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Archives of Environmental Contamination and Toxicology (v.48, #1)
Biological Activity and Physicochemical Parameters of Marine Halogenated Natural Products 2,3,3′,4,4′,5,5′-Heptachloro-1′-Methyl-1,2′-Bipyrrole and2,4,6-Tribromoanisole by W. Vetter; M. E. Hahn; G. Tomy; S. Ruppe; S. Vatter; N. Chahbane; D. Lenoir; K.-W. Schramm; G. Scherer (pp. 1-9).
Physicochemical parameters (vapor pressure, water solubility, Henry’s law constant) and biological activities of two halogenated natural products frequently detected in marine samples and food were determined. Synthetic 2,3,3′,4,4′,5,5′-heptachloro-1′-methyl-1,2′-bipyrrole (Q1) and 2,4,6-tribromoanisole (TBA) were available in pure form. The physicochemical parameters were in the range of anthropogenic chlorinated compounds of concern. The aqueous solubilities at 25°C (Sw,25) of Q1 and TBA were 4.6 μg/L and 12,200 μg/L, respectively, whereas subcooled liquid vapor pressures were 0.00168 Pa (Q1) and 0.06562 Pa (TBA) as measured by the gas chromatographic–retention time technique. Q1 was negative by established test systems for the determination of ethoxyresorufin-O-deethylase (EROD) induction and by sulforhodamine B assay. EROD induction potency was at least 10−7 times lower than that of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). At a relatively high concentration (20 μM), Q1 inhibited specific binding of 2 nM [3H]TCDD to the in vitro-expressed human aryl hydrocarbon receptor (AHR) by 18%; lower concentrations showed no effect. Molecular modeling showed that Q1 is nonplanar, consistent with its relatively modest affinity as an AHR ligand. When tested for cell-growth inhibitory/cytocidal activity in human tumor cells, Q1 was only marginally, if at all, active with an IC50 value >50 μM compared with five to ten times lower IC50 values for potent cytotoxins tested in the test system used. Furthermore, standard pesticide tests on insecticidal, herbicidal, and fungicidal activity did not provide any significant activity at highest concentrations. For TBA, the results in all tests were comparable with Q1. The SRB assay was also applied to the halogenated natural product 4,6-dibromo-2-(2′,4′-dibromo)phenoxyanisole, but no toxic response was found. Although it was apparent that Q1 and TBA had been proven to have relatively low biological activity in all tests performed, further research is necessary to clarify whether metabolites of the compounds eventually may possess a risk to humans or other living organisms. Nevertheless, the role of Q1 in nature remains uncertain.
Hexachlorocyclohexane Use in the Former Soviet Union by Y. F. Li; A. V. Zhulidov; R. D. Robarts; L. G. Korotova (pp. 10-15).
Because of the large size of the former Soviet Union (FSU) and the heavy use of organochlorine pesticides (OCPs) in the FSU, usage information regarding OCPs in the FSU is important in compiling global emission inventories and thus in studying the transport of OCPs among different environmental compartments worldwide. The availability of such information is limited. By analyzing the available 1,2,3,4,5,6-hexachlorocyclohexane (HCH) data in the FSU, this article presents estimates of HCH usage in this region from 1950 to 1990, when HCH was officially banned for agricultural use by the FSU government. The creation of HCH usage inventories for the FSU has paved the way to produce HCH emission inventories for this region. Total HCH usages for agricultural purposes in the FSU from 1950 to 1990 were estimated to be 1,960 kt for technical HCH and 40 kt for lindane. The total usage for the isomers was 270 kt for γ-HCH, 1,270 kt for α-HCH, and 170 kt for β-HCH. Use of HCH reached a peak in 1965: 130 kt for technical HCH, 2.7 kt for lindane, 18 kt for γ-HCH, 86 kt for α-HCH, and 11 kt for β-HCH. Gridded usage data sets in the FSU of technical HCH and lindane—and the α-HCH, β-HCH and γ-HCH isomers—on a 1o × 1o longitude and latitude grid system for 1980 are freely available to all users at http://www.msc.ec.gc.ca/data/gloperd/.
