Phosmet residues in an orchard and adjacent recreational area 1

Abstract

Two cover sprays of phosmet were applied to an orchard adjoining a camping area and a bird sanctuary with a resident goose population. Insecticide residues were monitored on orchard leaves, orchard ground cover, ground cover in the camp‐site and along the adjacent lakeshore. Despite attempts to minimize drift, significant spray residues were found outside the target area. Residues on ground cover and leaves were reduced by sprinkler irrigation subsequent to spray application.     

Residues of dicofol on cucumber grown under plastic covers in Jordan

Residues of dicofol were determined on cucumber leaves and fruits under plastic house (PH) and plastic tunnels (PT). Five sprays, 8 d apart, were applied at 0.15% concentration. Initial deposits on leaves were 48 and 58 ppm under PH and PT, respectively. In the last sampling date of leaves, the amounts of 191 and 135 ppm were detected under both cultures, respectively. There was a continuous increase in the initial residue after each spray. The highest amount of dicofol (401) was determined 1 d after the fifth spray under PH. The exposure to high residues may pose a risk to fieldworkers. On cucumber fruits, residues of 0.95 and 1.60 ppm were determined 1 d after the fourth spray under PH and PT, respectively. These residues decreased after 4 d to 0.40 and 1.49 ppm, respectively. Almost no detectable residues could be determined 8 d after sprays number 4 and 5 under both cultures. All dicofol residues on the fruits were below the tolerance level of 2 ppm.     

Residues of dicofol on cucumber grown under plastic covers in jordan

Abstract

Residues of dicofol were determined on cucumber leaves and fruits under plastic house (PH) and plastic tunnels (PT). Five sprays, 8 d apart, were applied at 0.15% concentration. initial deposits on leaves were 48 and 58 ppm under PH and PT, respectively. In the last sampling date of leaves, the amounts of 191 and 135 ppm were detected under both cultures, respectively. There was a continuous increase in the initial residue after each spray. The highest amount of dicofol (401) was determined 1 d after the fifth spray under PH. The exposure to high residues may pose a risk to fieldworkers.

On cucumber fruits, residues of 0.95 and 1.60 ppm were determined 1 d after the fourth spray under PH and PT, respectively. These residues decreased after 4 d to 0.40 and 1.49 ppm, respectively. Almost no detectable residues could be determined 8 d after sprays number 4 and 5 under both cultures. All dicofol residues on the fruits were below the tolerance level of 2 ppm.     

不同措施在防治山地果园水土流失及面源污染中的应用研究

通过施用生物毯、生物带和秸秆覆盖3种措施,模拟人工降雨,测定山地果园的水土流失量,比较不同措施在防治山地果园水土流失中的效果.结果表明,在降雨强度为1.33 mm/min时,与对照相比生物毯和秸秆覆盖能减少50%以上的氮磷流失量,生物带减少氮磷流失量也达到30%以上;在降雨强度为2.33 mm/min时,秸秆覆盖防治水土流失的效果最好;在高降雨强度(2.33mm/min)时,各种措施防治效果降低,但效果仍然明显,对磷的防治效果好于对氮的防治效果,与对照相比生物毯能减少44.5%的磷流失量.山地果园水土流失相当严重,施用生物毯和秸秆覆盖能有效防治山地果园的面源污染.     

Droplet size spectra and deposits of Bacillus thuringiensis aerial sprays,following application at two volume rates over an oak forest

Abstract

Dipel® 8AF, a commercial formulation of Bacillus thuringiensis (B.t.) was sprayed undiluted at 30 BIU in 1.8L/ha over a block B1, and sprayed after dilution with water at 30 BIU in 6.2 L/ha over another block B2 in an oak forest infested with the gypsy moth (Lymantria dispar L.) in southeastern Ontario, Canada. Spray was applied in May 1987 using a Cessna 188 Agtruck aircraft equipped with four Hicronair^® AU4000 atomizers. Droplet sizes were measured at mid‐canopy level of oak trees and at ground level using cylindrical Kromekote® cards. Deposit per unit area was assessed on aluminum oak leaves.

