Uptake and Phytotransformation of o,p‘-DDT and p,p‘-DDT by Axenically Cultivated Aquatic Plants

Abstract

The uptake and phytotransformation of o,p'-DDT and p,p'-DDT were investigated in vitro using three axenically cultivated aquatic plants: parrot feather (Myriophyllum aquaticum), duckweed (Spirodela oligorrhiza), and elodea (Elodea canadensis). The decay profile of DDT from the aqueous culture medium followed first-order kinetics for all three plants. During the 6-day incubation period, almost all of the DDT was removed from the medium, and most of it accumulated in or was transformed by these plants. Duckweed demonstrated the greatest potential to transform both DDT isomers; 50-66% was degraded or bound in a nonextractable manner with the plant material after the 6-day incubation. Therefore, duckweed also incorporated less extractable DDT (32-49%) after 6 days than did the other plants. The capacity for phytotransformation/binding by elodea is between that of duckweed and parrot feather; approximately 31-48% of the spiked DDT was degraded or bound to the elodea plant material. o,p'-DDD and p,p'-DDD are the major metabolites in these plants; small amounts of p,p'-DDE were also found in duckweed (7.9%) and elodea (4.6%) after 6 days. Apparently, reduction of the aliphatic chlorine atoms of DDT is the major pathway for this transformation. This study, which provides new information on plant biochemistry as related to pollutant accumulation and phytotransformation, should advance the development of phytoremediation processes.

Mitigating with macrophytes: Submersed plants reduce the toxicity of pesticide‐contaminated water to zooplankton

“…For example, Elodea could be sorbing malathion onto its surfaces and thus reducing water toxicity to Daphnia. However, although many highly-lipophilic insecticides with Log K OW values greater than 6.0 (e.g., pyrethroid and organochlorine insecticides) will bind rapidly to submersed macrophytes [20,21], malathion is relatively hydrophilic (Log K OW ¼ 2.3), and it remains unclear how much macrophytes will sorb this insecticide. In the aforementioned experiment by Gao et al [23], the authors found no evidence that malathion was taken up by macrophytes during the first 48 h following exposure.…”

“…For example, macrophytes can sorb insecticides, potentially reducing the duration and intensity of exposure experienced by aquatic taxa [18,19]. In fact, submersed macrophytes can sorb up to 90% of insecticides from the water column within 24 h, but such high sorption rates only occur for highly lipophilic compounds (i.e., Log octanolwater partition coefficient, K OW > 6.0), such as organochlorine (e.g., dichlorodiphenyltrichloroethane [DDT]) and pyrethroid (e.g., lambda-cyhalothrin) insecticides [20,21]. For less lipophilic compounds-such as the commonly applied organophosphate insecticides chlorpyrifos (Log K OW ¼ 4.81) and malathion (Log K OW ¼ 2.3)-the amount of insecticides removed from the water column by macrophytes typically ranges from 0 to 50% in a 24-h period [18,22,23].…”

The behavior of isopyrazam in aquatic ecosystems: Implementation of a tiered investigation

“…After 0, 3,8,11,15,21, and 29 d of continuous irradiation, duplicate vessels (one from each radiolabel position) were removed for analysis. The radioactivity in each aqueous sample and its corresponding NaOH trap was quantified by LSC to determine the mass balance, and each aqueous sample was analyzed by HPLC to determine the levels of isopyrazam and significant photodegradation products present at each timepoint.…”

Liquid phase hydrodechlorination of dieldrin and DDT over Pd/C and Raney-Ni

“…There are a number of studies reporting on phytoremediation [16] and bioremediation [17] of DDT. Reductive catalytic methods have been also reported, e.g.…”