Mutagenic effects of carbosulfan, a carbamate pesticide

Transgenerational effects of co-exposure to cadmium and carbofuran on zebrafish based on biochemical and transcriptomic analyses

The combined toxicity of heavy metals and pesticides to aquatic organisms is still largely unexplored. In this study, we investigated the combined impacts of cadmium (Cd) and carbofuran (CAR) on female zebrafish (F0 generation) and their following F1 generation. Results showed that mixtures of Cd and CAR induced acute synergistic effects on both zebrafish adults of the F0 generation and embryos of the F1 generation. Combined exposure to Cd and CAR could obviously alter the hepatic VTG level of females, and the individual exposures increased the relative mRNA levels of vtg1 and vtg2. Through maternal transmission, co-exposure of Cd and CAR caused toxicity to 4-day-old larvae of the F1 generation, evidenced by the significant changes in T4 and VTG levels, CYP450 activity, and the relative transcriptional levels of genes related to the hormone, oxidative stress, and apoptosis. These effects were also reflected by the global gene expression pattern to 7-day-old larvae of F1 generation using the transcriptomic analysis, and they could also affect energy metabolism. Our results provided a more comprehensive insight into the transgenerational toxic impacts of heavy metal and pesticide mixtures. These findings highlighted that it was highly necessary to consider transgenerational exposures in the ecological risk assessment of chemical mixtures.

Ecological risk assessment and long-term environmental pollution caused by obsolete undisposed organochlorine pesticides

Obsolete organochlorine pesticides (OSPs) are currently prohibited as persistent organic pollutants that contaminate the environment. If undisposed, they continue to pollute soil and water, to accumulate in the food chain and to harm plants, animals and the human body. The aim of the study was to assess water and soil pollution around the storehouses of undisposed, banned OSPs and their possible genotoxic effect. The storehouses in four villages near Almaty, Kazakhstan were investigated. Chemical analysis confirmed contamination of water and soil around storehouses with OSPs. The genotoxic effect of water and soil samples was evaluated using model objects: S.typhymurium, D.melanogaster, sheep lymphocytes cultures and human lymphocytes cultures. It was found that water and soil samples caused mutagenic effect in all model systems. They increased the frequency of revertants in Salmonella, the frequency of lethal mutations in Drosophila chromosomes, and the frequency of chromosome aberrations in cultures of human and sheep lymphocytes. Although a genotoxic effect was demonstrated for each of these models, various models showed different sensitivity to the effects of pesticides and they varied degree of response. The association between the total content of OCPs in soil and the level of mutations for different model systems was discovered.

Assessment of anilofos-induced mutagenicity in bone marrow and germ cells of Swiss albino mice

Anilofos is an organophosphate compound and is used extensively as a preemergence and early postemergence herbicide for the management of sedges, annual grasses, and some broad-leaved weeds in rice fields. The present study was aimed to assess the mutagenic potential of anilofos after sub-chronic exposure in Swiss albino mice. For this, a combined approach employing micronucleus (MN), chromosomal aberration (CA) studies and sperm-head abnormalities (SHAs) was used. Three dose levels of 1%, 2%, and 4% of maximum tolerated dose (MTD) (235 mg/kg b.wt.), that is, 2.35, 4.7 and 9.4 mg/kg b.wt., respectively, were administered orally daily for 90 days. A higher incidence of micronucleated erythrocytes (polychromatic erythrocytes + normochromatic erythrocytes), significant increase in CA frequency, and significant decrease in the ratio of polychromatic/normochromatic erythrocytes (P/N) ratio were observed at the 4.7 and 9.4 mg/kg b.wt. dose levels. A significant increase in SHA was observed in all treatment groups (2.35, 4.7, and 9.4 mg/kg b.wt.) from the control group. In conclusion, anilofos exposure of 2% and 4% of MTD caused a higher rate of micronucleated erythrocytes, increased frequency of CA, increase in SHA, and lower P/N ratio, and pesticide exposure of 1% of MTD only resulted in higher SHAs. Thus, anilofos was found to have mutagenic potential in mice when administered daily orally at dose rate of 4.7 and 9.4 mg/kg b.wt. for 90 days.

Assessment of chromosome aberrations in large Japanese field mice (Apodemus speciosus) in Namie Town, Fukushima

PURPOSE

After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in Japan on March 11 2011, the surroundings became contaminated with radionuclides. To understand the possible biological effects after chronic low dose-rate radiation in contaminated areas of Fukushima, we assessed the effects in large Japanese field mice (Apodemus speciosus) by means of chromosome aberration analysis.

