Characterization of phase I and phase II drug metabolism and the effect of Β-naphthoflavone in the liver and posterior kidney of the channel catfish,Ictalurs punctatus

Immature channel catfish (Ictalurus punctatus) were injected intraperitoneally with 50 mg/kg -naphthoflavone (BNF) and its effects on phase I and phase II xenobiotic metabolizing enzymes of liver and posterior kidney were evaluated. Microsomal monooxygenases in control animals exhibited higher specific activities in liver than in kidney although if data are expressed as turnover numbers, both organs have comparable activities, -naphthoflavone treatment resulted in increases in hepatic microsomal cytochrome P-450 content and ethoxyresorufin deethylase activity. Renal monooxygenases were not responsive to BNF injection. The phase II xenobiotic metabolizing systems of liver or kidney did not respond to BNF treatment. With the exception of epoxide hydrolase which was higher in renal microsomes, phase II drug metabolizing activity of liver cell fractions was about two-fold that observed in fractions isolated from posterior kidney.     

Poly cyclic aromatic hydrocarbon in sediments taken from the Severn Estuary drainage system

Conclusions The 9 PAH's studied are ubiquitous in the area considered. Levels of contamination appear to be highest in areas of recent coal mining activity. However, the contaminants are bound up in the sedimentary material of the drainage system. Translocation of the PAH's is thus slow and predictable and hence possible health hazards are much reduced.Although the pyro-synthesis of PAH's upon combustion of fossil fuels such as coal is well known little attention has been paid to the natural occurrence of PAH's in the various types of coal and to the liberation of these compounds by erosion and, more importantly, by mining activity. In view of the declining importance of oil and the re-emergence of coal as a primary source of energy the contribution to environmental contamination by PAH's from this source merits further study.     

Human exposure to volatile halogenated hydrocarbons from the general environment

Summary The objective of this study was to assess individual human exposure to volatile halogenated hydrocarbons (VHH) under normal environmental conditions by means of biological monitoring, i.e. by the measurement of these compounds or their metabolites in body fluids, such as blood, serum, and urine. Blood samples of 39 normal subjects without known occupational exposure to these agents were examined for the occurrence of VHH. The following compounds were present in quantifiable concentrations in 60 to 95% of the blood samples examined: chloroform (median 0.2 g/l; range < 0.1–1.7 g/l), 1,1,1-trichloroethane (median 0.2 g/l; range < 0.1–3.4 g/l), tetrachloroethylene (median 0.4 g/l; range < 0.1–3.7 g/l). Trichloroethylene could be detected in 31% of all blood samples (median < 0.1 g/l; range < 0.1–1.3 g/l). In addition, the levels of trichloroacetic acid (TCA) were determined in serum and 24-h urine samples of 43 and 94, respectively, normal subjects. TCA was present in measurable concentrations in all serum and urine samples examined. The median of the TCA levels in serum was 21.4 g/l (range 4.8–221.2 g/l) and in urine 6.0 g/24 h (range 0.6–261.4 g/24 h). The results are discussed in relation to data from the literature on human exposure to VHH from the general environment, i.e. via air, food, and water. The upper normal limits calculated from the results of this investigation can be used to detect even minor excessive exposures to VHH.     

Effects of medetomidine on hepatic EROD activity in three species of fish

Medetomidine, an antifouling candidate, was investigated for its effects on cytochrome P4501A (CYP1A) activity in fish. Rainbow trout (Oncorhynchus mykiss), turbot (Psetta maxima), and Atlantic cod (Gadus morhua) were exposed to medetomidine either via i.p. injection (<5 micromol (1mg)/kg) or via water (<50 nM). Enzyme activity was measured as ethoxyresorufin-O-deethylase (EROD) activity in liver microsomes. There was a small (2-7-fold) increase in EROD activity in rainbow trout. In turbot, EROD activity increased (4-fold) after injection, while a non-significant (50%) decrease was observed after water exposure. No effects on EROD activities were observed in Atlantic cod. In vitro inhibition studies of EROD activities in liver microsomes from all three species showed that medetomidine was a very potent CYP1A inhibitor. Thus, median inhibition values (IC(50)) were 35+/-10nM for rainbow trout, 47+/-17 nM for turbot, and 111+/-70 nM for Atlantic cod. These observed effects suggest that medetomidine interferes with CYP1A-dependent metabolism of xenobiotics in these fish species.     

