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PubMed1976

Radioisotope techniques in delineation of the environmental behavior of cadmium.

Radioisotope techniques are being developed and utilized at Oak Ridge National Laboratory (ORNL) for evaluating the environmental behavior of toxic elements such as cadmium in aquatic and terrestrial ecosystems. Tracer techniques using 109Cd in microcosm, field plot, and stream systems are providing information on biogeochemical cycling and distribution of cadmium in the environment. Parameters being measured include adsorption capacity for cadmium in mineral soils and sediments; uptake rates of cadmium in various plant species from both soils and nutrient solutions as affected by pH, competing cations, and chemical form of cadmium; and distribution of cadmium in various components of both aquatic and terrestrial ecosystems following application of 109Cd to soil vegetation, or directly to streams. Food chain parameters being estimated with 109Cd include uptake, assimilation, and turnover by both aquatic and terrestrial organisms. Information obtained in these radiotracer studies is providing insight into the behavior of cadmium in aquatic and terrestrial ecosystems, especially transport rates of cadmium and potential biomagnification or dilution in food chains. The factors which influence the incorporation of cadmium into vegetative material as well as those affecting residence time in ecosystems have been identified. Use of 109Cd also has permitted evaluation of a cadmium specific electrode as a tool for rapid assay of free cadmium ions in soil solutions.

Adsorption↗
PubMed2006

The occurrence of Campylobacter species in Hungarian broiler chickens from farm to slaughter.

The reported number of human enteric diseases caused by thermotolerant campylobacters increased in the last few decades worldwide. The microorganism gets into the food chain mostly with poultry meat or meat products. We are not aware of the way the campylobacters infect the broiler flocks, and there is little information about the real prevalence, about the reaction of thermotolerant campylobacters to the environmental factors and about the possibilities of elimination of the bacteria from the food chain. As a part of the long study, samples were collected from a broiler flock from the first day of life to the slaughter of the animals, in summer and in winter. In the summer period, at the first two sampling days (days 0 and 12) all of the samples were negative. At day 26, one cloaca sample, one sample from the surface of the wall near the ventilation aperture and an insect-sample were positive. At day 42, we found Campylobacter spp. on every sampling point at the slaughterhouse. In the winter period, we could not find Campylobacter spp. either from 0 day old, or from 10- and 31-day-old chickens, but we found them at 42 days of age on the slaughter plant. At the slaughtering place, 93.3% of the live birds were infected with Campylobacter spp., and at the end of the processing line, the infection rate was 100%. We could isolate campylobacters from the hands of the workers and from the processing environment as well. Out of the positive samples, 95.5% was contaminated with Campylobacter jejuni.

Abattoirs↗
PubMed2005

Parameterization of a dynamic specific activity model of 14C transfer from surface water-to-humans.

Carbon-14 is a particularly interesting radionuclide from the perspective of dose estimation because it mixes readily with stable CO2, and hence enters the food-chain as fundamental biomolecules. A model was developed for the situation of 14C releases to surface waters, where there are distinct changes in the water 14C activity concentrations throughout the year. The model computes the specific activity in water, phytoplankton, fish, crops, meat, milk and air, following a typical irrigation-based food-chain scenario. This paper describes the derivation of the required 14C-specific parameter values. Many of the key parameters are not commonly measured, at least not in the context of dose assessment. Thus, inference from other sources of data was required, and this is the scientific contribution described in this paper. The best estimates and appropriate measures of statistical dispersion are provided. This required consideration of both the temporal and spatial averaging domains to ensure they were correct for parameters as defined in the model. The model coupled with these parameter values represents several new developments for modelling 14C transfers.

Air Pollution, Radioactive↗
PubMed1999

Secondary exposure to dioxins through exposure to PCP and its derivatives.

