Low-cost agricultural measures to reduce heavy metal transfer into the food chain - a review

Abstract

Heavy metal contamination affects large areas of Europe and worldwide. Hot spots of pollution are located close to industrial sites, around large cities and in the vicinity of mining and smelting plants. Agriculture in these areas faces major problems due to heavy metal transfer into crops and subsequently into the food chain. This paper gives an overview on simple but effective countermeasures to reduce the transfer of heavy metals to edible parts of crops. Since crop species and varieties largely differ in their heavy metal uptake, choosing plants with low transfer factors (e.g., legumes, cereals) may reduce metal concentration in edible parts significantly. Cultivating crops with higher heavy metal uptake capacity, e.g., spinach or lettuce should be avoided. The application of soil amendments is another very effective measure to reduce the concentration of heavy metals in crops. Both organic (e.g., farmyard manure) and inorganic amendments (e.g., lime, zeolites, and iron oxides) were found to decrease the metal accumulation. Further effective methods to reduce metal transfer into food chain include crop rotation and cultivation of industrial or bio-energy crops. It is concluded that the methods presented here comprise several tools, which are easy to apply, and are effective to allow safe agriculture on moderately contaminated soils.

Tomato Fruit Quality from Organic and Conventional Production

“…As a result, one might expect that organic vegetables contain lower amounts of toxic heavy metals. The effect of manure on heavy metal availability is due to the introduction of organic matter to the soil, which may retain Cd in the soil and prevent it from both leaching and from crop uptake [75].…”

The Cd mobility in incubated sewage sludge after ameliorative materials additions

“…The ameliorative compounds such as lime and limestone are used for increase of pH value and consequently they can decrease heavy metals mobility and reduce the uptake of these elements by plants (Sloan andBasta 1995, Tlustoš et al 1995). The addition of material with high sorption capacity (bentonite and zeolite) can reduce the availability of heavy metals as well (Chlopecka and Adriano 1997, Adriano 2001, Puschenreiter et al 2005.…”

Heavy Metals and Nitrate Content in Tomato Fruit Grown in Organic and Conventional Production Systems

“…For this reason the type of farming techniques can affect the heavy metal content of tomatoes. Both organic (e.g., farmyard manure) and inorganic amendments (e.g., lime, zeolites, and iron oxides) were found to decrease metal accumulation [14].…”