A study on the lethal toxicity of aminocarb to freshwater crayfish and its in vivo metabolism

Adult crayfish (Orconetes limosus) were exposed to 0.1, 1.0, 5.0, 10.0, 25.0, 30.0, 40.0, 50.0 and 60.0 ppm of aminocarb in water at 15 degrees C under laboratory conditions for 144 h. No apparent behavioral changes were observed in crayfish exposed to 0.1, 1.0 and 5.0 ppm of aminocarb during the experiment. Symptoms of acute toxicity were apparent at concentrations greater than or equal to 10 ppm, and mortality occurred at and above 25 ppm. The LC50, 96 h, to adult crayfish was about 33 ppm. The parent compound and its metabolites, MA (4-methylamino-m-tolyl N-methylcarbamate) and AM (4-amino-M-tolyl N-methylcarbamate), were detected in crayfish 96 h after exposure to various concentrations of aminocarb. The primary metabolite detected was MA which accounted for 75% to 95% of the body residue. The highest total residue (Aminocarb + MA + AM) was 40 ppm detected in crayfish exposed to 60 ppm of aminocarb for 96 h.     

Pentachlorotoluene and pentabromotoluene: results of a subacute and a subchronic toxicity study in the rat

Pentachlorotoluene (PCT) and pentabromotoluene (PBT) are environmental contaminants detected in the Great Lakes ecosystem. In view of the paucity of toxicity data and the potential for human exposure, a subacute (28 day) and a subchronic (91 day) study were conducted in the rat. In the subacute study, groups of 10 male and 10 female rats were fed the diet containing PCT or PBT at 0, 0.5, 5.0, 50 or 500 ppm for 28-days. In the subchronic study, the group size was increased to 15, the dose levels were 0, 0.05, 0.5, 5.0, 50 and 500 ppm in the diet and the exposure period was 91 days. Growth rate and food consumption were not affected by exposure to either chemical in the subacute and subchronic study. Clinical observations revealed no abnormalities. Decreased hemoglobin was observed in female rats fed 5.0 ppm PCT and higher levels in the subacute (28 day) study. In the same study the hematocrit value and erythrocyte numbers of females fed 5.0 or 500 ppm PCT diets were significantly lower than the control. In both subacute and subchronic studies mild dose-dependent histopathological changes were observed in the thyroid, liver and kidney of rats fed PCT and PBT diets. In general male rats were more susceptible than females to the treatment of PCT and PBT. Based on these data, it was concluded that the no observable adverse effect level for PCT was 50 ppm in the diet (3.5 mg/kg b.w./day) and that of PBT was 5.0 ppm (0.35 mg/kg b.w./day).     

Effects of pH on the mortality and accumulation of copper in tissues of Oreochromis niloticus

In the present study, effect of pH on the mortality and accumulation of copper in various tissue and organs of Oreochromis niloticus were tested at varying concentrations of copper in the medium and over different periods of time. Experimental animals were exposed to pH 5.5, 7.8 and 9.5 and 0.1, 0.5, 1.0 and 5.0 ppm copper over periods of 7, 15 and 30 days in liver, gills and muscle were determined using atomic absorption spectrophotometric techniques. The rate of mortality at 1.0 and 5.0 ppm Cu was 100% after 7 days of exposure at pH 5.5 while at 5.0 ppm Cu was 66% after 30 days of exposure at pH 7.8. No mortality was observed in any of the copper concentrations tested at pH 9.5. In all pH levels, tissue accumulation of copper increased with increasing concentrations of copper in the medium at a given exposure period. In all pH values tested, highest levels of copper were found in the liver of O. niloticus, followed by the gills and muscle tissues. Accumulation of copper in all tissues were higher at pH 5.5 compared with the other pH values in all the conditions tested.     

