Aerogel: Llano De San Francisco, Querétaro, Mexico

Week #23: Heavy Metal Ions (Real-Life Stories)

Carlos Manuel Jarquín Sánchez
5 min readDec 31, 2022


Preface! ✨

Hello everyone!

My intentions for writing these articles are:

  • Explain technical information about aerogels in simple terms (to the public)
  • Store information and habits for my future self and others (in <7 minutes)

Coolio? Sweet. Enjoy the series :-)

Let’s Talk About Home ⌛️

Let’s give the basics. Here is a Google Earth Screenshot of Llano De San Francisco, Querétaro, Mexico.

The following stories/notes came from research and recorded audio. Muchas gracias por sus historias. 🙏

Welcome to their world.

69% of the inhabitants of El Llano de San Francisco have been poisoned with arsenic.

They suffer from respiratory infections, exhaustion, and skin peeling, among other ailments.

One of the inhabitants of the community Llano de San Francisco, municipality of Pinal de Amoles, Querétaro, had demonstrated the total number of people infected:

Some 20 houses in the community of El Llano de San Francisco can be seen through the fog, where 120 of its 172 inhabitants were poisoned by contaminated water, presumably with arsenic, which caused them respiratory infections, diarrhea, vomiting, fever and other illnesses.

Before the health emergency, the inhabitants consumed water from the El Llano spring, their primary supply source for the past 30 years.

“I take my clothes to wash where the tank leaks.”

Referring to the 50 cubic meter steel tank installed by CEA to supply the 172 inhabitants of the community.

Martha, Residente, El Llano

Martha’s main concern is not having enough money to eat. Sometimes she washes other people’s clothes. But at 68 years of age, she understands that her strength is giving away.

Peeled Skin From Arsenic-Contaminated Water

But where is the source of contamination? 🚱

In Madroño and El Llano de San Francisco they suspect that the contamination of El Cedral was caused by a mercury mine known as El Oyamel, operated by local people.

But Martha has her doubts about the mercury mine.

There are miners here who drink (water at the mine). It would have affected them by now. But it doesn’t.

- Martha, Resident, El Llano

The SSA (Secretary Of Health Mexico) determined that they were suffering from chronic arsenic intoxication. The patients are not at risk of dying from this cause, the Ssa said in a press release.

The contamination sprang from the El Cedral spring, a distribution system not operated by the CEA, which closed the spring and placed two tanks of 10,000 liters each.

But guess what? It’s not entirely the arsenic!!

Diana Citlalli García, a researcher at the University of Guadalajara, reported that 79 percent of 94 pregnant women from the municipalities of Jocotepec and Chapala, who underwent studies to detect toxins in Lake Chapala and nearby bodies of water, revealed that the patients’ blood contained hexachlorocyclohexane — a pesticide whose trade name is Lindane — a product that officially should not be manufactured in Mexico and whose use has been restricted since 2000.

The international standard is no more than 0.002 parts per million of the pesticide in their blood.

But the values found in the blood samples ranged from 0.009 to 21.8 parts per million. The compound alters hormonal balance, which could slow down metabolism and alter satiety mechanisms (feeling-full mechanism) in children.

River, El Cedral, El Llano De San Francisco, Mexico

Additional Key Points 📃

20% of the population (over 15 years of age) in Llano De San Francisco is illiterate and only 45% have completed primary school.

Most of the women in Llano de San Francisco are engaged in domestic work — with or without pay — and the men are involved in mining and artisanal mercury extraction.

Remember Martha? She had her doubts about the arsenic being the primary cause for the contamination…

She is probably right.

This was the response of her neighbors:

No, don’t believe them! Nothing happened here, nothing. Many of them just made up a lot of excuses because they can’t even find anything else to invent.

Look at that old man who is walking over there, he is Mr. José Hernández Aguas, he has been working in the mine all his life, he is about eighty years old & he is very healthy. Ask him to see!

The final person was a girl, Natalia Hernández. She had been summoned to answer questions regarding her intoxication with arsenic.

I asked Natalia if she knew the cause of her intoxication and she answered that she knew that she had high levels of arsenic in her body, but that she could not blame the Soledad mining company.

The personnel of the Ministry of Health told them that contact with the cinnabar calcination furnaces in the courtyards of their houses, a few meters away, a few steps from their rooms, could also have caused the intoxication.

P.S. All the families contain additional mercury in their blood.

El Llano Villager With Spots From Recent Contamination Of Mercury

All the neighbors’ last comments were an interesting point to dig further into the root cause of contamination (perhaps contamination via the air):

“Here all the families are working with mercury, because it is an area of that mineral.” says a lady.

“It’s a mining zone here, all of it. And mercury comes out everywhere,” interrupts another.

“All the water is infected, so we can’t say it’s from the mine because it’s not”, one more woman adds to the arguments of her neighbors and concludes:

Besides, the mine is far away, and our men didn’t even get sick, nothing happened to them”.

Why Did We Write About This? 💭

I wrote about these topics because we genuinely care about the people.

Yes, I faced a similar situation with heavy metal ions. But that is not the entire reason…but it helps with identifying pain points.

A necessity is easy to sell because your life depends on it.

This is why we take deep consideration of what the potential users think about.

One mistake costs a life.

Understanding people’s pain points allow us to build relationships and build the bridge of trust: the world’s most powerful currency.

El Llano De San Francisco, Mexico: Complete. ✔️

Connect →🔗



© 2023 by Carlos Manuel Jarquín Sánchez. All Rights Reserved.