A Pilot Study of the Measurement and Control of Deep Dust, Surface Dust, and Lead in 10 Old Carpets Using the 3-Spot Test While Vacuuming by J W Roberts; G Glass; L Mickelson (pp. 16-23).
This pilot study measured and examined the relationship between surface dust, deep dust, lead (Pb), and the 3-spot test during vacuuming of carpets. The 3-spot test measures the total time in seconds for the indicator light on a Hoover vacuum with dirt detector (HVDD) to turn from red to green on three spots 3 feet apart at least 4 feet from an entrance door. Ten older carpets were sampled in the Seattle area by using the following: (1) a 3-spot test to estimate the deep dust; (2) measuring the surface dust in g/m2 with the High-Volume Small Simplified Surface Sampler; (3) vacuuming with an HVDD to extract a portion of the deep dust in g/m2; and (4) repeating this cycle of a 3-spot test, surface dust sample, and deep dust sample until the clean-carpet criteria was reached. Dust particles <150 μm were analyzed for Pb. The surface dust, deep dust, and dust collection rate (g/min) decreased rapidly at first and then much more slowly as vacuuming continued. The initial 3-spot test ranged from 12 to 110 seconds (median 40). The starting surface dust loading was 0.7 to 21.1 g/m2 (median 2.9 g/m2), and it decreased by 84% to 99% when the deep dust was removed. Total dust—the sum of the surface dust and deep dust—ranged from 8.3 to 465 g/m2 (median 63.2 g/m2). It took from 2.3 to 92 min/m2 (median of 7.5 min/m2) to remove the total dust. The starting dust collection rate of 3.8 to 37 g/min decreased to final rates of 0.5 to 4.3 g/min. The 3-spot test (seconds) correlated with total dust (g/m2) (r = 0.63, p = 0.037) and cleaning time (min/m2) (r = 0.50, p = 0.12) when the data were log transformed. This study supports the utility of the 3-spot test. It tends to provide families and professional carpet cleaners with a quick and low-cost estimate of the deep dust present and the time required to clean carpets as well as indicating when the carpet is clean. Deep dust tends to accumulate in older carpets and becomes surface and airborne dust after activity on a carpet. Monitoring and removing the deep dust in old carpets may decrease the exposure of infants and sensitive adults to Pb, allergen, and other pollutants in house dust.
Pulsed Losses and Degradation of Aldicarb in a South Florida Agricultural Watershed by P. Chris Wilson; Jane Ferguson Foos; Russell L. Jones (pp. 24-31).
The objectives of these studies were to characterize patterns of movement of aldicarb, aldicarb sulfoxide, and aldicarb sulfone from a typical canalized South Florida watershed and to evaluate aldicarb dissipation in surface water in situ within a citrus grove. Surface water samples were collected daily or every other day from the discharge point for the watershed beginning May 15, 2001, through August 15, 2002. Of 457 samples collected, aldicarb, aldicarb sulfoxide, and aldicarb sulfone were detected in 6, 1, and 13, respectively. Aldicarb was detected from February through May 2002, corresponding to the legal application season of January 1 through April 30 in Florida. Aldicarb concentrations ranged from <0.16 to 4.97 ng ml−1. A single detection (0.99 ng ml−1) of aldicarb sulfoxide occurred in March 2001. The majority of aldicarb sulfone detections occurred during June and July, 2001, after the application season, and ranged from <0.22 to 0.89 ng ml−1. The half-life for aldicarb in fortified, native surface water ranged from 1.86 to 3.64 days depending on the source of water and the presence of sediments. These results demonstrated the utility of sampling on a frequent basis (compared with monthly or quarterly) for better characterizing pesticide discharges, especially in flashy systems such as canal-drained watersheds within South Florida.