Pentachlorotoluene and pentabromotoluene: Results of a subacute and a subchronic toxicity study in the rat

Abstract

Pentachlorotoluene (PCT) and pentabromotoiuene (PBT) are environmental contaminants detected in the Great Lakes ecosystem. In view of the paucity of toxicity data and the potential for human exposure, a subacute (28 day) and a subchronic (91 day) study were conducted in the rat. In the subacute study, groups of 10 male and 10 female rats were fed the diet containing PCT or PBT at 0, 0.5, 5.0, 50 or 500 ppm for 28‐days. In the subchronic study, the group size was increased to 15, the dose levels were 0, 0.05, 0.5, 5.0, 50 and 500 ppm in the diet and the exposure period was 91 days. Growth rate and food consumption were not affected by exposure to either chemical in the subacute and subchronic study. Clinical observations revealed no abnormalities. Decreased hemoglobin was observed in female rats fed 5.0 ppm PCT and higher levels in the subacute (28 day) study. In the same study the hematocrit value and erythrocyte numbers of females fed 5.0 or 500 ppm PCT diets were significantly lower than the control. In both subacute and subchronic studies mild dose‐dependent histopathological changes were observed in the thyroid, liver and kidney of rats fed PCT and PBT diets. In general male rats were more susceptible than females to the treatment of PCT and PBT. Based on these data, it was concluded that the no observable adverse effect level for PCT was 50 ppm in the diet (3.5 mg/kg b.w./day) and that of PBT was 5.0 ppm (0.35 mg/kg b.w./day).     

Tetrachloroethylene emissions and exposure in dry cleaning

Tetrachloroethylene (PCE) emissions and the exposure of workers in six commercial and three industrial dry-cleaning establishments that use dry-to-dry machines were determined. The personal samples and area samples [8-hr time-weighted average (TWA) and short-term exposure] were collected with charcoal tubes and passive monitors. The temporal variation of PCE concentration in the workplace air was monitored using a Fourier transform infrared analyzer (FTIR). The PCE emission rates were determined by multiplying the average PCE concentration in the room and the total airflow rate in the room. The PCE emissions were related to the cleaning rate in units of kg/hr. The operators' mean TWA exposure in commercial shops and industrial establishments was 28 (4.1 ppm) and 32 mg/m3 (4.6 ppm), and the pressers' exposure was 3.4 (0.5 ppm) and 7.7 mg/m3 (1.1 ppm), respectively. The customer service personnel had the lowest TWA exposure with a mean value of 0.8 mg/m3 (0.1 ppm). The highest peak concentration (2300 mg/m3; 334 ppm) was observed during cleaning of the lint and button trap, during which operation respirators were used. The PCE emission rates ranged from 4 to 118 g/hr corresponding to emission factors (mass of solvent evaporated per mass of cleaned cloths) of 0.3-3.6 g/kg. The workers' exposure to PCE was below the occupational limit values in the United States [according to the American Conference of Governmental Industrial Hygienists (ACGIH)] and in Finland. The outdoor PCE emissions were clearly below the limit values given in the European Union volatile organic compound (VOC) directive requirements.     

Formaldehyde Dose-Response in Healthy Nonsmokers

Industrial, commercial, and domestic levels of formaldehyde exposure range from <0.1 to >5.0 ppm. Irritation of the eyes and upper respiratory tract predominate, and bronchoconstriction is described in case reports. However, pulmonary function and irritant symptoms together have not been assessed over a range of HCHO concentrations in a controlled environment. We investigated dose response in both symptoms and pulmonary function associated with 3-h exposures to 0.0-3.0 ppm HCHO in a controlled environmental chamber. Ten subjects were randomly exposed to 0.0, 0.5, 1.0, and 2.0 ppm HCHO at rest plus 2.0 ppm HCHO with exercise and nine additional subjects were randomly exposed to 0.0,1.0,2.0, and 3.0 ppm HCHO at rest plus 2.0 ppm HCHO with exercise. Significant dose-response relationships in odor and eye irritation were observed (p < 0.05). Nasal flow resistance was increased at 3.0 ppm (p < 0.01), but not at 2.0 ppm HCHO. There were no significant decrements in pulmonary function (FVC, FEV₁, FEF_25-75%, SGaw) or increases in bronchial reactivity to methacholine (log PD_35SGaw) with exposure to 0.5-3.0 ppm HCHO at rest or to 2.0 ppm HCHO with exercise.     