Polycyclic aromatic hydrocarbon exposure in Steller's eiders (Polysticta stelleri) and Harlequin ducks (Histronicus histronicus) in the eastern Aleutian Islands, Alaska, USA

Seaducks may be affected by harmful levels of polycyclic aromatic hydrocarbons (PAHs) at seaports near the Arctic. As an indicator of exposure to PAHs, we measured hepatic enzyme 7-ethoxyresorufin-O-deethylase activity (EROD) to determine cytochrome P4501A induction in Steller's eiders (Polysticta stelleri) and Harlequin ducks (Histronicus histronicus) from Unalaska, Popof, and Unga Islands (AK, USA) in 2002 and 2003. We measured PAHs and organic contaminants in seaduck prey samples and polychlorinated biphenyl congeners in seaduck blood plasma to determine any relationship to EROD. Using Akaike's information criterion, species and site differences best explained EROD patterns: Activity was higher in Harlequin ducks than in Steller's eiders and higher at industrial than at nonindustrial sites. Site-specific concentrations of PAHs in blue mussels ([Mytilus trossilus] seaduck prey; PAH concentrations higher at Dutch Harbor, Unalaska, than at other sites) also was important in defining EROD patterns. Organochlorine compounds rarely were detected in prey samples. No relationship was found between polychlorinated biphenyl congeners in avian blood and EROD, which further supported inferences derived from Akaike's information criterion. Congeners were highest in seaducks from a nonindustrial or reference site, contrary to PAH patterns. To assist in interpreting the field study, 15 captive Steller's eiders were dosed with a PAH known to induce cytochrome P4501A. Dosed, captive Steller's eiders had definitive induction, but results indicated that wild Steller's eiders were exposed to PAHs or other inducing compounds at levels greater than those used in laboratory studies. Concentrations of PAHs in blue mussels at or near Dutch Harbor (approximately 1,180-5,980 ng/g) approached those found at highly contaminated sites (approximately 4,100-7,500 ng/g).     

Toxicity and Estrogenic Activity of a Wastewater Treatment Plant in Northern Italy

Many xenobiotics, widely diffused in the environment, have the potential to disrupt the delicate endocrine system balance of wildlife and humans. Substances showing hormone-like actions in living organisms are defined endocrine-disruptor chemicals and they may mimic, block, or interfere with the synthesis, release, transport, elimination, and binding of natural hormones. Different ecotoxicologic studies were applied to screen for the discharge of estrogenic and toxic substances into the aquatic environment from a small industrial wastewater treatment plant based in Northern Italy. Samples of wastewater (3 L) were taken at three different periods during the year from different points of the plants process: three phases of treatment, and effluent. Untreated samples (1 L) were assayed with two toxicity tests: Microtox and Daphnia magna. A simplified proliferation test using human estrogen receptor–positive MCF-7 breast cancer cells (E-screen assay) was performed on 2-L samples after solid-phase extraction for the determination of total estrogenic activity; the presence of estrogenic substances was evaluated by measuring the proliferation rate in cells exposed to samples. The results of the Microtox assay employing the marine bacterium Vibrio fischeri were compared with data obtained from whole-effluent toxicity testing methods employing D. magna. Toxicity was found only for the influent point. The proliferative effect of the five points, relative to the positive control 17-estradiol (relative proliferation effect), was between 2.4% and 39%, and the 17-estradiol equivalent concentrations were between 0.06 and 3.94 ng/L. A first comparison between results from toxicity load and estrogenic activity was performed. At all process points, the effluent samples were considered acceptable (taking only toxicity into account), but we demonstrated that they had estrogenic activity in the river water indicating an input of estrogenic substances by way of the treatment plant.     

