Connecting Global Priorities Biodiversity and Human Health

APIs with similar modes of action) or synergistic
effects (interaction between different APIs). The
kinds of potential impacts range from acutely
toxic events, including death for some species
(notably invertebrates), and sublethal impacts,
including behavioural, endocrine, immunological,
reproductive and mutagenic effects. This often
occurs in a context where wildlife is exposed
to other forms of pollution or disturbance, so
that APIs should be seen as adding to a larger
environmental burden.
Evidence for the ecotoxicological impacts of even
very low concentrations of APIs in the environment
has been noted in some studies. For human APIs,
a major area of concern is the impact of synthetic
hormones and hormonally active pharmaceutical
compounds. These add to an already significant
environmental burden of endocrine-disrupting
compounds (EDCs), which comprise a wider range
of chemicals, including various detergents, flame
retardants, pesticides, plant hormones and others,
as well as naturally occurring hormones that enter
sewage treatment works. The ecological impacts
of EDCs as a wider group of substances include
the occurrence of intersex characteristics in male
fish; this can be persistent and irreversible, with
subsequent impacts on fertility and population
stability (Orlando and Guillette 2007). These
effects have been particularly noted in aquatic
ecosystems, where eggs can develop in the testes
of male fish exposed to EDCs. There is a large body
of evidence that suggests that one particular API,
ethinylestradiol (EE2) plays a significant role even
at very low environmental concentrations. EE2 is
the active ingredient in the human contraceptive
pill, which is used by approximately 100 million
people worldwide (Jobling and Owen 2012). As
well as it use in birth control, EE2 is also used
for the treatment of various gynaecological
and endocrine disorders. Laboratory research
has shown that environmentally relevant
concentrations of EE2 alone can have dramatic
impacts on wildlife (Lange et al. 2001; Nash et al.
2004), while in one study in Canada, involving the
introduction of EE2 in a lake at a concentration
of just 5 parts per trillion (which is only slightly
higher than the concentrations expected in rivers
and streams) led to the complete collapse of an
entire population of fish (Kidd et al. 2007).
Another class of human APIs of current concern
is the antidepressants, which include compounds
such as fluoxetine, escitalopram and paroxetine.
Recent research has suggested that environmentally
relevant concentrations of fluoxetine, linked to
concentrations released in coastal and estuarine
habitats in the United Kingdom (UK), cause a
change in behaviour of the marine amphipod
Echinogammarus marinus by altering levels of
serotonin. Exposed amphipods showed an
increased tendency to swim close to the water
surface, which increases the likelihood of predation
by fish or birds (Guler and Ford 2010). Bean et al.
(2014) also demonstrated that environmentally
relevant levels of fluoxetine could have significant
behavioural and physiological effects on starlings
(Sturnus vulgaris), which could be exposed to the
drug when feeding at sewage treatment plants
or fields treated with sewage sludge. Recent
research has also indicated that environmentally
relevant levels of antidepressants can affect the
reproduction, feeding and predator-avoidance
behaviours of fathead minnows (Weinberger and
Klaper 2014). Brodin et al. (2014) demonstrated
that low μg/L levels of the anxiolytic oxazepam in
freshwater could lead to bioaccumulation in the
predatory European perch (Perca fluviatilis), with
significant impacts on feeding behaviour.
Impacts on wildlife have also been noted for
veterinary APIs. For example, Floate et al. (2005)
provide a comprehensive review of studies on
parasiticides applied to pasture animals. These
show that some classes of APIs are excreted to
pasture environments in concentrations that can
be lethal to coprophagous (dung-eating) insects
and to other species inhabiting the pasture soil
environment, over periods ranging from a few days
to several months (see also Lumaret et al. 2012).
This poses a potential risk to other species through
the food chain, including bats and birds. While
evidence for the direct toxicity of environmental
concentrations to vertebrate predators of pasture
insects has not been determined, there is concern
that reductions in farmland invertebrates may lead
to locally significant reductions in prey availability,
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