Environmental Engineering Reference
In-Depth Information
In this chapter, we provide an overview of the inputs, fate and behaviour and
environmental effects of a selection of emerging contaminants: engineered
nanomaterials, human and veterinary pharmaceuticals and transformation
products. We also discuss possible approaches for identifying those emerging
contaminants that are likely to pose the greatest risk to human health and the
environment. Finally, recommendations on future research priorities are given.
Engineered nanoparticles
Nanotechnology is a rapidly expanding area, and engineered nanomaterials/
nanoparticles (ENPs) are finding applications in a wide range of areas including
use in cosmetics, bioremediation and water treatment (e.g., Kamat & Meisel
2003
; Savage & Diallo
2005
; Aitken et al.
2006
). It is therefore inevitable that,
during their manufacture and use, ENPs will be released to the environment.
NPs may also exist naturally (e.g., Diallo et al.
2005
) or be formed in water
bodies (e.g., Nagy et al.
2003
) or be released to the environment in mine wastes
(e.g., Walker et al.
2005
). Concerns have therefore been raised over the potential
impacts of indirect human exposure to NPs on environmental and human
health (e.g., Banfield & Zhang
2001
; Biswas & Wu
2005
; Boxall et al.
2007
).
Inputs to the environment
Whilst ENPs may be emitted during the manufacturing process, the route of
input to the environment will primarily depend on the end use of the ENP
(Boxall et al.
2007
). For example, pharmaceuticals, cosmetics and sunscreens
may be emitted to the sewage system following excretion from the patient or
during washing and showering. Once they have passed through the sewer
system, they may be released to surface waters. Sunscreens and other cosmetics
applied on skin may also enter surface waters directly during swimming or
bathing. Waste cosmetics are most likely to be disposed of in household waste
that may be landfilled or incinerated. Paints containing ENPs can have both
industrial and domestic uses. It is possible that runoff from painted surfaces
and domestic use of paints could result in discharges to sewers. In instances
where paint is applied to underwater structures or ships, ENPs may be released
directly to surface waters. The use of ENPs in fuel and catalysts in vehicles will
result in direct aerial emission of particles through vehicle exhaust or emissions
to the surface waters and sewers through leakage and spills. Waste lubricants
are most likely to be disposed of as special waste that may be landfilled or
incinerated. The use of nanoparticles in treatment of polluted water is likely to
result in direct emissions to surface and groundwaters or soil. ENPs used to
deliver agrochemicals will be released directly to soils and surface waters.
Fate and behaviour of nanomaterials in the environment
Over the past few years, there has been increasing interest in the environ-
mental behaviour of ENPs. A number of studies have investigated the fate
