An inventory of trace element inputs to agricultural soils in China

It is important to understand the status and extent of soil contamination with trace elements to make sustainable management strategies for agricultural soils. The inputs of trace elements to agricultural soils via atmospheric deposition, livestock manures, fertilizers and agrochemicals, sewage irrigation and sewage sludge in China were analyzed and an annual inventory of trace element inputs was developed. The results showed that atmospheric deposition was responsible for 43–85% of the total As, Cr, Hg, Ni and Pb inputs, while livestock manures accounted for approximately 55%, 69% and 51% of the total Cd, Cu and Zn inputs, respectively. Among the elements concerned, Cd was a top priority in agricultural soils in China, with an average input rate of 0.004 mg/kg/yr in the plough layer (0–20 cm). Due to the spatial and temporal heterogeneity of the sources, the inventory as well as the environmental risks of trace elements in soils varies on a regional scale. For example, sewage sludge and fertilizers (mainly organic and phosphate-based inorganic fertilizers) can also be the predominant sources of trace elements where these materials were excessively applied. This work provides baseline information to develop policies to control and reduce toxic element inputs to and accumulation in agricultural soils.     

Investigation of trace element atmospheric pollution by nuclear analytical techniques at a global scale: harmonized approaches supported by the IAEA

In the framework of the IAEA programmes, Member States involved in air pollution studies using nuclear analytical techniques have harmonized their methodologies. Participants characterising chemical composition of size fractionated airborne particulate matter based their methodology on a common type of air sampler, centralised data collection and evaluation, and the same kind of data processing. Institutions involved in biomonitoring air pollution identified appropriate organisms to be applied at a regional scale, and harmonized procedures for sample preparation and analysis, as well as data processing and presentation. Both metrology approaches have been validated and disseminated in many Member States.     

Traditional agricultural practices enable sustainable remediation of highly polluted soils in Southern Spain for cultivation of food crops

This study relates elemental content of a range of edible crops grown in soils severely polluted by metals and metalloids as affected by traditional smallholder management practices. Five agricultural plots close to a sulfidic waste dump were monitored. Soil analysis demonstrated elevated concentrations of As, Cu, Pb and Zn that were greatly in excess of maximum statutory limits for agricultural soils in the studied region. The main vegetables (lettuce, chard, onion, potatoes) and lemon, together with their associated soils, were measured for elemental content. Extractable soil element concentrations were very low. There were differences in elemental accumulation between crops, but none exceeded statutory concentrations in edible parts. Soil-plant transfer factors were uniformly low for all elements and crops. It is concluded that traditional soil management practices (annual liming and application of animal manures) have created conditions for sustainable long-term safety use, with potential for multiple end-use, of these highly polluted soils.