ALBERT

Notizen: Abstract The acute toxicity of a technical formulation of pentachlorophenol (PCP) and pure pentachlorophenol to three age classes ofDaphnia magna, and adultD. pulex andD. galeata mendotae was determined by static toxicity tests. The influence of a number of factors on toxicity of PCP was also examined. The 48-hr LC50 estimates for adult daphnids of the three species exposed to pure PCP were 1.78, 4.59 and 0.51 mg/L, respectively, while those for the technical formulation were 2.57, 3.66 and 0.33 mg/L, respectively. There was little difference in toxicity between the technical and pure PCP; however, toxicity of both forms of PCP was influenced by duration of exposure, age (and/or size) and species of test organism and pH of the test solution. Pentachlorophenol caused a toxic response over a very narrow range of concentrations, with the greatest response occurring immediately between 0 and 24 hr. Pure PCP was equally toxic to all age classes ofD. magna but susceptibility to technical PCP decreased with maturation.D. g. mendotae was ten times more sensitive thanD. pulex to PCP. Pure PCP was significantly more toxic toD. magna at pH 5.5 than 7.0 with mean 48-hr LC50 values of 0.082 and 1.78 mg PCP/L, respectively. At 12°C, the toxicity of both forms of PCP toD. g. mendotae andD. pulex did not differ significantly from that at 20°C; however, technical PCP was significantly more toxic toD. magna at 12°C for an exposure duration of 48 hr. There was no effect of test container size (100, 250, 600 and 1,000 mL) on the toxicity of PCP toD. magna at 20°C with the lower pH of 5.5, suggesting that adsorption to glassware was not a factor in availability of PCP to test organisms. Beaker size had no effect on the toxicity of PCP toD. pulex at 20°C with test solutions having a pH of 7.0-8.0.

Notizen: Abstract Improvements in the calibration techniques used in a Video Imaging Technique for Assessing Exposure (VITAE) were examined. A series of standard curves measuring change in fluorescence with increased tracer deposition within narrow pre-exposure skin tone groupings on volunteer human subjects were developed. Nine highly linear curves were generated. Data from these curves were used to develop calibration curves which permitted the computerized correction of fluorescence based on the pre-exposure skin fluorescence. VITAE estimates of dermal tracer deposition were highly correlated with application rates (r2=0.98). The fluorescent tracer 4-methyl-7-diethylaminocoumarin was found to be stable for up to 48 h in a greenhouse environment when applied to chrysanthemum foliage or alpha-cellulose patches. The percentage of tracer which could be dislodged from chrysanthemum foliage was constant over 48 h. Improvements in the VITAE calibration techniques increase its value in providing full-body dosimetric estimates of dermal exposure to pesticides in enclosed environments.

Notizen: Abstract Products containing high density polyethylene plastic from recycled pesticide containers were tested for levels of dislodgeable pesticide under dry and damp conditions. Trifluralin was found to be the pesticide released in largest quantity from plastic curbstops. Levels dislodged ranged from 0.18 μg/100 cm2 to 4.18 μg/100 cm2 for all plastics tested. Significantly higher dislodgeability occurred from products where low density polyethylene plastics were used to dilute pesticide container plastics, compared to products containing only pesticide container plastics. Amounts of trifluralin dislodged by wiping with dry cheesecloth for 15 min were 0.83±0.50, 3.52±0.40, and 2.53±0.56 μg/100 cm2 for products containing 100%, 50%, and 25% pesticide container plastics, respectively. Respective levels of trifluralin dislodged with saline-dampened cheesecloth were 2.00±0.71, 3.21±0.82, and 1.16±0.51 μg/100 cm2. Decreased amounts of trifluralin were released after product weathering, with levels dislodged under dry conditions of 0.007±0.002, 0.0083±0.001 and 0.0089±0.001 μm/100 cm2, respectively. Similar studies of asphalt products containing recycled pesticide containers found the average amounts of trifluralin and 2,4-D iso-octyl ester dislodged were 0.33 μg/100 cm2 and 1.35 μg/100 cm2, respectively. Pesticide levels dislodged from all products tested were within acceptable daily intake levels. Calculations of margins of safety showed exposure to products made with recycled containers would not present an unacceptable risk to individuals coming in contact with them.