MATERIALS AND METHODS

We collected A. speciosus in five sites around Namie Town, Fukushima (contaminated areas) and in two sites in Hirosaki City, Aomori (control areas, 350 km north of FDNPP) from autumn 2011 to 2013. The number of mice captured and ambient dose-rates were as follows: high (n = 11, 10.1-30.0 µGy h^-1), moderate (n = 10, 5.7-15.6 µGy h^-1), low (n = 12, 0.23-1.14 µGy h^-1) and control (n = 20, 0.04-0.07 µGy h^-1). After spleen extraction from rodents, spleen cell culture was performed to obtain metaphase spreads. Chromosome aberrations were assessed on Giemsa-stained metaphase spreads.

RESULTS

Although the mice in the contaminated areas were chronically exposed, there was no radiation-specific chromosome aberrations observed, such as dicentric chromosomes and rings. Some structural aberrations such as gaps and breaks were observed, and these frequencies decreased annually in mice from Namie Town.

CONCLUSION

These findings suggest that chromosome aberration analysis is useful to evaluate and monitor radiation effects in wild animals.

Pesticide residues in breast milk and the associated risk assessment: A review focused on China

This review aims to provide an overview of studies on pesticide residues in breast milk in China and the related health risk to mother and infants. Results showed that the investigations of breast milk covered 22 provincial administrative regions of China. Beijing and some densely populated and economically developed areas have most publications. The study frequency was followed the order of DDTs>HCHs>HCB > ∑Drins,∑Chlordane. While the residue levels were ranked as DDTs, HCHs > ∑Drins>HCB > ∑Chlordane. The highest residue levels of DDTs and HCHs in breast milk were found in 1980s (~10,000 ng/g lipid), then experienced a sharp decrease in 1990s (~1000-2000 ng/g lipid). In 2000s and 2010s, DDTs, and HCHs residue still showed a decreasing trend. Spatially, people located in urban area, coastal areas and southern China tend to have higher pesticide residues as compared to rural area, inland area and northern China, respectively. Other factors such as dietary habit, living environment, the maternal age, the parity, body mass index, lactation period, menstruation characteristics as well as hormonal drug intake and infertility treatment will also affect the pesticide residues in breast milk of Chinese people. According to the estimated daily ingestion (EDI) of breast milk, the average health risk for infants were generally exceeded the acceptable level before 2006, while after that, most EDI values were within the standard. Body burden of pesticides in mother can also be evaluated by using the residue data in breast milk, but no relevant guidelines were available. Other knowledge gap included 1) for some provinces with large consumption of pesticides or located in remote and plateau areas, there are few/no studies available; 2) current study on pesticide residues in breast milk in China were only focused on organochlorine pesticides, research on current used pesticides (such as pyrethroids, organophosphorus, carbamate) were necessary in the future.

Chromosomal Instability in Farmers Exposed to Pesticides: High Prevalence of Clonal and Non-Clonal Chromosomal Alterations

Introduction

An important economic activity in Colombia is agricultural production and farmers are frequently exposed to pesticides. Occupational exposure to pesticides is associated with an increased incidence of various diseases, including cancer, Parkinson’s disease, Alzheimer’s disease, reproductive disorders, and birth defects. However, although high genotoxicity is associated with these chemicals, information about the type and frequency of specific chromosomal alterations (CAs) and the level of chromosomal instability (CIN) induced by exposure to pesticides is scarce or absent.

Methods

In this study, CAs and CIN were assessed in peripheral blood lymphocytes (PBLs) from five farmers occupationally exposed to pesticides and from five unexposed individuals using GTG-banding and molecular cytogenetic analysis.

Results

A significant increase in clonal and non-clonal chromosomal alterations was observed in pesticide-exposed individuals compared with unexposed individuals (510±12,2 vs 73±5,7, respectively; p<0.008). Among all CAs, monosomies and deletions were more frequently observed in the exposed group. Also, a high frequency of fragilities was observed in the exposed group.

Conclusion

Together, these findings suggest that exposure to pesticides could be associated with CIN in PBLs and indicate the need for the establishment of educational programs on safety precautions when handling pesticides, such as wearing gloves, masks and boots, changing clothes and maintaining proper hygiene, among others. Further evaluation in other similar studies that include a greater number of individuals exposed to pesticides is necessary.

