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PubMed2024

Epigenetic alterations in bioaccumulators of cadmium: Lessons from mammalian kidneys and plants.

Faced with unpredictable changes in global weather patterns, release and redistribution of metals through land erosion and water movements add to the increasing use of metals in industrial activities causing high levels of environmental pollution and concern to the health of all living organisms. Cadmium is released into the environment by smelting and mining, entering the food chain via contaminated soils, water, and phosphate fertilizers. Bioaccumulation of cadmium in plants represents the first major step into the human food chain and contributes to toxicity of several organs, especially the kidneys, where biomagnification of cadmium occurs over decades of exposure. Even in small amounts, cadmium brings about alterations at the molecular and cellular levels in eukaryotes through mutagenicity, molecular mimicry at metal binding sites and oxidative stress. The epigenome dictates expression of a gene's output through a number of regulatory steps involving chromatin remodeling, nucleosome unwinding, DNA accessibility, or nucleic acid modifications that ultimately impact the transcriptional and translational machinery. Several epigenetic enzymes exhibit zinc-dependence as zinc metalloenzymes and zinc finger proteins thus making them susceptible to deregulation through displacement by cadmium. In this review, we summarize the literature on cadmium-induced epigenetic mechanisms in mammalian kidneys and plants, compare similarities in the epigenetic defense between these bioaccumulators, and explore how future studies could advance our understanding of the cadmium-induced stress response and disruption to biological health.

Cadmium↗
PubMed2002

Symptoms and implications of selenium toxicity in fish: the Belews Lake case example.

Belews Lake, North Carolina was contaminated by selenium in wastewater from a coal-fired power plant during the mid-1970s, and toxic impacts to the resident fish community (20 species) were studied for over two decades. Symptoms of chronic selenium poisoning in Belews Lake fish included, (1) telangiectasia (swelling) of gill lamellae; (2) elevated lymphocytes; (3) reduced hematocrit and hemoglobin (anemia); (4) corneal cataracts; (5) exopthalmus (popeye); (6) pathological alterations in liver, kidney, heart, and ovary (e.g. vacuolization of parenchymal hepatocytes, intracapillary proliferative glomerulonephritis, severe pericarditis and myocarditis, necrotic and ruptured mature egg follicles); (7) reproductive failure (reduced production of viable eggs due to ovarian pathology, and post-hatch mortality due to bioaccumulation of selenium in eggs); and (8) teratogenic deformities of the spine, head, mouth, and fins. Important principles of selenium cycling and toxicity were documented in the Belews Lake studies. Selenium poisoning in fish can be 'invisible', because, the primary point of impact is the egg, which receives selenium from the female's diet (whether consumed in organic or inorganic forms), and stores it until hatching, whereupon it is metabolized by the developing fish. If concentrations in eggs are great enough (about 10 microg/g or greater) biochemical functions may be disrupted, and teratogenic deformity and death may occur. Adult fish can survive and appear healthy despite the fact that extensive reproductive failure is occurring--19 of the 20 species in Belews Lake were eliminated as a result of this insidious mode of toxicity. Bioaccumulation in aquatic food chains causes otherwise harmless concentrations of selenium to reach toxic levels, and the selenium in contaminated sediments can be cycled into food chains for decades. The lessons learned from Belews Lake provide information useful for protecting aquatic ecosystems as new selenium issues emerge.

Abnormalities, Drug-Induced↗
PubMed2005

Baby food production chain: pesticide residues in fresh apples and products.

During 3 years of a monitoring programme, 522 samples of fresh apples, six brands of fruit purées and various types of fruit baby food prepared from these materials were analysed. Each sample was examined for the presence of 86 GC amenable pesticide residues. The reporting limits of the procedure employed for sample analyses were in the range 0.003-0.01 mg kg(-1). Pesticide residues were detected in 59.5% of the samples of fresh apples. However, maximum residue levels (European Union MRLs) were exceeded only in 1.4% of samples. The levels of residues in 'positive' fruit purées were substantially lower, overall with residues detected in 33% of samples. Fruit baby food represented the commodity with the lowest incidence of residues being detected in only 16% of samples. The 0.01 mg kg(-1) MRL was exceeded in 9% of these products. Multiple residues were found in 25% of fresh apples and in 10% of fruit purées. None of fruit baby food samples contained more than a single residue. Organophosphorus insecticides and fungicides representing phtalimides, sulphamides and dicarboximides were the most frequently found residues. To obtain more knowledge on the fate of residues during fruit baby food production, processing experiments employing apples with incurred residues (fenitrothion, phosalone and tolylfluanid) were conducted. Washing of apples did not significantly reduce the content of pesticides. Steam boiling followed by removal of peels/stems was identified as the most efficient steps in terms of residues decrease (phosalone) or complete elimination (fenitrothion and tolylfluanid).

