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Assessment of stress-related gene expression in the heavy metal-exposed nematode Caenorhabditis elegans: a potential biomarker for metal-induced toxicity monitoring and environmental risk assessment.

The toxicity of cadmium, lead, chromium, and arsenite on Caenorhabditis elegans was investigated to identify sensitive biomarkers for environmental monitoring and risk assessment. Effects of these metals on stress-related gene expression, growth, reproduction, and mortality of C. elegans were investigated under laboratory conditions. The possibility of using C. elegans as a biosensor for environmental toxicity monitoring was also tested using a green fluorescent protein transgenic nematode. The 24-h median lethal concentrations of cadmium, lead, chromium, and arsenite in C. elegans were 846, 34, 115, and 92 mg/L, respectively. Cadmium exposure led to an increase in the expression of most of the genes tested. The degree of increase was more than threefold compared to control in heat shock protein 16.2, heat shock protein 70, metallothionein 2, cytochrome P450 family protein 35A2, glutathione-S-transferase 4, superoxide dismutase 1, catalase 2, C. elegans p53-like protein 1, and apoptosis enhancer 1 genes. The lead-, chromium-, and arsenite-exposed nematode, on the other hand, showed little change in gene expression. Alterations in growth and reproduction were observed in cadmium- and chromium-exposed worms. To consider a transgenic nematode as a biosensor for toxicity monitoring, the responses of stress-related gene promoters need to be tested with a variety of metals. The overall results suggest that cadmium exhibits a high level of tolerance compared to the other metals tested. Use of the responses of stress-related gene expression therefore has considerable potential as a sensitive biomarker for the diagnosis of cadmium contamination, and C. elegans seems to be a good biological model for this approach.

Animals↗

Monitoring for environmental mutagenesis in wild animals--lessons from human studies.

The increasing realisation that environmental monitoring practices need to demonstrate radiological protection of the whole ecosystem has led to suggestions that genotoxic techniques derived from human monitoring of radiation exposure could be applied to other animal species. Human studies have highlighted the need to establish the relationship between exposure, genetic effect and biological consequence so that different study objectives, e.g. hazard identification, dose estimation, risk evaluation, can be addressed by the application of the most appropriate and informative assay.

Animals↗

Aquatic environmental effects monitoring guidance for environmental assessment practitioners.

The Canadian Environmental Assessment Act (CEAA) defines the federal environmental assessment (EA) process for evaluating the likelihood that development projects (e.g., roads, buildings, factories) will have impacts on the environment. Environmental effects monitoring (EEM) programs for mining and pulp and paper mills under the Federal Fisheries Act, define the process that is to be used to evaluate existing effects caused by liquid effluents discharged by operating facilities. The EA process occurs before a project is approved, and involves predicting whether the project is going to cause significant environmental impacts. The EEM process occurs after a project is operational, and involves determining whether an existing project has had or is continuing to have significant impacts on the environment. Ideally, the processes are complimentary, with the EA process identifying environmental attributes considered important, and the EEM process demonstrating whether predicted or unpredicted impacts occurred. The two processes are usually done in isolation so potential synergies are lost. The point of this manuscript is to justify bridging the two processes. We use the aquatic environment as the example, and briefly describe the EEM process, aquatic environment indicators, experimental designs, and typical environmental thresholds, to illustrate how the EEM and EA processes link.

Canada↗

Enhancement of micronuclei frequency in the Tradescantia/micronuclei test using a long recovery time.

The Tradescantia/micronuclei test (TRAD/MCN) is a well-validated test for monitoring environmental genotoxicants. These pollutants induce at the early meiotic stage of pollen mother cells chromosome fragments which become micronuclei at the tetrad stage. The standard test protocol requires some hours of exposure of the inflorescences and a recovery time of about 24 hours to reach the early tetrad stage. Since the recovery period represents a critical step of the TRAD/MCN, experiments were performed to establish its length in plants of clone #4430 of the hybrid T. hirsutiflora x T. subacaulis which is widely used in environmental monitoring. The aim of the present research was to ascertain the exact duration of recovery time in order to improve the sensitivity of the TRAD/MCN test. First, studies were performed to select the flowers at the beginning of the meiosis, and then anthers were sampled and studied for a period of 48-86 hours. The complete meiosis in the plants examined required about 80 hours. Second, exposure to genotoxic substances followed by different recovery times was carried out to demonstrate that effectiveness of the TRAD/MCN test is closely related to the duration of the recovery time. The test was carried out by exposing inflorescences to known mutagens (sodium azide and maleic hydrazide) for six hours followed by different recovery times (24-72 hours). The results showed that the frequency of micronuclei in the pollen mother cells increased with the length of the recovery time.

