Medieval bear’s teeth shed light on historic heavy metal pollution in Romania

The proverbial good old times!

"Abnormally high levels of lead in the teeth of a brown bear, which died 1000 years ago down a cave shaft in the Southern Carpathian mountains, represent the earliest known evidence of human-induced heavy metal pollution in a wild animal. The finding pushes back the date of such pollution affecting terrestrial wildlife by several centuries before the Industrial Revolution began around 1760. ...

Analyses of sediment cores revealed such pollution had already begun at low levels at the onset of the Bronze Age 5200 years ago in northern Greece. Then, 2150 years ago the pollution intensified, aligning with when the Roman Empire began to occupy Ancient Greece.

However, although historic heavy metal pollution likely affected ecosystems, little is known about its impacts due to a lack of direct evidence. Now, palaeontologist[s] ... have found the earliest evidence yet of lead pollution in a wild animal after analysing the teeth of a bear that lived around 1000 years ago. ..."

From the highlights and abstract:

"Highlights

• multi-elemental concentration maps of the dentition of a sub-fossil brown bear from the Carpathian Mountains.

• Anomalous concentrations of heavy metals (lead, zinc, lithium) are detected in the last deposited layers of dentine.

• Radiocarbon data of the sampled bone indicate the individual is 1000 BP-year-old, at a time and place known for ore smelting.

• Earliest-known evidence for anthropogenic pollution on the wildlife.

Abstract

Effects of past anthropogenic metal pollution on the wildlife are understudied. We investigate trace element incorporation in the dentition of a 1000 BP-year-old brown bear from the Romanian Carpathians, an area known historically for strong metallurgical activities.

Background values as well as unnatural high lead (Pb), lithium (Li) and zinc (Zn) levels in a circa 5‒6-year-old brown bear male were detected using trace element maps across its functional dentition.

High-resolution elemental transects and histological sections reveal the seasonal extent of lead intake, which occurred during five recorded summers, i.e. when the animal was actively foraging.

We interpret the elevated Pb, Li and Zn concentrations in the terminal growth lines as evidence for the earliest-known anthropogenic heavy metal pollution in a wild animal.

Our study underlines the impact of early industrial activities in a large terrestrial omnivore, demonstrating that anthropogenic threats on wildlife were not solely driven by hunting or landscape modification during the most recent decades."

Medieval bear’s teeth shed light on historic heavy metal pollution | Research | Chemistry World

Societal changes in Ancient Greece impacted terrestrial and marine environments (open access)

Earliest evidence for heavy metal pollution on wildlife in Middle Age Europe (open access)

This 20m vertical shaft is the only way in or out of the cave where the bears’ remains were found

Graphical abstract

Study reveals key gene protecting plants from harmful metals in soil

Amazing stuff! Could be very useful!

"The negative impact of human activity on Earth doesn’t just affect our planet’s atmosphere—it goes much deeper, into its soils. For instance, excessive application of manure or sewage sludge can increase heavy metal concentrations in agricultural land where vital crops are grown. One of these heavy metals is zinc, a micronutrient necessary for plant and animal health. In excess, however, zinc can be extremely damaging to sensitive plant species. ...
The findings ... reveal that plants tolerate high levels of zinc by trapping it in their root cell walls, a process facilitated by a gene called trichome birefringence or TBR. Scientists and farmers can now use this information to develop and grow crops that are more resilient to soil contamination. ...
A cell wall’s capacity to store zinc is largely dependent on a process called pectin methylesterification—a process that alters the structure of the spongy pectin molecules inside cell walls so that they can absorb more zinc. To better understand this, the researchers performed a genome-wide association study to identify plant genes associated with increased pectin methylesterification. ...
“We found that TBR allele variants influence changes in pectin methylesterification and help determine a plant’s ability to tolerate higher zinc levels,” ..."

From the abstract:

"Zinc (Zn) is an essential micronutrient but can be cytotoxic when present in excess. Plants have evolved mechanisms to tolerate Zn toxicity. To identify genetic loci responsible for natural variation of plant tolerance to Zn toxicity, we conduct genome-wide association studies for root growth responses to high Zn and identify 21 significant associated loci. Among these loci, we identify Trichome Birefringence (TBR) allelic variation determining root growth variation in high Zn conditions. Natural alleles of TBR determine TBR transcript and protein levels which affect pectin methylesterification in root cell walls. Together with previously published data showing that pectin methylesterification increase goes along with decreased Zn binding to cell walls in TBR mutants, our findings lead to a model in which TBR allelic variation enables Zn tolerance through modulating root cell wall pectin methylesterification. The role of TBR in Zn tolerance is conserved across dicot and monocot plant species."