This study discusses the potential exposure of occupational workers and general consumers in the European Union (EU) to polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) caused by exposure to pentachlorophenol (PCP) and its derivatives. A synthesis of reported exposure data relating exposure to PCP and its derivatives in an occupational setting has indicated that the PCDD/F intake for exposure in the 1990s averaged over a lifetime is likely to be in the order of 0.02-1 pg I-TEQ kg-1 bw day-1 with actual exposures more likely to occur at the lower end of the range, around the median of 0.16 pg I-TEQ kg-1 bw day-1. Workers who have experienced past exposure to PCP and its derivatives especially in the early to mid 1980s, will have been subjected to higher exposures to PCDD/Fs due to the generally higher concentrations of PCDD/Fs in PCP products at that time. Exposure to PCP and its derivatives via the food chain is judged to be the most significant intake route of PCDD/Fs into consumers. The ingestion of milk and dairy products obtained from cows grazed on pasture dressed with sewage sludge has the potential to raise the average daily intake of PCDD/Fs via the diet by about 40% if all foods consumed derived from sludge amended soil. To the extent quantifiable, exposure to PCP in an occupational setting contributed approximately 16% as a median to the overall background exposure to PCDD/Fs, while for consumers this contribution ranged from 2 to 60% depending on the exposure to sludge amended foods.

Adolescent↗
PubMed2006

Mycotoxin contamination of food in Europe: early detection and prevention strategies.

This paper reviews the early detection and prevention strategies which have been employed in Europe for the control of mycotoxin contamination of food in the context of a hazard analysis critical control point (HACCP) framework. The critical control points (CCPs) in the whole food chain where mycotoxins such as trichothecenes and ochratoxins are important have been identified. Ecological studies on the effect of environmental factors which are marginal for growth and mycotoxin production have been identified for Fusarium culmorum and F. graminearum (deoxynivlenol production), and for Penicillium verrucosum and Aspergillus ochraceus (ochratoxin production) in relation to cereal production and for A. carbonarius in relation to grapes and wine production (ochratoxin formation). To minimise the entry of these mycotoxins into the food chain, effective and rapid diagnostic tools are required to monitor the CCPs effectively. To this end the potential use of molecular imprinted polymers, lateral flow devices and molecular-based techniques for the rapid detection and quantification of the mycotoxigenic moulds or their toxins have also been developed.

Aspergillus ochraceus↗
PubMed2003

The accumulation of potentially-toxic metals by grazing ruminants.

The main factors affecting the accumulation of potentially-toxic metals (PTM) by grazing animals are the presence of the metal, its concentration in herbage and at the soil surface, and the duration of exposure to the contaminated pasture and soil. In addition, the elapsed time between the contamination of the pasture and grazing, the quantity of soil ingested together with herbage, the mechanism of absorption of the metal into blood and the presence or absence of antagonistic metals can interact to influence the rate and extent of accumulation of heavy metals in edible body tissues. Models of the accumulation of metals by grazing animals may be used to determine the statutory limits of radionuclides and PTM in soils under grazed pastures. Meta-analysis of existing data, using a random-effects model, is a useful approach to understanding the factors affecting the accumulation of some metals, e.g. Cd. The target edible body tissues for the accumulation of most PTM are the liver and kidneys, with the exception of radiocaesium, which accumulates in muscle to a greater extent than in other tissues. The livers and kidneys of mature livestock that have been grazed on areas of pasture at the legal limit of contamination by Cd for more than one grazing season should be removed from the human food chain in order to reduce the risk of intake of Cd by the human population.

Animal Feed↗
PubMed2006

[Dioxins: risk management by agriculture and feed industry--options and limits].

Dioxins represent a group of undesired substances that may contaminate feedstuffs. Due to their persistency in the environment it can be expected that feed contamination by dioxins will occur in the future, too. Therefore efforts in agriculture and in the feed industry have to be focussed on measures that minimize the dioxin contamination of feedstuffs, especially under the aspects of food safety. Several dioxin scandals in the past have contributed to a higher awareness in feed production as well as on the side of food consumers and administration resulting in changes of feed legislation (implementation of maximum levels of dioxins in feed and food). Some of the dioxin scandals enlarged the knowledge concerning the potential ways dioxins entering the food chain (for example dioxin contamination during the drying process of grass meal, recycling of contaminated oils, use of contaminated kaolinit a.s.o.). In difference to those accidents in feed producing agriculture there is a main influence of potential soil contamination on the dioxin contents in feedstuffs (like roughage). Producing roughage (green fodder, silage, hay) on areas with grass land by grazing animals can result in corresponding consumption of soil that contaminates the green fodder. Intending a lowest feed contamination by dioxins implies that the soil contamination is known. Depending on the rate of soil contamination farmers should decide on the kind of feed production and on the techniques of harvesting the fodder. For example it is possible to produce maize (whole plant in high cut technique) without higher dioxin contents in maize silage, on the other hand it can not be recommended to use contaminated fields for growing beets or by grazing ruminants, pigs or poultry (outdoor systems). In general during the harvesting process technical measures have to be chosen that reduce/minimize the soil contamination because the dioxin concentration in the soil of exposed areas is much more higher than the dioxin concentration within the feedstuffs. The high costs of dioxin analyses limit an implementation of a monitoring program including samples of soil and feedstuffs of each feed producing unit or individual farms. Therefore it is necessary to focus the monitoring efforts on areas and samples that let expect a higher risk of dioxin contamination. New screening tests should be developed and implemented that allow a higher frequency and density of control measures concerning dioxin. In the case of suspicious findings only those samples could be analysed by the classic chemical procedure (time consuming, high costs). Especially in cases of food contamination (for example detected in monitoring programs of the food industry) it is necessary to find out the way and cause, not neglecting the potential role of the contaminated soil. Last but not least it is recommended to inform the public continuously about levels of dioxins that are actually found in food as well as in feed (and soils), especially on behalf of the consumers confidence in food and feed control and its related administration. Continuous information will increase the consumers understanding that there is (and will be for further years) a background contamination of feed and food in general (that decreased markedly in the last decades), and that cases of detected higher dioxin levels are exceptional findings that result immediately in efforts of the food and feed industry to obstruct the way that enabled an entering to the food chain.

