Evaluation of biological (feed, water), seasonal, and geological factors affecting the heavy metal content of raw milk

Abstract

In volcanic regions worldwide, soil and water can be contaminated with heavy metals. Aksaray province is also an important region in this respect. Because this city is located around Hasandağı, an extinct volcanic mountain. In addition, the city is also an important dairy center. In this regard, evaluating the milk produced in Aksaray in terms of heavy metal contamination and studying the effect of feed and water on this contamination is essential. For this purpose, feed, water, and milk samples from 7 milk producers determined in Aksaray province were collected in 3 different seasons within six months. The presence and levels of arsenic (As), aluminum (Al), nickel (Ni), cadmium (Cd), and lead (Pb) were determined by ICP-MS analysis of the 126 samples obtained. The study found varying levels of heavy metals in feed, water, and milk. It was also observed that milk contained considerably lower quantities of metals and metalloids than feed and water. In addition, it has been determined that the distance to Hasandağı does not affect the trace element levels in water, milk, and feed, but there is a significant relationship between seasonal changes and trace elements in the samples. According to the analysis results, the highest level is the feed’s aluminum level (298290.1 µg/kg). However, the aluminum level in milk remained well below this level (96.15 µg/kg). It was determined that the cadmium level in milk reached the highest level in spring (average 0.06 µg/kg), whereas lead levels reached the highest level in summer (average 2.14 µg/kg). On the other hand, the arsenic level showed a relatively small change according to the distance to the volcanic region. The average arsenic level in milk from regions near the volcanic area was measured as 1.01 µg/kg. In remote areas, this amount was measured as 0.94 µg/kg. Furthermore, the highest heavy metal level in the milk was 182.08 µg/kg for nickel during the summer months in the study.