Stimulation of oxyradical production of hepatic microsomes of flounder (Platichthys flesus) and perch (Perca fluviatilis) by model and pollutant xenobiotics

Stimulation of hepatic microsomal NAD(P)H-dependent hydroxyl radical (·OH) production by model compounds, viz. menadione (2-methyl-1,4-naphthoquinone) and nitrofurantoin (N-(5-nitro-2-furfurylidene)-1-aminohydantoin), and pollutant xenobiotics, viz. benzo[a]pyrene (BaP) diones (products of microsomal BaP metabolism), duroquinone (tetramethyl-1,4-benzoquinone—present in pulp mill effluent), and the pesticide lindane (-hexachlorocyclohexane), was examined in flounder Platichthys flesus. Duroquinone was also studied in perch Perca fluviatilis, a freshwater species used in studies of pulp mill effluents in the aquatic environment. Microsomal ·OH production was detected by the oxidation of the scavenging agent 2-keto-4-methiolbutyric acid (KMBA), using FeCl₃/EDTA as a promotor of the Haber-Weiss reaction (O ₂ ^– +H₂O₂=·OH+OH^–+O₂). All xenobiotics tested, except lindane, showed synergistic interactions with ferric/EDTA indicative of redox cycling of the xenobiotic. Inhibition of menadione- and nitrofurantoin-stimulated ·OH production by superoxide dismutase (50% inhibition) and catalase (80%) indicated respectively the involvement of O ₂ ^– and H₂O₂ in ·OH production. Maximal rates of KMBA oxidation (Vmax in nmol ethylene/min/mg protein) were similar for NADH and NADPH for menadione (4.58–4.61) and duroquinone (0.26–0.3 [flounder] and 0.93–0.99 [perch]), higher for NADPH than NADH for nitrofurantoin (1.21 and 0.77), and higher for NADH than NADPH for BaP diones, decreasing in the order 1,6-dione (1.12 and 0.14), 3,6-dione (0.75 and 0.25), and 6,12-dione (0.31 and 0.09). Rates for lindane, lacking a redox cycling structure, were low (0.01–0.05). Apparent K_m (app. K_m) values for xenobiotic were 1–2 orders of magnitude lower for BaP diones than the other compounds. App. K_m was lower for NADH than NADPH for 3,6-dione (1.23 and 1.66 M) and 6,12-dione (0.85 and 1.81 M), but the reverse of this was found for the 1,6-dione (1.41 and 0.78 M). App. K_m values were almost identical for menadione and duroquinone and lower for NADPH (32–44 M) than NADH (346–382 M). The reverse was seen for nitrofurantoin, viz., 76 M (NADH) and 269 M (NADPH). Hepatic 1000 g supernatants of P. flesus metabolized BaP to oxyradical-generating products, moreso for -naphthoflavone-induced than control fish, and production was reduced by UDP-glucuronic acid for the latter but not the former. The studies indicate a widespread potential for contaminant-stimulated oxyradical generation via redox cycling and other free radical interactions of xenobiotics and their metabolites.     

Induction of CYP1A in Primary Cultures of Rainbow Trout (Oncorhynchus mykiss) Liver Cells: Concentration–Response Relationships of Four Model Substances

The study aims to evaluate short-term teleost hepatocyte cultures to establish dose-response curves for CYP1A induction and to rank the relative potencies of xenobiotics. Hepatocytes isolated from rainbow trout (Oncorhynchus mykiss) were incubated in vitro in coculture with RTG-2 cells in serum-free, chemically defined medium. Concentration-dependent induction of cytochrome P4501A was observed after treatment of the hepatocytes for 48 h with one of the four polyaromatic hydrocarbons: 3-methylcholanthrene, benzo[a]pyrene, benz[a]anthracene, and beta-naphthoflavone. The induction response was assessed by measuring 7-ethoxyresorufin-O-deethylase (EROD) and 7-ethoxycoumarin-O-deethylase (ECOD). From the data, EC50 and maximal induction response values were calculated. The rank order of EC50 values differed among the four model compounds, depending on the endpoint parameter. EC50 values for EROD and ECOD also differed in comparison to published affinity data for mammalian arylhydrocarbon receptor. The results of this study indicate the potential of primary teleostean hepatocyte cultures for studies on induction potency and regulation of piscine cytochrome P4501A. A drawback, however, appears to be the pronounced interindividual variation of the quantitative response of the cells.     

