Environmental Engineering Reference
In-Depth Information
Zhu et al. 2006 ), although they may cause oxidative stress and affect the
physiology and reproduction (Lovern & Klaper 2006 ; Oberdorster et al. 2006 ;
Templeton et al. 2006 ). Studies with algae have demonstrated that titanium
dioxide nanoparticles inhibit algal photosynthesis (Kim & Lee 2005 ). Studies
with fish have demonstrated oxidative stress in the brains of fish exposed to
fullerenes at very low concentrations (Oberdorster 2004 ), although there is
some debate over whether the effects were caused by the fullerenes or the
carrier solvent. Studies with plants have shown alumina nanoparticles loaded
with phenanthrene to inhibit plant growth (Yang & Watts 2005 ).
Just like exposure, the factors and processes affecting ecotoxicity seem to be
complex. The impacts of ENPs on environmental organisms seem to be deter-
mined by a range of characteristics including dissolution potential, aggrega-
tion potential, particle surface properties and the characteristics of the
exposure environment and the biochemical, physiological and behavioural
traits of the organism of interest (e.g., Dhawan et al. 2006 ; Rogers et al. 2007 ).
In the future, therefore, we need to bring the exposure and effects studies
closer together in order to determine whether ENPs can pose a risk to the
environment (SCENIHR 2007 ; Tiede et al. 2009 ).
Human and veterinary medicines
Medicines play an important role in the treatment and prevention of disease in
both humans and animals. Whilst the side effects on human and animal health
have been widely documented, only recently have the potential environmental
impacts of the manufacture and use of medicines been considered. Much of the
data on environmental impacts has been collated in a number of topics and
review articles (e.g., Halling-Sørensen et al. 1998 ; Daugton & Ternes 1999 ; Boxall
et al. 2003a , 2004a ; Boxall 2004 ; Floate et al. 2005 ; Crane et al. 2008 ).
Inputs to the environment
Human and veterinary medicines may be released to the environment by a
number of routes. During the manufacturing process, residues may be released
from the process and may ultimately enter surface waters. Following adminis-
tration, human medicines may be absorbed, metabolised and then excreted to
the sewer system. They will then enter a treatment works before being
released to receiving waters or land during the application of sewage sludge.
When used to treat pasture animals, veterinary medicines may be excreted
directly to soils or surface waters. Aquaculture treatments will be released
directly to surface waters. For intensive livestock treatments, the medicines are
likely to enter the environment indirectly through the application of slurry and
manure as fertilisers to land. Other minor routes of entry include emissions to
air and through the disposal of unused medicines and containers. Once released
into the environment, pharmaceuticals will be transported and distributed to
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