Sorption of Chlorophenolates in Soils and Aquifer and Marine Sediments by S. Fingler; V. Drevenkar; Z. Fröbe (pp. 32-39).
This article describes the sorption behavior of 3 hydrophobic ionizable chlorophenols—2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol, and pentachlorophenol—in different types of natural sorbents. A series of experiments was carried out with 11 topsoil samples, 9 aquifer sediments, and 12 marine sediments differing in pH, organic-matter content, and mineral composition and presumably also in type of organic matter due to their differing origins. Ionized forms of chlorophenols dominated in almost all sorption experiments. Freundlich isotherm coefficients Kf and 1/n, as well as organic-matter sorption coefficient (log Kom) and free-energy change (ΔGo), were calculated for all 3 compounds in all sorbents. The sorption intensity of predominantly ionized chlorophenols increased linearly with the increase of sorbent organic-matter content and decreased with the increasing sorbent pH. Different sorption behavior of all 3 compounds in marine sediments with respect to topsoils and aquifer sediments was indicated by significant differences in Kf and 1/n coefficients as well as in log Kom and ΔGo values. The highest Kf and log Kom values were obtained for sorption of chlorophenolic compounds in topsoils and the lowest in marine sediments, although both groups of sorbents had similar organic-matter content. The 1/n coefficient, reflecting the isotherm nonlinearity, was considerably lower than unity for all compounds in almost all sorbents. The most significant deviation of sorption isotherms from linearity was observed in marine sediments. Only marine sediments showed a linear increase in sorption intensity of all 3 compounds with the increase in sorbent-specific surface area. These results pointed to a different mechanism of sorption in marine and terrestrial sorbents and confirmed that the capacity of sorption was related to amount as well as type and origin of organic matter.
Effects of Heavy-Metal Stress on Cyanobacterium Anabaena flos-aquae by W. Surosz; K. A. Palinska (pp. 40-48).
The influence of two metals, copper and cadmium, was studied on the growth and ultrastructures of cyanobacterium Anabaena flos-aquae grown at three different temperatures: 10°C, 20°C, and 30°C. The highest concentration of chlorophyll a was observed at 20°C and the lowest at 10°C. Both toxic metal ions, Cu2+ and Cd2+, inhibited growth of the tested cyanobacterium. Chlorophyll a concentration decreased with the increase of metal concentration. A 50% decrease in the growth of A. flos-aquae population, compared with the control, was reached at 0.61 mg l−1 cadmium and at 0.35 mg l−1 copper (at 20°C). Copper at all temperatures tested was proven to be more toxic than cadmium. At 3 mg l−1, the lysis and distortion of cells was observed; however, after incubation at 9 mg l−1 cadmium, most of the cells were still intact, and only intrathylakoidal spaces started to appear. Copper caused considerably greater changes in the protein system of A. flos-aquae than did cadmium; in this case, not only phycobilins but also total proteins were destructed. The aim of this study was also to identify the place of metal accumulation and sorption in the tested cyanobacterium. Analysis of the energy-dispersion spectra of the characteristic x-ray radiation of trichomes and their sheaths showed that cadmium was completely accumulated in cells but was not found in the sheath. Spectrum of the isolated sheath after treatment with copper exhibited only traces of the metal, but isolated cells without a sheath showed a high peak of copper.
Toxicity Assessment of Pesticide Mixtures Typical of the Sacramento–San Joaquin Delta Using Chironomus tentans by M. J. Lydy; K. R. Austin (pp. 49-55).