The content of polychlorinated hydrocarbons in Arctic mammals

Summary 17 fat tissue samples of four different Arctic seals species shot in Greenland, fat samples of one polar bear, two polar foxes and one sheep from south west Greenland were assayed for polychlorinated hydrocarbons (PCHC), aldrin, heptachlor, heptachlorepoxide, lindane, raw DDE and PCB.Raw pp 'DDE and PCB were found in all specimens in highest amount, peak values of pp 'DDE were found in the polar bear and highest amount of PCB was found in a hooded seal.Aldrin was also found in most samples, but only trace amounts of lindane, heptachlor and its epoxide were found variably. In PCHC content great variation from specimen to specimen was found in all species.The data obtained are discussed in relationship to the possible sources of PCHC contamination of the Arctic.     

Comprehensive pediatric primary care vs traditional care in an israeli population: Their influence on pediatric emergency room use and hospitalization

Emergency room (ER) utilization and hospitalization were studied as indicators of the impact of improvements in pediatric primary care services in an Israeli development town, Ofakim, population 12,000. One of the two pediatric services was upgraded in 1976 through the introduction of pediatric faculty, integration of preventive and curative services and conversion of the medical records to a problem-oriented format ( experimental clinic B ). The primary care system remained unchanged in the second clinic ( traditional clinic A ). During 1980, ER utilization by the B clinic population was 9.3/100 compared with 17.6/100 for the A clinic population. Fifty two percent of the B clinic population patients reaching the ER were hospitalized compared with 25% of A clinic patients.The lower ER utilization rate represents a significant saving for the health services, and educational interventions are suggested from the study. Analysis of ER utilization data seems to offer useful information for overall planning and monitoring of ambulatory services for a community.Corresponding author.     

Monitoring of Antifouling Booster Biocides in Water and Sedimentfrom the Port of Osaka, Japan

Concentrations of booster antifouling compounds in the port of Osaka, Japan were assessed. Concentrations of Sea-Nine 211 (4,5-dichloro-2-n-octyl-3-isothiazolone), thiabendazole (2-(4-thiazolyl)-benzimidazole), IPBC (3-iodo-2-propynyl butylcarbamate), Diuron (3,4-dichlorophenyl-N, N-dimethylurea), Irgarol 1051 (2-methylthio-4-t-butylamino-6-cyclopropylamino-s-triazine), and M1 (2-methylthio-4-t-butylamino-6-amino-s-triazine) in port water samples were in the range of <0.003–0.004 g L^–1, <0.0008–0.020 g L^–1, <0.0007–1.54 g L^–1, <0.0008–0.267 g L^–1, and <0.0019–0.167 g L^–1, respectively. IPBC was not detected in the water samples, but the concentration of Diuron was higher than any previously reported. The concentrations of Sea-Nine 211, thiabendazole, Diuron, Irgarol 1051, and M1 in sediment samples were in the range of <0.04–2.4 g kg^–1 dry, <0.08–1.2 g kg^–1 dry, <0.64–1350 g kg^–1 dry, <0.08–8.2 g kg^–1 dry, and <0.18–2.9 g kg^–1 dry, respectively. IPBC was again not detected. The levels of Sea-Nine 211, Diuron, and Irgarol 1051 in water and sediment samples were high in a poorly flushed mooring area for small and medium-hull vessels. Levels of Diuron and Irgarol 1051 were highest in summer. The concentration of Sea-Nine 211 in water increased between August and October 2002. Except for M1, increases in the levels of booster biocides in sediment were observed during the study period. The sediment–water partition (Kd) was calculated by dividing the concentrations in sediment by the concentrations in water. The Kd values for Sea-Nine 211, thiabendazole, Diuron, Irgarol 1051, and M1 were 690, 180, 2700, 300, and 870. The Kd value for these alternative compounds was lower than for TBT.     

