2003-01-30-世界卫生组织-Benzene_in_drinking-water_2页_54kb

Guidelines for Drinking-Water Quality

Benzene

• Use/Presence: Primarily in organic chemical production, petrol; major environmental source from vehicular emissions; also from industrial effluents and atmospheric pollution.
• Guideline Value: 0.01 mg/litre
  • Establishment Basis: Robust linear extrapolation model applied to leukaemia and lymphomas in female mice and oral cavity squamous cell carcinomas in male rats; lower end corresponding to an upper-bound excess lifetime cancer risk of 10⁻⁵.
  • Toxicity: Acutely affects CNS; at lower levels, toxic to haematopoietic system (causes leukopenia, leukaemia); classified Group 1 (carcinogenic to humans) by IARC.
• Occurrence: Concentrations in drinking-water generally less than 5 mg/litre; corresponded to a 10⁻⁵ risk estimate by epidemiological data.
• Treatment: Achievable using Granular Activated Carbon (GAC) or air stripping.
• Analysis: Limit of detection 0.2 mg/litre (GC-PID/MS confirmation).
• History: Guideline value retained from previous (first) edition (1984) based on similar risk assessment principle.

Boron

• Use: Compounds used in glass, soaps, detergents, flame retardants.
• Exposure: Primarily via food; naturally in groundwater and surface water due to sewage effluent containing boron from detergents.
• Provisional Guideline Value: 0.5 mg/litre (considered provisional due to difficulty achieving in high natural boron areas).
• Toxicity: No specific NOAEL found; TDI based on developmental toxicity (NOAEL=9.6 mg/kg/day rats) with uncertainty factors; wide natural occurrence variability (0.1 to 0.3 mg/litre globally).
• Analysis: Limit of detection varies (0.2 mg/litre by ICP/MS, 6–10 mg/litre by ICP/AES).

Assessment/Reference

• Original Risk Assessment: 1993.
• Update: Risk assessment updated and included in 3rd Edition (2003).
• Primary References Cited: WHO (2003) documents on Benzene and preceding editions of GDWQ.