Aniline Compounds↗
PubMed2004

[Host transfer of Beauveria bassiana population in pine stand ecosystem and impact of its genetic diversity on sustainable control of Masson's pine caterpillars].

In an anniversary investigation post inoculative release of Beauveria bassiana against Masson's pine caterpillars in a Masson's pine plantation, 119 strains were isolated from 30 host insects, soil, litter and air. Based on an esterase isozyme analysis, all these strains were assigned to 32 esterase types, suggesting abundant genetic diversity. The esterase type 2 was assigned including 18 other strains from 11 different host insects, indicating that the released strain had successfully survived in different insect populations and persisted in enzootic condition in 12 insect populations including pine caterpillars and grey pine weevils. Other host insects could maintain the food chain when the target insect population was low. The other esterase types included 1-23 strains. The anniversary host transfer dynamics further revealed that B. bassiana could transfer among different host insects in the pine ecosystem. The virulence of the strains of each esterase differed substantially, which suggested that B. bassiana persisted and dispersed along more than one route, and each esterase stood for at least one branch in the food web. Some hosts connected different esterase types at nodal points, making the food web very complicated. In addition, the strains isolated from soil, litter, forest crown and air belonged to different esterase types, suggesting that a complex of saprophytic food chains existed in the plantation, which made the food web more complicated, and benefited the sustainable control of the Masson's pine caterpillar and other pest insects in the ecosystem.

Animals↗
PubMed1975

Residue of organochlorine compounds and mercury in birds' eggs from the Niagara Peninsula, Ontario.

Eggs (307) were collected in 1971 from twenty species of birds with a variety of feeding habits from the Niagara Peninsula. This area of ontario is intensively developed for agriculture and heavy industry and has a large urban population. Representative species were obtained from both the terrestrial and aquatic food chains. Eggs were analyzed for organochlorine insecticides, polychlorinated biphenyls, and total mercury. Eggs from carnivorous species at the top of the aquatic food chain had the highest mean residues of signa DDT(7.6to 22.4 pm), PCB (3.5 to 74.0 ppm) and total mercury (0.64 to 0.83 ppm). Eggs from some terrestrial carnivores (red-tailed hawk and great horned owl) also had relatively high residues (2.5 to 3.9 ppm of sigmaDDT, 0.2 to 1.0 ppm of PCB, 0.06 to 0.09 ppm of mercury, however levels were much lower than those found in eggs from aquatic-feeding carnivores. Eggs from one red-shouldered hawk had residues comparable to the aquatic feeding carnivores. Eggs from herbivorous and insectivorous birds of both aquatic and terrestrial environments contained much lower residues. PCB residues were slightly lower in eggs among the terrestrial feeding species (0.05 to 2.0 ppm) than among the aquatic feeders (0.14 to4.0 ppm) and tended to be lower in eggs from terrestrial species collected in rural than incity environs. Levels of sigmaDDT were similar in both groups with eggs from terrestrial feeders containing mean resisues between 0.15 and 2.64 ppm and those from aquatic feeders between 0.33 and 2.79 ppm.

Animals↗
PubMed2003

Comparison of enterococcal populations in animals, humans, and the environment--a European study.

