Thanks for that detailed reply, and yes the way plant cells connect intra-cellular is quite a bit different from animal cells, and thus entry of these substances should be more difficult.
On the other hand, these are substances often especially engineered for easy tissue access, and since they are active in such small quantities it could still be an issue (maybe also as surface contamination?).

But to figure this out you definitely need a well equipped lab. I would be interested to read those Swedish studies (but in Sweden the unchecked use of pharmaceuticals is probably quite a bit lower too).

Last but not least, I really don't want to spread any FUD about the use of urine, which is probably perfectly fine in most cases

Dear Julius and everyone,

Yes, the possibility of pharmaceuticals from the urine being absorbed into the vegetables fertilized with it is a big concern. There have been some high-tech studies (it seems largely in Sweden) and none seem have found these in the fruits and vegetables, as far as I remember.

I think I have a simple answer to this, but I would like to ask everyone on the Forum who is based at a good university to walk into the office of a Plant Physiologist to confirm the following:

- - -
"Plants actively transport nutrients into their root hairs, mostly as ions or tiny molecules, right? So, could big organic compounds, like artificial hormones from birth control pills, even get into plants and contaminate the fruits and vegetables that people would eat?"
- - -

Here is some supporting information:

The intro of this video has a good explanation of how limited is the entry of different substances into plants. (although this is an advertisement.)


en.wikipedia.org/wiki/Nutrition#Processes
Plants uptake essential elements from the soil through their roots and from the air through their leaves. ... Nutrient uptake in the soil is achieved by cation exchange, wherein root hairs pump hydrogen ions (H+) into the soil through proton pumps. These hydrogen ions displace cations attached to negatively charged soil particles so that the cations are available for uptake by the root.

en.wikipedia.org/wiki/Soil#The_mechanism_of_nutrient_uptake
Plants move ions of out of their roots in proportion to the amount of nutrients they move in. Hydrogen H+ is exchanged for cations and carbonate, HCO3- and hydroxide OH- anions are exchanged for nutrient anions. Plants derive most of their anion nutrients from decomposing organic matter, which hold 95 percent of the nitrogen, 5 to 60 percent of the phosphorus and 80 percent of the sulfur. As plant roots remove nutrients from the soil water solution, nutrients are added as ions move off of clay and humus, are added from decomposition of soil minerals, and released by the decomposition of soil organic matter. Where crops are produced, the nutrients must be augmented by fertilizer or added organic matter.[73]

Plant nutrients, their chemical symbols, and the ionic forms common in soils and available for plant uptake[70]
Element Symbol Ion or molecule
Carbon C CO2 (mostly through leaves)
Hydrogen H H+, HOH (water)
Oxygen O O2-, OH -, CO32-, SO42-, CO2
Phosphorus P H2PO4 -, HPO42- (phosphates)
Potassium K K+
Nitrogen N NH4+, NO3 - (ammonium, nitrate)
Sulfur S SO42-
Calcium Ca Ca2+
Iron Fe Fe2+, Fe3+ (ferrous, ferric)
Magnesium Mg Mg2+
Boron B H3BO3, H2BO3 -, B(OH)4 -
Manganese Mn Mn2+
Copper Cu Cu2+
Zinc Zn Zn2+
Molybdenum Mo MoO42- (molybdate)
Chlorine Cl Cl - (chloride)

Note that these are individual atoms or very small, mostly inorganic molecules ... not big, complex organic molecules, like hormones, antibiotics, etc.

Here is a relevant lecture from University of California at Berkeley, explaining how plants control what goes in and out of their roots. At first, it sounds like everything can get in, but then the lecturer explains about Casparian Strips.

(Starting minute 37:07)

To put this into perspective, the human gut is not so selective, absorbing a great variety of things, and we depend on our sight, smell and taste being selective so that we only allow good food to go into the gut. The root of a plant, in contrast, grows into the soil among all sorts of good and bad things and must selectively up-take that which it needs.

I hope you find this interesting food for thought ... and thought for food.

Best wishes,
Chris Canaday

Note by moderator (EvM):
This post is following on from this thread:
forum.susana.org/forum/categories/78-by-...mber-17-out-now#6026

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Great, thanks. Sadly we didn't get around submitting something for this issue.

Especially the last article (about pharmaceutical remains in urine) raises a very important but yet not so much focused on issue with urine as a fertilizer.
I think at least the middle class in countries like Uganda are actually consuming a lot more pharmaceuticals (antibiotics, painkillers etc.) than is common in (northern) Europe, where the critical awareness and restrictions in sale are much higher.