A review of the biological toxicity effects of Ammonia exposure
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The sources of ammonia exposure in the environment were discussed.
The direct and indirect toxicity of ammonia exposure to human health was emphasized.
The metabolism of endogenous ammonia in the human body and the role of intestinal microbiota were also presented.
The development of ammonia-oxidizing bacteria and broader and more flexible engineering strategies was further explored and envisioned.
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ABSTRACT
Ammonia exposure is a significant environmental concern, as it can enter the human body through multiple exposure routes, including the atmosphere, water sources, and the food chain, posing a multidimensional threat to public health. This review first describes the sources of ammonia exposure and its direct and long-term effects on human health, including respiratory diseases, the risk of gastrointestinal cancer, and liver toxicity from water eutrophication. Physiologically, the urea cycle in the liver and intestinal microorganisms mainly converts ammonia into relatively non-toxic compounds. However, when liver function is impaired, elevated blood ammonia can induce hyperammonemia, accompanied by intestinal microbiota imbalance. Existing treatments, such as drugs and dialysis, are limited by long cycles and high costs. In recent years, fecal microbiota transplantation based on engineered bacteria has shown potential therapeutic promise. Finally, we discuss the ammonia metabolism mechanisms and key enzyme systems of autotrophic and heterotrophic ammonia-oxidizing bacteria, and then talk about using these genes for therapeutic intervention. This review first elaborates on the effects of ammonia exposure on various aspects of the human body, then discuss the physiological aspects of intestinal microbiota disorder caused by elevated blood ammonia under impaired liver function. -
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REFERENCES
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Ma M.-Y., Zhu Z., Zhou Y., et al. (2026). A review of the biological toxicity effects of Ammonia exposure. The Innovation Reviews 1:100013. https://doi.org/10.59717/j.tirv.2026.100013
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Ma M.-Y., Zhu Z., Zhou Y., et al. (2026). A review of the biological toxicity effects of Ammonia exposure. The Innovation Reviews 1:100013. https://doi.org/10.59717/j.tirv.2026.100013
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Figure 1.
Ammonia exposure and its negative effects on the human body
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Figure 2.
The way ammonia is metabolized in living organisms
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Figure 3.
The effect of hyperammonemia on intestinal microbiome and therapeutic strategies of microbiome modulation
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Figure 4.
Effects of Ammonia exposure on soil and earthworms
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Figure 5.
Model of electron flow in N. europaea
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Figure 6.
An overview of microbe-driven N2 transformation in nature (Heterotrophic AOB)