In vitro effect of profenofos, fenvalerate and dimilin on protein and RNA biosynthesis by rabbit liver and muscle tissues

The present study was carried out to investigate the effect of Curacron (profenofos), Sumicidin (fenvalerate) and Dimilin (difluobenzuron) on the in vitro rate of protein and RNA synthesis by rabbit liver and muscle tissues. The synthesis of protein and RNA were significantly stimulated in the liver and inhibited in the muscle by graded doses of these insecticides. Profenofos showed maximum effect on protein synthesis in both tissues at a dose of 0.2 microgram/mL, while the maximum effect on RNA synthesis occurred at 0.2 microgram/mL, while the maximum effect on RNA synthesis occurred at 0.2 microgram mL in the liver and at 2 micrograms/mL in the muscle. Fenvalerate caused maximum stimulation in both liver protein and RNA synthesis at a dose of 2 micrograms/mL, and maximum inhibition in the muscle at 10 and 0.2 micrograms/mL for protein and RNA synthesis respectively. The maximum effect of Dimilin on both tissues was reached at 5 micrograms/mL for protein synthesis and at 0.2 microgram/mL for RNA synthesis. The effect of Dimilin on RNA synthesis was more pronounced in both tissues than its effect on protein synthesis, but this trend was reversed in the case of profenofos and fenvalerate. Present data also showed antagonism between these insecticides on the rate of protein and RNA synthesis.     

Cyanide residue levels in extracted honey, comb honey and wax cappings.

Cyanide (CN) residue levels were determined in samples of extracted honey, comb honey and was cappings at 1 hr, 24 hr, and 48 hr intervals after destroying the bees in honey bee colonies with normal (ca. 8.5 g) and twice normal (ca. 17 g) doses of CyanogasR A-dust. Applications of CyanogasR A-dust, administered by means of a dust pump at normal and twice normal doses, gave an average residue of 0.01 and 0.04 microgram CN/g of extracted honey, 0.01 and 0.02 microgram CN/g of comb honey and 0.04 and 0.06 microgram CN/g of wax cappings, respectively. When the CyanogasR A-dust (ca. 17 g) was placed on a tray and placed on the bottom board of the hive, the average residue levels for extracted honey, comb honey and wax cappings were less than 0.004, 0.01 and 0.02 microgram CN/g, respectively. Random honey samples from beekeepers, who used CyanogasR to destroy bees, had a median level of 0.031 microgram CN/g, whereas honey from a packing plant and other commercial samples contained less than 0.004--0.026, median less than 0.004 microgram CN/g. Based on residue data from this study, the temporary registration for CyanogasR, to kill honey bees after crop removal, was revised to a full registration in May 1977.     

Residues of EBDC fungicides and ETU in experimental and commercial beverages (beer and wine)

Residues of EBDC (ethylenebisdithiocarbamate) fungicides and ETU (ethylenethiourea; 2-imidazolidinethione) were monitored in beers and wines from different locations. No EBDC residues were detected in any of the samples examined. Concerning the ETU residues, the residue levels higher than the limit of method detection (0.01 ppm) were 22.6% and 7.3% in the commercial beer and wine samples respectively, but the number of samples containing more than 0.1 ppm of ETU was practically negligeable.     

Development of emission factors for polycarbonate processing

Emission factors for selected volatile organic compounds (VOCs) and particulate emissions were developed while processing eight commercial grades of polycarbonate (PC) and one grade of a PC/acrylonitrile-butadiene-styrene (ABS) blend. A small commercial-type extruder was used, and the extrusion temperature was held constant at 304 degrees C. An emission factor was calculated for each substance measured and is reported as pounds released to the atmosphere/million pounds of polymer resin processed [ppm (wt/wt)]. Scaled to production volumes, these emission factors can be used by processors to estimate emission quantities from similar PC processing operations.     