Bioaccumulation and Metabolism of Carbosulfan in Zebrafish (Danio rerio) and the Toxic Effects of Its Metabolites

Carbosulfan is a carbamate insecticide that has been widely used in agriculture. However, studies showed that carbosulfan could be highly toxic to aquatic organisms. The metabolism of carbosulfan in adult zebrafish is still largely unexplored, and the metabolites in individual or in combination may pose a potential threat to zebrafish. In the present study, the bioaccumulation and metabolism of carbosulfan in zebrafish (Danio rerio) were assessed, and the main metabolites, including carbofuran and 3-hydroxycarbofuran, were determined. The toxicity of carbosulfan and its metabolites individually or in combination to zebrafish was also investigated. The bioaccumulation and metabolism experiment indicated that carbosulfan was not highly accumulated in zebrafish, with a bioaccumulation factor of 18 after being exposed to carbosulfan for 15 days, and the metabolism was fast, with a half-life of 1.63 d. The two main metabolites were relatively persistent, with half-lives of 3.33 and 5.68 d for carbofuran and 3-hydroxycarbofuran, respectively. The acute toxicity assay showed that carbofuran and 3-hydroxycarbofuran had 96-h LC₅₀ values of 0.15 and 0.36 mg/L, showing them to be more toxic than carbosulfan (96-h LC₅₀ = 0.53 mg/L). Combinations of binary or ternary mixtures of carbosulfan and its metabolites displayed coincident synergistic effects on acute toxicity, with additive index (AI) values of 1.9-14.3. In the livers and gills of zebrafish exposed to carbosulfan, carbofuran, and 3-hydroxycarbofuran, activities of catalase, superoxide dismutase, and glutathione-S-transferase were significantly changed in most cases, and the content of malondialdehyde was greatly increased, indicating that carbosulfan and its metabolites induced varying degrees of oxidative stress. The metabolites were more persistent and toxic to zebrafish and exhibit coincident synergistic effects in combination. These results can provide evidence for the potential risk of pesticides and highlight the importance of a systematic assessment for the combination of the precursor and its metabolites.

Are Our Farm Workers in Danger? Genetic Damage in Farmers Exposed to Pesticides

Modern agriculture, practiced after the "green revolution" worldwide, aims to maximize production in order to provide food for the growing world population. Thus, farmers are required to modernize their practices through the mechanization of land use and, above all, the use of chemical pesticides to control agricultural pests. However, in addition to combating the target pest, chemical pesticides indirectly affect a wide range of species, including humans, leading to health damage. Among the main problems caused by the use of pesticides is the genotoxicity caused by chronic exposure. The present study aims to verify the occurrence of genetic damage in farmers who are occupationally exposed to agrochemicals compared to people of other professions that do not use toxic substances (control group). The research was conducted with 36 male participants (18 farmers and 18 control group, ages 24⁻71 for the farmer group and 22⁻61 for the control group). The comet assay and micronucleus test results revealed a higher rate of genetic damage in the group of farmers than in the control group. A questionnaire answered by the farmers showed that the Personal Protect Equipment (PPE) is used incorrectly or not used. In summary, our results indicate that farmers are exposed to occupational hazards. To mitigate this risk, we conducted awareness campaigns to notify the farmers of the risks and highlight the importance of using PPE correctly. Intensive efforts and training are thus required to build an awareness of safety practices and change the attitudes of farm workers in the hope of preventing harmful environmental and anthropogenic effects.

Hazardous effects of chemical pesticides on human health-Cancer and other associated disorders

Poisoning from pesticides is a global public health problem and accounts for nearly 300,000 deaths worldwide every year. Exposure to pesticides is inevitable; there are different modes through which humans get exposed to pesticides. The mode of exposure is an important factor as it also signifies the concentration of pesticides exposure. Pesticides are used extensively in agricultural and domestic settings. These chemicals are believed to cause many disorders in humans and wildlife. Research from past few decades has tried to answer the associated mechanism of action of pesticides in conjunction with their harmful effects. This perspective considers the past and present research in the field of pesticides and associated disorders. We have reviewed the most common diseases including cancer which are associated with pesticides. Pesticides have shown to be involved in the pathogenesis of Parkinson's and Alzheimer's diseases as well as various disorders of the respiratory and reproductive tracts. Oxidative stress caused by pesticides is an important mechanism through which many of the pesticides exert their harmful effects. Oxidative stress is known to cause DNA damage which in turn may cause malignancies and other disorders. Many pesticides have shown to modulate the gene expression at the level of non-coding RNAs, histone deacetylases, DNA methylation patterns suggesting their role in epigenetics.