Measuring the impact of onychomycosis on patient quality of life

According to survey research, onychomycosis, a fungal infection of the toenail or fingernail, affects quality of life including physical and social functioning and emotional health. We developed an onychomycosis disease-specific questionnaire (ODSQ) that sensitively assessed symptom distress, functional impact, and social stigma associated with the disease. Samples of patients enrolled in a randomized controlled clinical trial were used for the psychometric evaluations. The multi-item scales were internally consistent ( 0.80) and reproducible (ICC > 0.85). Interscale correlations between the ODSQ and generic scales were moderate and consistent with the hypothesized magnitude and directions. Construct validation, employing known groups analysis, supported the hypothesized impact of onychomycosis on three domains of quality of life: physical functioning, emotional health, and social functioning. Significant differences were found between clinically cured, improved, or failed patients, and between mycologically eradicated and persistent patients. The ODSQ was responsive to clinical change and more sensitive than derived Medical Outcomes Study Short Form-36 scales. The ODSQ provides reliable, validated and responsive information about the consequences of onychomycosis and its treatment.     

Sublethal effects of esfenvalerate pulse-exposure on spawning and non-spawning Australian crimson-spotted rainbowfish (Melanotaenia fluviatilis)

The spawning activity of the Australian crimson-spotted rainbowfish (Melanotaenia fluviatilis) was monitored over a period of nine days. After the first three days, groups of rainbowfish were pulse-exposed with the pyrethroid insecticide esfenvalerate at one of six nominal concentrations (0, 1, 3.2, 10.0, 32.0, or 100 /L). The effects of esfenvalerate on fecundity, total hatch, hatchability of eggs, frequency of hatch defects, and the survival and growth of subsequent larvae were monitored. Hepatic cytochrome P-450 activity (ECOD, EROD, EFCOD) was measured six days post-exposure in controls and fish exposed to 32 g/L esfenvalerate. Cytochrome P-450 activity was also measured in single sex populations of male and female rainbowfish similarly exposed. The effects of esfenvalerate pulse-exposure on the lymphoproliferation of immune cells isolated from spawning and non-spawning groups of rainbowfish were examined in a second experiment.Over 75% of fish pulse-exposed to 100 g/L esfenvalerate died, and males in all treatments were more strongly affected than females. There was a negative correlation between pesticide concentration, fecundity, and total hatch. All eggs laid in the first three days post-exposure failed to hatch in some treatments, although esfenvalerate pulse-exposure did not increase the prevalence of deformed larvae. Esfenvalerate pulse-exposure significantly increased hepatic ECOD activity in male rainbowfish but had no effect on male EROD or EFCOD activities. There was no significant effect of esfenvalerate pulse-exposure on hepatic EROD, ECOD, or EFCOD activities of female rainbowfish. Unstimulated lymphocyte proliferation was lower in treated female rainbowfish than non-exposed female fish, and there was some evidence of an interaction with spawning activity.     

温石棉对A549细胞细胞色素P4501A1和谷胱甘肽S转移酶活性的影响

目的：探讨温石棉对体外培养细胞中外源性化合物代谢酶活性的影响。方法：采用不同剂量的UICC温石棉（UC）和国产茫崖温石棉（MC）分别作用于A549细胞,测A549细胞中细胞色素P4501A1（CYPA1）和谷胱甘肽S转移酶（GST）活性,并用苯并（a)芘对酶活性进行诱导,再测定温石棉对2种酶诱导活性的影响。结果：UC与A549细胞作用24h,乙氧基异酚恶唑－O－去乙基酶（EROD）活性随剂量增加呈缓慢递趋势,200mg/L UC可使EROD活性升高40％,但200mg/L UC作用48h则使其活性下降32％,提示UC对A549细胞EROD活性的影响呈现低剂量短时间诱导,而高剂量长时间抑制的趋势,MC对EROD活性的影响呈现多向性,无论作用24h还是48h,25mg/L UC作用48h则使其活性下降32％,提示UC对A549细胞EROD活性的影响呈现低剂量短时间诱导,而高剂量长时间抑制的趋势,MC对EROD活性的影响呈现多向性,无论作用24h还是48h,25mg/L的MC诱导作用最强（分别为对照组的1．86和1．28倍）,但随MC剂量增大和作用时间延长,EROD活性也随之下降,最低仅为对照组的35％,UC作用对GST的影响不明显,最高仅使GST活性升高20％,MC在25mg/L时驿GST的诱导最强,为对照组的1．4倍,但随着剂量的增加,对GST活性的上诱导转为抑制,200mg/L时GST活性下降了18．7％,先用温石棉与A549细胞作用24h,再加入苯并(a)芘对酶活性进行诱导,发现无论是UC还是MC,均未对苯并(a)芘诱导的EROD活性产生明显影响。但200mg/L的UC和100mg/L的MC均可增加GST的诱导活性。结论：不同剂量温石析对EROD和GST活性表现出不同的效应,其原因可能与2种温石棉的物理化学特性及表面活性有关。     

