Organic or not, your garden soil's own type decides metal levels
George NP, Ray JG
Soil Health
If you grow vegetables in raised beds or backyard plots, this shows that switching to organic compost won't guarantee clean soil, since your native soil type and the amendments you bring in both add metals like zinc and lead.
Researchers tested soil in organic and chemically fertilized vegetable fields across South India. The kind of soil a field sits on mattered most for metal levels, and farming style came second. Chemical fertilizer pushed up nickel, cobalt and manganese, while organic fields showed zinc and lead that likely came from contaminated compost or manure.
Key Findings
Soil type (soil order and soil series) was the primary factor controlling heavy metal distribution across fields, with manure and other human activity as a secondary source.
Chemical-fertilised fields generally had higher trace metals, especially nickel, cobalt and manganese, and a higher overall pollution load than organic fields.
Organic fields were not contamination-free: elevated zinc and lead pointed to contaminated organic amendments, and Monte Carlo risk modelling showed children faced non-carcinogenic and carcinogenic risks from chromium and nickel.
chevron_right Technical Summary
A study of vegetable fields in South India found that soil type shapes heavy metal levels more than farming method does. Chemical fertilizer raised nickel, cobalt and manganese, but organic fields weren't clean either, and children faced health risks from chromium and nickel.
Abstract Preview
Original paper
Heavy metal accumulation in vegetable production soils under organic and chemical-fertilised practices: influence of soil and other environmental factors.
Heavy metal contamination in crop fields is considered critical to food safety and human health. Therefore, we aimed to generate empirical evidence for the influence of soil and other environmental...
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