Carcinogenicity testing of chemicals with particular reference to organochlorine pesticides.

The organochlorine chemicals comprise a large number of pesticides that are used widely throughout the world. The organochlorine pesticides given in the diet to mice are carcinogenic for the liver. They induce not only carcinomas of the liver, particularly at the higher doses, but also carcinomas and sarcomas in other organs in rats. They cause acute and chronic liver and kidney injury, which interferes with the development of carcinomas and sarcomas in rats. The testing of chemicals for carcinogenicity, with particular reference to organochlorine pesticides, includes discussions on the following topics: classification of hepatic lesions in mice and rats, toxicity versus carcinogenicity in the testing of chemicals, a comparison of carcinomas and cirrhosis of the liver in experimental animals and humans, and the significance of laboratory carcinogenicity findings to human health.     

Evaluation of toxic and interactive toxic effects of three agrochemicals and copper using a battery of microbiotests

Three commonly used test organisms of different trophic levels (Vibrio fischeri, Pseudokirchneriella subcapitata and Daphnia magna) were exposed to selected agrochemicals (fosthiazate, metalaxyl-M, imidacloprid) and copper, in single doses or in binary mixtures. The toxicity of each single compound varied up to two orders of magnitude, depending on the test species examined. V. fischeri was the most sensitive test organism regarding fosthiazate and metalaxyl-M, indicating an IC₅₀ value of 0.20 mg/L (0.17-0.25 mg/L) and 0.88 mg/L (0.35-1.57 mg/L), respectively. Imidacloprid was the least toxic compound, indicating an EC₅₀ value on D. magna of 64.6 mg/L (43.3-122.5 mg/L) and an IC₅₀ value on V. fischeri of 226 mg/L (159-322 mg/L), while for imidacloprid at a concentration of 1000 mg/L the effect on P. subcapitata was lower than 50%. Copper was the most toxic compound towards all test organisms exhibiting the highest toxic effect on P. subcapitata, with an IC₅₀ value of 0.05 mg/L (0.003-0.008 mg/L). The toxic effects of the binary mixtures have been compared to the theoretically expected effect, resulting from a simple mathematical model based on the theory of probabilities. The independent action model was used in order to predict the theoretically expected effect. The interactive effects were mostly antagonistic or additive, while in few cases (interactive effects of metalaxyl-M and copper on V. fischeri) a synergistic mode of action was observed for some concentration combinations. Experiments showed that interactive effects of chemicals may vary depending on the test species used as well as on the chemicals and their respective concentrations. Although most of the concentrations of chemicals tested in this study are higher than the ones usually found in natural environment, the evaluation of their interactive toxic effects using a battery of bioassays may comprise a useful tool for the estimation of the environmental hazard of chemicals.     

港口液体化学品废水处理工程实例

液体化学品废水有毒有害物质多,水质波动大.采用隔油气浮/曝气生物滤池蠕动床/臭氧氧化/曝气生物滤池固定床组合工艺进行处理,COD由进水的1 200 mg/L左右降到100 mg/L以下,SS由进水的600 mg/L左右降到30 mg/L以下,出水水质达到<污水综合排放标准>(GB 8978-1996)的一级标准,可回用作生活杂用水.实际运行结果表明,该组合工艺有效、稳定,污泥产量少,可操作性强,有很好的环境效益和经济效益.     

Carcinogenicity study in rats with a mixture of eleven volatile halogenated hydrocarbon drinking water contaminants

A lifetime carcinogenicity study was carried out in Wistar rats, with a mixture of the following halogenated hydrocarbons: trichloromethane, tetrachloromethane, monobromodichloromethane, trichloroethylene, tetrachloroethylene, 1,2,-dichlorobenzene, 1,3,-dichlorobenzene, 1,4,-dichlorobenzene, 1,2,3,-trichlorobenzene, 1,2,4,-trichlorobenzene, 1,3,5-trichlorobenzene. From this mixture 0.22, 2.2, or 22 mg was added per liter drinking water representing concentrations being three orders of magnitude higher than found in several water wells. Most of the changes found in body weight, hematology and pathology correlated with intercurrent diseases or were in accordance with background pathology. With respect to incidence and time of occurrence of tumors, no significant differences were found between the control and the high dose group when lifespan correction was applied. Thus it is concluded that in the present study no significant toxic or carcinogenic effects are induced by lifetime exposure of rats to a mixture of volatile halogenated hydrocarbons in the drinking water.     