Study reveals key gene protecting plants from harmful metals in soil - Salk Institute for Biological Studies "... scientists find a gene to enhance plants’ zinc tolerance, an important step for producing crops resilient to heavy metals"

Natural variation of TBR confers plant zinc toxicity tolerance through root cell wall pectin methylesterification (open access)

Lotus japonicus sprouts, wildtype (left) and TBR homolog (right), in normal zinc levels (top) and high zinc levels (bottom).

Fig. 2: Natural allelic variation of TBR is associated with root growth responses to high Zn levels.

High levels of dangerous metals like lead and cadmium found in exclusive marijuana users

Recreational poisoning!

"... cannabis plant is known to accumulate metals found in water, soil, fertilizers and pesticides. ...
After adjusting for age, sex, race and ethnicity and education, the researchers found higher levels of cadmium and lead in the blood and urine of participants reporting exclusive marijuana use when compared with non-marijuana/non-tobacco use. Cadmium and lead levels were also higher in exclusive marijuana users who’d reported using the drug within the last seven days, with metal levels falling with increased time since last use. ...
In terms of limitations, the researchers recognize that their study did not include how the marijuana was used, such as vape, combustibles and edibles, so they were unable to determine the difference in metal concentrations by method of use. ..."

"... Marijuana is the third most commonly used drug in the world behind tobacco and alcohol. As of 2022, 21 states and Washington D.C., covering more than 50 percent of the U.S. population, have legalized recreational use of marijuana; and medical marijuana is legal in 38 states and Washington D.C. However, because marijuana is still illegal at the federal level, regulation of contaminants in all cannabis-containing products remains piecemeal and there has been no guidance from federal regulatory agencies like the FDA or EPA. As of 2019, 48.2 million people, or 18 percent of Americans, report using marijuana at least once in the last year.
While 28 states regulate inorganic arsenic, cadmium, lead, and total mercury concentrations in marijuana products, regulation limits vary by metal and by state. ..."

From the abstract:

"Abstract

Background:

Marijuana is the third most used drug in the world.

Objectives:

Because the cannabis plant is a known scavenger of metals, we hypothesized that individuals who use marijuana will have higher metal biomarker levels compared with those who do not use.

Methods:

We combined data from the National Health and Nutrition Examination Survey (2005–2018) for 7,254n=7,254

 participants, classified by use: non-marijuana/non-tobacco, exclusive marijuana, exclusive tobacco, and dual marijuana and tobacco use. Five metals were measured in blood and 16 in urine using inductively coupled plasma mass spectrometry; urinary metals were adjusted for urinary creatinine.

Results:

Participants reporting exclusive marijuana use compared with non-marijuana/non-tobacco use had statistically significantly higher mean cadmium levels in blood [1.22 micrograms per liter1.22μg/L (95% CI: 1.11, 1.34); less than 0.001p<0.001] and urine [1.18 micrograms per gram1.18μg/g (95% CI: 1.0, 1.31);  0.004p=0.004] and statistically significantly higher mean lead levels in blood [1/27 micrograms per deciliter1.27μg/dL  (95% CI: 1.07, 1.50); 0.006p=0.006 ] and urine [1.21 micrograms per gram1.21μg/g  (95% CI: negative 0.006−0.006, 1.50); 0.058p=0.058].

Discussion:

Our results suggest marijuana is a source of cadmium and lead exposure. Research regarding cannabis use and cannabis contaminants, particularly metals, should be conducted to address public health concerns related to the growing number of cannabis users. https://doi.org/10.1289/EHP12074"

High levels of dangerous metals found in exclusive marijuana users A new study has found that people who exclusively use marijuana have higher levels of potentially dangerous metals in their blood and urine than those who don’t. The findings suggest that marijuana may be an overlooked source of metal exposure, an important consideration given the rise in its use.

Blood and Urinary Metal Levels High among Exclusive Marijuana Users

Blood and Urinary Metal Levels among Exclusive Marijuana Users in NHANES (2005–2018) (open access)

Engineered yeast can remove heavy metals from wastewater

Good news! Unfortunately, article is behind paywall!

Engineered yeast can remove heavy metals from wastewater | Research | Chemistry World: Easy storage and rapid growth could see yeast compete with bacterial and chemical remediation