - page 592

environment, and the need for improved understanding of the behavior of NMs towards
living organisms and in the environment.

17.2 Routes of NMs into the Water Environment
In general, environmental cycling and exposure routes of a contaminant (e.g., NMs)
involve three major components: source(s), media, and receptor(s). Fig. 17.1 shows
some possible exposure routes for NMs and nanoparticles (NPs) to living organisms
including human beings. Among these, water environment is one of the most important
media for NMs/NPs exposure. It is inevitable that nano-sized products and by-products
will enter into the water (Daughton, 2004). Thus, in this section, routes of NMs/NPs into
the water environment will be discussed. These routes mainly include effluent from
products manufacturing and storm runoff, treatment processes of drinking water and
wastewater, and uptake.

Soil

Sorption,
transport

Deposition,
uptake

Sorption,
sedimentation

Release,
desorption

Living
organisms

Uptake, effluent,
transformation

Drinking, food,
biotransformation

Water

NMs/NPs

Acculmulation,
aggregation
Inhalation,
ingestion,uptake

Transformation

Transport,
exposure, diffusion

Air

Figure 17.1 Possible exposure routes of NMs/NPs to living organisms.

17.2.1 Effluent from Manufacturing and Storm Runoff

NMs come from point sources, such as factories or landfills, and from nonpoint
sources, such as wet deposition from the atmosphere, storm-water runoff. Attrition from