Cadmium levels in Ontario moose and deer in relation to soil sensitivity to acid precipitation

This study examines the influence of buffering capacity of the soil on the levels of cadmium in the kidney, liver and muscle of moose and white-tailed deer from nine sampling sites (four buffered and five non-buffered) in Ontario, Canada. Tissues collected from hunter-killed moose and deer during 1984 and 1985 were analysed for cadmium. Tissue from moose in the non-buffered Algonquin Park site (21.9 +/- 1.1 mg/kg wet weight) and the buffered St. Joseph Island site (12.7 +/- 3.2 mg kg-1) had the highest mean levels of kidney cadmium compared with other sites sampled in Ontario. The highest mean levels of kidney cadmium in deer were found in the non-buffered Loring site (15.1 +/- 0.8 mg kg-1) adjacent to Algonquin. From all sites, the level of cadmium was highest in kidney, lower in liver and was often undetectable in muscle. Cadmium level increased with animal age (p less than 0.05). Levels of cadmium in Ontario moose from some regions are comparable to those found in Quebec and Manitoba and are considerably higher than those of Maine and Scandinavia. Levels of cadmium in kidneys and livers of white-tailed deer in parts of Ontario are considerably lower than those in Pennsylvania. As a result of this study, the Ontario Ministry of Natural Resources, in consultation with the Ontario Ministry of Health, has recommended that the public not consume kidneys or livers of Ontario moose and deer.     

上海市白龙港城市污水处理厂中水回用工程

采用曝气生物滤池/流砂过滤器/二氧化氧工艺处理上海市白龙港城市污水处理厂的高效沉淀池出水,达到了中水回用的设计目标.该系统运行稳定,出水COD<50 mg/L、BOD5<10 mg/L、NH3-N≤10 mg/L、SS<5 mg/L、大肠杆菌<3个/L,回用作污水厂主工艺段三座高效沉淀池的加药稀释水、污泥脱水装置的加药稀释水和冲洗用水、绿化用水、道路冲洗用水等,大大节约了新水取用量,取得了良好的经济效益和社会效益.     

Accumulation of heavy metals in circumpolar willow ptarmigan (Lagopus l. lagopus) populations

A circumpolar survey of heavy metals in willow ptarmigan liver and kidney revealed considerable variations in Cd content in Canada and Scandinavia. The Cd content in central Canada was comparable with that in Scandinavia and Russia, at least for kidney. However, in both liver and kidney the median for Canada as a whole was much higher than in the other countries. Some Canadian locations had exceptionally high levels, several birds having >50 mg kg(-1) in liver and >400 mg kg(-1) in kidney. In Norway, the Cd content was highest in central mountain areas in south Norway and inland locations in the two northernmost counties. Five locations in central and north Norway showed mean Cd levels in kidney above 100 mg kg(-1). It is difficult to evaluate regional differences in Sweden, but most locations had the same Cd level as moderately contaminated locations in Norway. Cd levels in Russia were comparable to moderately contaminated locations in the other countries. Due to a high intake of willow, naturally rich in Cd, direct comparison of the Cd level in willow ptarmigan from different locations cannot reveal the effects of long-range pollution. The Pb concentration in willow ptarmigan kidney and liver varied significantly in Norway and Canada, but not in Sweden and Russia. Levels in Sweden and Russia were comparable to those in Canada and low levels in Norway. The highest median value from all locations within countries was found in Norway, both in liver and kidney. The highest Pb content was found in south Norway, indicating an effect of long-range pollution in willow ptarmigan. The level in western Canada was significantly higher than in central Canada. The Hg content in liver varied significantly from one location to another in all the countries and in kidney everywhere except Sweden. In Scandinavia, there is no distinct regional pattern. Canada had a significantly higher Hg level in central than western regions in both tissues the opposite of that found for Cd and Pb. Cu and Zn showed significant variations from one location to another in liver and kidney in Canada and Norway, but only in kidney in samples from Sweden. Comparison between western and central Canada revealed a significant difference for Cu in liver, samples from central Canada having more. There are no significant differences from one country to another, but some localities in Canada seem to have higher Cu concentrations in kidney than are found in Scandinavia and Russia.     