This study examined the effects of nine commonly detected pesticides in the Sacramento–San Joaquin Delta on the aquatic midge Chironomus tentans. Pesticides were chosen from a variety of chemical classes including organophosphate (OP) insecticides as well as triazine, triazinone, and substituted urea herbicides. Both single toxicant and binary mixture bioassays were performed. In addition, midges were pre-exposed to DDE at environmentally relevant concentrations and then challenged by exposing them to chlorpyrifos or diazinon in single-toxicant acute bioassays. Results indicate that most of the binary mixtures elicited additive responses in C. tentans, whereas OP insecticides in combination with various herbicides caused greater-than-additive responses. Pre-exposures with DDE did not have a significant impact on subsequent OP challenges at DDE concentrations of 0.2, 2, and 20 μg/kg. This study represents an important first step in understanding the interactions among various pesticides commonly detected throughout the Delta.
Assessment of a 2,4,6-Trinitrotoluene–Contaminated Site Using Aporrectodea rosea and Eisenia andrei in Mesocosms by P.Y. Robidoux; C. Svendsen; M. Sarrazin; S. Thiboutot; G. Ampleman; J. Hawari; J.M. Weeks; G. I. Sunahara (pp. 56-67).
Polynitro-organic compounds such as 2,4,6-trinitrotoluene (TNT) can be released into the environment from production and processing facilities and military firing ranges as well as through field use and disposal practices. Based on laboratory toxicity data, TNT has lethal (at ≥260 mg TNT/kg dry soil) and sublethal effects (at ≥59 mg TNT/kg dry soil) to the earthworm. However, field studies are needed to relate exposure of organisms to explosives in mixed-contaminated soil under field conditions and to define effects-based ecotoxicologic benchmarks for TNT-contaminated soil. In the present study, the lethal and sublethal effects of a 10-day in situ exposure at a TNT-contaminated field site using mesh-bag mesocosms were assessed. In addition to the survival end point, the biomarkers of earthworm exposure and effect—including tissue residues, lysosomal neutral red retention time (NRRT), and total immune activity (TIA)–were measured. Concentrations of TNT in soil mesocosms ranged from 25 to 17,063 mg/kg. Experiments indicated a trend toward decreasing survival of caged Aporrectodea rosea and Eisenia andrei as the concentration of TNT and total nitroaromatic compounds increased. E. andrei tolerated higher concentrations of TNT (up to 4050 mg/kg dry soil) in mesocosms than did indigenous earthworms, who survived only at ≤1146 mg TNT/kg. Earthworms E. andrei and A. rose survived in 67% and 75% of TNT-contaminated mesocosms, respectively, compared with references groups. NRRT was significantly decreased in surviving earthworms from the contaminated areas compared with those from the reference site. TIA was not affected by field exposure to TNT. Earthworm tissue concentrations of TNT metabolites 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitrotoluene were not correlated with TNT soil concentrations. In addition, higher tissue concentrations of TNT metabolites were observed at concentrations ranging from 116 to 130 mg TNT/kg soil. The results showed that earthworm exposure in TNT-contaminated soil produced both lethal and sublethal effects in the field. The results of study indicated that mesocosm experiments would be useful to assess the toxicity of a site and to characterize the overall effects of contaminants. However, mesocosm experiments present special considerations (e.g., abiotic factors, exposure period) when used at heterogenous sites, and data must be interpreted with caution.
Influence of Ploidy and Metal–Metal Interactions on the Accumulation of Ag, Cd, and Cu in Oysters Crassostrea Gigas Thunberg by J.-C. Amiard; H. Perrein-Ettajani; A. Gérard; J. P. Baud; C. Amiard-Triquet (pp. 68-74).
The present study was designed to compare the response to contaminants in diploid with triploid specimens of the oyster Crassostrea gigas. The reproduction investment in bivalve molluscs has priority on somatic growth. Thus, genetic sterilization by triploidy induction enables the energy flux to be directed toward somatic growth and glucide storage. Bioaccumulation was examined for Ag (10 μg/L), Cd (10 μg/L), and Cu (30 μg/L) to determine if the response to metals follows similar patterns in diploid (2n) and triploid (3n) groups. The effect of ploidy was also evaluated as a function of dry weight of soft tissue and condition index. Moreover, the reciprocal influence of these metals on their incorporation was studied. The results showed that the major factor governing the degree of metal bioaccumulation by oysters is the nature of the metal introduced in the experimental medium. Thus, the uptake of Cd is proportionally more important than in the case of Ag and even more in Cu. For Cu-treated samples, the influence of ploidy on weight and metal body burden (and Cu concentration) was not significant, whereas for Ag and Cd, significant differences according to genetic type were evidenced by higher tissue weight and lower concentrations in triploid than diploid specimens. Metal–metal interactions study especially showed a reciprocal antagonism between Ag and Cu.