Tissue-specific induction of EROD activity and CYP1A protein in Sparus aurata exposed to B(a)P and TCDD

The purpose of this study was to compare xenobiotic CYP1A induction in liver, gills, and excretory kidney of gilthead seabream, Sparus aurata. Fishes were exposed via water for 20 days to different concentrations of benzo(a)pyrene (B(a)P) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). CYP1A was measured at the enzyme activity level as 7-ethoxyresorufin-O-deethylase (EROD) activity, and at the protein level by means of ELISA. The liver displayed the highest absolute levels of EROD activity, both under non-exposed and exposed conditions. Organ- or inducer-related differences in the time course of CYP1A induction were moderate; however, the magnitude of the induction response varied between the organs and between B(a)P and TCDD. In the case of TCDD, liver, and kidney yielded a comparable induction response, whereas in the case of B(a)P, the kidney showed a substantially higher maximum induction factor than the liver. In the gills, the two xenobiotics resulted in similar maximum induction factors. In B(a)P-exposed seabream, EROD activities and CYP1A protein levels showed a good correlation in all three organs, whereas with TCDD as inducer the correlation was poor, what was mainly due to a decrease of EROD activities at the higher concentrations of TCDD, while CYP1A protein levels showed no concomitant decline. Overall, the study revealed both similarities and differences in the time-, concentration-, and inducer-dependent CYP1A responses of the three target organs, liver, kidney, and gills. Although, the findings of this study principally confirm the notion of the liver as the major metabolic organ in fish, they also provide evidence for substantial metabolic potential in gills and particularly in the kidney.     

DDT contamination in selected estuarine and coastal marine finfish and shellfish of New Jersey

Analysis of DDT contamination in selected finfish and shellfish species from estuarine and coastal marine waters of New Jersey (USA) reveals consistently highest organochlorine pesticide levels in samples from the north and northeast regions of the state. The mean concentrations of DDT and its metabolites, DDE and DDD, in bluefish, striped bass, weakfish, and blue crabs collected at 27 stations throughout the state between 1988 and 1991 ranged from <25 to >300 g/kg wet weight (wet wt). Gas chromatographic analysis of 175 tissue samples from these four species showed that the highest levels of DDTs (DDT plus DDE and DDD), exceeding 300 g/kg wet wt, occurred in blue crabs (hepatopancreas) from the Hudson—Newark—Raritan Bay complex in the northeast region. Lower mean concentrations of DDTs (<200 g/kg wet wt) were recorded in tissue samples of these species from all other regions of the state. The lowest levels of DDT contamination (mean <110 g/kg wet wt) were found in samples from the south coast region. The greatest impact of DDT contamination is nearby metropolitan areas of the state, although the total concentrations of DDT in tissue samples from these areas are far less than the U.S. Food and Drug Administration action level of 5,000 g/kg wet wt for this contaminant.     

Duckweed Lemna minor as a tool for testing toxicity of coal residues and polluted sediments

Duckweed, Lemna minor, was used for testing single elements and leachates of coal ashes and sediments by expressing growth as surface coverage. The EC₅₀ for the elements Cd, Cu, Zn, As(III), As(V), Se(IV), Se(VI), SeO₂ were 0.86, 2.2, 4.4, 8.4, 297, 21, 67, 37 M, respectively. Leachates were tested of pulverized coal fuel ash (PFA), including low NOx ashes, coal gasification slag (CGS), and, as a reference, the polluted sediments of a canal. The concentrations of elements in leachates of low NOx PFA were higher than those in leachates of conventional PFA. The leaching of anions from PFA was more quickly than the cations. CGS showed an absolutely minimal element leaching. Comparison of the effects of conventional PFA with sediments from Rotterdam harbor, River Rhine, and the canal shows PFA to be the far less toxic one. The sediment samples from the canal demonstrated strong growth inhibition, probably due to high zinc concentrations originating from industrial activity.     