Chromosomes↗

Mutagenesis by environmental pollutants and bio-monitoring of environmental mutagens.

There is serious concern about the adverse effects of environmental pollutants on human health. Various mutagens, which pollute air, water, and food, possibly induce mutations in humans, and are suspected of causing cancer. Environmental mutagens, such as polycyclic aromatic hydrocarbons (PAH) and heterocyclic amines are known to bind to nucleotides, resulting in the formation of DNA adducts. Some DNA adducts are fixed as mutations through replication of DNA. Reactive oxygen species generated by pollutants also induce the formation of DNA adducts. DNA adducts have been detected as a marker for the exposure of humans and wild life to mutagens. Because of its high sensitivity the 32P-postlabel-thin layer chromatography (TLC) method is widely used for the analysis of DNA adducts formed by PAH and related bulky compounds. However, new systems are required for detecting mutations induced in genomic DNA in vivo to monitor environmental mutagens. Recently, transgenic animals, in which a target gene for detecting mutations is integrated, have been developed. With these transgenic animals, not only mutant frequency but mutation spectra can be determined. We review here recent advances in the detection of DNA adducts formed by environmental pollutants and their application for biological monitoring of environmental mutagens. We also discuss transgenic animals as important tools for evaluating the total mutagenic potential of environmental chemicals.

Animals↗

Residential exposure to chromium waste--urine biological monitoring in conjunction with environmental exposure monitoring.

To determine whether a population living on or adjacent to four sites of chromate production waste was measurably exposed to environmental chromium, spot samples of urine were collected along with wipe samples of household dust and lifestyle/activity interview data. Findings were compared to those from a control population in two communities with no significant chromium use or waste sites. Urine samples were collected and analyzed, employing measures to minimize background chromium contamination. The average Cr mass in dust was 3.7 times that in control houses. The mean creatinine-corrected urine Cr (Cr/c) level of the exposed subgroup residing in households in the 75th percentile of Cr mass in wipe samples was significantly greater than that of the control population. This subgroup was primarily located at a single exposure location. Using lifestyle/activity data, significantly elevated Cr/c urine levels were identified in other exposed subgroups defined by employment location and by outside play time. These data show an association between elevated exposure to chromium in household dust and elevated urine levels of chromium, consistent with residential exposure to chromate production waste. These data also suggest an association between chromium exposure and activities outside the home which are consistent with exposure to chromate production waste.

Adolescent↗

In-vitro assays for determination of oestrogenic activity.

At present, in-vitro bioassays are predominantly being seen as tools to identify, through screening programs, whether or not individual chemical compounds have an effect on the endocrine system. However, as the techniques mature, they are likely to find use in the future in monitoring of discharges to the environment for any biological effect and will compliment the range of chemical and biological techniques also available for monitoring environmental quality. Such an approach has already been utilised by a number of workers to fractionate mixtures (e.g. final effluents from STW), to isolate the oestrogenically active components and subsequently identify the compounds which are active. This paper reviews the present state of in-vitro techniques for determination of oestrogenic activity and discusses present approaches to their use in environmental monitoring in conjunction with chemical analyses in toxicity identification and evaluation.

Cell Division↗

[Proposal for an outline to be used in the assessment of chemical risk according to the legislative decree 25/20002].

We present an operative outline for the evaluation of chemical risk in the work environment, according to the legislative decree 25/2002. It includes the following points: identificative data of the company, scope and field of application, description of the working activities, preventive and protective measures, medical report (including biological monitoring), environmental monitoring, conclusive evaluation. The scheme is a quali-quantitative instrument for the employer and his collaborators to establish whether the chemical risk present in the single productive sites can be considered "moderate" or "not moderate".

Chemical Industry↗

[A study of waste anesthetic gases monitoring and working environmental controls in hospital operating rooms].

