Pesticide decontamination from fabric by laundering and simulated weathering1

Abstract

This laboratory study investigated the effectiveness of selected detergents and the phenomenon of simulated environmental conditions (weathering) on the removal of a commercial‐grade mixture of parathion and methyl parathion from a three‐layer laminated fabric. The weathering treatment consisted of exposure and non‐exposure to simulated environmental conditions of heat, light, and humidity. Contaminated fabric samples were laundered in one of three detergents containing an anionic, a nonionic, and a combined anionic and nonionic surfactant. The test fabric, a three‐layer fabric containing an impermeable microporous film laminated between two layers of nylon, was pipette‐contaminated with 400 microliters of field strength pesticide solution and allowed to dry. Half of the contaminated samples were weathered in an Atlas Fade‐Ometer. All of the contaminated samples were subsequently laundered in a Launder‐Ometer. Percent of pesticide residue was determined by gas chromatography. Weathering did significantly reduce both parathion and methyl parathion residues remaining in the test fabric. No statistically significant difference was found among the three detergents. High amounts of both parathion and methyl parathion remained in the test fabric after weathering and laundry treatments. Before the test fabric can be recommended for use in protective garments further research is needed to develop more effective decontamination procedures.     

Degradation of disulfoton,oxydemeton‐methyl,methamidophos and demeton in asparagus plant

Abstract

Disulfoton and methamidophos (both at 1.12 kg a.i./ha), oxydemeton‐methyl and demeton, (both at 0.56 kg a.i./ha) were applied as post‐harvest foliar sprays to control the European asparagus aphid, Brachycolus asparagi. Oxidation of disulfoton, oxydemeton‐methyl and demeton to their corresponding sulfoxides and sulfones occurred in asparagus foliage 2 to 5 days after application. The total residues of these three compounds, including their toxic oxidative metabolites declined to less than 0.5 ppm about 47 days after the spray application whereas methamidophos persisted longer; 0.84 ppm of its residue was found even after 85 days. No residue was found above the limit of detection of 0.002 ppm in any asparagus spears which were produced in the following spring; the four compounds were sprayed on the asparagus plants during the previous season at realistic rates for aphid control.     

Metabolism of 14C‐carbaryl and 14C‐1‐naphthol in moist and flooded soils

Abstract

The metabolism of ¹⁴C‐carbaryl and ¹⁴C‐1‐naphthol in moist and flooded soils was studied in a continuous flow‐through system over a period of 28 days permitting ¹⁴C‐mass balance. The percent distribution of radiocarbon in organic volatiles, carbon dioxide, extractable and non‐extractable (bound) fractions of soils were determined. Organic volatiles could not be detected in both carbaryl and 1‐naphthol treated soils. More of ¹⁴CO₂ (25.6%) was evolved from moist than flooded soil (15.1%) treated with carbaryl. However, the mineralization of ¹⁴C‐1‐naphthol was negligible. The extractable radiocarbon was more in flooded soil (28.9%) than moist soil (5.5%) from carbaryl treatment. Less than one percent was present as parent compound, whereas carbaryl was mainly metabolized to 5‐hydroxy carbaryl in moist soil and to 4‐ and 5‐hydroxy carbaryl in flooded soil. The extractable radiocarbon amounted to 18.2 and 24.3% in moist and flooded soils respectively and the parent compound was less than one percent with 1‐naphthol treatment. Most of the radiocarbon was found as soil bound residues; the formation being more with 1‐naphthol than carbaryl. Humin fraction of the soil organic matter contributed most to soil bound residues of both carbaryl and 1‐naphthol.     

Residues of 2,4‐D in air samples from Saskatchewan: 1966–1975

Abstract

Residues of 2,4‐D (2,4‐dichlorophenoxyacetic acid) in air samples from several sampling sites in central and southern Saskatchewan during the spraying seasons in the 1966–68 and 1970–75 periods were determined by gas‐liquid Chromatographic techniques. Initially, individual esters of 2,4‐D were characterized by retention times and confirmed further by co‐injection and dual column procedures. Since 1973, however, only total 2,4‐D acid levels in air samples have been determined after esterification to the methyl ester and confirmed by gc/ms techniques whenever possible.

Up to 50% of the daily samples collected during the spraying season at any of the locations and during any given year contained 2,4‐D, with butyl esters being found most frequently. The daily 24‐hr mean atmospheric concentrations of 2,4‐D ranged from 0.01 to 1.22 μg/m³, 0.01 to 13.50 μg/m³, and 0.05 to 0.59 μg/m for the iso‐propyl, mixed butyl and iso‐octyl esters, respectively. Even when the samples were analysed for the total 2,4‐D content, i.e. from 1973 onwards, the maximum level of the total acid reached only 23.14 μg/m. In any given year and at any of the sampling sites, about 30% of the samples contained less than 0.01 μg/m³ of 2,4‐D. In another 40% of the samples, the levels of 2,4‐D ranged from 0.01 to 0.099 yg/m. Only about 30% of the samples contained 2,4‐D concentrations higher than 0.1 μg/m³, with only 10% or less exceeding 1 μg/m³.

None of the samples, obtained with the high volume particu‐late sampler, showed any detectable levels of 2,4‐D, indicating little or no transport of 2,4‐D adsorbed on dust particles or as crystals of amine salts.     

