How much fluorine is too much fluorine? 多少氟被認為是太多氟

Comment: It is weird that scientists show more concern about environmental health than humans’ health. Fluoride is harmful to humans. It causes disease and promotes aging. Its damages to humans include death, bone cancer, genetic damage, premature aging of skin and arteries, brittle bones, immune suppression, cancer growth, infertility, lowering IQ, etc.

評論：奇怪的是，科學家對環境健康的關注比對人類健康的關注更多。 氟化物對人體有害。 它會引起疾病並促進衰老。 它對人類的損害包括死亡，骨癌，遺傳損害，皮膚和動脈的過早老化，骨骼脆弱，免疫抑制，癌症生長，不育，智商降低等。

News Release 15-Jul-2020

American Society of Agronomy

For most of us, our closest encounter with the element fluorine is likely to be our toothpaste or a municipal water supply with added fluoride.

But excess fluorine can be a problem. For example, high levels of fluorine in the soil can hurt plants. Fluorine in soils may also affect microbes and other organisms higher along the food chain.

A new study explored whether soil fluorine levels in New Zealand are high enough to hurt a specific microbe called Rhizobium.

Rhizobium bacteria live in root nodules of legume plants, like beans and lentils. These bacteria ‘fix’ atmospheric nitrogen, making the nutrients into a form the host plant can use.

Nitrogen fixation by Rhizobia means farmers need to use less nitrogen fertilizer. That can save significant costs.

If soil fluorine levels become high enough to hurt Rhizobia, it could impact the legume crops the bacteria help support.

In addition, pastures for grazing livestock often contain clover, another legume. High fluorine levels could harm Rhizobia living in clover root nodules. Ultimately, that could impact the livestock that eat the clover.

But there are a lot of unknowns about fluorine and its specific effects on microbes. “No one has investigated the potential impact of fluorine on Rhizobia,” says Christopher Anderson, a researcher at Massey University in New Zealand.

In the study, Anderson and colleagues found that high levels of fluorine are toxic to Rhizobia and white clover.

In laboratory studies, fluorine levels above 100 mg per liter hampered Rhizobia growth. High fluorine concentrations also led to changes in the shape and metabolic activity of the bacteria.

These high fluorine levels also impacted white clover. At fluorine concentrations above 100 mg per liter, white clover seedlings did not survive.

Fortunately, there’s some good news as well. The concentration of fluorine at which it is toxic is much greater than the concentration the researchers found in New Zealand soils.

“This means that there is no problem, right now, of fluorine levels in soil affecting Rhizobia in New Zealand’s soils,” says Anderson.

This finding gives confidence to agencies in New Zealand that are tasked with ensuring sustainable farming systems. “Without our research, they would still be in the dark,” says Anderson.

Rhizobia – and one of the host plants, white clover – are key parts of the New Zealand way of animal husbandry.

“In New Zealand, we are fortunate that we can grow grass year-round,” says Anderson. “Our livestock are kept on pasture all year.”

Rhizobium bacteria associated with clover fixes nitrogen from the atmosphere. When clover plants die, they break down in the soil. The fixed nitrogen becomes available to other plants.

“So, we don’t need to apply as much synthetic nitrogen fertilizers, such as urea, to our pastures with clover” says Anderson.

But farmers need to apply other fertilizers to New Zealand’s pastures, including phosphorus fertilizers. That’s where concerns about fluorine levels come in.

Fluorine is a fairly common element in Earth’s crust. It is concentrated in some materials, like phosphate rocks. These rocks are the main ingredient in many fertilizers with phosphorus.

In areas where phosphorus fertilizers are applied year after year, fluorine can accumulate in soils over time. This accumulated fluorine can become a soil contaminant.

“But in some cases, biological systems are very tolerant of contaminants,” says Anderson.

Anderson aims to determine fluorine levels at which it is toxic to animals. “In particular we would like to look at earthworms,” says Anderson. “Earthworms are very useful ecological indicators.”