There are hazardous factors threatening health care workers, and many hazardous chemical substances have been reported in operating rooms, central supply facilities, laboratories and so on. In Japan, little attention has been paid to exposure to these chemicals and to working environmental controls. Waste anesthetic gases are chemicals concerned, and we conducted environmental monitoring continuously and measured exposure to nitrous oxide, isoflurane and sevoflurane in operating rooms, and examined working environmental controls. The average environmental concentrations of nitrous oxide were about 400 ppm in anesthetists' working areas, and about 180 ppm in surgeons' and instrument nurses' working areas under unscavenged conditions. Under scavenged conditions, environmental concentrations were 70-190 ppm in anesthetists' zones, and 70-90 ppm in surgeons' and instrument nurses' zones. Even under scavenged conditions, operating room personnel are presumed to be exposed to high concentrations of nitrous oxide above ACGIH's TLV and NIOSH's REL. The level of exposure of isoflurane and sevoflurane was 2-4 ppm. Managing general ventilation system and airflow direction, working area under scavenged system, environmental concentration levels of nitrous oxide could be reduced to 20-30 ppm. In order to control occupational exposure to anesthetic gases, it is not sufficient to merely adapt scavenging systems in operating rooms. Working environmental control and occupational hygiene management should be required.

Air Pollutants, Occupational↗

Statistical analysis of real-time, environmental radon monitoring results at the Fernald Environmental Management Project.

A comprehensive real-time, environmental radon monitoring program is being conducted at the Fernald Environmental Management Project, where a large quantity of radium-bearing residues have been stored in two covered earth-bermed silos. Statistical analyses of radon measurement results were conducted to determine what impact, if any, radon emitted by the radium bearing materials contained in the silos has on the ambient radon concentration at the Fernald Environmental Management Project site. The distribution that best describes the outdoor radon monitoring data was determined before statistical analyses were conducted. Random effects associated with the selection of radon monitoring locations were accommodated by using nested and nested factorial classification models. The Fernald Environmental Management Project site was divided into four general areas according to their characteristics and functions: 1) the silo area, where the radium-bearing waste is stored; 2) the production/administration area; 3) the perimeter area, or fence-line, of the Fernald Environmental Management Project site; and 4) a background area, located approximately 13 km from the Fernald Environmental Management Project site, representing the naturally-occurring radon concentration. A total of 15 continuous, hourly readout radon monitors were installed in these 4 areas to measure the outdoor radon concentration. Measurement results from each individual monitor were found to be log-normally distributed. A series of contrast tests, which take random effects into account, were performed to compare the radon concentration between different areas of the site. These comparisons demonstrate that the radon concentrations in the production/administration area and the perimeter area are statistically equal to the natural background, whereas the silo area is significantly higher than background. The study also showed that the radon concentration in the silo area was significantly reduced after a sealant barrier was applied to the contents of the silos.

Environmental Monitoring↗

Environmental toxicity monitoring using electrochemical biosensing systems.

Environmental monitoring faces the challenge of measuring an increasing number of analytes at ever decreasing concentrations. Since not all species of a given analyte have the same detrimental impact on the environment, new analytical devices and techniques are required to distinguish between the different species of a pollutant or different groups of pollutants. This paper describes analytical techniques based on biomaterials that are toxically sensitive to pollutants. This approach permits the biomonitoring of certain compounds by looking at their toxic properties. Although these techniques are based on a sound analytical strategy, their applications are limited because most of the interactions between the biological material and the analyte are irreversible. Additionally, the immobilised biological material has a limited stability. Several biomonitoring strategies based on electrochemical biosensing are discussed here and how to recover the bioactivity of biosensing system, both in discrete and automated procedures, is also reviewed.

Biosensing Techniques↗

Epidemiological monitoring in environmental health: introduction and overview.

Epidemiological monitoring as used here is the repeated standardized evaluation of the health status of a population for the purpose of protecting this population from environmental health hazards. It is contrasted with epidemiological studies and environmental monitoring. Non-specificity of environmental monitoring is an important justification for epidemiological monitoring. In considering why epidemiological monitoring has not been more extensively used, historical, conceptual, and technical reasons are suggested. A modest increase in resources in this field is likely to be relatively cost-effective.

Environmental Health↗

Wild rats as monitors of environmental lead contamination in the urban area of Milan, Italy.

