Dr. Eduardo Galiano-Riveros - McMaster University


Date: 21 September 2022
Time: 3:30 pm
Location: ABB 102

Guest: Dr. Eduardo Galiano-Riveros
Professor, McMaster University

Title: The Effects of Dietary Ingestion of Nickel Recovery Slag as a Grit Source in Avian Bone

Introduction: Slag from nickel smelting operations in the Sudbury basin is ubiquitous. This material rich in heavy metals such as iron, upon ingestion has the potential to effect physical, radiological, chemical, mechanical, and structural changes in biological systems. In this presentation, I will go over the effects of diet-ingested slag on several quantitative and qualitative parameters of the tibio-tarsal bones in pigeons (Columbia Livia Domestica).

Methods: The specimens were maintained on a seed diet and divided into a control group (n = 9) provided (normal) limestone grit, and an experimental group (n = 9) provided slag-based grit, both for a period of one year. Their tibio-tarsal bones were harvested for analysis. Quantitative analytical methods included density measurements, caliper-based cortical thickness measurements, bone mineral density measurements using Dual Energy X-ray Absorptiometry (DEXA), Ca and Fe concentration measurements using mass spectrometry, measurement of Young’s Moduli and breaking strength (both in compression) using a universal testing machine (UTM), and metal fingerprinting using Electro Thermal Vaporization - Inductively Coupled Plasma - Optical Emission Spectroscopy (ETV-ICP-OES). Samples from both groups were subjected to qualitative microscopy studies - both optical and electron - including Energy Dispersive Spectroscopy (EDS).
Results: A Welch’s t-test (single tail) was used to compare means of the seven quantitative parameters between control and experimental samples; in six of these parameters, a statistically significant difference was found (p ≤ 0.05). EDS measurements revealed a high concentration of Fe in the experimental samples, compatible with a condition of osteosiderosis. ETV-ICP-OES analysis detected the presence of S in bone compatible with a condition of homocystinuria. It also established that ingested slag is deposited in bone. Microscopy revealed structural differences between the two groups.

Conclusion: Slag ingestion through diet is associated with measurable changes in mechanical, chemical, structural, and radiological properties of the tibio-tarsal bones in the examined species.
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