Development of Emission Factors for Polycarbonate Processing

Abstract

Emission factors for selected volatile organic compounds (VOCs) and particulate emissions were developed while processing eight commercial grades of polycarbonate (PC) and one grade of a PC/acrylonitrile-butadiene-styrene (ABS) blend. A small commercial-type extruder was used, and the extrusion temperature was held constant at 304 °C. An emission factor was calculated for each substance measured and is reported as pounds released to the atmosphere/million pounds of polymer resin processed [ppm (wt/wt)]. Scaled to production volumes, these emission factors can be used by processors to estimate emission quantities from similar PC processing operations.     

PCBs and DDT in Saginaw Bay white suckers

Fillets from 25 white suckers ( ) obtained from the Saginaw Bay, Lake Huron commercial fishery were analyzed for PCBs and ∑DDT (DDE-DDD-DDT). PCB levels ranged from 0.01 – 0.18 ppm while ∑DDT levels ranged from < 0.001 – 0.044 ppm. These results, combined with previous survey data, indicate steady declines in the levels of these contaminants in Saginaw Bay suckers.     

Speciation and uptake of arsenic accumulated by corn seedlings using XAS and DRC-ICP-MS

ICP-MS was used to investigate the uptake of As(III) and As(V) from hydroponics growth media by corn seedlings. It was found that arsenic uptake by the plant roots for the arsenic(V) and arsenic(III) treatments were 95 and 112 ppm, respectively. However, in the shoots of the arsenic (V) treatments had 18 ppm whereas arsenic(III) treatments had 12 ppm. XANES studies showed that As for both treatments arsenic was present as a mixture of an As(III) sulfur complex and an As(V) oxygen complex. The XANES data was corroborated by the EXAFS studies showing the presence of both oxygen and sulfur ligands coordinated to the arsenic. Iron concentrations were found to increase by 4 fold in the As(V) contaminated growth media and 7 fold in the As(III) treatment compared to the control iron concentration of 500 ppm. Whereas, the total iron concentration in the shoots was found to decrease by approximately the same amount for both treatments from 360 ppm in the control to approximately 125 ppm in both arsenic treatments. Phosphorus concentrations were found to decrease in both the roots and shoots compared to the control plants. The total sulfur in the roots was found to increase in the arsenic(III) and arsenic(V) treatments to 560 ppm and 800 ppm, respectively, compared to the control plants 358 ppm. In addition, the total sulfur in shoots of the plants was found to remain relatively constant at approximately 1080 ppm. The potassium concentrations in the plants were found to increase in the roots and decrease in the shoots.     

Effect of squalane on hexachlorobenzene (HCB) concentrations in tissues of mice

Abstract

Female mice were given 100 mg HCB/kg body weight i.p. and fed diets containing 0, 2.5, 5.0, and 7.5% of squalane. After 3 weeks samples of livar, blood and abdominal fat ware analysed for HCB as well as for squalane. HCB concentrations were significantly lowered as comoared to controls in all tissues and at all dietary concentrations of squalane to a maximum of about 36% in fat, 44% in liver and 47% in blood. The effect of squalane upon HCB concentrations was strongly dose depedent in abdominal fat. In contrast, no significant differences were seen with liver and blood between animals fed 5.0 or 7.5% of squalane. Squalane was detected in considerable amounts in the livers (50–100 ppm) but r.ct in abdominal fat (<1 ppm) of mice fed squalane.     

Mortality response and LC50 values for juvenile and adult crayfish, Procambarus clarkii exposed to Thiodan (insecticide), Treflan, MSMA, Oust (herbicides) and Cutrine-Plus (algicide)