Metabolism of gamma‐hexachlorocyclohexah (HCH) in vivo. Metabolism of orally administered gamma‐2,3,4,5,6‐pentachlorocyclohexen (PCCH)

Abstract

Mexacarbate (4‐dimethylamino‐3,5‐xylyl N‐methylcarbamate) insecticide has potential for use in spruce budworm (Choristoneura fumiferana Clem.) control operations in Canada. Its persistence and fate in balsam fir (Abies balsamea (L.) Mill.), litter and soil samples were studied by spraying aerially oil‐based and water‐based formulations, each at 70 g A.I./ha over a coniferous forest near Bathurst, New Brunswick. The oil‐based formulation gave the maximum concentration of the chemical in the substrates studied. In fir needles, the highest concentrations observed were 0.51 ppm and 0.19 ppm (fresh weight) for the oil‐based and emulsion formulations respectively, 1 h after application. The residue levels decreased very rapidly with a half‐life of approximately 5 h. Three and eight days after the spray application of the emulsion and oil formulations respectively, the concentrations of mexacarbate in foliage decreased to trace levels ( 0.008 ppm). Only very low levels of residue were detected in litter and soil. The peak concentrations for the two formulations ranged from 0.02 to 0.11 ppm (fresh weight) in litter and from 0.01 to 0.06 ppm (fresh weight) in soil. The residue levels in both litter and soil decreased to below the detection limit (0.005 ppm) within 1 d. The ground deposit levels found on glass plates and the droplet density and size spectra measured on Kromekote® cards reflected the variations in concentrations found in fir needles, litter and soil samples and correlated with the observed maximum concentrations in them. Under the stipulated use pattern, mexacarbate concentrations found in the terrestrial components studied were low and are not likely to have any undue adverse effects on non‐target species.     

Attractancy evaluation of ceralure‐B1 isomer via field captures of mediterranean fruit flies (Diptera: Tephritidae)

Abstract

Commercially prepared ceralure‐B1, an attractant for the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), was evaluated in trapping tests by comparison with commercial ceralure and trimedlure. Jackson traps were used for medfly captures. The residual ceralure‐B1, ceralure, and trimedlure contents of aged dispensers were determined. The results of this study show that male medfly captures from traps with ceralure‐B1 were as high or higher than male medfly captures from traps with twice the quantity of ceralure or trimedlure. The use of regioselectively synthesized ceralure‐B1, enriched in B1, as a source of a more potent attractant than commercial ceralure and as a more persistent male medfly attractant than trimedlure is reported.     

Hydrotalcites and organo‐hydrotalcites as sorbents for removing pesticides from water

Abstract

This paper reports on the adsorption of different organic pesticides by hydrotalcite, hydrotalcite heated to 500°C and organo‐hydrotalcite in aqueous medium by employing adsorption isotherms, and using X‐ray diffraction and infrared spectroscopy techniques. The results suggest that the adsorption capacity of the different materials depends on their nature as well as on the structure, polarity and hydrophobic or anionic nature of the pesticides. The results also show that hydrotalcite, both natural and after calcination at 500°C, is not a good sorbent of hydrophobic pesticides. The data demonstrated that both types of hydrotalcite, however, are very good sorbents of glyphosphate. Furthermore, the organo‐hydrotalcites may be as good sorbents as organo‐montmorillonites for hydrophobic pesticides.     

Short‐Term Effects of Hydrogen Fluoride on Nicotiana tabacum L

Data on the short‐term effects of fumigation with hydrogen fluoride (HF) on the response behavior of the Nicotiana tabacum L. cv. St. Karabalar 6265 are being presented. Growth rate, fluoride accumulation in leaves and soils, and degradation in chlorophyll and nicotine contents of the plant species against the variations in two experimental factors, namely the exposure concentration and exposure time parameters, were investigated. Resulting data reveals that the variety selected for this study is not so tolerant to fluoride as generally reported in the literature, if only the individual effects of the pollutant is considered.     

Enhanced Desorption of Phenanthrene from Soils Using Hydroxypropyl‐β‐cyclodextrin: Experimental Results and Model Predictions

Objective of this study was to evaluate the effects of hydroxypropyl‐β‐cyclodextrin (HPCD) on the removal of phenanthrene from solid phase. Batch tests for the phenanthrene distribution between aqueous and solid phase were conducted in the presence of HPCD. Column tests and numerical simulations were conducted to evaluate the roles of HPCD cavities and interaction rates between water, HPCD, and solid phase in the enhanced removal of phenanthrene. Experimental results showed that HPCD was effective in removing sorbed phenanthrene from subsurface environment, primarily due to its negligible sorption to the solid phase and the partitioning of phenanthrene into HPCD cavities. From the numerical simulations, it was found that rate‐limited partitioning of phenanthrene into HPCD cavities was most influential factor in the enhanced elution of phenanthrene. Sorption and desorption rate of phenanthrene between aqueous and solid phase was very fast or near equilibrium state. Interaction rates of contaminant between water, HPCD, and solid phase could be affected by other factors such as soil types and organic matter contents. Results from this study implied that HPCD flushing could be effectively applied for the removal of hydrophobic organic pollutants existing in the soils as sorbed or NAPL state.     

1‐Aminobenzotriazole increases glutathione‐s‐transferase activity of maize

Abstract

Glutathione‐S‐transferase (GST) activity of maize (Zea mays L.) seedlings treated with 1‐aminobenzotriazole (ABT) derivatives and/or EPTC were measured using EPTC‐sulfoxide as substrate. Both safeners and ABT derivatives significantly elevated the GST activity in the concentrations needed for effective safening action. ABT is considered as an inhibitor of plant cytochrome P‐450 monooxygenases (P‐450) and, because of this, used to study herbicide mode of action. Our data indicate that ABT has multiple effects on plants influencing not only P‐450 but GST as well. Thus the role of ABT in herbicide metabolism needs reconsideration.