From immunotoxicity to carcinogenicity: the effects of carbamate pesticides on the immune system

The immune system can be the target of many chemicals, with potentially severe adverse effects on the host's health. In the literature, carbamate (CM) pesticides have been implicated in the increasing prevalence of diseases associated with alterations of the immune response, such as hypersensitivity reactions, some autoimmune diseases and cancers. CMs may initiate, facilitate, or exacerbate pathological immune processes, resulting in immunotoxicity by induction of mutations in genes coding for immunoregulatory factors and modifying immune tolerance. In the present study, direct immunotoxicity, endocrine disruption and inhibition of esterases activities have been introduced as the main mechanisms of CMs-induced immune dysregulation. Moreover, the evidence on the relationship between CM pesticide exposure, dysregulation of the immune system and predisposition to different types of cancers, allergies, autoimmune and infectious diseases is criticized. In addition, in this review, we will discuss the relationship between immunotoxicity and cancer, and the advances made toward understanding the basis of cancer immune evasion.

Arsenic and smokeless tobacco induce genotoxicity, sperm abnormality as well as oxidative stress in mice in vivo

BACKGROUND

Arsenic, a naturally occurring metalloid is a well-known water contaminant which causes a wide range of serious adverse health effects including cancer upon long-term exposure. Recent studies have shown high arsenic contamination in the ground water of North Eastern states of India including Southern Assam. Smokeless tobacco consumption locally known as "sadagura" is one of the most prevalent life style habit in southern Assam. The present study was undertaken in mice test system in vivo. Mice were exposed to smokeless tobacco (5 mg/kg body weight /day) and sodium arsenite (0.2 mg/kg body weight /day, 2 mg/kg body weight/day) independently and in combination for 90 days.

RESULTS

The results were compared with groups with only sodium arsenite exposure and groups which were exposed to only smokeless tobacco extract. Genotoxicity was evaluated by studying the incidence of micronucleated polychromatic erythrocytes from bone marrow. Both the tested doses of sodium arsenite induced statistically significant micronucleated polychromatic erythrocytes as compared to control group, however, sodium arsenite and smokeless tobacco extract could not increase the incidence of micronucleated polychromatic erythrocytes as compared to their individual counterparts when treated in combination in mice test system. Germ cell toxicity was evaluated by recording the sperm head abnormalities and total sperm count. Combined treatment of sodium arsenite and smokeless tobacco extract in lower dose induced a significant increase in sperm head abnormality as compared to only sodium arsenite and smokeless tobacco extract. Liver, kidney and intestine tissues were analyzed for various oxidative stress evaluations such as lipid peroxidation (MDA), Glutathione (GSH) and superoxide dismutase (SOD) assay. Sodium arsenite in combination with smokeless tobacco extract show higher genotoxic and germ cell toxic effects as compared to control but not when compared to their individual counterparts.

CONCLUSION

Impairment of the sperm head morphology by sodium arsenite and smokeless tobacco extract alone and in combination with lower dose of sodium arsenite could be oxidative stress mediated effects. Besides, combination treatment of both the agents may not produce additive effects related to micronucleated polychromatic erythrocytes induction and decline of total sperm count.

Curcumin protects metronidazole and X-ray induced cytotoxicity and oxidative stress in male germ cells in mice

Metronidazole (MTZ) is a common antiparasitic and antibacterial drug. The drug and X-ray induced effects in mouse sperm count, sperm head abnormality and some oxidative stress parameters have been studied. Simultaneously the protective role of curcumin has been evaluated. MTZ, 40 mg/kg bw and 13.4 mg/kg bw × 3 days exposure induced abnormal sperm head and reduced total sperm count in Swiss albino mice both after 24 h and 35 days of exposure. However, MTZ treatment in mice receiving X-ray irradiation (0.5 Gy) did not changed the incidence of abnormal sperm population or decrease in the total sperm count. Hepatic glutathione (GSH), superoxide dismutase (SOD) declined significantly during the treatment phase with significant rise in lipid peroxidation of the tissue. The cellular changes were estimated by using lipid peroxidative indices like thiobarbituric acid reactive substances (TBARS). Elevated TBARS is indicative of oxidative stress in treated mice. Furthermore, curcumin pre-treatment apparently reduced the frequency of sperm head abnormality and TBARS induced by MTZ alone or in combination with X-ray and increased the levels of hepatic GSH and SOD. The additive effects of MTZ and X-ray could not be observed with regards to sperm head abnormality and total sperm count in the tested dose range although the cellular antioxidants were found to be significantly lowered and lipid peroxidantion increased. The possible role of MTZ and X-ray inducing sperm abnormality, decreased sperm count and alteration in GSH, SOD and TBARS and defensive role of curcumin have been evaluated.

