Bioavailability of aluminum from drinking water

Area of Science:

• Environmental Toxicology
• Trace Element Metabolism
• Food Chemistry

Background:

• Aluminum is a common element in drinking water, with solubility limits impacting its bioavailability.
• Understanding aluminum's absorption and tissue accumulation is crucial for public health risk assessment.

Purpose of the Study:

• To investigate aluminum accumulation in rat tissues at typical drinking water doses.
• To determine the influence of citrate as a ligand and pH on aluminum absorption.
• To assess the impact of aluminum exposure on other essential metal ions.

Main Methods:

• Male Sprague-Dawley rats were administered aluminum (Al(OH)3 or AlCl3) at varying doses (0-100 mg/L) with or without citrate at different pH levels for 10 weeks.
• Tissues (tibia, brain, liver, blood, kidney, intestine) were analyzed for aluminum content using flameless atomic absorption spectrometry.
• Concentrations of copper, iron, and zinc were measured using flame atomic absorption spectrometry.

Main Results:

• Aluminum did not significantly accumulate in tibia, brain, liver, blood, or kidney across treatment groups.
• Significant aluminum accumulation occurred in intestinal cells at 100 mg Al/L, enhanced by citrate.
• Intestinal aluminum accumulation showed a dose-dependent increase in the citrate-administered group.
• Intestinal iron levels decreased significantly in all groups receiving 100 mg Al/L.
• Intestinal copper levels decreased in the distilled water group and showed a trend toward decrease in other groups at 100 mg Al/L.

Conclusions:

• Low-dose aluminum exposure leads to accumulation in intestinal tissue, particularly when complexed with citrate.
• Citrate enhances aluminum absorption in the intestine.
• High aluminum intake (100 mg/L) reduces intestinal iron and marginally affects copper levels.