Historical and Other Patterns of Monomethyl and Inorganic Mercury in the Florida Panther (Puma concolor coryi) by J. Newman; E. Zillioux; E. Rich; L. Liang; C. Newman (pp. 75-80).
Since the late 1980s, elevated levels of mercury have been reported in the tissues of the Florida panther (Puma concolor coryi) from the Florida Everglades. The extent, degree, and length of time of mercury contamination in the Florida panther are unknown. The objective of this study was to determine the historical and other patterns of monomethyl and inorganic mercury in the Florida panther by analysis of mercury in panther hair from museum collections. In addition, this study evaluated the effects of preservation of skins on mercury concentrations in hair and the representativeness of museum collections for evaluating historical trends of contamination in the Florida panther. Hair from 42 Florida panther specimens collected from 1896 to 1995 was analyzed for both monomethyl and inorganic mercury. Monomethyl mercury (MMHg) and inorganic mercury (IHg) were found in all specimens. Monomethyl mercury in hair from untanned skins was significantly higher than MMHg in hair from tanned skins. For untanned specimens, the mean MMHg concentration in hair was 1.62 ± 1.87 μg/g (range 0.11 to 6.68 μg/g, n = 16). Monomethyl mercury accounted for 88% of the total mercury in untanned Florida panther hair. No sexual or geographical differences were found. Although MMHg is generally stable in hair, the tanning process appears to reduce the amount of MMHg in hair. In addition, exogenous IHg contamination of the panther hair was found in museum specimens, especially in older specimens. The implication of these and other factors in interpreting results of museum studies is discussed. The presence of MMHg in panther hair since the 1890s indicates long-term and widespread exposure of the Florida panther to mercury. Levels of MMHg are significantly greater in the 1990s than the 1890s. When combined with field studies of mercury in the Florida panther, considerable individual variability is observed, reflecting short-term changes in exposure of individual panthers to mercury. Although museum specimens showed a significant increase in MMHg over the last 100 years, they did not show the magnitude of increase that field populations of Florida panthers did. A number of Florida panthers appeared to be at risk from mercury over their lifetimes, especially individuals from the early 1990s.
Evaluation of Wetland and Tertiary Wastewater Treatments for Estrogenicity Using In Vivo and In Vitro Assays by L Xie; Y Sapozhnikova; O Bawardi; D Schlenk (pp. 81-86).
The effects of wetland wastewater treatment on estrogenic activity and estrogenic activity of water after tertiary treatment were evaluated using in vivo (rainbow trout vitellogenin [VTG] expression) and in vitro (yeast estrogen screening) assays. Juvenile rainbow trout exposed to tertiary-treated wastewater from the Green Acres Treatment Plant in Orange County Water District had increased plasma VTG levels compared with control fish. When trout were exposed to wastewater-dominated water before it entered into Prado Wetland (Riverside County, CA), VTG concentrations were increased above those of controls and were not significantly different from fish exposed to water exiting the wetland. VTG E2-equivalent concentrations (EEQs) of the water samples from the Green Acres Plant were 16.92 ± 16.49 ng/L. Activity of water entering Prado Wetland was 29.80 ± 28.41 ng/L EEQ, and water exiting was 24.34 ± 23.17 ng/L EEQ. In vitro assays estimated that estrogenic activity of water from the Green Acres Plant was <1 ng/L EEQ, whereas water entering and exiting Prado Wetland had yeast estrogen screening EEQs of 2.57 and <1 ng/L, respectively. Our results suggest that environmental estrogens that are not potent estrogen-receptor ligands exist in wastewaters from the Green Acres Plant as well as water entering and exiting Prado Wetland. Wetland treatment did not remove environmental estrogens in the water. Our results also suggest that in vitro assays may underestimate estrogenic activity of sampled water.
