Document Type


Date of Award



College of Science, Engineering, and Technology (COSET)

Degree Name

Ph.D. in Environmental Toxicology

Committee Chairperson

Sonya Good

Committee Co-Chairperson

Ayodotun Sodipe

Committee Member 1

Tuan Phan

Committee Member 2

Desiree Jackson


Heavy metals, ICPMS, Milk, Pesticides, Plant based milk alternatives


Milk is a dietary component consumed all over the world and is known to be essential for development in children. Despite all the nutritional advantages associated with milk consumption, several issues like lactose intolerance, and high lipid content, etc., negatively affects the perception of cow milk consumption, and has grown into general health concerns. Issues with cow milk consumption drove for a healthier alternative and this led to plant-based milk alternatives (PBMA). Several studies have linked consumption of these PBMAs with other negative effects such as: allergy, poor nutrient profile and the presence of other foreign chemicals. This study’s main objective is to investigate the chemical profile of milk samples to detect the presence of toxic chemicals such as heavy metals and pesticides. As well as detect the concentration of essential elements present in milk samples. This study uses instrumentation analysis such as an inductively coupled plasma mass spectrometry (ICPMS) device to analyze the presence of heavy metals as well as essential elements in milk samples. For organic contaminants which include pesticides, the gas chromatography (GC) with electron capture detector (ECD) is used. Results obtained for heavy metals showed trace concentration of Pb, Cd and Cr in the majority of the PBMA samples, specifically Hemp milk (1.0 µg/l for Pb; 1.2 µg/l for Cr) and Soy milk (0.4 µg/l for Cd), while heavy metal concentration for cow milk was below detection limit. Organochlorine pesticide (OCPs) residue limit was present in all milk samples. The concentrations for the OCPs banned by the Stockholm Convention was higher than the residue limits set by EPA and FAO-WHO. This is of concern as most banned OCPs are classified as carcinogens, even at trace concentrations. HCB, Mirex, toxaphene, and Chlordane had residue concentrations above 200 µg/kg. Overall, cow milk had no significant difference in pesticide residue limits compared to PBMAs like almond, coconut, soy, and oat. Almond, coconut and soy milk were more fortified in essential elements than cow milk. However, heavy metal concentration in cow milk was BDL compared to that of most PBMAs.



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