Antidepressants don´t make wildlife happier: how the pills you take impact nature

Today people in Europe live up to 30 years longer than they did 100 years ago.

This is partly due to pharmaceuticals of all sorts, which are also one of the reasons for the increase in life quality we have experienced in the past few decades.

Nowadays, a life without medicine is unimaginable. And pharmaceutical consumption has

increased systematically in the past decades.

While that helps us live longer, there are unwanted side effects: 73 percent of the toxic load in wastewater comes from pharmaceuticals and personal care products, according to several studies (see here and here).

On top of that, predictions on future use show an expected rise due to our longer life span and especially the enhanced need to treat aging-related and chronic diseases.

In this article, we explain how our pharmaceutical consumption affects the environment.

How it ends up in nature

But why do we find these chemicals in the wastewater?

The oral dose we consume of pharmaceuticals, like antidepressants, diabetes medicine, and antibiotics, is often much higher than the dose our body can take up and metabolize.

This means that, when we get sick and take a medicine, we are going to excrete a good amount of it in our feces and urines.

When our excrement is flushed out with the wastewater to the sewage treatment plant, it carries pharmaceutical residuals.

But the wastewater treatment plants are not designed to fully rinse the pharmaceuticals from the water. The medicine can consequently influence plants and animals when the wastewater is discharged into nature.

It has been estimated that a minimum of 30 percent and up to 90 percent of the oral doses are excreted in their active form.

When we flush urine and faeces with the wastewater to the wastewater treatment plant, the remnants of the medication go with it.

But wastewater treatment plants are not designed to completely remove the medicines from the water. The medicine can therefore affect plants and animals when the wastewater is discharged into nature.

Difficult to remove all types of drugs with the same technique

The active part of a medicament is designed to interact with a specific biological target in our body, and the active part often remains unchanged when it is metabolized, and it has a long half-life.

Indeed, the concern about environmental impact of pharmaceuticals rely on the persistency of these chemicals outside the human body, creating environmental problems.

The concern about the environmental impact of pharmaceuticals is due to the fact that the substances are not easily degradable outside the human body, which has consequences for the environment.

One of the biggest challenges is that these drugs have very different physio-chemical-properties, making it extremely arduous to design a unique technique capable of removing them all from wastewater.

Researchers from Aarhus University are testing a technique that uses ozone and coal to remove pharmaceutical residues from wastewater, and it will be exciting to see the results.

Besides human waste coming from households, farm activities such as aquaculture, livestock and industry, also contribute to pharmaceuticals' presence in the environment.

However, the largest cause of pharmaceuticals in the environment in Europe is represented by patients´ daily use and excretion. 

Moreover, still nowadays a substantial amount of unused and expired pharmaceuticals is poured into the sinks or trashed as household waste.

Affects reproduction and behavior in fish 

Pharmaceuticals have been found in surface water, groundwater, and soil. This wide presence in all kinds of environments is a threat to our health and wildlife.

Additionally, the long half-life and continuous release of pharmaceuticals in wastewater effluents means that plants and animals can be exposed for long periods, and often to multiple drugs at the same time.

The scientific community has already provided studies showing fish and amphibians' impairment of reproduction due to estrogen exposure from 17 α-ethinylestradiol (EE2) and levonorgestrel, which are synthetic steroids widely used in contraceptive drugs.

Exposure to psychiatric drugs change fish behavior, making them bolder and more aggressive. 

The alteration of reproduction and behavior, as well as other adverse effects from pharmaceuticals, can impact population dynamics in nature, potentially changing ecosystems interactions and ecosystem services.

Fish exposed to drugs through waters can also accumulate these medicines in their tissues. Thus, the consequences of introducing medical waste into the environment are also potentially exposing humans to a mix of pharmaceuticals via food consumption. This needs to be thoroughly investigated.

Antidepressant and the unhappy environment under the sea surface

In the past 20 years, antidepressant consumption has doubled in the OECD area. Hence, these substances have been listed among the emerging contaminants in our water, groundwater and soil.

However, we know little about the effect of these compounds on the environment, and we have even lesser understanding of the impact of those compounds which tend to settle into the sediment compartment.

Indeed, substances that mix easily with oil and fat do not like to stay in the water compartment and tend to settle out of the water and accumulate in sediments.

So, that is the reason behind our research focus on antidepressants´ toxicity in sediment-living worms inhabiting estuarine waters.

Our research group focuses on how antidepressants, at levels we can expect to find in the aquatic environment (i.e., ng/L level), impact small sediment-dwelling worms not just over a short time but over multiple generations.

Chemicals in sediment affect both animals and humans

Why is it so important to study the effects of chemicals over time? We have to remember that we keep discharging medicines every day, either via flushing of toilets or in our household waste.

Thus, unfortunately we are continuously exposing organisms to these chemicals. 

This means it is essential to investigate their potential adverse effects over a good span of the organism’s lifetime, and, whenever possible, on their progeny.

Otherwise, we would not have a realistic picture of the likely outcomes when low but continuous doses of chemicals are present in the environment.

The reason why we focus on sediment is that most of these compounds will accumulate in this environment. The animals living in the sediment, like worms and snails, constitute a main food source for demersal fish.

So, fish populations may be impacted by a change in the number of worms (i.e., food limitation in the case of a decrease of the worm population) and can also accumulate pharmaceuticals when consuming the worms and thereby become, once again, a route of exposure to humans.

Can we keep up our consumption without hurting the environment?

So, how can we keep up our medicine consumption whilst protecting the environment and wildlifeas well?

Among all the actions Europe is working on, an important part of it is making pharmaceutical production and consumption more sustainable, following the principle of a Green Pharmacy.

A higher focus has also been given to the development and implementation of environmental risk assessment tools in the manufacturing process of pharmaceuticals, and of an additional wastewater treatment step focused on removing medical waste.

Pharmaceuticals should be designed so that their overall manufacturing process does not generate many hazardous substances, Wastewater Treatment Plants should also implement methods or techniques to reduce pharmaceutical residues.

To achieve these goals, more research is needed to comprehend the mechanisms, fate, and effects of pharmaceuticals in the aquatic, and particularly in the sediment compartment.

Finally, communication on the environmental fate and effects of pharmaceuticals to the industry, doctors, pharmacists and consumers is crucial to raise awareness on the topic.

This would hopefully lead to a more mindful production process, consumption, and disposal.