Effects of radiation and vitamin C treatment on metronidazole genotoxicity in mice

The impact of exposure to low dose radiation (LDR) on human health is not clear. Besides, cross adaptation or sensitization with pharmaceutical agents may modify the risk of LDR. In the present study, we analyzed the interaction of radiation and metronidazole (MTZ) in inducing chromosome aberration (CA) and micronucleus (MN) in the bone marrow cells of Balb/C mice in vivo. Further, we evaluated the efficacy of vitamin C to reduce MTZ induced genotoxicity. We found that 10, 20 and 40mg/kg of MTZ induced dose dependent increase in the frequency of CA (r=0.9923, P<0.01) as well as MN (r=0.9823, P<0.05) in polychromatic erythrocytes. However, MTZ did not affect the ratio of polychromatic erythrocytes to normochromatic erythrocytes indicating lack of cytotoxicity. Supplementation with vitamin C prior to MTZ treatment significantly reduced the frequency of CA (P<0.001) as well as MN (P<0.001). Radiation (0.5Gy) exposure prior to MTZ treatment produced a less than additive (for CA) to additive (for MN) effects. However, radiation exposure following MTZ treatment produced additive (for CA) and synergistic (for MN) effects. Further, vitamin C pre-treatment also reduced the genotoxicity indices following the combined treatment of MTZ and radiation. Our findings suggest that MTZ may sensitize bone marrow cells to radiation exposure and enhances genotoxicity. We recommend more studies on the interaction of LDR and marketed pharmaceuticals to minimize possible harmful outcomes through appropriate precautionary measures.

Genetic damage in soybean workers exposed to pesticides: evaluation with the comet and buccal micronucleus cytome assays

Soybean cultivation is widespread in the State of Rio Grande do Sul (RS, Brazil), especially in the city of Espumoso. Soybean workers in this region are increasingly exposed to a wide combination of chemical agents present in formulations of fungicides, herbicides, and insecticides. In the present study, the comet assay in peripheral leukocytes and the buccal micronucleus (MN) cytome assay (BMCyt) in exfoliated buccal cells were used to assess the effects of exposures to pesticides in soybean farm workers from Espumoso. A total of 127 individuals, 81 exposed and 46 non-exposed controls, were evaluated. Comet assay and BMCyt (micronuclei and nuclear buds) data revealed DNA damage in soybean workers. Cell death was also observed (condensed chromatin, karyorhectic, and karyolitic cells). Inhibition of non-specific choline esterase (BchE) was not observed in the workers. The trace element contents of buccal samples were analyzed by Particle-Induced X-ray Emission (PIXE). Higher concentrations of Mg, Al, Si, P, S, and Cl were observed in cells from workers. No associations with use of personal protective equipment, gender, or mode of application of pesticides were observed. Our findings indicate the advisability of monitoring genetic toxicity in soybean farm workers exposed to pesticides.

Effect of N-metylcarbamate pesticide bendiocarb on cattle lymphocytes after in vitro exposure

Bendiocarb is a carbamate broad-spectrum insecticide used to control disease vectors such as mosquitoes and flies, as well as household and agricultural pests. Nowadays, only few papers reporting cytogenetic or possible genotoxic effect of this insecticide on mammalian cells are available. In the present study 24-hour exposure to bendiocarbamate at concentrations ranging from 20 to 160 μg/ml was used for investigation of unstable chromosomal aberrations (CA), sister chromatid exchanges (SCE) and stable chromosomal aberration induction in cultured bovine peripheral lymphocytes. The slight but no significant increase of chromatide breaks frequency was observed after the exposure of lymphocytes to 80 μg/ml of bendiocarb. At the highest concentration added to the cell cultures (160 μg/ml) mitotic index decrease was shown in both donors (p < 0.05; p < 0.01). Both statistically significant elevation of SCEs (p < 0.05) and a reduction of proliferative indices (PI) (p < 0.01) were shown at a dose of 80 μg/ml. By means of two fluorescent-labelled whole chromosome-painting probes, stable aberrations such as bovine chromosome 1 and 5 translocation as well as numerical aberrations (polyploidies, heteroploidies) were visualised under fluorescent microscope in some examined metaphases.

