Eco-pharmacology: drug contamination

Francisco Stefano – Director
Mailen Agüero – Business Development Analyst

Contamination of drugs raises concern because of the risks that constant exposure to drugs in the environment and in humans can bring.

In recent years, professionals began to speak of emerging pollutants, elements of different origins whose presence in the environment is not new, but the knowledge that they can cause environmental damage is. Among these, the ones that generate the greatest concern are medications.

The main sources of contamination are related to the consumption and excretion of drugs in urine and feces, and also to the inappropriate disposal of expired or unused drugs.

These pharmaceutical products are deposited in our environment through wastewater, which includes urban, hospital, industrial, and agricultural or livestock origin. In addition, drug residues can be deposited on the ground through direct excretion (animals) or due to the reuse of organic residues. In Europe, the entry of pharmaceutical waste for human consumption through domestic wastewater is estimated at around 80%, while 20% comes from hospitals

A study by the United States Geological Survey found detectable amounts of one or more chemicals in 80% of a sample of 139 susceptible streams in 30 states. The most frequently detected pharmaceutical products were over-the-counter.

Also, in 2006, a study found detectable concentrations of 28 pharmaceutical compounds in wastewater, surface water, and sediment treatment plants.


Pollution through human consumption

The most common way for these pharmaceutical waste to end up in the environment is through human excretion. A high proportion of pharmaceutical substances are not destroyed by our body and are eliminated intact in the urine. Between 30 and 90% of the orally administered dose is generally excreted as the active substance in the urine.

Another source of contamination is the inappropriate disposal of unused or expired drugs. Medications can be improperly disposed of in household garbage or reach sewage through sink or toilet drains.

In European countries there are collection systems for such waste but they are not used to its fullest extent, while in the United States there are only voluntary initiatives at the local level.

The use of drugs in animals

Both the pharmaceutical products used in veterinary medicine, and the antibiotics that are administered in the livestock industry with the purpose of increasing production and reducing food and water costs, pose a different problem, since they are excreted directly to the ground or in surface waters. open.

Veterinary lipid-soluble pharmaceutical residues can bind strongly to soil particles, with little tendency to leach into groundwater or local surface waters. The more water-soluble residues can be removed by rain or snowmelt and reach both groundwater and surface water streams.

What effects does it bring to our ecosystem?

Between 2000 and 2003 an unusual increase in the mortality rate of specimens of a vulture species was observed in Pakistan, drastically reducing the population and placing it on the list of endangered animals. The vultures would have been exposed to diclofenac by feeding on the carcasses of cattle previously treated with this drug, causing acute kidney failure and death. It is the first documented case of an ecological disaster due to drug contamination.

Today more examples of drugs with toxic effects in various species are known, for example, the alteration in the reproduction of fish exposed to ethinyl estradiol.

Due to the low concentrations in which contaminants are usually found, it can appear to be a negligible risk when analyzed product by product, with the exception of allergic sensitization problems. But there is concern about the risk of long-term exposure (at low doses, but to a mix of active pollutants).

The pharmacological groups whose residues are of greatest concern are chemotherapeutics due to the possibility of resistant strains developing, as well as antineoplastic groups due to their carcinogenic, mutagenic and teratogenic properties.

How to reduce this form of pollution?

These facts have led to the development of the so-called ecopharmacovigilance, defined by the World Health Organization as the set of actions aimed at the detection, evaluation, understanding and prevention of the harmful effects in the environment of pharmaceutical compounds.

Ecopharmacovigilance is responsible for monitoring the adverse effects of pharmaceuticals on humans through environmental exposure. Researchers are continually developing and understanding the impacts of pharmaceuticals on the environment and their risk to humans and animals.

Environmental risk assessment is a regulatory requirement in the launch of any new drug. This precaution has become a necessary step towards understanding and preventing the adverse effects of pharmaceutical waste in the environment.

At the social level, one way to reduce or end this form of pollution is:

  • Educating professionals and patients undergoing pharmaceutical treatments the importance of the proper disposal of expired or unused medications.
  • Require pharmaceutical industries to implement strategies for the proper disposal of drugs or recycling strategies.
  • Require hospitals to implement best management practices for the disposal of pharmaceutical waste.

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