Twenty-one wild brown rats (Rattus norvegicus) were collected from four areas of Milan (Italy). Main organs were harvested from each rat, fixed in 10% neutral buffer formalin, and embedded in paraffin. Organ sections were stained with hematoxylin and eosin, kidney sections were also stained with the Ziehl-Neelsen method. Graphite furnace atomic absorption spectrophotometry was performed on all kidney samples. The presence of inclusion bodies and karyocytomegaly was scored. Six adult rats out of 21 (28.6%) showed kariocytomegaly and intranuclear inclusion bodies of the renal proximal tubules, characteristic of lead toxicity. The nuclear inclusion bodies were always Ziehl-Neelsen positive. The six rats which showed the characteristic histological alterations ascribed to lead, had lead concentrations statistically higher than the three control rats (4 microg/g wet wt. versus 0.09 microg/g wet wt., P<0.001) and than the captured wild rats. Intranuclear inclusion bodies were found in rats with kidney lead concentrations greater than 0.6 microg/g wet weight. There were significant differences between the four areas of capture. The incidence of intranuclear inclusion bodies and karyocytomegaly in proximal tubular cells was higher in rats with high lead levels detected by spectrophotometry. The present results indicate a renal lead concentration of 0.6 microg/g wet weight as a threshold to detect histologic kidney changes due to lead absorption. Results demonstrate that the examination of adult free-living rats may be considered an appropriate method to obtain a rapid, sensitive, easy, cost effective estimate of lead contamination in urban areas. Animal models allow us to evaluate potential human health risk associated with environmental contamination.

Animals↗

[Environmental pollution and congenital abnormalities according to the data of environmental health monitoring].

Study of the environmental pollution (ambient air, drinking water, food and fodder) in southern Ukraine industrial region and study of congenital developmental defects were carried out. 78,678 newborns were examined. The most significant environmental factors responsible for congenital developmental defects, as authors proposed, were the ambient air pollution and environmental radioactivity.

Abnormalities, Drug-Induced↗

Electrochemical methods for monitoring of environmental carcinogens.

The use of modern electroanalytical techniques, namely differential pulse polarography, differential pulse voltammetry on hanging mercury drop electrode or carbon paste electrode, adsorptive stripping voltammetry and high performance liquid chromatography with electrochemical detection for the determination of trace amounts of carcinogenic N-nitroso compounds, azo compounds, heterocyclic compounds, nitrated polycyclic aromatic hydrocarbons and aromatic and heterocyclic amines is discussed. Scope and limitations of these methods are described and some practical applications based on their combination with liquid-liquid or solid phase extraction are given.

Azo Compounds↗

Biological monitoring of environmental exposure to polycyclic aromatic hydrocarbons in subjects living in the vicinity of a creosote impregnation plant.

OBJECTIVE: This study was undertaken to evaluate the environmental exposure to polycyclic aromatic hydrocarbons (PAHs) in nonsmoking adult subjects living in the vicinity of a creosote impregnation plant in Delson, Canada. Urinary metabolites of naphthalene, alpha- and beta-naphthol, and pyrene metabolite 1-hydroxypyrene (1-OHP), were used as biomarkers of exposure. METHODS: Morning and evening urine samples were collected in mid-August from 30 exposed individuals living at a distance of 50-360 m downwind of the plant and from a control group in the adjoining municipality residing at a distance of 1.9-2.7 km upwind of the plant. Metabolites were measured by gas chromatography/ mass spectrometry. RESULTS: Excretion values of alpha- and beta-naphthol were significantly higher in the exposed group than in controls (P < 0.04), after accounting for possible confounding variables by multivariate analyses. The respective geometric mean concentrations (5th and 95th percentiles) of alpha-naphthol for the exposed and nonexposed groups were 2.04 (0.55-6.00) and 1.37 (0.39-7.02) micromol/mol creatinine for evening samples, and 2.49 (0.77-8.43) and 1.17 (0.37-6.88) micromol/mol creatinine for morning samples. Corresponding values for beta-naphthol were 1.78 (0.82-3.67) and 1.36 (0.63-5.07) micromol/mol creatinine for evening samples, and 1.94 (1.03-4.96) and 1.08 (0.49-5.05) micromol/mol creatinine for morning samples. On the other hand, no significant difference in 1-OHP excretion was observed between the exposed and the control group (P>0.5). The respective geometric mean concentrations (5th and 95th percentiles) of 1-OHP for these groups were 0.05 (0.01-0.17) and 0.06 (0.01-0.48) micromol/mol creatinine for evening samples, and 0.05 (0.02-0.12) and 0.05 (0.01-0.42) micromol/mol creatinine for morning samples. CONCLUSIONS: The measurement of alpha- and beta-naphthol urinary concentrations appears to be an approach sufficiently sensitive to reveal differences in low exposure levels of volatile PAHs due to creosote impregnation plant emissions. However, uptake of pyrene due to the plant was too small to contribute significantly to 1-OHP excretion.

Adolescent↗