Roy Greenhalgh

The sorptive capacity of an aquatic macrophyte for the pesticide aminocarb.

Ceratophyllum demersum exposed to a constant 1 microgram/ml aminocarb exhibited a large capacity for the sorption of the pesticide, up to 400 micrograms/g fresh weight in the dark and 1000 micrograms/g fresh weight in the light. Smaller, actively growing sprigs sorbed 5 times more pesticide per gm fresh weight than larger, older sprigs, although total uptake per plant was greater in the larger plants. Membrane conformation and integrity appear to be important factors in determining the capacity of this aquatic plant for pesticide sorption.

Interaction between co-solvents and algae in the residue dynamics of fenitrothion.

Fresh and estuarine water algae maintained in laboratory microcosms simulating river-lake/estuary-bay systems were exposed to 14C-fenitrothion formulated with Atlox and tank mixed with Aerotex or Dowanol (11.5:1.5:1.5 w/v/v). Generally, the tank mix co-solvents determined the amount of uptake and the array of derivatives formed by the algae. Typically, exposed to an Aerotex mix the ratio of ethyl acetate extractable (NP) fraction: ethyl acetate unextractable (P) fraction was as 3.5:1.0, exposed to a Dowanol mix the ratio was as 1.5:1.0. Within any comparable time period, fresh water algae turned over more of the 14C-ring of fenitrothion than the estuarine genera. Turn-over was enhanced when Aerotex was the tank mix co-solvent.

Fate of Fenitrothion in Forest Trees VI. Some Factors Affecting Rate of Dissipation from Balsam Fir and White Spruce

Publisher Summary This chapter presents some of the factors affecting the rate of dissipation from balsam fir and white spruce. A study was undertaken to determine specifically the mode of penetration, translocation, and the fate of fenitrothion applied to young seedlings of white spruce (Picea glauca) and balsam fir (Abies balsamea) under greenhouse conditions. Twelve healthy specimens of each of the two species were selected and set up in an area enclosed by plastic sheeting. Environmental conditions were adjusted to 22°C, 50% relative humidity, and a 12-hour photoperiod with fluorescent daylight tubes supplying an illumination of about 200 lux. A 10% aqueous emulsion of fenitrothion is emitted during aerial spraying at the average rate of 4 oz/acre. For the painting technique, four branches per tree were selected and 0.5 ml of emulsion was carefully applied with the aid of a small 1/8 in. brush in an attempt to obtain uniform coverage. The result shows that fenitrothion levels decreased rapidly during the first seven days following the treatment. The fenitrothion content of the tissue extracts however decreased less rapidly than in the corresponding surface washes.