Notizen: Abstract Chronic toxicity test procedures (static, with renewal) were used to determine the chronic toxicity of sublethal concentrations of a technical formulation of pentachlorophenol (PCP) and pure pentachlorophenol toDaphnia magna. Test organisms 48+-12 h old were exposed for their entire lifespan (i.e., until death) to 0.01, 0.05, 0.1 and 0.5 mg technical PCP/L and 0.01, 0.087 and 0.1 mg pure PCP/L. Criteria used to assess chronic toxicity were mean time to appearance of the primiparous instar in the brood chamber, mean number of days to release of the first brood, mean number of broods produced per female, mean brood size per female, mean number of reproductive days, mean number of young produced per reproductive day per female and survivorship. Pentachlorophenol differentially affected maturation and reproduction but not survivorship or longevity. Mean number of broods produced per daphnid, length of the reproductive period, longevity and survivorship were insensitive criteria relative to mean time to appearance of the primiparous instar, time to release of first brood, brood size, and number of young produced per daphnid per reproductive day. Generally, there was little difference in toxicity of the three concentrations of pure PCP, for they significantly reduced mean brood size and rate of reproduction of young and significantly but differentially affected maturation. Technical PCP, at the highest concentration of 0.5 mg/L, significantly reduced mean brood size and the rate of production of young, and significantly delayed both time to appearance of the primiparous instar and release of the first brood. When differences in toxicity occurred, generally, pure PCP was more toxic than comparable concentrations of technical PCP. Although enhanced maturation was observed there was no compensatory reproduction. Similar conclusions regarding maturation and survivorship would have been derived from this study had it been terminated after the standard 21 d; however, the conclusions would have been different for reproduction. Only the highest concentration of technical PCP reduced brood size, the rate of production of young and total number of young produced per daphnid in 21 d. Only pure PCP at 0.05 mg/L caused daphnids to produce significantly fewer broods and, although the mean brood size was significantly larger than those in the controls, the mean number of young produced in 21 d was significantly reduced. These results differ substantially from those based on the entire life-cycle study and one of the most obvious differences is the much lower rates of young production in the entire life cycle study (2.41–3.03 young per daphnia per reproductive day) opposed to the first 21 days of the study (5.13–7.5 young per daphnia per reproductive day).

Notizen: Abstract The toxicities of 2,3,4,6-tetrachlorophenol (TeCP) and pentachlorophenol (PCP) were determined in standardized, single-species laboratory toxicity tests using daphnids and rotifers. For Daphnia magna, 48-h LC50 estimates with neonates indicated that PCP was more toxic than TeCP. The commercial TeCP formulation DIATOX®, containing a 6.5:1 ratio of TeCP:PCP, exhibited intermediate toxicity. Mean LC50 estimates were 1.23, 2.66, and 2.07 mg/L, respectively. All three LC50 estimates were significantly different (p〈0.05). Daphnia galeata mendotae was more sensitive to TeCP than D. magna displaying a mean 48-h LC50 value of 0.58 mg/L. A 21-d partial life cycle test with D. magna revealed no effects at 0.25 mg/L TeCP, but a significant (p〈0.05) increase in adult mortality was noted at 0.50 mg/L TeCP. There was no effect on reproductive success of surviving adults at any test concentration. Rotifer tests, conducted with a commercially available species (Brachionus calyciflorus) and a field collected species (Keratella cochlearis), also indicated that PCP was more acutely toxic than TeCP. LC50 estimates for B. calyciflorus were highly variable depending upon the source of resting eggs (cysts) and the test conditions. LC50 estimates (24-h) ranged from 2.09 to 7.76 mg/L for PCP and from 2.31 to 〉16.00 mg/L for TeCP. In general, B. calyciflorus was less sensitive to TeCP and PCP than D. magna and D. g. mendotae. Assays with K. cochlearis were only marginally successful, but the mean 12-h LC50 estimate for TeCP of 0.96 mg/L suggested that this species may be more sensitive to TeCP than B. calyciflorus.

Notizen: Abstract Exposure of greenhouse chrysanthemum workers to the pesticide pirimicarb was measured by the Video Imaging Technique to Assess Exposure (VITAE) along with air monitoring and biological assessment techniques. Workers at five commercial chrysanthemum operations were video imaged prior to debudding plants which had been treated with a fluorescent tracer and the pesticide, pirimicarb, 36–48 h earlier. After 1–4 h of debudding, workers were again imaged and the rates of tracer deposition determined with the VITAE system. Tracer deposition from contact with treated foliage was found to increase in a linear fashion over 4 h. Greatest deposition occurred on the hands and arms and represented 42% and 20% of total exposure, respectively. No detectable air residue samples of pirimicarb were found while workers were debudding plants. Monitoring of four workers for pirimicarb and its urinary metabolites revealed no detectable residues following 4 h of contact with foliage, which had been treated 48 h earlier.

Notizen: Summary A field experiment was conducted using a linear-move irrigation machine to test the interactive effects of irrigation uniformity, a representative length of nonuniformity and water quality on crop yield and growth responses. Christiansen's uniformity coefficient values of 60, 80, and 90% were achieved with a sinusoidal pattern of applied water superimposed on the 60 and 80% uniformity treatments. Two wave-lengths 2.4 m (S) and 4.9 m (L), were used. Water qualities used were: 0.3 dS m-1 and 3 to 5 dS m-1. Results showed that both the magnitude and the scale of the nonuniformity affect the water use efficiency. Sugar yields were not affected by water quality. Yields on a row basis were significantly correlated to applied water in the 60% uniformity, long scale length (60-L) treatment.