Agriculture↗
PubMed1988

Acetylene as a substrate in the development of primordial bacterial communities.

The fermentation of atmospheric acetylene by anaerobic bacteria is proposed as the basis of a primordial heterotrophic food chain. The accumulation of fermentation products (acetaldehyde, ethanol, acetate and hydrogen) would create niches for sulfate-respiring bacteria as well as methanogens. Formation of acetylene-free environments in soils and sediments would also alter the function of nitrogenase from detoxification to nitrogen-fixation. The possibility of an acetylene-based anaerobic food chain in Jovian-type atmospheres is discussed.

Acetylene↗
PubMed1995

Arctic air pollution and human health: what effects should be expected?

Persistent contaminants such as heavy metals and organochlorine compounds are transported from distant sources to the Arctic by oceanic and atmospheric currents. Natives inhabiting the Arctic can be exposed, because they exist at the highest trophic level of the arctic aquatic food chain, along which biomagnification of contaminants occurs. We reviewed the data available on heavy metal and organochlorine body burden in natives from different regions of Nunavik (northern Québec) and assessed the potential risk of health effects. In addition, we investigated the relationship between each contaminant plasma level and omega-3 fatty acid content of plasma phospholipid, a surrogate measure for aquatic food consumption. Cadmium exposure appears to be unrelated to the consumption of species from the aquatic food chain (r = 0.0004; P = 0.99), whereas PCBs and mercury were (r = 0.49 and 0.52, respectively; P < or = 0.0001). Mean blood mercury levels measured in northern Québec natives were below those associated with significant neurological disorders. Typical daily intakes of dioxin-like compounds, PCBs, DDE, and dieldrin were estimated from the mean concentration in milk fat and pharmacokinetic models. The calculated PCB intake (0.3 microgram/kg/day) exceeds the acceptable daily intake, with effects on reproduction and development being the most relevant to assess in future epidemiological studies.

Air Pollution↗
PubMed2001

Symbiotic fungal endophytes control insect host-parasite interaction webs.

Symbiotic microorganisms that live intimately associated with terrestrial plants affect both the quantity and quality of resources, and thus the energy supply to consumer populations at higher levels in the food chain. Empirical evidence on resource limitation of food webs points to primary productivity as a major determinant of consumer abundance and trophic structure. Prey quality plays a critical role in community regulation. Plants infected by endophytic fungi are known to be chemically protected against herbivore consumption. However, the influence of this microbe-plant association on multi-trophic interactions remains largely unexplored. Here we present the effects of fungal endophytes on insect food webs that reflect limited energy transfer to consumers as a result of low plant quality, rather than low productivity. Herbivore-parasite webs on endophyte-free grasses show enhanced insect abundance at alternate trophic levels, higher rates of parasitism, and increased dominance by a few trophic links. These results mirror predicted effects of increased productivity on food-web dynamics. Thus 'hidden' microbial symbionts can have community-wide impacts on the pattern and strength of resource-consumer interactions.

Animals↗
PubMed2005

Distribution of polycyclic aromatic hydrocarbons in the food web of a high mountain lake, Pyrenees, Catalonia, Spain.