Trichothecene mycotoxins in the dust of ventilation systems in office buildings

Summary Analysis of trichothecene mycotoxins in dust samples from ventilation systems of office buildings was applied as a rapid and inexpensive method for the detection of mycotoxins. Dust samples from three different office spaces of the Montreal urban area, reportedly affected by the sick buildings syndrome, were analysed by thin-layer chromatography (TLC). Positive colour reaction on TLC plates with 4-(p-nitrobenzyl) pyridine, specific for the 12,13-epoxy group in the trichothecene nucleus, was obtained for the extracts of 0.5- to 50-g dust samples. The dust samples contained at least four trichothecenes: T-2 toxin, diacetoxyscirpenol, roridine A and T-2 tetraol. The results were confirmed by high-performance liquid chromatography analysis. Screening of dust samples from air ventilation systems of reportedly affected buildings provided direct evidence of trichothecene mycotoxins, with the detection limit estimated as 0.4-4 ng/mg dust. Thus, the dust sample analysis is suggested as a rapid technique for detecting the presence of mycotoxins in the dust of ventilation systems.     

Short-term exposure of zooplankton to the synthetic pyrethroid,fenvalerate, and its effects on rates of filtration and assimilation of the alga,Chlamydomonas reinhardii

In acute tests of toxicity, two cladocerans,Daphnia galeata mendotae andCeriodaphnia lacustris, and the calanoid,Diaptomus oregonensis, were more sensitive to fenvalerate thanDaphnia magna, the organism used in standard laboratory bioassays. The 48-hr EC₅₀s for each species/stage in order of increasing sensitivity were adultD. magna — 2.52 g/L;D. magna (48-hr old) — 0.83 g/L; adultD. galeata mendotae — 0.29 g/L; adultC. lacustris — 0.21 g/L;D. galeata mendotae (48-hr old) — 0.16 g/L; adultDiaptomus oregonensis — –0.12 g/L. No toxicity was observed when these organisms were exposed to a range of concentrations of the emulsifiable concentrate without fenvalerate (the EC blank).Rates of filtration of the¹⁴C-labelled alga,Chlamydomonas reinhardii byD. galeata mendotae, C. lacustris andD. oregonensis were decreased significantly at sublethal concentrations of fenvalerate after only 24-hr exposure.Ceriodaphnia lacustris showed the greatest sensitivity with rates of filtration significantly decreased at 0.01 g fenvalerate/ L. Concentrations of fenvalerate 0.05 g/L resulted in decreased rates of filtration byD. galeata mendotae. A concentration of 0.10 g fenvalerate/ L caused rates of filtration to increase inD. oregonensis. whereas 0.05 and 0.5 g/L resulted in a decrease in these rates.Rates of assimilation of algae byD. galeata mendotae, C. lacustris andD. oregonensis exposed to similar concentrations of fenvalerate were decreased at concentrations 0.05 g fenvalerate/L. Changes in rates of assimilation were not as sensitive a parameter of toxicity as changes in rates of filtration. The EC blank had no significant effects on rates of filtration or assimilation for all three species.     

Serum hexachlorocyclohexane residues in workers engaged at a HCH manufacturing plant

Summary The accumulation of hexachlorocyclohexane, one of the most commonly used chlorinated insecticides, was studied in a high-risk group of people who are exposed during its manufacturing process. The serum HCH concentration was estimated by quantitating its , , and -isomers with the help of GLC analysis. Exposed workers involved in maintenance work were found to have 3 times higher HCH residues than the controls, while in the plant operators and supervisors the levels were 5 times higher. The most severely exposed were the handlers who are in direct contact with the insecticide. The level of serum HCH residues in them was found to be about 12 times higher than those in the controls. The percentage composition of the insecticide, with respect to the different isomers, varied up to 20% for the -isomer, up to 30% for -isomer and had between 60%–100% of the -isomer in the samples. The serum levels of the insecticides were clearly related to the workers' job-related close contact, intensity, frequency, and the duration of their exposure. The total of HCH residues in the sera studied were in the range of 0.143–1.152 ppm. The importance of these findings and the relevant protective measures are discussed.