Multivariate analysis of toxicological and environmental properties of soil nematicides

BACKGROUND

In intensive agriculture, the use of pesticides and soil fumigants is necessary to produce economically viable crops worldwide. However, this practice may involve undesirable effects on human health and the environment. In 1995, methyl bromide was restricted by the Montreal Protocol because of possible ozone depletion. The objective of this study was to compare intrinsic environmental and toxicological properties of 11 active substances with nematicidal properties, some of them recognized as methyl bromide alternatives.

RESULTS

Four groups of active substances were discriminated by a series of principal component analyses (PCAs): (a) high toxicity to non-target fauna, humans and animals and medium persistence in the environment (cadusafos, ethoprophos and fenamiphos); (b) high toxicity to humans, animals and non-target fauna and high persistence (carbofuran and fosthiazate); (c) low toxicity to non-target fauna, humans and animals and low persistence (carbosulfan, benfuracarb and oxamyl); (d) low toxicity to humans, animals and non-target fauna and medium persistence in the environment (1,3-dichloropropene, chloropicrin and methyl bromide).

CONCLUSION

Evaluating the multiple aspects of toxicological and environmental properties of active substances through PCA is proposed as a helpful tool for initially comparing the complex toxicological behaviour of active substances as plant protection products.

Effects of low dose radiation and vitamin C treatment on chloroquine-induced genotoxicity in mice

Chloroquine (CHQ) is a commonly used antimalarial agent. We evaluated the genotoxic potential of CHQ using chromosome aberration (CA), micronucleus (MN), and sperm head abnormality (SA) assays in vivo in Swiss albino mice. The interaction between a low dose of radiation and CHQ, as well as the effect of vitamin C on CHQ-induced genotoxicity, was also evaluated. It was observed that CHQ induced CA, as well as MN, in the bone marrow cells under certain treatment conditions. Further, CHQ induced significant increase in the frequency of SA both at 24 hr and 21 days of the treatment. In the present study vitamin C pretreatment apparently reduced the frequency of CA, MN, and SA induced by CHQ. In the combination studies with radiation and CHQ, we found that exposure to low doses of radiation (0.5 Gy) either prior to or following CHQ treatment, in the dose ranges tested, has little or no synergistic effect in the mutagenic evaluations in somatic cells. However, radiation exposure along with CHQ treatment resulted in significant increase in the frequency of SA as compared to the groups receiving CHQ alone at 21 days of the treatment. In summary, CHQ has the potential to induce genotoxicity in mammalian cells. Further, germ cells may be relatively more sensitive as compared to the somatic cells.

A bioluminescent signal system: detection of chemical toxicants in water

Prototype technologies of a bioluminescent signal system (BSS) based on the luminous bacterium Photobacterium phosphoreum and three enzymatic bioluminescence systems have been proposed for detecting and signalling the presence of toxicants in water systems. A number of pesticides, mostly known as poisonous substances, similar in their structures and physicochemical properties, have been taken as model compounds of chemical agents. The effect of toxicants (organophosphates, derivatives of dithiocarbamide acid, and pyrethroid preparations) on the bioluminescence of the four systems has been analysed. EC(50) and EC(80) have been determined and compared to the maximum permissible concentration for each of the analysed substances. The triple-enzyme systems with ADH and trypsin have been shown to be more sensitive to organophosphorous compounds (0.13-11 mg/L), while the triple-enzyme system with trypsin is highly sensitive to lipotropic poison, a derivative of dithiocarbamine acid (0.03 mg/L). Sensitivities of the triple-enzyme systems to pyrethroid preparations are similar to those of luminous bacteria (0.9-5 mg/L). The results can be used to construct an alarm-test bioluminescence system for detecting chemical toxicants, based on intact bacteria or enzyme systems.