We investigated the contents of polycyclic aromatic hydrocarbons (PAHs) in the food web organisms included in the diet of brown trout from a remote mountain lake. The preferential habitat and trophic level of the component species have been assessed from the signature of stable isotopes (delta13C and delta15N). Subsequently, the patterns of accumulation and transformation of these hydrocarbons in the food chain have been elucidated. Most of the food web organisms exhibit PAH distributions largely dominated by phenanthrene, which agrees with its predominance in atmospheric deposition, water, and suspended particles. Total PAH levels are higher in the organisms from the littoral habitat than from the deep sediments or the pelagic water column. However, organisms from deep sediments exhibit higher proportions of higher molecular weight PAH than those in other lake areas. Distinct organisms exhibit specific features in their relative PAH composition that point to different capacities for uptake and metabolic degradation. Brown trout show an elevated capacity for metabolic degradation because they have lower PAH concentrations than food and they are enriched strongly in lower molecular weight compounds. The PAH levels in trout highly depend on organisms living in the littoral areas. Fish exposure to PAH, therefore, may vary from lake to lake according to the relative contribution of littoral organisms to their diet.

Altitude↗
PubMed2004

[Up-to-date information from the German QS salmonella monitoring and reduction programme].

In the beginning, the history, objectives and basic principles of the samonella monitoring and reduction programme that has been developed and implemented since 2002 in the framework of the German cross-sectional quality management and assurance programme "QS" for the food chain are expained in detail. It is a semi-quantitative assessment of the intra-herd prevalence of animals (60 samples per slaughter pig herd and year) with antibodies against salmonella species. By means of this asessment, herds are assigned to one of three risk categories (I = low risk, II = medium risk, and III = high risk) in terms of the probability to introduce Salmonella spp. into the food chain via slaughter pigs. The assignment to the categories is the basis of salmonella-reducing intervention measures. The implementation of the programme is considerably behind the schedule by mid-2004. The reasons for the delay are explained and conclusions for the further development of the programme are drawn.

Animals↗
PubMed2001

Development of a metabolism factor for polycyclic aromatic hydrocarbons for use in multipathway risk assessments of hazardous waste combustion facilities.

As a state authorized to permit hazardous waste combustion facilities, the Texas Natural Resource Conservation Commission (TNRCC) has conducted several site-specific, multipathway risk assessments in support of permitting actions. These risk assessments were carried out in accordance with guidance provided in U.S. Environmental Protection Agency's Human Health Risk Assessment Protocol for Hazardous Waste Combustion Facilities, Peer Review Draft (HHRAP). This protocol uses a prospective, screening-level, risk assessment paradigm and incorporates conservative default assumptions. In conducting such risk assessments, staff of the Toxicology and Risk Assessment Section have found that modeled emissions of polycyclic aromatic hydrocarbons (PAHs) at concentrations near or below detectable levels can produce unacceptable risk in the "farmer" exposure scenario. In accordance with recommendations in HHRAP, the TNRCC followed a tiered approach, whereby additional site-specific information is incorporated in place of standard default assumptions in cases where the initial screening-level risk assessment yielded unacceptable risk or hazard. Sensitivity analyses indicated that one of the key parameters affecting the risk estimates for PAHs in the farmer exposure scenario was the way in which PAHs were modeled up through the food chain. Therefore, refinement of the model focused on the development of a PAH-specific metabolism factor, as described in the article.

Animals↗
PubMed1979

Geochemical ecology and problems of health.

The state of health or disease is determined by the nature of the organism, the properties of the biosphere, the heterogeneity of its natural geochemical composition and changes brought about by technology (technogenic changes). For a systematic study of the conditions of health and endemic diseases we have suggested a system of biogeochemical regionalizing of the biosphere with the aid of biospheric taxa: regions of the biosphere, subregions of the biosphere, biogeochemical provinces. The main criteria of the regionalizing are biogenous cycles of chemical elements (links of the biogeochemical food chain from soil-forming rocks to man). An important criterion of the biogeochemical regionalizing is threshold concentrations of chemical elements. The organism regulates its metabolism within the ranges of chemical element concentration between the upper and lower thresholds (necessity range). When chemical elements are present in concentrations above the upper threshold and below the lower threshold, dysfunctions and endemic diseases are observed. Hence, the biogeochemical food chain allows us to establish critical links responsible for the state of health or endemic disease. Principles of optimizing the conditions of the environment and life have been worked out. The creation by us in the U.S.S.R. of biogeochemical maps relating conditions of the environment to biological reactions of organisms has proved a useful method of studying the ecological structure of the biosphere.