At the lower volume rate of 1.8 L/ha, spray droplets were smaller and droplets/cm² were lower on the cylindrical Kromekote cards in B1 than those obtained in B2 which received the higher volume rate of 6.2 L/ha. The average deposit per unit area of the aluminum oak leaves, expressed in nL of the spray volume per cm² surface area, was also correspondingly lower in B1 than in B2. This was attributed to the higher volume rate of spray application used in B2 than in B1, which resulted in larger droplets and a greater volume deposit/cm² in B2.     

Spray deposits of crop protection products on plants--the potential exposure of non-target arthropods.

Spray deposits of plant protection products on cultivated plants present a potential hazard to non-target arthropods. This hazard is considered in the risk assessment procedure when such products are registered. The results of deposit measurements in the laboratory and field, including mean spray deposits on plant surfaces, their variability and their relation to the delivered dose are presented. Initial deposits expressed as ng/cm2 plant surface were measured on individual leaves of various plant species using a fluorescent tracer. The results show that the mean deposit is plant-specific but with a high degree of variability. Mean deposits on field-grown cereals were 3, 9 (growth stage BBCH 10) and 4, 7-14 ng/cm2 (growth stage BBCH 29-63) at a delivered dose rate of 20 g sodium flourescein (SF) per ha. This is equivalent to 200 ng tracer per cm2 ground area. On apple leaves, mean deposits varied between 18 and 50 ng/cm2 at a rate of 20 g tracer/10,000 m2 fruitwall. Coefficients of variation of leaf deposits ranged between 30% and 90%. In addition to the leaf-to-leaf variability, there was a notable variation of the deposit on individual leaves themselves as shown for wheat. Data from field measurements were supported principally by data from tray-grown plants on a laboratory spray track which gives information on targets positioned in a more or less two-dimensional system.     

Phosalone applied to cotton (Gossypium hirsutum L.): its deposition and persistence on foliages, soils and final residues in seeds

Phosalone, O,O-diethyl-S-(6-chloro-1,3-benzoxazol-2(3H)-onyl)methyl phosphorodithioate, was field-applied by ground equipment to cotton (Gossypium hirsutum L.) at the rates of 1050 and 2100 g a.i./ha, respectively, to determine its dissipation on leaves and soils and the residues in seeds at harvest. The insecticide concentrations on cotton leaves and soils were measured periodically for 14 days following its application. It was found that the half lives of the insecticide on cotton leaves at the dosages of 1050 and 2100 g a.i./ha were 6.8 and 6.3 days, respectively. And the half lives on soils for the 2 dosages were 7 and 5.8 days, respectively. The residues remaining in soils at harvest time were 0.072 and 0.121 mg/kg 14 days post-application and the residues in cotton seeds were relatively low (less than 0.02-0.12 mg/kg).     

Assessing possible exposures of ground troops to agent orange during the vietnam War: The use of contemporary military records

