2021-12-21-世界卫生组织-Background_documents_for_development_of_WHO_Guidelines_for_drinking-water_quality,_4th_ed._incorporating_the_first_and_second_addenda_2页_115kb

WHO Guidelines for Drinking-Water Quality: Fourth Edition Summary

Core Content

The World Health Organization (WHO) Guidelines for Drinking-Water Quality (GDWQ), 4th edition incorporating the 1st and 2nd addenda, published in March 2022, were developed with the support of a series of background documents. These documents, published in 2020 and 2021, provided critical scientific and technical information to inform the updates in the guidelines, which supersede the previous 4th edition incorporating the 1st addendum (2017).

Main Topics Covered in Background Documents

1. Cyanotoxins

Cyanotoxins are toxic compounds produced by cyanobacteria (blue-green algae) and can contaminate water sources. The background documents focused on several key cyanotoxins:

• Anatoxin-a and analogues: These neurotoxins can cause rapid poisoning in humans and animals, particularly through ingestion or contact with contaminated water.
• Cylindrospermopsins: These toxins are hepatotoxic and can lead to liver damage. They are often found in freshwater systems.
• Microcystins: A group of cyclic hepatotoxins that can cause severe liver damage. The documents highlight their prevalence in water bodies and the health risks associated with exposure.
• Saxitoxins: Neurotoxins responsible for paralytic shellfish poisoning, which can occur when water is used for irrigation or in aquatic environments.

The updated GDWQ includes new or revised guideline values for these cyanotoxins, reflecting the latest scientific understanding of their health impacts and the effectiveness of monitoring and mitigation strategies.

2. Other Chemicals

The background documents also addressed a range of other chemical contaminants that may be present in drinking water, including:

• Asbestos: A known carcinogen, asbestos fibers can be ingested or inhaled, leading to serious health consequences.
• Bentazone: A herbicide that may pose risks to human health if present in high concentrations.
• Chromium: Can be toxic in certain forms, particularly hexavalent chromium, which is a known carcinogen.
• Iodine: Essential for human health in small amounts, but excessive levels can lead to thyroid issues.
• Manganese: While necessary in trace amounts, high levels can cause neurological effects.
• Nickel: A potential carcinogen, nickel compounds are of concern in drinking water.
• Organotins: Toxic compounds used in antifouling paints and industrial applications.
• Silver: Used in water treatment, but at high concentrations can be harmful.
• Tetrachloroethene (PCE) and Trichloroethene (TCE): Industrial solvents that are potential carcinogens and can cause reproductive and developmental effects.

The recommendations from these documents, including updated guideline values and risk assessments, were incorporated into the GDWQ 4th edition to ensure the guidelines remain scientifically robust and relevant.

Key Information

• The GDWQ 4th edition, incorporating the 1st and 2nd addenda, is the most recent update to the WHO guidelines for safe drinking water.
• The background documents were essential in providing evidence-based recommendations for contaminant levels.
• The updated guidelines reflect advancements in scientific research and improved understanding of the health risks associated with various contaminants.
• The documents also informed the WHO Guidelines for safe recreational water environments (2021), demonstrating the cross-disciplinary relevance of the findings.
• All background documents and related publications are available for reference at the provided link.

Conclusion

The 4th edition of WHO GDWQ represents a comprehensive update to the standards for drinking water quality, informed by the latest scientific research. It includes new guidance on cyanotoxins and other chemicals, with updated guideline values and risk assessments to protect public health. The integration of the 1st and 2nd addenda ensures that the guidelines remain current and effective in addressing emerging water quality challenges.