Pharmaceuticals in our drinking water

Sailaja Chandramohan

Medicines should not be disposed of via wastewater or household waste

This article discusses the impact of human pharmaceutical
contamination of our water supply and focuses on the role that pharmacists can
play in minimizing the environmental impact.

How do drugs get into our water?

Drugs consumed by humans are eliminated (either unchanged or
as metabolites) via flushing into the sewer or septic system.  Consumers and healthcare professionals also
discard outdated and unused drugs down sinks and toilets into the sewer system
or into landfill (regular garbage).

Which drugs get into the water?

Antibiotics, anti-inflammatories, antiepiteptics, beta-blockers, lipid regulators,
vasodilators and sympathomimetics have been detected
in drinking water, ground water, and wastewater.      

What is the impact?

Even though most drugs break down over time through
biological and photochemical processes, they are considered

persistent

due to the fact that they
are continually discharged from sources such as sewage treatment plants.  The impact of chronic exposure to low
concentrations of drugs in the water on humans and nontarget
plants and animal species is not known.

Drugs are
designed to be both biologically active and rapidly eliminated in humans and
animals.  However, in species that are
unable to metabolize and eliminate certain drugs, these agents may bioaccumulate (concentrate).  As well, some species may be sensitive to the
effects of even very low concentrations of drugs.  This is less likely in humans, who metabolize
most drugs to more polar compounds that are less toxic and less active than the
parent compounds.

Which drugs are of most concern?

While many drugs have been detected at low levels in water,
their impact has not been adequately investigated, and establishing a causal
relationship between drugs and specific toxicities is difficult.  However, there is evidence that estrogenic
compounds may cause adverse effects even at low levels of exposure.

Continuous exposure to low concentrations of


antibiotics


in the environment, due to misuse or overuse by humans and use in
animals, may promote the development of new strains of antibiotic-resistant
bacteria.  Antibiotics may also affect
the beneficial microbes necessary to break down organic matter in sewage
treatment plants.  Sensitization or
development of an allergic response to antibiotics in the water supply may be
an additional concern.

Pharmacist’s role in ensuring appropriate drug disposal:

• Start
  or strengthen medication takeback programs -
  Pharmacists are recommended to accept the return of unused drugs for safe,
  appropriate disposal or redistribution.
• Dispose
  of unused/outdated medications appropriately (via waste management
  company)
• Educate
  the patient as they may not be aware that a pharmacy will take back unused
  medications.
• Include
  information on proper drug disposal in the pharmacy’s own patient
  information leaflets
• Advocate
  for risk assessments and standards for drugs in the water supply.

Conclusion:

Pharmacists can take a role in minimizing drug contamination
of our water supply by informing patients of the fact that drugs are getting
into our drinking water and providing a way for patients to dispose of unused
drugs appropriately, pharmacists are communicating their concern for the
environment.  Ideally, pharmacies would
provide medications returns program that is simple for the patient to
understand, and accept all unused medications (including herbal and
alternatives medications), regardless of whether they were sold by that store.

To reinforce the
message, pharmacist can provide patient with a handout about how to properly
dispose of unused medications. 
Alternatively, a statement to this effect could be added to product
information leaflets the pharmacy already provides to patients. 

We know very
little about how drugs in our water supply affect humans, animals and
plants.  Even if cause and effect
relationships are not fully established, precautionary measures are warranted
when any activity raises threats of harm to human health or the environment.

Ref: Pharmacy practice, January 2007.