BACKGROUND: Potential exposure of ground troops in Vietnam to Agent Orange and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) remains controversial despite the passage of 30 years since the Vietnam War. Because of uncertainty over the serum dioxin levels in ground troops at the end of their service in Vietnam, attempts have been made to develop a methodology for characterizing exposure of ground troops in Vietnam to Agent Orange and other herbicides based upon historical reconstruction from military records. Historical information is often useful in evaluating and modeling exposure, but such information should be reasonably accurate, complete, and reliable. METHODS: This paper reviews the procedures and supporting historical information related to the spraying of herbicides in Vietnam. The historical information is classified into two categories: procedural information and operational information. Procedural information covered the process and procedures followed in spraying herbicides from US Air Force fixed wing aircraft (Operation RANCH HAND) in Vietnam, and included approval procedures for spray missions, the criteria required to conduct a mission, the control exercised by the Forward Air Controller and the Tactical Air Control Center and the characteristics of the equipment used to apply the herbicides. Operational information includes data from the RANCH HAND Daily Air Activities Reports, which included geographic locations of specific spray missions, the amount of herbicide sprayed by a specific mission, reports of battle damage to spray aircraft, reports of fighter aircraft support for aerial spray missions, and any comments, such as reasons for canceling a mission. RESULTS: Historical information demonstrates that herbicide spray missions were carefully planned and that spraying only occurred when friendly forces were not located in the target area. RANCH HAND spray missions were either not approved or cancelled if approved when there were friendly forces in the area designated for spraying. Stringent criteria had to be met before spray missions could be approved. The operational information shows that spray missions for both defoliation and crop destruction were conducted in an extremely hostile environment. Heavy 'fighter suppression' with antipersonnel ordnance was used to minimize the impact of hostile ground fire on RANCH HAND aircraft. Procedures were in place that prohibited movement of troops into sprayed areas immediately after a mission due to the possible presence of unexploded ordnance delivered by fighter aircraft supporting RANCH HAND missions. The optimal nature of the spray equipment and application procedures minimized the possibility of significant spray drift. Conclusions. Few friendly troops were sprayed by fixed wing aircraft during Operation RANCH HAND, which delivered 95% of all defoliants used in Vietnam. Similarly, few troops were sprayed during helicopter or surface-based spray operations, which constituted the remaining 5% of defoliants. Detailed policies and procedures for approval and execution of spray missions ensured that friendly forces were not located in the areas targeted for spraying. Fighter aircraft assigned to accompany each spray mission frequently suppressed much of the hostile fire with bombs and other ordnance. Confirmed clearance of the target area was necessary to avoid friendly casualties. Historical records establish that these policies and procedures were strictly followed. Exposure of troops whether from direct spraying or movement through areas recently sprayed was very unlikely. The wartime military records of troop positions and herbicide operations are valuable for some purposes, but have specific limitations in exposure reconstruction. The completeness and accuracy of the geographic data (maps used by RANCH HAND and military ground units) were dependent upon the inherent precision of the map, the accuracy with which it depicted surface features, and the completeness and accuracy of the information on which it is based. Navigation by the crew using visual orientation and reference to the map was the only means that aircrew on spray missions had for establishing their locations. A Forward Air Controller independent of Operation RANCH HAND was present at the location of each spray target immediately before and during spraying operations to verify the target location and ensure that friendly forces were clear of the target area. Anecdotal reports of direct spraying of troops in Vietnam likely reflect the RANCH HAND missions spraying insecticide for mosquito control at regular intervals from March 1967 through February 1972. Outlook. The distribution and levels of serum dioxin in RANCH HAND veterans and the US Army Chemical Corps Vietnam veterans (the unit responsible for helicopter and ground-based spray operations) are distinguishable from typical levels in the population decades after the Vietnam conflict. An exposure model similar to that proposed in the 2003 report of the Institute of Medicine's Committee on 'Characterizing Exposure of Veterans to Agent Orange and Other Herbicides Used in Vietnam' was tested in 1988 by the Centers for Disease Control and Prevention and found to be a poor predictor of absorbed dose of TCDD. Military records during the Vietnam War lack the precision to determine that troops were directly sprayed with herbicides during Operation RANCH HAND, especially given the procedures in place to ensure clearance of friendly forces from the target area and the lack of elevated serum levels of TCDD in ground troops judged to have operated in heavily sprayed areas.     

Protectiveness of Gore-Tex and PVC spray suits in orchard pesticide spraying

An experimental Gore-Tex spray suit and a commercial polyvinylchloride suit were equally protective in orchard spraying with a fungicide. No pesticide was detected on patches inside the suits at six upper body sites, though outside deposition was substantial and variable. Body sites and spray replications were significant sources of variation in depositions. Contrasts between certain body sites indicated that more deposition occurred on the chest than on the back and that more occurred on the shoulders than on the upper arms.     