Stage-Specific Toxicity of Cypermethrin to Medaka (Oryzias latipes) Eggs and Embryos Using a Refined Methodology for an In Vitro Fertilization Bioassay by M. González-Doncel; C. Fernández-Torija; D. E. Hinton; J. V. Tarazona (pp. 87-98).
Using original artificial fertilization methods with medaka (Oryzias latipes), the effects of exposure to cypermethrin on gametes, fertilization, and embryonic development were investigated. The relative sensitivity was studied with 96-hour duration, 24-hour renewal exposures to six nominal concentrations of cypermethrin ranging from 3.1 100.0 μg cypermethrin/L. Tests were initiated at different developmental stages: unfertilized egg (stage 0), late morula (stage 9), eminence of swim bladder (stage 29), and maximum flexion of the atrioventricular region (stage 34). Cypermethrin did not affect the fertilization process. Predominant sublethal effects in embryos included transient visceral edemas intimately associated to the gall bladder with subsequent pericardial edemas. Other sublethal effects were observed in surviving larvae and included spastic movements with or without ability to respond to stimulus (≥6.3 μg cypermethrin/L), spinal curvatures, and delayed or absence of swim bladder inflation (≥12.5 μg cypermethrin/L). The exposure of the gametes (stage 0) or animals during earlier embryonic development (stages 9 or 29) was not a critical window for cypermethrin exposure. Although the incidence of edemas in embryos occurred mainly during exposure of these early developmental stages, embryo and larva lethality and the incidence of transient sublethal effects in hatchlings showed that the later exposure window (stage 34) was the most sensitive. The stage 34 group involved advanced organogenetic stages in which the chorion partially degraded before hatching. Our studies reinforced the idea that a combination of morphologic and functional impairment evaluation is a more sensitive response to developmental toxicants than morphologic defects alone.
A Biopsy Procedure for Determining Filet and Predicting Whole-Fish Mercury Concentration by S. A. Peterson; J. Van Sickle; R. M. Hughes; J. A. Schacher; S. F. Echols (pp. 99-107).
Although mercury contamination of fish is a widespread phenomenon, its regional evaluation is hindered by the reluctance of permitting agencies to grant collection permits, problems in securing adequate freezer space, and time to process whole, large fish or filets. We evaluated mercury concentrations in 210 filet biopsies from 65 sites in 12 western states relative to whole-body mercury concentration in the same fish. We found a highly significant relationship (r2 = 0.96) between biopsy and whole-fish mercury concentrations for 13 piscivorous and nonpiscivorous fish species. We concluded that relative to conventional fish-tissue sampling and analysis procedures for whole fish or filets, the biopsy procedure for mercury in fish tissue is nonlethal, less cumbersome, more likely to be permitted by fisheries agencies, and a precise and accurate means for determining both filet and whole-fish mercury concentrations.
Zinc and Lead Poisoning in Wild Birds in the Tri-State Mining District (Oklahoma, Kansas, and Missouri) by W. N. Beyer; J. Dalgarn; S. Dudding; J. B. French; R. Mateo; J. Miesner; L. Sileo; J. Spann (pp. 108-117).