Toxicities of three herbicides (Treflan, MSMA and Oust), an algicide (Cutrine-plus) and an insecticide (Thiodan) to juvenile (3.0-3.4 cm) and adult (9.0-10.0 cm) crayfish, Procambarus clarkii, were determined by 96 h static bioassays. Freshly prepared 0.01% and 1.0% aqueous stock solutions of these pesticides were diluted to desired concentrations. Mortalities were recorded each day up to 96 h. Aged tap-water was used for preparing all test solutions. Per cent mortalities were analyzed for linear regression and LC(50) values were computed by probit analysis. LC(50) values for juvenile P.clarkii in the descending order of toxicity were: 24 ppb Thiodan, 13 ppm Treflan, 101 ppm MSMA, 461 ppm Cutrine-plus, 12,174 ppm Oust; and for adults these values were: 423 ppb Thiodan, 26 ppm Treflan, 1019 ppm MSMA and 2945 ppm Cutrine-plus. No LC(50) values for adult crayfish could be computed for Oust herbicide which caused no mortalities up to 60,000 ppm concentration. Comparing the overall toxicities of these pesticides, Thiodan was the most toxic to all crayfish; followed by Treflan, MSMA, Cutrine-plus and Oust. Oust was more than 1/2 million times less toxic than Thiodan to juvenile crayfish. Published LC(50) values indicate that freshwater crayfish are more tolerant than marine decapods, Crangon septemspinosa and Mysidopsis bahia, to Thiodan insecticide and Treflan herbicide.     

Tetrachloroethylene Emissions and Exposure in Dry Cleaning

ABSTRACT

Tetrachloroethylene (PCE) emissions and the exposure of workers in six commercial and three industrial dry-cleaning establishments that use dry-to-dry machines were determined. The personal samples and area samples [8-hr time-weighted average (TWA) and short-term exposure] were collected with charcoal tubes and passive monitors. The temporal variation of PCE concentration in the workplace air was monitored using a Fourier transform infrared analyzer (FTIR). The PCE emission rates were determined by multiplying the average PCE concentration in the room and the total airflow rate in the room. The PCE emissions were related to the cleaning rate in units of kg/hr.

The operators' mean TWA exposure in commercial shops and industrial establishments was 28 (4.1 ppm) and 32 mg/m³ (4.6 ppm), and the pressers' exposure was 3.4 (0.5 ppm) and 7.7 mg/m³ (1.1 ppm), respectively. The customer service personnel had the lowest TWA exposure with a mean value of 0.8 mg/m³ (0.1 ppm). The highest peak concentration (2300 mg/m³; 334 ppm) was observed during cleaning of the lint and button trap, during which operation respirators were used. The PCE emission rates ranged from 4 to 118 g/hr corresponding to emission factors (mass of solvent evaporated per mass of cleaned cloths) of 0.3–3.6 g/kg. The workers' exposure to PCE was below the occupational limit values in the United States [according to the American Conference of Governmental Industrial Hygienists (ACGIH)] and in Finland. The outdoor PCE emissions were clearly below the limit values given in the European Union volatile organic compound (VOC) directive requirements.     

Terbufos residues in wheat and barley

A granular formulation of terbufos (Counter 15G) was added in-furrow at time of planting of wheat and barley. Foliage collected at several times was analyzed for total terbufos residues as terbufoxon sulfone. Maximum residues from application of 1.5 and 3.0 kg/ha were 7.4 and 10.6 ppm, respectively, in wheat foliage samples collected 10 days postseeding. Wheat foliage collected at 53 days postseeding had residues averaging 0.32 and 0.58 ppm from the 1.5 and 3.0 kg/ha applications, respectively. In 1985 residues in barley were consistently less than in wheat in 1985 with 4.4 and 7.0 ppm detected in foliage collected 10 days post application from the 1.5 and 3.0 kg/ha applications, respectively and 0.21 and 0.34 ppm detected at 53 days. Grain samples had 0.01 ppm or less residue at harvest. Straw samples had up to 0.75 ppm total terbufos residues at harvest.     