Diflubenzuron residue and persistence on an oak forest after aerial application

Abstract

A twenty hectare forest block in central Pennsylvania was aerially sprayed with diflubenzuron (Dimilin 25W®) at the dose of 33.23g A.I./ha in 9.4 litres/ha. Leaf samples were collected from the upper and lower canopies of 27 oaks and understory within this block on the day of spray, May 29, 1991. Canopy leaves were also collected on May 31, June 10, July 29 and September 26, 1991.

Recovery of diflubenzuron residues on fortified canopy‐leaf and litter‐leaf samples using analytical techniques employed in this study averaged 87.4% (SE = 7.5%) and 66.2% (SE = 8.2%), respectively.

On the day of spray, diflubenzuron residues on the upper canopy, lower canopy and understory averaged 81.18, 39.65 and 8.35 ng/cm², respectively. Diflubenzuron residues on canopy‐leaf samples collected 2, 12, 61 and 120 days post‐spray averaged 14.83 (SE = 10.19), 16.75 (SE = 9.95), 12.84 (SE = 8.25) and 11.20 (SE = 7.52) ng/cm², respectively. Diflubenzuron residues on litter‐leaf samples collected after leaf senescence ‐ 169 and 323 days post spray contained measurable amounts of diflubenzuron in 51 and 59% of the samples, respectively. Of the samples with measurable amounts of diflubenzuron, residues averaged 1.36 (SE = 2.44) and 0.65 ng/cm² (SE = 0.73) respectively.     

Agrochemical spray drift; assessment and mitigation--a review

During application of agrochemicals spray droplets can drift beyond the intended target to non-target receptors, including water, plants and animals. Factors affecting this spray drift include mode of application, droplet size, which can be modified by the nozzle types, formulation adjuvants, wind direction, wind speed, air stability, relative humidity, temperature and height of released spray relative to the crop canopy. The rate of fall of spray droplets depends upon the size of the droplets but is modified by entrainment in a mobile air mass and is also influenced by the rate of evaporation of the liquid constituting the aerosol. The longer the aerosol remains in the air before falling to the ground (or alternatively striking an object above ground) the greater the opportunity for it to be carried away from its intended target. In general, all size classes of droplets are capable of movement off target, but the smallest are likely to move the farthest before depositing on the ground or a non-target receptor. It is not possible to avoid spray drift completely but it can be minimized by using best-management practices. These include using appropriate nozzle types, shields, spray pressure, volumes per area sprayed, tractor speed and only spraying when climatic conditions are suitable. Field layout can also influence spray drift, whilst crop-free and spray-free buffer zones and windbreak crops can also have a mitigating effect. Various models are available to estimate the environmental exposure from spray drift at the time of application.     

Influence of formulation properties on droplet spectra and soil residues of aminocarb aerial sprays in conifer forests

The influence of formulation properties on spray droplet spectra and soil residues was studied in conifer forests in New Brunswick following aerial application of two oil-based aminocarb formulations of variable viscosities and volatilities. For a given volume rate of application, the formulation of low viscosity and high volatility provided a spectrum of small droplets and a low volume deposit on ground cards. For the same volume rate, the nonvolatile formulation of high viscosity provided a spectrum of larger droplets and consequently a higher volume deposit. Both formulations provided low soil residues, although those obtained with the nonvolatile formulation were much higher and persisted for much longer periods than those obtained with the volatile formulation. However, with both formulations the soil residues decayed to undetectable levels (less than 3 ng/g) within 5 days after spraying, indicating that none of the formulations caused any undue persistence of aminocarb in forest soils.     

