Maintaining the cultivation of vegetables with low Pb accumulation while remediating the soil of an allotment garden (Nantes, France) by phytoextraction.

Lead (Pb) is commonly found in urban soils and can transfer to vegetables. This entails a health risk for consumers of garden crops. The increasing demand of gardening on urban soil linked to the population increase and concentration in urban areas induces an increase in the risk, as people could be forced to cultivate contaminated soils.

Drivers to improve metal(loid) phytoextraction with a focus on microbial degradation of dissolved organic matter in soils.

Bioaugmentation of soils can increase the mobilization of metal(loid)s from the soil-bearing phases. However, once desorbed, these metal(loid)s are mostly complexed to the dissolved organic matter (DOM) in the soil solution, which can restrict their availability to plants (roots mainly taking up the free forms) and then the phytoextraction performances. Firstly the main drivers influencing phytoextraction are reminded, then the review focuses on the DOM role.

Advantages and limits to copper phytoextraction in vineyards.

Copper (Cu) contamination of soils may alter the functioning and sustainability of vineyard ecosystems. Cultivating Cu-extracting plants in vineyard inter-rows, or phytoextraction, is one possible way currently under consideration in agroecology to reduce Cu contamination of vineyard topsoils. This option is rarely used, mainly because Cu phytoextraction yields are too low to significantly reduce contamination due to the relatively "low" phytoavailability of Cu in the soil (compared to other trace metals) and its preferential accumulation in the roots of most extracting plants.

Bioaugmentation coupled with phytoextraction for the treatment of Cd and Sr, and reuse opportunities for phosphogypsum rare earth elements.

The environmental and health impacts caused by phosphogypsum (PG) make it necessary to carefully manage these wastes. Bioaugmentation of a PG-compost mix with Bacillus cereus was associated with Trifolium pratense or Helianthus annuus for the phytoextraction of metal trace elements (MTE). In hydroponics, MTE concentrations in sunflower shoots are higher than in clover; however, as opposed to clover, it regulates their accumulation.

Isolation and screening of indigenous bacteria from phosphogypsum-contaminated soils for their potential in promoting plant growth and trace elements mobilization.

Bacteria isolated from soils in the vicinity of phosphogypsum (PG) stockpiles were studied for their potential use in bioaugmentation-assisted phytoextraction. Quick, miniaturized biochemical tests were performed in the presence of metal trace elements (MTE), including rare earth elements (Cd, Sr, Ce, La, Nd and Y), corresponding to their bioavailable concentrations in PG. The intention herein was to assess the capacity of bacteria to: i) grow in PG; ii) produce indole acetic acid and ACC deaminase to promote plant growth and reduce stress; and iii) produce siderophores, including pyoverdine, to mobilize MTE.