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An outdoor lysimeter experiment was conducted to investigate the fate of 14C-labeled phenanthrene in the soil planted with wheat and rice in rotation. Results showed that applied 14C-activity in the soil decreased mainly through gaseous losses; 67.5% of it evaporated as 14CO2. After the rice harvest, the surface soil retained 21.7% of applied 14C-activity, of which 92.4% remained in nonextractable soil residues. The 14C-activities found in deeper layers of the soil column indicated vertical migration of phenanthrene or metabolites. Furthermore, the 14C-activities detected in five organs of mature wheat or rice decreased in the order: roots > leaves > shells>stems > grains. The vertical migration and its accumulation by grains suggest that PAHs in field have adverse effects on the security of groundwater and food., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Analyzing the effect of circular-agriculture (CA) measures could be helpful to promote its scientific development. Previous research has focused on technological measures and their effects on the agricultural sector. However, economic measures can also promote the development of CA, and due to their correlation with socio-economic sectors, CA measures can impose effects on non-agricultural sectors and on the whole socioeconomic system. In this research, a computable general equilibrium (CGE) model was established to comprehensively reveal the effects of CA measures. In this model, measure simulation and environmental blocks were extended. The production tax was adopted as the economic measure for adjusting the development of CA. Both environmental and socioeconomic effects have been explored. Hebei Province in China was adopted as the study case. Three kinds of production tax adjustment scenarios were considered: a promotion-measure scenario (decreasing the production tax for CA sectors), an inhibition-measure scenario (increasing the production tax for traditional-agriculture sectors), and a hybrid-measure scenario (implementing the promotion- and inhibition-measures simultaneously). The results showed that all three scenarios could promote the development of CA. The inhibition and hybrid measures had positive effects on GDP, and all the scenarios could decrease the intensities of CO2, COD and NH3–N emissions and water resource consumption. In addition, higher measure intensity could bring more significant effects. • Economic measures can promote the development of circular agriculture (CA). • CA economic measure can improve the cleanliness of economic development. • Higher measure intensity can bring more significant effects. [ABSTRACT FROM AUTHOR]