Evaluating the respiratory bioaccessibility of nickel in soil through the use of a simulated lung fluid

Abstract

Simulated lung fluids are solutions designed to mimic the composition of human interstitial lung fluid as closely as possible. Analysis of mineral dusts using such solutions has been used to evaluate the respiratory bioaccessibility of various elements for which solubility in the lungs is a primary determinant of reactivity. The objective of this study was to employ simulated lung fluid analysis to investigate the respiratory bioaccessibility of nickel in soils. Current occupational guidelines in Australia regulate nickel compounds in terms of water solubility, though this may not be an accurate estimation of the total nickel that will dissociate in the lungs. Surface soils were collected from the city of Kalgoorlie in Western Australia, the site of an operational nickel smelter and metal mining activities. The fraction of the samples less than 10 μm was extracted from the soil, and it was this sub-10-μm fraction that was found to hold most of the total nickel present in the soil. The fine fraction was analyzed using a simulated lung fluid (modified Gamble's solution) to isolate the nickel phases soluble in the lungs. In addition, a sequential extraction was employed to compare the bioaccessible fraction to those dissolved from different binding forms in the soil. In all samples, the simulated lung fluid extracted more nickel than the two weakest leaches of the sequential extraction combined, providing a more representative nickel bioaccessibility value than the current water leach method.

Design and Characterizations of Inhalable Poly(lactic-co-glycolic acid) Microspheres Prepared by the Fine Droplet Drying Process for a Sustained Effect of Salmon Calcitonin

“…To estimate the release behavior of sCT from PLGA particles in the respiratory system, a dissolution test of sCT samples was carried out using biorelevant media mimicking lung conditions. The composition of SLF was based on a previous report with some modifications [46]. The dissolution test was carried out in 10 mL of SLF with constant shaking at 30 spm using an Incubator M-100 (TAITEC Co., Nagoya, Japan) at 37 • C. The samples were weighed to give 1 mg of sCT in each sample tube.…”

In Vitro Investigations of Human Bioaccessibility from Reference Materials Using Simulated Lung Fluids

“…Many studies used Gamble’s solution or slightly modified versions. Modifications included adjusting the pH, addition of surfactant, and not performing the test in anoxic conditions with argon gas (e.g., [15,19,53,62,66,67]). In the present study, Gamble’s solution and modified Gamble’s solution with addition of 0.01% (w/v) dipalmitoyl phosphatidyl choline (DPPC) were tested in order to investigate the influence of this surfactant on the dissolution profile of metals (Table 2).…”

Evaluation of bioaccessible heavy metal fractions in PM10 from the metropolitan region of Rio de Janeiro city, Brazil, using a simulated lung fluid

“…The accumulation of insoluble particle is probably not the cause of respiratory diseases. However, if the particles manage to pass into the tracheobronchial system in the alveolar system, the remaining soluble compounds will dissolve in the interstitial lung fluids while the insoluble compounds will start to accumulate in the lungs [11]. Particles less than 10 μm in size can reach the lower respiratory tract and cause adverse respiratory health effects [12].…”

“…However, to estimate the potential effect on health, it is crucial to know their chemical forms, which determine if the metals are accessible for cell uptake (or bioaccessible) [3,11,12,14,15].…”