Dose-Response Relationship, Drug↗
PubMed2006

Assessment of the impact of cattle testing strategies on human exposure to BSE agents in Japan.

In Japan, cattle screening tests for BSE are conducted at slaughterhouses for surveillance purposes and as a meat safety measure, but the public health impacts of such testing and the subsequent removal of positive animals from the food chain have not been quantitatively assessed. We evaluated the influence of removing specified risk materials and the alternation of age limits for testing cattle at the slaughterhouse on human exposure to the BSE agent in Japan by constructing a probabilistic risk model. A stochastic model using Monte Carlo simulation was constructed in order to estimate the BSE infectivity destined for the food chain from a single BSE-infected animal at slaughter. The impact of different testing strategies and risk material removal were then compared. Murine intra-cerebral ID50 (m.i.c. ID50) units were used as units for BSE infectivity. Sensitivity analysis was conducted for key input variables by changing values within plausible ranges. The expected fraction of BSE-infected cattle presented for slaughter that would be detected by screening tests was 20%, even if all slaughtered cattle were tested. The removal of risk materials reduced the median value estimate of infectivity destined for human consumption by 95%. Cattle screening tests reduced the infectivity further, but reduction efficacy did not differ among the various testing strategies. Sensitivity analysis indicated that the characteristics of BSE infectivity accumulation during the incubation period, extension of the incubation period, and lowering the detection limit of screening tests had no significant impact on relative infectivity reduction, which remained stable irrespective of testing strategy or changes in these parameters. This study suggests that the impact of changing the age limit for testing cattle on beef safety is small, provided that the removal of risk materials is conducted properly.

Abattoirs↗
PubMed2003

Risk assessment and pathway study of arsenic in industrially contaminated sites of Hyderabad: a case study.

Different areas in the industrial region of Patancheru near Hyderabad, Andhra Pradesh (A.P), India are contaminated with high concentration of arsenic, which is attributed to industrial source like veterinary chemicals, pharmaceuticals, pesticide industries, etc. Fourteen villages of this area of Patancheru were assessed for arsenic contamination by collecting samples of water (surface and ground), soil, fodder, milk, and vegetables. The total arsenic content in the whole blood, urine, hair, and nails of the residents showing arsenical skin lesions and other clinical manifestations were also studied. To understand the bioavailability of arsenic in this environment and its possible entry into human food chain, speciation studies of arsenic was carried out and the results are presented in this paper.

Animals↗
PubMed1979

A review of recent activity in the United States.

Either an overabundance or a deficiency of trace metals in the food chain can ultimately affect adversely the health of livestock and man. Increasing interest in the United States in the distribution of metals in the environment and in metal pollutants has led to widespread interdisciplinary research sponsored by governmental, private and academic groups concerning the availability of trace elements for absorption by plants and animals, and the effects of trace elements throughout the food chain. The state of the art and the needs for research are reviewed by interdisciplinary committees in the National Academy of Sciences and in many government agencies. Research is encouraged through contracts and grants awarded by federal and state agencies and the National Science Foundation to universities for studies of specific metals, specific diseases and correlations between metals and health in specific geographic areas. Effects on the environment of coal-fired power plants, the mining and processing of metals, asbestos, and phosphate, and the disposal of industrial and nuclear wastes have also received much attention in the past few years.

Animals↗
PubMed1992

[Cooperation of veterinarians in legislation in the area of environmental hygiene (Germany and the European Economic Community)].

After a brief exposition of the tasks about the protection against chemical, physical, and biological environmental risks, a demonstration will be given according to deliberations of our law system about the possibilities for veterinarians to cooperate in the legislative branches. A detailed examination on former activities in the fields of pollution and the food-chain are to serve as a model for the future legislative process in Germany with the intention to strive for a harmonization of the in parts independently developed legislative branches. The external harmonization, a long-term objective, is to be found in the form of an uniform environmental law. Veterinarians take a great interest to work in advance for this uniform law in the way they bring new perspectives by cooperating in the fields of environmental hygiene and toxicology for the protection of the environmental media, of species and the food-chain. In conclusion one finds a brief documentation about the impact of the adaptation of law and the process on the EC-level.

Environmental Health↗