Conventional and toxicogenomic assessment of the acute pulmonary damage induced by the instillation of Cardiff PM10 into the rat lung

There is strong epidemiological evidence of association between PM10 (particulate matter with an aerodynamic diameter less than or equal to 10 microm) and adverse health outcomes including death and increased hospital admissions for cardiopulmonary conditions. Ambient PM10 surrogates such as diesel exhaust particles (DEP), a common component of UK PM10 have been shown to induce lung inflammation in both humans and rodents. To date, few studies have reported on the toxicological response of UK PM10 in experimental animals. This study examines the pulmonary toxicological responses in male Sprague Dawley rats following the intratracheal instillation of Cardiff urban PM10. A mild but significant change in lung permeability was observed in the lung post-instillation of a high (10 mg) dose of the whole PM10 as adjudged by increases in lung to body weight ratio and total acellular lavage protein. Such effects were less marked following instillation of a water-soluble fraction (80% of the total mass) but histological examination showed that lung capillaries were swollen in size with this treatment. In conclusion, conventional toxicological, histological and toxicogenomic studies have indicated that Cardiff PM10 exhibits low bioreactivity in the form of mild permeability changes. Differential gene expression was observed when the lung was treated with whole PM10, containing durable particles, in comparison with the water-soluble fraction of PM10 that was devoid of particles. Such changes were linked to different histopathological events within the lung.     

The influence of subcutaneously administered lead(II) acetate on the concentrations of copper, iron, and zinc in the blood, kidney, liver, and spleen of rats

The concentrations of copper, iron, lead, and zinc in the blood, kidney, liver and spleen were determined before and after subcutaneous administration of lead(II) acetate (100 mg Pb kg-1 body weight) to male albino Wistar rats. The control rats had the following concentrations (microgram g-1 dry weight) of Cu, Fe, Pb and Zn: blood, 4.5, 3200, 2.1, 182; kidney, 36, 585, 120, 92; liver, 11.1, 720, 14.3, 124; spleen, 4.5, 420, 7.0, 76. After administration of lead, rats were sacrificed after 12, 24, 48, 72 and 96 h. The Pb concentration in the blood remained constant for the first 24 h at the level of the control group (2.1 micrograms g-1) and had decreased to half that level at 96 h. The lead concentrations peaked in the organs at 110-142% of those in the control group and had decreased at 96 h to levels considerably below those in the control group. The concentrations of Cu, Fe and Zn increased in the three organs to values 117-161% found for the control group. At 96 h the concentrations of Cu, Fe and Zn in the spleen had returned to levels of the control group; the concentrations in the liver were 112-153%, and in the blood 89-93% of those of the control group. In the kidney the iron (110%) and the zinc (126%) concentrations at 96 h were higher than the control values, whereas the copper concentration was the same as the control value. The concentrations in the blood were least affected. The most drastic changes were observed in the liver.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intracellular interaction and biotransformation of arsenite in rats and rabbits

The accumulation of arsenic with time in tissues of rats and rabbits was determined by neutron activation analysis (NAA). Rats showed a steady increase in the As-concentrations with age, whereas in rabbits it was nearly the same for adults and in young animals. The metabolism of arsenic was studied in both animal species after i.p. injection of 50/μg As/kg b.w. as ⁷⁴As labelled arsenite. Eight tissues, as well as blood and urine, were analysed for ⁷⁴As content after 16 and 48 hours. The binding of ⁷⁴As to hematic and intracellular components and the chemical forms of arsenic in tissues and urine were investigated. In the plasma and the RBC-fraction of the rabbit, the As concentration decreased during the first two days, while in the rats it only disappeared from the plasma, but was retained in the RBC-fraction. Liver, kidney and lung of rabbits with the highest As concentrations at 16 and 48 hours showed a rapid clearance of As in the first 48 hours. In the corresponding tissues of the rats, the rate of decline was significantly lower, due to the higher binding of ⁷⁴As to tissue constituents. Poor binding of As to plasma proteins was seen in rabbits while in rats it was totally bound to this fraction. In the RBC, liver and kidney cytosols, however, the affinity of As for intracellular proteins was higher in both animal species but characterized by a rate of binding different between the two animal species. The amount of dimethylarsinic acid (DMA) in the tissues was significantly lower in the rat than in the rabbit, reflecting the total amount of diffusible arsenic, which was also much lower in the tissues of rats than in rabbits.     

