Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are emerging pollutants in agricultural product, and the residual patterns and the uptake potentials were only studied on several crops, not on rice. The residue level and bioconcentration factor (BCF) of PFOA and PFOS were investigated on the low (1 mg kg-1) and the high contaminated soil (5 mg kg-1) groups. The residue levels in brown rice in the low group and in the high group were 0.002-0.004 and 0.008-0.030 mg kg-1 of the each perfluorinated compounds (PFCs), and in the rice husk were 0.035-0.074 mg kg-1 and 0.125-0.376 mg kg-1 of the each PFCs, respectively. Furthermore, the residues in rice straw were the highest level in the all rice parts both in the groups. The PFOA and PFOS were reached to 3.723 mg kg-1 and 7.641 mg kg-1 , respectively, and the BCF (1.474 and 4.700) as well.

No abstract

The use of the pesticide chlorfenapyr has been increasing over time, with a consequent wider application to crops. However, there is limited information available on the amount and safety of the residues it leaves on crops. The amount of chlorfenapyr residues in sweet persimmon (Diospyros kaki L.) at both the pre- and postharvest stages were investigated in this study by calculating its biological half-life. The half-life at the preharvest stage was 8.8 days, shorter than that found during the storage periods at 4 and 20°C, when the half-lives were 11.0 and 23.9 days, respectively. In addition, peeling and washing after harvesting reduced residue content. The majority of the chlorfenapyr residues in sweet persimmon were found in the peel of the fruit, with the pulp containing less than 25% of the total. Thus, peeling effectively removed chlorfenapyr residues and diminished the residues below the limit of quantification in the pulp. In addition, washing with 1.0% alcohol and 0.2% Tween 20 solutions effectively removed 47.8 and 55.6% of the residues, respectively. Furthermore, a 1.0% alcohol solution showed high reduction efficiency for other hydrophobic pesticides, such as dimethomorph and fluquinconazole, up to 78.0%. Chlorfenapyr residues in sweet persimmon can be effectively reduced via storage or peeling and washing practices or a combination of them.

No abstract

Endosulfan was widely used as an insecticide in the agricultural sector before its environmental persistence was fully understood. Although its fate and transport in the environment have been studied, the effects of historic endosulfan residues in soil and its bioaccumulation in crops are not well understood. This knowledge gap was addressed by investigating the dissipation and bioaccumulation of endosulfan in ginseng as a perennial crop in fresh and aged endosulfancontaminated fields. In addition, the effect of granular biochar (GBC) treatment on the bioaccumulation factor (BAF) of endosulfan residue in ginseng was assessed. The 50% dissipation time (DT50) of the total endosulfan was over 770 days in both the fresh and aged soils under mulching conditions.; This was at least 2-fold greater than the reported (6->200 days) in arable soil. Among the endosulfan congeners, the main contributor to the soil residue was endosulfan sulfate, as observed from 150 days after treatment. The BAF for the 2-year-old ginseng was similar in the fresh (1.682-2.055) and aged (1.372-2.570) soils, whereas the BAF for the 3-year-old ginseng in the aged soil (1.087-1.137) was lower than that in the fresh soil (1.771-2.387). The treatment with 0.3 wt% GBC extended the DT50 of endosulfan in soil; however, this could successfully suppress endosulfan uptake, and reduced the BAFs by 66.5-67.7% in the freshly contaminated soil and 32.3-41.4% in the aged soil. Thus, this adsorbent treatment could be an effective, financially viable and sustainable option to protect human health by reducing plant uptake of endosulfan from contaminated soils.