Assessing the health risks of heavy metals and seasonal minerals fluctuations in Camellia sinensis cultivars during their growth seasons

Abstract

The risk assessment of heavy metals in tea is extremely imperative for the health of tea consumers. However, the effects of varietal variations and seasonal fluctuations on heavy metals and minerals in tea plants remain unclear. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to evaluate the contents of aluminum (Al), manganese (Mn), magnesium (Mg), boron (B), calcium (Ca), copper (Cu), cobalt (Co), iron (Fe), sodium (Na), zinc (Zn), arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), and antimony (Sb) in the two categories of young leaves (YL) and mature leaves (ML) of tea (Camellia sinensis) cultivars throughout the growing seasons. The results showed significant variations in the contents of the investigated nutrients both among the different cultivars and growing seasons as well. Furthermore, the average concentrations of Al, Mn, Mg, B, Ca, Cu, Co, Fe, Na, Zn, As, Cd, Cr, Ni, and Sb in YL ranged, from 671.58–2209.12, 1260.58–1902.21, 2290.56–2995.36, 91.18–164.68, 821.95–5708.20, 2.55–3.80, 3.96–25.22, 37.95–202.84, 81.79–205.05, 27.10–69.67, 0.028–0.053, 0.065–0.127, 2.40–3.73, 10.57–12.64, 0.11–0.14 mg kg−1, respectively. In ML, the concentrations were 2626.41–7834.60, 3980.82–6473.64, 3335.38–4537.48, 327.33–501.70, 9619.89–13153.68, 4.23–8.18, 17.23–34.20, 329.39–567.19, 145.36–248.69, 40.50–81.42, 0.089–0.169, 0.23–0.27, 5.24–7.89, 18.51–23.97, 0.15–0.19 mg kg−1, respectively. The contents of all analyzed nutrients were found to be higher in ML than in YL. Target hazard quotients (THQ) of As, Cd, Cr, Ni, and Sb, as well as the hazard index (HI), were all less than one, suggesting no risk to human health via tea consumption. This research might provide the groundwork for essential minerals recommendations, as well as a better understanding and management of heavy metal risks in tea.