Preliminary evidence that copper inhibits the degradation of DDT to DDE in pip and stonefruit orchard soils in the Auckland region,New Zealand

Orchards (n=13) were sampled as part of a larger survey investigating agrichemical residues (pesticides and trace elements) in cropping soils in the Auckland region, New Zealand. SigmaDDT concentrations in orchard soils ranged from <0.03 to 24.41 mg kg(-1). DDT (o,p'- and p,p'-) comprised at least 40% of the SigmaDDT residues in 67% of orchards in which DDT residues were detected. There was a highly significant negative correlation (-0.924, P<0.001) between copper concentration (21-490 mg kg-1) and the ratio of DDE:DDT (0.4-5.2) in pip and stonefruit orchard soils. In further investigations involving five pip and stone fruit orchard sites and one grazing paddock it was found that soil respiration and the ratio of soil microbial carbon to soil carbon (%Cmic/Org-C) in orchard soils decreased with increasing copper concentration. These findings are consistent with the conclusion that elevated soil copper concentrations in pip and stone fruit orchard soils in the Auckland region may have reduced the ability of the indigenous soil microbial community to degrade DDT to DDE     

Long overlooked historical information on agent orange and TCDD following massive applications of 2,4,5-t-containing herbicides,eglin air force base,sFlorida

BACKGROUND: From 1961-1971, The Air Development Test Center, Eglin Air Force Base (AFB), Florida, developed, tested, and calibrated the aerial spray systems used in support of Operation RANCH HAND and the US Army Chemical Corps in Vietnam. Twenty major test and evaluation projects of aerial spray equipment were conducted on four fully instrumented test grids, each uniquely arrayed to match the needs of fixed-wing, helicopter, or jet aircraft. Each of the grids was established within the boundary of Test Area 52A of the Eglin Reservation. METHODS: The tests, conducted under climatic and environmental conditions similar to those in Vietnam, included the use of the military herbicides (Agents) Orange, Purple, White, and Blue. Approximately 75,000 kg of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 76,000 kg of 2,4-dichlorophenoxyacetic acid (2,4-D) were aerially disseminated on an area of less than 3 km2 during the period 1962-1970. Data from the analysis of archived samples suggested that an estimated 3.1 kg of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), present as a contaminant, were aerially released in the test area. Because most of the vegetation had been removed before establishing the test site in 1961, there was an opportunity to follow ground-based residues independent of canopy interception, and the resulting high solar exposure of initial residues. Studies of the soils, fauna, flora, and aquatic ecosystems of the test grids and associated perimeters of Test Area C-52A (an area totally more than 8 km2) were initiated in 1969 and concluded in 1984. RESULTS AND DISCUSSION: Data from soil samples collected from 1974 through 1984 suggested that less than one percent of the TCDD that was present in soil when sampling began persisted through the ten-year period of sampling. More than 340 species of organisms were observed and identified within the test area. More than 300 biological samples were analyzed for TCDD and detectable residues were found in 16 of 45 species examined. Examination of the ecological niches of the species containing TCDD residues suggested each was in close contact with contaminated soil. Indepth field studies, including anatomical, histological and ultrastructural examinations, spanning more than 50 generations of the Beachmouse, Peromyscus polionotus, demonstrated that continual exposure to soil concentrations of 0.1 to 1.5 parts-per-billion (ng/g) of TCDD, had minimal effects upon the health and reproduction of this species. CONCLUSIONS: Since Agent Orange with its associated TCDD contaminant was aerially disseminated on the test grids, Test Area C-52A provided a 'field laboratory' for what may have happened in Vietnam, had there been no intercepting forest cover. However, in Vietnam a 'typical' mission would have disseminated 14.8 kg of 2,4,5-T/ha, most of which was intercepted by the forest canopy, versus the 876 kg 2,4,5-T/ha on the test grid at Eglin. Moreover, each hectare on the Eglin test grid received at least 1,300 times more TCDD than a hectare sprayed with Agent Orange in Vietnam. The disappearance or persistence of TCDD is dependent upon how it enters the ecosystem. Spray equipment test and evaluations missions at Eglin were generally scheduled and conducted with environmental conditions that were optimal for spray operations. This suggests that conditions favorable for dissemination of herbicide were the same conditions favorable for photodegradation of TCDD. It was likely that 99 percent of the TCDD never persisted beyond the day of application. No long-term adverse ecological effects were documented in these studies despite the massive quantities of herbicides and TCDD that were applied to the site. Reviews by the US Environmental Protection Agency and the National Academy of Sciences' Institute of Medicine did not address the fate of Agent Orange and TCDD as described in these studies from Eglin AFB, Florida.     

