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.
Since middle 1970's, many studies have been carried out on disaggregate travel demand models. However, applications of those models to transportation planning are limited: they are usually applied to the local and short-term transportation planning, or they are used in the frame of traditional 4-step travel demand forecasting models by replacing some of those steps. That is, there have been few attempts to develop and apply disaggregate travel demand model systems for predicting travel demand in metropolitan areas. This paper develops a disaggregate model system for the travel demand of
Since middle 1970's many studies have been carried out on disaggregate travel demand models. However, applications of those models to transportation plannings
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