Brain acetylcholinesterase,malondialdehyde and reduced glutathione as biomarkers of continuous exposure of tench,Tinca tinca,to carbofuran or deltamethrin

In this study, the chronic effect of the insecticides carbofuran and deltamethrin on acetylcholinesterase (AChE) activity and malondialdehyde (MDA) and reduced glutathione (GSH) levels were examined in the brain of tench. Both pesticides were evaluated in two separate experiments, and animals were exposed in a continuous flow-system to three different concentrations of carbofuran (0, 10 and 100 μg/L) and deltamethrin (0, 0.0039 and 0.039 μg/L) for 60 days. After that period, animals were kept into pesticide-free water for other 30 days. In all cases, animals were sampled every 10 days all along the experience. AChE activity was significantly inhibited in fish exposed to 100 μg/L of carbofuran, during the first 30 days of exposition, returning to basal levels after this initial period. With respect to deltamethrin exposure, AChE activity was not significantly affected. When considering MDA levels, significant changes could only be detected during the recovery period for both pesticides, with a maximum of induction at 70 and 80 days, respectively associated to the highest dose of carbofuran and deltamethrin. Similarly, GSH levels varied all along the experience, with a maximum of significant increase at day 80 of exposition to the highest dose of both pesticides. This study shows that changes in AChE brain activity in tench can be used as a biomarker of early pesticide exposition in environmental monitoring programs, whereas MDA and GSH levels could be more associated to long-term expositions. The above results confirm and broaden former observations, suggesting that more investigations are needed before these biochemical parameters can be used as biomarkers.     

Metallothionein and metal levels in cytosol of liver, kidney and brain in relation to growth parameters of Mullus surmuletus and Liza aurata from the Eastern Adriatic Sea

Two wild fish populations (Mullus surmuletus (striped red mullet) as a bottom, and Liza aurata (golden grey mullet) as a pelagic species, were sampled in Kastela Bay, Middle Dalmatia. Metallothionein (MT) and metal content (Cu, Zn, Cd) was determined in heat-treated supernatants (S50) of fish tissues. MT levels were statistically different in liver and kidney of sampled species, with highest value in kidney of M. surmuletus (31.1 +/- 7.96 micrograms mg-1 proteins). Metal levels are statistically different between all tissues. Highest metal concentrations are in liver cytosols, especially of Cu in L. aurata (6.46 +/- 3.45 micrograms ml-1 S50). High positive correlation of MT and cytosolic metals is established with Zn in liver of M. surmuletus (0.95) and with Cu in liver of L. aurata (0.69). Total length, body weight and age are mostly correlated biometric parameters with MT and soluble metal concentrations. MT and metal levels increase with age in liver cytosol of both species.     

Cadmium content of indicator and target organs in rats after graded doses of cadmium

Eleven groups of inbred Wistar rats, five males and five females in each group, received graded doses of CdCl₂, from 0–25 ppm, in the drinking water from conception until sacrifice at ten weeks of age. Litter‐size, weight and water consumption were recorded at different ages of the animals. The Cd levels of indicators as blood, hair, incisors and molars, and target organs as femur, kidney cortex, liver, spleen, heart, gastrocnemius muscle and adrenal glands were recorded by atomic absorption spectrophotometry. Cd in the drinking water had no influence on number of animals in each litter, water consumption and growth of the animals. The results further confirmed that the primary target organs of Cd were the soft tissues, but that Cd can to some degree accumulate in teeth and bone, especially molars. The Cd content of all tissues, both indicators and targets, was positively and significantly correlated with dose. The positive significant correlation between the Cd levels of hair or molars, and every target organ suggests that hair and molars of rats are very useful indicators of a Cd exposure in progress. It is supposed that rodent molars are comparable to human deciduous teeth. It is thus suggested that human deciduous teeth and human hair can be used as an indicator of a Cd exposure in progress.     