Environmental fate and bioavailability of agent orange and its associated dioxin during the vietnam war

BACKGROUND: In 1996, the Committee on the Assessment of Wartime Exposure to Herbicides in Vietnam of the National Academy of Sciences' Institute of Medicine (IOM) issued a report on an exposure model for use in epidemiological studies of Vietnam veterans. This exposure model would consider troop locations based on military records; aerial spray mission data; estimated ground spraying activity; estimated exposure opportunity factors; military indications for herbicide use; and considerations of the composition and environmental fate of herbicides, including changes in the TCDD content of the herbicides over time, the persistence of TCDD and herbicides in the environment, and the degree of likely penetration of the herbicides into the ground. When the final report of the IOM Committee was released in October 2003, several components of the exposure model envisioned by the Committee were not addressed. These components included the environmental fate of the herbicides, including changes in the TCDD content over time, the persistence of TCDD and herbicides in the environment, and the degree of likely penetration of herbicides into the ground. This paper is intended to help investigators understand better the fate and transport of herbicides and TCDD from spray missions, particularly in performing epidemiological studies. METHODS: This paper reviews the published scientific literature related to the environmental fate of Agent Orange and the contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and discusses how this affected the potential exposure to TCDD of ground troops in Vietnam. Specifically, the mechanisms of dissipation and degradation as they relate to environmental distribution and bioavailability are addressed. RESULTS: The evaluation of the spray systems used to disseminate herbicides in Vietnam showed that they were capable of highly precise applications both in terms of concentrations sprayed and area treated. Research on tropical forest canopies with leaf area indices (a measure of foliage density) from 2 to 5 indicated that the amount of herbicide and associated TCDD reaching the forest floor would have been between 1 and 6% of the total aerial spray. Studies of the properties of plant surface waxes of the cuticle layer suggested that Agent Orange, including the TCDD, would have dried (i.e., be absorbed into the wax layer of the plant cuticle) upon spraying within minutes and could not be physically dislodged. Studies of Agent Orange and the associated TCDD on both leaf and soil surface have demonstrated that photolysis by sunlight would have rapidly decreased the concentration of TCDD, and this process continued in shade. Studies of 'dislodgeable foliar residues' (DFR, the fraction of a substance that is available for cutaneous uptake from the plant leaves) showed that only 8% of the DFR was present 1 hr after application. This dropped to 1% of the total 24 hrs after application. Studies with human volunteers confirmed that after 2 hrs of saturated contact with bare skin, only 0.15-0.46% of 2,4,5-T, one of the phenoxy acetic acid compounds that was an active ingredient of Agent Orange, entered the body and was eliminated in the urine. CONCLUSIONS: The prospect of exposure to TCDD from Agent Orange in ground troops in Vietnam seems unlikely in light of the environmental dissipation of TCDD, little bioavailability, and the properties of the herbicides and circumstances of application that occurred. Photochemical degradation of TCDD and limited bioavailability of any residual TCDD present in soil or on vegetation suggest that dioxin concentrations in ground troops who served in Vietnam would have been small and indistinguishable from background levels even if they had been in recently treated areas. Laboratory and field data reported in the literature provide compelling evidence on the fate and dislodgeability of herbicide and TCDD in the environment. This evidence of the environmental fate and poor bioavailability of TCDD from Agent Orange is consistent with the observation of little or no exposure in the veterans who served in Vietnam. Appreciable accumulation of TCDD in veterans would have required repeated long-term direct skin contact of the type experienced by United States (US) Air Force RANCH HAND and US Army Chemical Corps personnel who handled or otherwise had direct contact with liquid herbicide, not from incidental exposure under field conditions where Agent Orange had been sprayed.     