Population-level effects of the neem insecticide, Neemix, on Daphnia pulex

Although natural insecticides from the neem tree are generally perceived as less harmful to the environment than synthetic insecticides, new evidence indicates that these products may pose a risk to certain nontarget organisms. In this paper, acute and chronic effects of commercial neem insecticides on the aquatic invertebrate, Daphnia pulex were examined. The acute toxicity of two commercial neem insecticides, Neemix, Azatin and the experimental insecticide, RH-9999 to D. pulex was investigated using traditional 48 hr concentration-mortality estimates. Neemix and Azatin were equitoxic with LC50's of 0.68 and 0.57 ppm; RH-9999 was significantly less toxic with an LC50 of 13 ppm. A 10 d population growth study was conducted for Neemix and a Neemix formulation blank (Neemix devoid of the active ingredients) to determine whether the active ingredients of Neemix and/or components of the formulation were responsible for toxicity. D. pulex populations went to extinction after exposure to a Neemix concentration of 0.45 ppm azadirachtin (equivalent to the acute LC7). Neemix No Observable Effect Concentration (NOEC) and Lowest Observable Effect Concentration (LOEC) values for population growth were 0.045 and 0.15 ppm azadirachtin, respectively. The mean number of offspring per surviving female (Ro) declined in a concentration-dependent manner after exposure to Neemix with no offspring being produced after exposure to 0.45 ppm. Neemix NOEC and LOEC values for reproduction were 0.045 and 0.15 ppm, respectively. The formulation blank caused no mortality in the individuals used to start the population growth study but reduced reproduction and population growth accounting for 47% of the toxicity caused by Neemix at a concentration of 0.15 ppm. Thus, the formulation contributes substantially to the toxicity of Neemix but neem components are also toxic to D. pulex. Because the NOEC for population growth and reproduction were higher than the estimated environmental concentration of 0.035 ppm (a measure developed for forest pest mananagement), Neemix should pose little risk to populations of D. pulex.     

Organochlorine residues in roof timbers and possible implications for bats

In Britain, many species of bat regularly use buildings as roosts. DDT, DDE, dieldrin (HEOD) and gamma-HCH (lindane) have been detected in carcasses of bats that had died a short while before they were found. Roof timbers may be a source of this contamination. This study reports concentrations of organochlorines in (i) roof timbers known to have been treated in the past (spot samples; n - 17) and (ii) timbers before and after treatment with commercial permethrin formulations (pre-treatment and post-treatment samples, n = 11). Gamma-HCH was detected in 13 spot samples and HEOD in 6. Where present, mean (+/-1 SE) concentrations in wood were 15.6+/-6.5 microg g-1 WW (n = 13) and 25.0+/-11.8 microg g-1 WW (n = 6), respectively. DDT was not detected in any spot samples, but permethrin was detected in four (1264+/-567 microg g(-1) WW) samples, but not in the corresponding pre-treatment samples; in one other pair of samples, concentrations of gamma-HCH increased from 74 to 2468 microg g-1 WW after treatment. Both DDT and HEOD occurred in low (<2 microg g-1 WW) concentrations in five post-treatment samples and in one and zero pre-treatment samples, respectively; the highest dieldrin concentration measured was 30.9 microg g-1 WW. Permethrin was not detectable in any pre-treatment samples but was present in ten post-treatment samples in concentrations ranging from 93 to 2995 microg g-1 WW. The spot results suggest that low concentrations of organochlorines can persist in treated roof timbers for at least 13 years post-treatment. Occasionally, these pesticide residues in timber may be of sufficient magnitude to result in bats absorbing a substantial proportion of a lethal dose. Results also suggest that there is organochlorine contamination of permethrin formulations and that the solvents used in new applications of pesticide may re-mobilise organochlorines already present in wood.     

Natural organic compounds as alternative to methyl bromide for nematodes control

Thirty-three organic acids and furfural metabolites were examined for their nematicidal activity against plant-parasitic, free-living and predacious nematodes. Propionic acid, 2-methylhexanoic acid, lactic acid, maleic acid, and furic acid were the most effective nematicides among normal chain organic acids, branched organic acids, hydroxy/keto-acids, dicarboxylic acids and furfural metabolites, respectively. Seven of the tested compounds were found to have more than 90% mortality thus designating them as highly active nematicides. Of the highly active tested compounds, an average octanol/water log P of 0.97 was observed with a range from 0.28 to 2.64, and a Henry's Law constant averaging 2.6 x 10(- 7) atm.m3/mole. Tested chemicals with minor or low nematicidal activity showed an average log P of 1.76 with a range from 0.15 to 3.42 and a Henry's Law constant averaging 16.6 x 10(- 7) atm.m3/mole.