Researchers also want to look at grazing animals, which can eat a considerable amount of soil. When animals ingest too much fluorine, they can develop fluorosis. That can cause bone, teeth, and kidney problems.

“We have to make sure the science is looking after all aspects of the pastoral system – soil, microorganisms, plants, and animals,” says Anderson.

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Read more about this research in Journal of Environmental Quality. This work is supported by The Fertiliser Association of New Zealand.

對於我們大多數人而言，與氟元素最接近的接觸可能是牙膏或添加了氟化物的市政供水。

但是過量的氟可能是個問題。例如，土壤中高含量的氟會傷害植物。土壤中的氟還可能影響食物鏈中較高的微生物和其他生物。

一項新的研究探討了新西蘭的土壤氟含量是否高到足以傷害一種稱為根瘤菌的特定微生物。

根瘤菌生活在豆類植物的根瘤中，如豆類和小扁豆。這些細菌“固定”了大氣中的氮，使養分成為宿主植物可以利用的形式。

根瘤菌固氮意味著農民需要減少使用氮肥。這樣可以節省大量成本。

如果土壤中的氟含量高到足以傷害根瘤菌，則可能會影響細菌幫助支撐的豆類作物。

此外，用於放牧牲畜的牧場通常含有三葉草（另一種豆類）。高氟含量可能危害生活在三葉草根瘤中的根瘤菌。最終，這可能會影響食用三葉草的牲畜。

但是，關於氟及其對微生物的特殊影響，還有許多未知數。新西蘭梅西大學的研究員克里斯托弗·安德森說：“沒有人研究氟對根瘤菌的潛在影響。”

在這項研究中，安德森及其同事發現，高含量的氟對根瘤菌和白三葉草有毒。

在實驗室研究中，每升100 mg以上的氟水平阻礙了根瘤菌的生長。高氟濃度還導致細菌的形狀和代謝活性發生變化。

這些高氟含量也影響了白三葉草。在氟濃度高於每升100 mg時，白三葉草幼苗無法存活。

幸運的是，還有一些好消息。有毒的氟的濃度比研究人員在新西蘭土壤中發現的濃度高得多。

“這意味著，目前影響新西蘭土壤中的根瘤菌的土壤中的氟含量沒有問題，”安德森說。

這一發現使負責確保可持續農業體系的新西蘭機構充滿信心。 “沒有我們的研究，他們將仍然處於黑暗之中，”安德森說。

根瘤菌和寄主植物之一，即白三葉草，是新西蘭畜牧業的重要組成部分。

“在新西蘭，我們很幸運能夠終年種草，”安德森說。 “我們的牲畜全年都在牧場上飼養。”

與三葉草相關的根瘤菌可以固定大氣中的氮。當三葉草植物死亡時，它們在土壤中分解。固定氮可用於其他植物。

“因此，我們在三葉草的牧場上不需要施用太多的合成氮肥（例如尿素）”，安德森說。

但是農民需要在新西蘭的牧場上施用其他肥料，包括磷肥。那就是人們對氟含量的擔憂。

氟是地殼中相當普遍的元素。它集中在某些材料中，例如磷酸鹽岩。這些岩石是許多含磷肥料中的主要成分。

在年復一年施用磷肥的地區，氟會隨時間累積在土壤中。積累的氟會變成土壤污染物。

“但是在某些情況下，生物系統對污染物的耐受性很高，”安德森說。

安德森的目標是確定氟對動物有毒的水平。 “特別是我們要研究earth，”安德森說。 “ E是非常有用的生態指標。”

研究人員還希望研究放牧的動物，它們可以吃大量的土壤。當動物攝入過多的氟時，它們會發展為氟中毒。那會導致骨骼，牙齒和腎臟問題。

“我們必須確保科學正在照顧牧民系統的各個方面-土壤，微生物，植物和動物，”安德森說。