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

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 9.1 m 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.     

Detached leaf culture: viability to evaluate 2,4-D toxicity symptoms in cotton apex leaves

To study the viability of detached leaf culture technique, studies were carried out with detached leaves from cotton apex (true trilobed leaves). The prepared leaves were sprayed with 2,4-D amine and ester, at rates of 10, 30, 70, and 100% of the recommended doses. Detached leaves without herbicide spray were used as controls. Simultaneously, a greenhouse experiment was conducted with the same treatments as used for the detached leaves experiment. Toxicity was measured through a 0-to-5 grading according to the percentage of affected leaf area in the detached leaves experiment or examining the affected rate of whole plant as indicated in the greenhouse. Results showed that the ester form of the herbicide induced earlier and more severe toxicity symptoms in detached leaves and greenhouse grown plants. Positive and significant correlations (p < 0.001) were found between toxicity results obtained at 7 and 14 days after application in detached leaves and greenhouse plants (r = 0.97 and 0.92, respectively). Negative, significant correlations (p < 0.005) were found between the toxicity levels found at 7 and 14 days after application in detached leaves and dry matter of cotton plants grown in the greenhouse (r= - 0.92 and -0.92, respectively).     

Effect of additives in the Neem formulations on deposition,volatilization and persistence of Azadirachtin in spruce foliage

Abstract

Foliar deposits, volatilization and persistence of azadirachtin‐A (AZ‐A) were investigated after application of four spray mixes prepared from a wettable powder (WP) and three emulsifiable concentrate (EC) formulations of neem. They were applied at the dosage rate of 50 g AI in 4 L/ha onto potted spruce seedlings in a laboratory spray chamber. Droplet‐size spectra and deposits were assessed using Kromekote^® card/glass plate collection units. Foliar residues [dislodgeable residues (DR), penetrated residues (PR) and total residues (TR)] of AZ‐A and their volatilization were measured by HPLC at different intervals of time up to 60 h after treatment. Differences in the droplet‐size spectra and deposit levels were observed among the four spray mixes due to the influence of additives present in them. Dissipation half‐lives (DT₅₀) of the DR, PR and TR in the foliage were low (range, 19.5 to 38.9 h) and varied according to the residue type and the spray mix used. The DT₅₀ values of the DR were consistently lower (range, 19.5 to 31.9 h) than those of the PR (range, 30.5 to 38.9 h) due to preferential loss of the surface residues. The low DT₅₀ values observed for the DR and TR in the foliage sprayed with the WP spray mix were attributed to the particulate nature of the deposit. AZ‐A volatilized appreciably from the DR rather than from the PR. The variations found in the amounts of AZ‐A volatilized (42 to 58%) and unaccountable (38 to 46%) from the initial TR values in spruce foliage, after 60 h, were attributed to the physical form of the deposits on the target surface and the influences of additives present in the different spray mixes.     

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.     

Fabricated soils for landscape restoration: an example for scientific contribution by a public-private partnership effort

Public-private partnership efforts are working towards creating green landscapes from abandoned industrial sites. Fabricated soils, potentially an essential element of such landscapes, are designed to substitute for top-soil on the areas free from ground cover and plant community. The aluminosilicate matrix and humus form the soil micelle – the primary unit of any soil complex. Humus formation is a process based on carbon–nitrogen interaction. Sources of carbon can be materials rich in easily composted products like cellulose and polyphenols (plant leaves) or aged lignin polymers (saw dust from different woody plants). The pathways of carbon–nitrogen complexes are discussed. Properties of the fabricated soil components were examined by bio-tests and plant models.