Intrinsic bioavailability of 14C-heptachlor to several plant species

Abstract

14C-heptachlor for 72 hr. The levels and nature of 14 C-residues in roots and shoots of treated plants were determined to estimate the values of the root concentration factor (RCF) and the transpiration stream concentration factor (TSCF). RCF and TSCF values ranged from 126 (corn) to 4086 (lettuce) and 0.052 (Chinese cabbage) to 0.494 (zucchini), respectively. In pumpkin and zucchini, unmetabolized heptachlor itself was translocated from the root to the shoot via a transpiration stream and no further extensive metabolism was observed. cis-Heptachlor epoxide was the predominant metabolite in the shoots of tomato, cabbage, Chinese cabbage and lettuce. Less metabolism of cis-heptachlor epoxide was suggested in the shoots of these plants.

Degradation of the Persistent Organic Pollutant [14C]Heptachlor in Japanese Field Soils

“…Radiolabeled heptachlor ( [4,5,6,7,[8][9][10][11][12][13][14] C]heptachlor, specific radioactivity 11.5 MBq/mg, radiochemical purity 97.9%), prepared by custom synthesis, was purchased from Moravek Biochemicals (Brea, CA). 9) Non-radiolabeled heptachlor and 1-hydroxychlordene were purchased from Wako Pure Chemical Industries (Osaka, Japan), and cis-and trans-heptachlor epoxides were from Hayashi Pure Chemical Industries (Osaka, Japan).…”

Root uptake and translocation of ¹⁴C-heptachlor and its degradation products in soil by zucchini and tomato seedlings

“…[1][2][3] However, there is little information regarding the uptake of heptachlor by crops after soil treatment. We previously reported the root uptake of 14 C-heptachlor to various plants under hydroponic cultivation 4) and indicated that the 14 C-concentrations in shoots of wheat, cucumber, tomato, and zucchini were higher than those of other plant seedlings after exposed via the hydroponic solution. In addition, we reported the degradation of 14 C-heptachlor in Japanese soils 5) and found that the concentration ratio of heptachlor and its degradation products remained constant in the soil three to four months after the application of 14 C-heptachlor.…”

“…The pre-cultivation method of treating the test plant was described in the previous report. 4) The numbers of pre-cultivation days from sowing of the test plants used are 19 days (tomato) and 12 days (zucchini).…”

“…The HPLC analysis conditions were the same as those in our previous paper. 4) The radioactivity in a liquid sample was measured individually by liquid scintillation counting (LSC). Duplicate aliquots of each liquid sample were dissolved in Pico-Fluor ™ Plus scintillation cocktail (PerkinElmer, Wellesley, MA, USA) prior to LSC analysis.…”

“…PESs from plant samples were analyzed using an automatic sample oxidizer (Model 307, PerkinElmer) described in our previous paper. 4) The ratio of the extractable concentration of the chemical from the soil is described by the AW ratio. The AW ratio=(concentration in acetone extracted from the soil)/(concentration in water extracted from the soil).…”