Environmental exposure to residential pesticides, chemicals, dusts, fumes, and metals, and risk of childhood germ cell tumors

We examined relationships between exposure to residential pesticides, chemicals, dusts, fumes, and metals, and childhood germ cell tumors (GCTs) in the largest case-control study to date on the topic. We recruited 272 children under 15 years old who had GCT diagnosed between January 1, 1993 and December 31, 2001. Controls were selected by random-digit dialing and were frequency matched to cases by sex, age, and geographic area. Telephone interviews and self-administered questionnaires of parents were used to collect exposure information. We used unconditional logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI). Maternal and paternal exposure from 6 months before pregnancy to during breastfeeding and children's postnatal exposure to residential pesticides were generally unrelated to risk of childhood GCT. Elevated OR were observed for mothers' exposure to hair dyes 1 month before pregnancy for boys (OR = 1.7, 95% CI = 1.0-2.8) and during breastfeeding for boys and girls combined, and for girls (OR = 1.5, 95% CI = 1.0-2.2 and OR = 1.7, 95% CI = 1.1-2.6, respectively). Among boys, OR for paternal exposure to insecticides more often than four times or exposure to indoor insecticides more often than three times were 0.5 (95% CI = 0.2-0.9, trend test p = 0.05) and 0.3 (95% CI = 0.2-0.8, trend test p = 0.02) during the index pregnancy. Overall this study produced no strong evidence linking parental and child residential exposure to pesticides, certain chemicals, dusts, fumes, and metals to increased risk of childhood GCT. Statistically significant associations need to be confirmed in future studies.

Effect of environmental contaminants on male reproduction

A substantial body of evidence has accumulated in recent years that consistently indicate various adverse effects of environmental contaminants on human health. Decreasing trend of male fertility in terms of sperm counts and sperm quality, along with other changes in male reproductive health, including congenital malformations and testicular cancer in humans, and similar problems in wildlife has been correlated to the exposure to environmental contaminants. Many environmental chemicals have been reported to cause these reproductive abnormalities by eliciting changes in endocrine control of reproduction; however the specific underlying mechanisms are poorly understood. The present review summarizes recent studies on environmental contaminants and associated possible mechanism leading to adverse effects on male reproduction. Numerous studies demonstrate the interaction of environmental toxicants with steroid receptors and thereby causing interference with developmental and functional aspects of testis, epididymis and accessory sex organs. Induction of reactive oxygen species (ROS) by environmental contaminants and associated oxidative stress also have role in defective sperm function and male infertility.

Parental occupational exposure to pesticides and childhood germ-cell tumors

In a recently completed US case-control study (Children's Oncology Group, 1993-2001) with 253 cases and 394 controls, the authors investigated the association between parental occupational exposure to pesticides and risk of childhood germ-cell tumors. Information on occupational pesticide exposure was collected using job-specific module questionnaires and assessed by an experienced industrial hygienist. Odds ratios for childhood germ-cell tumors associated with maternal exposures before pregnancy, during pregnancy, and after the birth of the index child were 1.0 (95% confidence interval (CI): 0.8, 1.4), 1.1 (95% CI: 0.7, 1.6), and 1.3 (95% CI: 0.9, 1.8), respectively. Paternal exposures before pregnancy, during pregnancy, and after the birth of the index child were not related to germ-cell tumors (odds ratios (ORs) were 0.9 (95% CI: 0.7, 1.2), 0.8 (95% CI: 0.5, 1.2), and 0.8 (95% CI: 0.5, 1.3), respectively). When both parents had ever been occupationally exposed to pesticides before the index pregnancy, the odds ratio was 0.8 (95% CI: 0.4, 1.3). Subgroup analyses showed a positive association between maternal exposure to herbicides during the postnatal period and risk of germ-cell tumors in girls (OR = 2.3, 95% CI: 1.0, 5.2) and an inverse association between paternal exposure to pesticides during the index pregnancy and germ-cell tumors in boys (OR = 0.2, 95% CI: 0.1, 1.0). This study did not provide strong evidence supporting a relation between parental pesticide exposure in the workplace and risk of germ-cell tumors among offspring.

Genotoxicity study in lymphocytes of offset printing workers

The potential cytogenetic damage in offset printing workers was evaluated using sister chromatid exchanges (SCEs), chromosome aberrations (CAs) and micronuclei (MN) as biomarkers in peripheral lymphocytes of 26 volunteers (14 workers, 12 controls). The CA, SCE and MN frequency of offset printing workers was significantly higher than in their controls. The replication index (RI) was not affected while the mitotic index (MI) was affected most in the workers. It can be concluded from this study that chronic occupational exposure to printing dyes and thinner may lead to a slightly increased risk of genetic damage among offset printing workers.