A preliminary examination of the translocation of microencapsulated cyfluthrin following applications to the perimeter of residential dwellings

Abstract

Methods have been developed to monitor the translocation of microencapsulated cyfluthrin following perimeter applications to residential dwellings. A pilot study was implemented to determine both the potential for application spray to drift away from dwellings and the intrusion of residues into homes following perimeter treatments. Residential monitoring included measuring spray drift using cellulose filter paper and the collection of soil samples from within the spray zone. In addition, interior air was monitored using fiberglass filter paper as a sorbent medium and cotton ball swabs were used to collect surface wipes.

Fortification of matrixes resulted in recoveries of >90%. Spray drift was highest at the point of application and declined to low but measurable levels 9.1m from the foundations of dwellings. Soil residues declined to low, but measurable levels by 45 days post‐application. No cyfluthrin was measured from indoor air; however, some interior surfaces had detectable levels of cyfluthrin until three days post‐application.

Findings indicate that spray drift resulting from perimeter applications might contaminate non‐target surfaces outside the spray zone. Soil borne residues may serve as persistent sources for human exposure and potentially intrude into dwellings through the activities of occupants and pets. Residues do not appreciably translocate through air and consequently inhalation is not a likely route for human exposure. Surface residues detected indoors suggest that the physical movement of residues from the exterior to the interior might be a viable route of movement of residues following this type of application.     

ELISA AND GC/MS ANALYSIS OF PESTICIDE RESIDUES IN NORTH CAROLINA1

ABSTRACT: Studies were conducted to analyze the presence of 11 pesticide residues in 12 surface waters in the Piedmont and coastal plain regions of North Carolina. Samples were assayed using enzyme‐linked immunosorbent assays (ELISAs). All ELISA results of one part per billion (ppb, μg/L) or greater were confirmed using gas chromatography/mass spectrometry (GCIMS). ELISA detection limits were approximately an order of magnitude higher than GCJMS methods. Of the 5,035 analytical results from 742 surface water samples, atrazine was detected in approximately 45 percent of the samples, five of which were at or above the Maximum Contaminant Level (MCL) of 3‐ppb. Metolachlor was detected in 64 percent of the samples. Aldicarb, 2,4‐D, chlorpyrifos, and chlorothalonil were also detected, and each was found in less than 12 percent of the samples. The remaining pesticides, including carbaryl, acetochior, methomyl, carbofuran, and alachlor, were not detected during the study period.     

Indicators Assessment for Habitat Conservation Plan of Yolo County, California, USA

/ Whereas habitat conservation plans (HCPs) have been intended to provide comprehensive environmental mitigation for multiple species, they often narrow in focus to one species and either one mitigation site or unspecified sites. We developed an indicators framework from which to rate land units for their ecological integrity, collateral values (nonbiological qualities that can improve conservation), and restoration and conservation opportunities. The ratings of land units were guided by the tenets of conservation biology and principles of landscape and ecosystem ecology, and they were made using existing physical and floral information managed on a GIS. As an example of how the indicators approach can be used for HCPs, the 29 legally rare species targeted by the Yolo County HCP were each associated with vegetation complexes and agricultural crops, the maps of which were used for rating some of the landscape indices. The ratings were mapped so that mitigation can be directed to the places on the landscape where the legally rare species should benefit most from conservation practices. The most highly rated land units for conservation opportunity occurred along streams and sloughs, especially where they emerged from the foothills and entered the Central Valley and where the two largest creeks intersected the Sacramento River flood basin. We recommend that priority be given to mitigation or conservation at the most highly rated land units. The indices were easy to measure and can be used with other tools to monitor the mitigation success. The indicators framework can be applied to other large-area planning efforts with some modifications.KEY WORDS: Ecosystem; Indicators; Landscape; Mitigation; Planning; Yolo County; California     

DDVP residues in air following application to a tobacco-storage warehouse

A 10% solution of DDVP was sprayed until a total volume of 20.9 liters of the solution had been released into the air in a tobacco-storage warehouse. Air samples were taken at various times after application in three different experiments to measure DDVP levels with time and to determine if DDVP concentrations exceeded the threshold limit (TVL). In the three experiments, residue levels were highest initially in the center of the warehouse compared to a corner, but residue levels tended to equalize over the sampling period. The data indicated that workers entering storage warehouses after application of DDVP would not encounter hazardous levels of this material.     

A sampling method to determine insecticide residues on surfaces and its application to food-handling establishments

Known amounts of acephate, chlorpyrifos, and diazinon were applied to Formica, unfinished plywood, stainless steel, and vinyl tile. Cotton-ball and dental wick materials were dipped in 2-propanol and swiped over the treated surface area two time. More acephate was found on the second swipe compared to the first from vinyl tile, similar amounts on both swipes from plywood, and less on the second swipe from formica and stainless steel. The ratio of chlorpyrifos on Swipe 1 compared to Swipe 2 found with cotton-ball on both formica and stainless steel surfaces was equivalent (6:1), but a considerable difference was seen when two dental wick swipes were used. Residues of diazinon removed from formica and stainless steel were equivalent, regardless of the swiping material used. Residues of chlorpyrifos were detected by taking swipes of surfaces in two restaurants and a supermarket up to 6 mo after a prescribed application by a commercial pest control firm. The data show that measurable amounts of chloropyrifos can be detected on surfaces not treated with the insecticide for at least 6 mo.     

Concentration and movement of diazinon in air

Abstract

Airborne concentrations of diazinon were measured in rooms for 21 days after crack and crevice application. Residue levels were largest in treated rooms (38 μg/m³ ) after application, followed by adjacent (1 μg/m³ ) and upper and lower rooms (ca. 0.4 μg/m ). Low levels of diazinon were detected in all rooms 21 days after application. Small amounts of diazinon (corrected to an 8 min application period) were detected on respirator pads ( 2.6 μg) and waist pads (2.3 μg) worn by the applicator.     

Concentration and movement of diazinon in air

Abstract

The vertical distribution of diazinon in air was measured for 35 days after a label‐prescribed crack and crevice application. Residue levels were higher at floor level than at chest and ceiling heights on day 0, but levels tended to equalize by 7 days. Concentrations were greater at chest and ceiling levels on days 14 and 21, but were equivalent on days 28 and 35. Residues in the adjacent, upper and lower rooms generally were equivalent at all sampling positions and maximum residues occurred in these rooms, and in three other rooms on the same floor level as the treated room, 3 days after application. Low but measurable residues were found in air samples 35 days after application, which indicates that low concentrations of relatively nonpersistent diazinon will remain within structures protected from direct sunlight and ventilation for several weeks.