The Tri-State Mining District (Oklahoma, Kansas, and Missouri) is contaminated with Pb, Cd, and Zn from mining, milling and smelting. Metals have been dispersed heterogeneously throughout the District in the form of milled mine waste (“chat”), as flotation tailings and from smelters as aerial deposition or slag. This study was conducted to determine if the habitat has been contaminated to the extent that the assessment populations of wild birds are exposed to toxic concentrations of metals. American robins (Turdus migratorius), northern cardinals (Cardinalis cardinalis), and waterfowl had increased Pb tissue concentrations (p < 0.05) compared with Pb tissue concentrations from reference birds, and the exposure of songbirds to Pb was comparable with that of birds observed at other sites severely contaminated with Pb. Mean activities of the Pb-sensitive enzyme delta-aminolevulinic acid dehydratase (ALAD) were decreased by >50% in red blood cells in these birds (p < 0.05). Several birds had tissue concentrations of Pb that have been associated with impaired biological functions and external signs of poisoning. Cadmium was increased in kidneys of songbirds (p < 0.05), but no proximal tubule cell necrosis associated with Cd poisoning was observed. Zinc concentrations in liver and kidney of waterfowl were significantly higher (p < 0.05) than reference values. The increased environmental concentrations of Zn associated with mining in the District accounted for the pancreatitis previously observed in five waterfowl from the District. The District is the first site at which free-flying wild birds have been found to be suffering severe effects of Zn poisoning.
Effects of Azinphos-Methyl on Cholinergic Responses and General Health in Zebra Finches (Taeniopygia guttata) After Previous Treatment with p,p′-DDE by H Gill; T D Williams; C A Bishop; K M Cheng; J E Elliott (pp. 118-126).
Although organochlorine (OC) pesticides were replaced with organophosphates (OPs) in the early 1970s, they continue to persist in orchard environments today. Extensive research has been conducted to determine the effects of currently used OPs on cholinesterase (ChE) activity; however, although OCs continue to be prevalent in areas of previous use, few studies have looked at the toxicity of a combination of residual OC compounds with currently used OP pesticides. The focus of our study was to determine the effects of azinphos-methyl (a common OP used in apple orchards today) on ChE activity and general health in zebra finches (Taeniopygia guttata) previously exposed to p,p′-DDE (a commonly detected metabolite of DDT). The main results of our study were as follows: (1) azinphos-methyl alone caused a dose-dependent inhibition of plasma and brain ChE activity; (2) p,p′-DDE in combination with azinphos-methyl did not change azinphos-methyl inhibition of ChE activity; and (3) there were suggestions of immunostimulation in birds dosed 1 year previously to p,p′-DDE and of anemia when p,p′-DDE was combined with azinphos-methyl; however, there was no dose–response for these parameters in birds subsequently dosed with p,p′-DDE.
Evaluation of Skin and Respiratory Doses and Urinary Excretion of Alkylphosphates in Workers Exposed to Dimethoate During Treatment of Olive Trees by C. Aprea; B. Terenzoni; V. De Angelis; G. Sciarra; L. Lunghini; G. Borzacchi; D. Vasconi; D. Fani; A. Quercia; A. Salvan; L. Settimi (pp. 127-134).
This article describes a study of exposure to dimethoate during spraying of olive trees in Viterbo province in central Italy. Airborne concentrations of dimethoate were in the range 1.5 to 56.7 nmol/m3. Total skin contamination was in the range 228.4 to 3200.7 nmol/d and averaged 96.0% ± 3.6% of the total potential dose. Cotton garments afforded less skin protection than waterproof ones, which were in turn associated with higher skin contamination than disposable Tyvek overalls. Total potential doses and estimated absorbed doses, including their maxima, were below the acceptable daily intake of dimethoate, which is 43.6 nmol/kg body weight (b.w.). Urinary excretion of alkylphosphates was significantly higher than in the general population, increasing with exposure and usually showing a peak in the urine sample collected after treatment. Metabolite concentrations were influenced by the type of individual protection used: minimum levels were associated with the closed cabin and maximum levels with absence of any respiratory or hand protection. Urinary alkylphosphates showed a good correlation with estimated absorbed doses and are confirmed as sensitive biologic indicators of exposure to phosphoric esters.