Effect of food deprivation on low level hexachlorobenzene exposure in rats

The purpose of the present study was to determine if food deprivation could modify the biological activity of hexachlorobenzene (HCB) in the rat. Male and female Wistar rats were divided into 6 groups containing 6 animals. Groups 1, 3 and 5 were fed standard control diet ad libitum for 2 weeks. For the next 4 weeks their respective diets contained 0, 20 and 100 ppm HCB. Groups 2, 4 and 6 were also fed a standard control diet for 2 weeks but at an intake of approximately 50% of those groups fed ad libitum. For the following 4 weeks food deprivation was continued but the control diets were replaced with diets containing 0, 40 or 200 ppm HCB. The parameters measured were food, body weight changes, changes in tissue weights, microsomal enzyme activity and histopathology of the liver, kidneys, adrenals and pancreas. Tissue residue profiles were established for plasma, liver, brain and adrenals. Food deprivation augmented the induction of microsomal enzyme activity by HCB in both males and females at both dose levels. Liver hypertrophy was observed in both males and females fed 200 ppm HCB and subjected to food restriction. No such effects were observed in animals receiving HCB and fed ad libitum. Food deprivation resulted in a higher plasma, liver, brain and adrenal accumulation of HCB in both males and females.     

Removal of Congo Red from Aqueous Solutions by Spent Black Tea as Adsorbent

Herein we present spent black tea as an adsorbent for the removal of Congo red dye from aqueous solutions. The effects of various parameters such as pH, time, temperature, adsorbent dosage and adsorbate dosage on dye adsorption were investigated. Batch experiments were conducted using different amount of adsorbent material (2.5–1000 mg) at varying amounts of adsorbate (5–500 mg/L) at 35°C and different pH (1–13). A maximum dye removal of >80% was achieved with an adsorbent dose of 100 mg, adsorbate concentration of 5 mg/L under pH range of 6 within 5 min at room temperature. The experimental data were modeled by Langmuir, Freundlich and Temkin isotherms and conforms to both Langmuir and Freundlich isotherms but not to Temkin isotherm. The proposed spent black tea can be effectively used as a low cost adsorbent for the removal of Congo red dye.     

Chronic exposure to sublethal hexavalent chromium affects organ histopathology and serum cortisol profile of a teleost, Channa punctatus (Bloch)

Effects of chronic exposures (one and two months) to sublethal doses of hexavalent chromium (2 and 4 mg/L potassium dichromate) on organ histopathology and serum cortisol profile were investigated and their overall impact on growth and behavior of a teleost fish, Channa punctatus was elucidated. Histopathological lesions were distinct in the vital organs gill, kidney and liver. The gill lamellae became lifted, fused, and showed oedema. Hyperplasia and hypertrophy of lamellar epithelial cells were distinct with desquamation. Hypertrophy of epithelial cells of renal tubules and reduction in tubular lumens were observed in the trunk kidney. The atrophy of the head kidney interrenal cells and decreased serum cortisol level indicated exhaustion of interrenal activity. Hepatocyte vacuolization and shrinkage, nuclear pyknosis and increase of sinusoidal spaces were observed in the liver. Abnormal behavioral patterns and reduced growth rate were also noticed in the exposed fish. The chronic hexavalent chromium exposure thus by affecting histopathology of gill, kidney (including interrenal tissue) and liver could impair the vital functions of respiration, excretion, metabolic regulation and maintenance of stress homeostasis which in the long-run may pose serious threat to fish health and affect their population.     

