Nickel in agri-food systems: a review

Area of Science:

• Environmental Science
• Agronomy
• Toxicology
• Food Science

Background:

• Nickel (Ni) is ubiquitous in agri-food systems from natural and industrial sources.
• Plants are the primary interface for Ni transfer into the food chain and human diet.
• Ni is an essential micronutrient but becomes phytotoxic at higher concentrations.

Purpose of the Study:

• To analyze Ni transfer pathways from environmental sources to plants, food, and humans.
• To integrate physiological, agronomic, toxicological, and regulatory aspects of Ni.
• To identify key factors governing Ni transfer in the soil-plant-food continuum.

Main Methods:

• Literature review integrating environmental, agronomic, physiological, toxicological, and regulatory data.
• Analysis of Ni transfer pathways, particularly in soilless cultivation systems.
• Mass balance analysis of Ni inputs in nutrient solutions.

Main Results:

• Mineral fertilizers contribute over 80% of total Ni input in soilless nutrient solutions.
• Pesticides and growing media play a secondary role in Ni accumulation.
• Agronomic inputs are central to determining Ni accumulation in crops.

Conclusions:

• Agronomic practices, especially mineral fertilizer use, are critical for controlling Ni levels in crops.
• Understanding Ni transfer is vital for agricultural management, food security, and 'Ni-free' production.
• Standardized approaches are needed for 'Ni-free' claims and systems.