Pharmaceutical residues in sewage sludge and cattle manure do not have
the feared effect

Date:
February 16, 2022
Source:
University of Copenhagen - Faculty of Science
Summary:
Pharmaceutical residues and chemicals from personal care products
in sewage sludge and cattle manure do not have a detectable toxic
effect on nematodes living in agricultural fields, according to
14-year-long experiments. At the same time, manure and sewage sludge
enhance soil quality more than conventional mineral fertilizers
and can contribute to more sustainable, circular agriculture.



FULL STORY ========================================================================== Pharmaceutical residues and chemicals from personal care products in
sewage sludge and cattle manure do not have a detectable toxic effect
on nematodes living in agricultural fields, according to 14-year-long experiments by the University of Copenhagen. At the same time, manure
and sewage sludge enhance soil quality more than conventional mineral fertilizers and can contribute to more sustainable, circular agriculture.


========================================================================== Organic fertilizers in the form of urban sewage sludge and cattle manure
can contribute to more circular and sustainable agriculture and prevent
the exhaustion of agricultural soils. However, a fear that pharmaceutical
and personal care product residues in these types of fertilizers will
pollute soil has caused several EU countries to ban or restrict the use
of sludge in agriculture.

This fear explains the widespread skepticism among Danish organic farmers
as well. In Denmark, it is legal to use treated sewage sludge -- known
as biofertilizers, which are controlled for excessive concentrations of
heavy metals, among other things. However, pharmaceutical residues and
most personal care product chemicals are not tested for in Denmark.

A new University of Copenhagen study demonstrates that pharmaceutical
and household chemicals can be measured in sludge fertilized soil, but
that the quantities were insignificant for the biological parameters
measured. At the same time, sludge and manure provide significantly
better soil quality than conventional mineral fertilizers.

"We expected to find a lot of pharmaceutical residues in the soil --
which is why the use of sludge is prohibited in many countries. And we
also hypothesised that these residues might stay in the soil and become problematic for soil organisms. The latter doesn't seem to be the case,"
says professor and lead author Nina Cedergreen from the Department of
Plant and Environmental Sciences.

The researchers measured soil quality based on certain physical
characteristics and on the abundance and reproductive capacity of
nematodes in the soil, as they serve as recognized bioindicators of soil health. PhD fellow and first author Jeanne Vuaille elaborates: "The
small worms grow and reproduce significantly better in the soils that
receive sludge and manure than in those where conventional fertilizers
are applied. The soil has better structure, a higher carbon content and
greater humidity. At the same time, we see no toxic effect on the worms
from the pharmaceuticals and personal care chemicals that we were able
to measure in the soil. This is most likely because their concentrations
were incredibly small."


========================================================================== Fourteen years of experimentation The research, which is a case study,
is based on fourteen years of experiments.

Throughout the years, University of Copenhagen researchers -- led by
Associate Professor Jakob Magid -- fertilized the experimental fields
in Taastrup with different types of organic matter and conventional NPK fertilizers. To calculate worst-case scenarios, sewage sludge and cattle
manure were added in quantities approximately four times greater than
what Danish law allows.

"It is unique for a research project to apply fertilizer to the same tract
of soil for 14 years -- and in extreme quantities for most years. So,
if the chemicals were to have accumulated and have a toxic effect,
one ought to have been able to see it after so many years. But there
is nothing to note when we measure the well-being of the worms. The pharmaceutical residues are probably broken down in time, as there is
so much biological activity in the soil," says Jeanne Vuaille.

The researchers identified twelve different substances derived from
various pharmaceuticals and personal care products in the soil that
had been fertilized with sewage sludge, which is in line with what
previous studies have shown. The substances came from painkillers, antidepressants, heart medication and perfume residues. As expected,
none of these chemicals were present in the conventionally fertilized
fields. Nevertheless, the nematodes thrived better in the organically fertilized soil.

"We need a new narrative" The researchers emphasize that the results
in themselves cannot guarantee that there are no environmental risks
associated with using sewage sludge and cattle manure in agricultural
fields. Therefore, the researchers hope that this study will allow for
more research to support these findings. Among other things, there is
currently a great deal of focus on fluorinated substances, which are
also found in sewage sludge.



==========================================================================
"A range of substances are present in organic fertilizers. Therefore,
we need to look at all of the potential risks associated with using it
and hopefully demonstrate that they are minimal when compared to the
many benefits. Right now, sludge has been branded as a "bad" type of
fertilizer by some. So, we need a new narrative about organic fertilizer
from cities for it to gain social acceptance," says Nina Cedergreen,
who continues: "If we are to move society toward a circular economy
and sustainability, we need to find a way to replace the soil nutrients
that we remove when harvesting crops. And ideally, with a minimal use of conventional fertilizers, which are energy-intensive and expensive to
produce. This is currently not the case. But it's where we ought to be
headed. Otherwise, we will exhaust our soils, as has occurred many places
on Earth." Other studies are currently underway at the University of Copenhagen, based in the same experimental fields. Among other things,
these focus on how organic fertilizer affects plant production, and to
what extend chemicals measured in the soils can be taken up by the crops.

========================================================================== Story Source: Materials provided by University_of_Copenhagen_-_Faculty_of_Science. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Jeanne Vuaille, Thorsten Klaus Otto Gravert, Jakob Magid, Martin
Hansen,
Nina Cedergreen. Long-term fertilization with urban and animal
wastes enhances soil quality but introduces pharmaceuticals and
personal care products. Agronomy for Sustainable Development,
2021; 42 (1) DOI: 10.1007/s13593-021-00726-8 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220216095836.htm

--- up 10 weeks, 4 days, 7 hours, 13 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)