Environmental impact assessment - A bibliography with abstracts: by B. B. Clark,R. Bisset and P. Wathern,Mansell Publishing, 3 Bloomsbury Place,London WC1A 2QA, 1980, 516 pp. Price: $23.50

The effect of fluoride administration on zinc levels in liver, kidney and bone, and on protein content (μg/mg tissue wt) in liver and kidney was investigated by subjecting albino mice for 16 weeks to different concentrations of fluoride (0 ppm — control; 10 ppm — group I; 25 ppm — group II; 50 ppm — group III; 100 ppm — group IV; and 200 ppm — group V) in drinking water. Zinc levels decreased significantly in liver and bone of groups III, IV and V; the decrease being 17%, 25% and 44% (p < 0.005) in the case of liver, and 14% (p < 0.01), 24% (p < 0.005), and 39% (p < 0.005) in the case of bone in groups III, IV and V respsectively. Zinc depletion in the kidney of the fluoridated animals was only statistically significant (p < 0.005) in groups IV and V. Similarly the protein content also decreased in liver and kidney (in liver significant at p < 0.005, p < 0.01 and p < 0.005; in kidney significant at p < 0.005, p < 0.05 and p < 0.005 in groups III, IV and V respectively). The experimental animals, especially in groups IV (100 ppm F) and V (250 ppm F), also exhibited retardation in growth.     

Lead and cadmium in red deer and wild boar from different hunting grounds in Croatia

The concentration and relations of Cd and Pb as environmental risk factors were studied by atomic absorption spectrophotometry in the liver, kidney and muscle of free ranging wild boar (n = 94) and red deer (n = 45) from hunting grounds in four counties of north-east Croatia. In all four counties, the levels of Cd found in the kidney of red deer ranged from 2.28 to 5.91 mg/kg, and in wild boar from 3.47 to 21.10 mg/kg. The mean renal concentration of Cd was significantly higher in wild boar than in red deer from all four study areas. The mean hepatic (0.11 to 0.49 mg/kg, respectively) and muscle (0.01 to 0.04 mg/kg, respectively) Cd concentrations were similar in both species. The mean renal Cd concentration in wild boar and red deer exceeded 1 mg/kg in all four counties, ranging from 67.0% to 91.4% and from 45.5% to 69.2%, respectively. Also, the hepatic Cd/renal Cd ratio was lower than 1 in all animals. In all four counties, renal Pb concentration ranged from 0.058 to 3.77 mg/kg in red deer and from 0.056 to 11.60 mg/kg in wild boar. Hepatic Pb concentration was similar in both species (0.061 to 0.202 mg/kg in wild boar and 0.077 to 0.108 mg/kg in red deer). Because of the high Cd level in the organs of wild boar and red deer, further research is needed to identify the source of contamination in order to preserve the health of animals and humans.     

A study of occupational exposure to isopropylbiphenyls (Sure Sol-250)

Environmental and medical examinations in workers exposed to the isopropylbiphenyl (IPBs) mixture, Sure Sol-250, in a capacitor-manufacturing plant were carried out once a year for three years. Levels of the total IPBs ranged from 0.03 to 36.6 mg/m3 with a mean of 5.6 mg/m3. The time-weighted average (TWA) exposures varied between 0.3 and 1.8 mg/m3. Physical and laboratory examinations (blood cell count, liver and kidney function tests and also antipyrine metabolism were normal) revealed no adverse effects of IPBs. Based on these observations as well as on the results of our six-month oral toxicity studies in rats, not presented in this paper, we recommend a TWA-MAC (maximum allowable concentration) of 10 mg/m3 for IPBs.     

Bioaccumulation of arsenic in aquatic plants and animals near a municipal landfill

This study was conducted to assess the water quality and arsenic (As) concentrations in water, sediment, aquatic plants and animals near a municipal landfill. The As concentration in the samples was analysed using inductively coupled plasma optical emission spectrometry. Thirty-six aquatic plants of four species were collected. The highest As concentration was found in Limnocharis flava (0.78 ± 0.31 mg/kg). The aquatic animals included 31 fish of four species and 27 freshwater snails of three species. The highest As concentrations in the fish and freshwater snails were found in Oreochromis niloticus (0.16 ± 0.16 mg/kg) and Filopaludina sumatrensis (0.18 ± 0.06 mg/kg), respectively. The highest bioaccumulation factor of As in the aquatic plants, fish and freshwater snails were found in L. flava (131.30 ± 15.35), O. niloticus (228.21 ± 26.99) and F. sumatrensis (33.04 ± 10.58), respectively. Since the accumulation of As was higher in the sediment than in the water, aquatic plants and animals took up As directly from the environment, resulting in As accumulation in the aquatic food web.