Aluminium leaching in fluid warming devices – A Review

Current guidelines recommend the use of an intravenous fluid warmer to prevent perioperative hypothermia. Among the various methods of warming intravenous fluids, contact warmers are among the most effective and accurate, particularly in clinical conditions requiring rapid infusions of refrigerated blood or fluids. Contact warmers put the infusate in direct contact with a heating block. Some fluid warmers use heating blocks manufactured from aluminium. Several recent publications, however, have shown that uncoated aluminium blocks can leach potentially toxic amounts of aluminium into the body. In this review we performed a systematic literature review on aluminium leaching with contact fluid warmers and describe what manufacturer and competent authorities did in the past years to ensure patient safety. The search resulted in five articles describing the aluminium leaching. Four different devices (Level 1 Fluid Warmer from Smiths Medical, ThermaCor from Smisson-Cartledge Biomedical, Recirculator 8.0 from Eight Medical International BV, enFlow from Vyaire) were shown to leach high levels of aluminium when heating certain intravenous fluids. One manufacturer (Vyaire) voluntarily removed their product from the market, while three manufacturers (Eight Medical International BV, Smisson-Cartledge Biomedical, and Smiths Medical) revised the instructions for use for the affected devices. The enFlow fluid warmer was subsequently redesigned with a parylene coating over the heating block. The scientific literature shows that by using a thin parylene layer on the heating block, the leaching of aluminium can be nearly eliminated without affecting the heating performance of the device.

Aluminium leaching from red muds for their complexing reprocessing

Complexing processing of «red muds» (R.M.) - waste of bauxite reprocessing by the Bayer's method, is one of the important tasks of toxic industrial waste utilization. Studied the possibility of aluminum leaching from the R.M. which content reach 14 %, received from Bogoslovsky aluminum plant of JSC «Siberian-Urals Aluminium Company» by aqueous solutions of NaOH. The process was carried out at atmospheric pressure and temperatures near to the boiling point of leaching solutions with the utilization of the residual alkali. The time’s dependence of the aluminum leaching degree from the R.M. by aqueous solutions of NaOH passes through the maximum due to the formation of secondary precipitation of aluminum. The cause of secondary sedimentation is the interaction of silicon with aluminum with formation of insoluble aluminosilicates, for example, Nа2Аl2Si2O8·2Н2O. The conditions of leaching, under which the formation of stable aluminate solutions during the time do not form of secondary precipitations were established. The maximum achieved values of the aluminum leaching degree in autoclave-free conditions was reach 20-25 %. The removal of alkali and part of aluminum under the first stage of complexing processing of R.M. leads to their enrichment in iron. The cakes from aluminum leaching and next carbonate scandium leaching can be used for pyrometallurgical recovery of iron and slag, in which untreated elements are passed, including residual aluminum, scandium, sum of rare earth elements, titanium and zirconium. A significant decrease in the volume of slag opens more opportunities for further isolation their components by acidic methods.

Comparative Study of Leaching of Aluminium from Aluminium, Clay, Stainless Steel, and Steel Cooking Pots

Analyses on the absorption of aluminium by rice boiled in distilled water in a variety of containers, such as old and new aluminium pots, clay receptacles, stainless steel pots, and steel pots, were carried out. 10 g of rice was taken as a representative sample. Colorimetric analysis of classical methods was used to determine the concentration of aluminium. The control for aluminium was 350 ± 130 μg/g. The new aluminium pots had a concentration of 126 ± 64 μg/g, old aluminium pots had 314 ± 128 μg/g, new clay pots had 132 ± 68 μg/g, old clay pots had 195 ± 137 μg/g, new steel pots had 241.00 ± 200 μg/g, old steel utensils had 186.83 ± 75.18 μg/g, new stainless steel utensils had 294.83 ± 163 μg/g, and old stainless steel utensils had 289.00 ± 75.155 μg/g. Aluminium leaching was detected in all forms of new and old cooking utensils, and leaching was below and within the control concentration range. Old aluminium pots had the highest concentration of leaching while new steel pots had the least leaching of aluminium. However, the aluminium contamination of the foods tested was insufficient to constitute a hazard to health.