Residues from billions of doses of antibiotics, painkillers and antidepressants pose a significant risk to freshwater ecosystems and the global food chain, a new analysis said Thursday.
There are growing fears that the unchecked use of antibiotics in both medicine and agriculture will have adverse effects on the environment and on human health.
When animals and humans ingest medicines, up to 90 percent of active ingredients are excreted back into the environment.
Many medicines are simply discarded — in the United States alone an estimated one third of the four billion drugs prescribed each year ends up as waste.
The Organisation for Economic Co-operation and Development (OECD) compared data on concentrations of pharmaceutical residue in water samples worldwide as well as prescribing trends and water purification regulations in various countries.
One study cited in its report estimates that 10 percent of all pharmaceuticals are potentially harmful to the environment — including hormones, painkillers and antidepressants.
The OECD said that antibiotic use for livestock is predicted to rocket by more than two thirds in the next decade, stoking concerns over antibiotic resistance.
Human prescriptions are also set to drastically increase, according to the report.
"We're seeing constant engineering of new pharmaceuticals and seeing clinical practices evolve to include recommendations of earlier treatment and higher doses," said the lead report author Hannah Leckie.
Another study cited said "extremely high" concentrations of pharmaceutical products had already been detected in water ways in China, India, Israel, South Korea and the United States.
In Britain alone, ethinyloestradiol, diclofenac, ibuprofen, propranolol and antibiotics are now present in the run-off of 890 wastewater treatment plants at high enough levels to cause "adverse environmental effects", according to another study.
"The residues of pharmaceuticals have been detected in surface and ground water across the world," said Leckie.
"However there's still a lot we don't know about their occurence, and know even less about the concentrations we find."
– Resistance set to skyrocket –
More than 700,000 people already die each year from drug-resistant infections.
As the global population grows and ages and prescribing rates continue to climb, that figure is set to hit 10 million annually by 2050 — higher than the number of people dying from cancer.
"Unless adequate measures are taken to manage the risks, pharmaceutical residues will increasingly be released into the environment as ageing populations, advances in healthcare, and intensification of meat and fish production spur the demand for pharmaceuticals worldwide," the report said.
And the situation is set to get even more acute as climate change increases the spread and frequency of infectious diseases such as malaria and dengue.
Leckie said there was something of a vicious circle when it came to medical prescriptions and climate-related disease.
"Human activity such as population (growth) and transport combined with climate change increases antibacterial resistance… and therefore the need for more pharmaceuticals."
Human link in spread of infectious cancer in mussels
Paris (AFP) Nov 14, 2019 –
Mussels hitching a ride on ocean-going ships are likely responsible for the spread of an infectious cancer found in different species on either side of the Atlantic, scientists say.
A recent study in the journal eLife suggests that human activity may "unwittingly be contributing to the worldwide spread of infectious cancers" affecting mussels, clams and cockles.
Most often, cancer arises from DNA mutations in an organism's cells which lead to uncontrolled cell growth — it does not normally spread from one organism to another, although it can.
"Tasmanian devils, dogs and bivalves have all developed cancers that can spread to others, acting more like a pathogen or parasite," lead author Marisa Yonemitsu, Research Technician at the Pacific Northwest Research Institute in Seattle, Washington, said in a summary of the study findings.
Yonemitsu said one such cancer, called a bivalve transmissible neoplasia, was previously found in a mussel species, Mytilus trossulus, in British Columbia, Canada.
Similar cancers have also been found in related mussel species around the world but it was not known if they were transmissible.
To find out, the scientists sequenced DNA from cancer cells in a related species, M. edulis found in France and the Netherlands, and M. chilensis, from Chile and Argentina.
The aim was to establish whether their cancers were transmissible and of the same line as that found in M. trossulus, or if these species had transmissible cancers of their own.
"This would help us understand how often transmissible cancers can occur, how far they can spread in nature and whether they are able to affect new populations and new species," Yonemitsu said in the summary.
The team was surprised to discover that cancer cells collected from the European and South American mussels were "nearly identical" genetically.
"(This suggests) they came from a common origin — likely a single M. trossulus mussel with a primary cancer at some point in the past," said Yonemitsu.
Another scientist on the team, Michael Metzger, said that since "Mytilus mussels do not live in the equatorial zone, it would have been nearly impossible for them to have spread this cancer between South America and the Northern Hemisphere on their own."
The most likely cause — "human intervention may be responsible for introducing them into new susceptible populations and species", Metzger said.
