Nitrate, arsenic, cadmium, and lead concentrations in leafy vegetables: expected average values for productive regions of Chile

ABSTRACT

High arsenic (As), cadmium (Cd), lead (Pb), and nitrate (NO₃⁻) concentrations in soil pose a risk for the human population and compromise food safety. The goal of this study was to obtain preliminary approximations for the expected mean values of As, Cd, Pb, and N-NO₃ in three leafy vegetables (lettuce, spinach, and chard) grown in the central farming regions of Chile. Representative samples (n = 148) of these crops were collected from the Coquimbo, Valparaíso, and Metropolitana Regions. Water extraction and an ion-selective electrode were used to determine NO₃⁻ contents, while total As, Cd, and Pb contents were determined by atomic absorption spectroscopy. The recorded values were 23.8%, 59.2%, and 97.9% below detection limits for As, Cd, and Pb, respectively. Furthermore, As and Cd intake by leafy vegetables reached 0.26 and 2.30% of the daily intake levels estimated by Chilean authorities. The daily NO₃⁻ intake by leafy vegetables was 0.44 mg per kg of bodyweight per day (kgbw⁻¹day⁻¹), or 12% of the WHO-recommended intake. No analyses were performed for Pb due to highly left-censored data. While the recorded NO₃⁻, As, and Cd concentrations in lettuce, spinach, and chard do not apparently pose a health risk, further detailed studies are suggested.

KEYWORDS:

• Vegetable crops
• heavy metals
• nitrate
• contaminated soils

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Ministerio de Agricultura (CHL) [502061-70];