Regional and Seasonal Dynamics of Heavy Metal Accumulation in Saudi Dromedary Camel Serum and Milk as Bioindicators of Environmental Quality

This study evaluated regional and seasonal variations in cobalt (Co), cadmium (Cd), and lead (Pb) concentrations in the serum and milk of she-camels and their calves across five regions of Saudi Arabia to evaluate their potential as bioindicators of environmental contamination. A total of 450 biological and environmental samples (serum, milk, soil, water, and feed) were analyzed using inductively coupled plasma optical emission spectrometry (ICP–OES). Regional, seasonal, and physiological effects were assessed by analysis of variance and Pearson correlation. Serum Co varied significantly (p < 0.05) by region and season, with the highest values in the Eastern region during spring. She-camel cadmium showed significant regional differences, particularly higher concentrations in the Southern region, while Pb displayed pronounced seasonal variation, peaking in spring serum and milk of she-camel. In she-camel milk, Co, Cd, and Pb were significantly influenced by region and season interactions (p < 0.05). Correlation analysis revealed strong positive associations between Cd and Pb (r = 0.85, p < 0.001) and between Co and Pb (r = 0.70, p < 0.01), indicating shared exposure pathways. In conclusions, although all metal concentrations remained below FAO/WHO permissible limits, the observed variability highlights the camel’s value as a bioindicator of environmental contamination. Continued monitoring is recommended to safeguard food safety and support Saudi Vision 2030 sustainability goals.