Contamination of irrigation water of tea plantations in Gilan province with some trace elements and risk assessment

Tea plants can absorb trace elements from irrigation water, which accumulate in their leaves, which are ultimately harvested for human consumption. Chronic exposure to elevated levels of trace elements has been associated with various adverse health effects. This study investigates the presence of trace elements in irrigation water of tea plantations in Gilan Province, focusing on assessing the associated health risks and environmental consequences. Water samples were collected from areas with high tea cultivation in Gilan Province in the spring of 2023. The samples were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The health risk associated with contamination of five trace elements in agricultural water, including beryllium (Be), lithium (Li), boron (B), strontium (Sr), and selenium (Se), was assessed.

The highest concentration of B was observed in Lahijan with an average of 21.05 mg/L. Be was below the detection limit in all cities. The highest concentration of Li was in Langrud with 0.56 mg/L, and other cities were mostly below the detection limit. Mean Se concentrations were 2.77 mg/L in Siahkal and 0.02 mg/L in Rudsar; other cities usually report levels below 0.01 mg/L. Sr also has the highest level in Siahkal, with 9.77 mg/L; other cities show levels of 0.09–1.72 mg/L. Health risk assessments based on hazard quotients and hazard indices were below thresholds of immediate concern.The results indicate significant variations in trace element concentrations in the sampled counties, reflecting the influence of local factors such as soil physicochemical properties, human activities, and environmental conditions.