The objectives of the present study were to generate knowledge of enterococcal populations in the food chain, by studying the population structure (in measures of abundance and diversity) among enterococci in different geographical regions and in different parts of the food chain, as well as the similarities between different enterococcal populations. Altogether, 2868 samples were collected from humans (healthy and hospitalised individuals and clinical isolates), animals (slaughterhouse carcasses and farm animals), and the environment (pig farms, sewage, and surface water) in four European countries-Sweden, Denmark, UK, and Spain. The samples were characterised with regard to presence and numbers of enterococci, and eight (for faecal samples) or 24 (for environmental samples) isolates per sample were phenotyped and preliminarily identified with the PhP-RF system. In total, more than 20,000 isolates were typed. A majority of the samples (77%) showed the presence of presumed enterococci. The diversities of enterococci in environmental samples were generally high, and also faecal samples normally showed presence of more than one enterococcal strain. The most common species found were Enterococcus faecium (33%), E. faecalis (29%), and E. hirae (24%), but different enterococcal populations differed in their species distribution. Clinical isolates, hospitalised patients, and hospital sewage in Sweden showed a clear dominance of E. faecalis (80%, 57%, and 54%, respectively) whereas healthy individuals and urban sewage contained less E. faecalis (39% and 40%, respectively). The species distribution among isolates from slaughterhouses varied between animal species and also between countries, but E. faecalis seemed to be mainly associated with broiler, and E. hirae with cattle and pigs. The results from the study have indicated a simplified method to study the diversity of bacterial populations. Instead of collecting many samples and analysing one or a few isolates per sample, it is possible to collect fewer samples and analyse several isolates per sample. Both approaches yielded similar information on the diversity of the populations. Another useful information was that since samples from hospital sewage, urban sewage, and manure contained enterococcal populations that reflected those in faecal samples of hospitalised patients, healthy humans, and animals, respectively, such samples may be used as pooled faecal samples and may replace cumbersome samplings from many individuals.

Animals↗
PubMed2004

Biological and chemical factors of importance in the bioaccumulation and trophic transfer of persistent organochlorine contaminants in Arctic marine food webs.

Recent studies of arctic marine food webs have provided detailed insights regarding the biological and chemical factors that influence the bioaccumulation and trophic transfer of persistent organochlorine (OC) contaminants in aquatic systems. The present paper summarizes the recent literature with an emphasis on identifying important ecological factors for explaining variability of OC concentrations among organisms. The Arctic ecosystem has a number of unique attributes, including long food chains, reduced diversity of species, similar food webs across the entire region, and limited influence from pollution point sources. Lipid content, body size, age, gender, reproduction, habitat use, migration, biotransformation, seasonal changes in habitat conditions, feeding ecology, and trophic position have all been demonstrated to influence OC concentrations and bioaccumulation in arctic marine biota. The relative importance of each factor varies among OCs and organisms. Diet or trophic level is the dominant factor influencing OC concentrations and dynamics in seabirds and marine mammals, although biotransformation can significantly influence nonrecalcitrant OCs, such as hexachlorocyclohexane isomers. Dietary accumulation of OCs is also an important route of exposure for arctic fish and zooplankton, and biomagnification of OCs may also occur among these organisms. To date, only limited attempts have been made to model trophic transfer of OCs in the arctic marine food web. Although models developed to assess OC dynamics in aquatic food webs have included some biological variables (e.g., lipid content, feeding rate, diet composition, and growth rate), selection of processes included in these models as well as their mathematical solutions and parameterization all introduce simplification. This reduces biological validity of the models and may be particularly problematic in a highly seasonal environment, such as the Arctic Ocean.

Age Factors↗
PubMedDate not supplied

Risk Analysis of Antibiotic Resistance, Berlin, BfR, 10-12 November 2003: activities of the Codex Alimentarius Commission related to antibiotic resistance.

The FAO/WHO Codex Alimentarius Commission develops recommendations concerning risk management related to regulatory issues, on the basis of scientific advice provided by FAO and WHO. The complex question of anti-microbial resistance that requires a multidisciplinary approach, has been considered from different point of views in the framework of Codex, especially food hygiene and veterinary drugs and to a lesser extent, plant protection. Antibiotic resistance was considered from the perspective of the food chain and a risk profile was developed. Risk management options were also considered and may be grouped in two main categories: prevention of contamination through the food chain; and prudent use of anti-microbials. It is recognized that further scientific advice is necessary before developing specific risk management options in the framework of Codex. It is expected that the results of the FAO/OIE/WHO Expert Consultations on anti-microbial resistance will provide the necessary guidance for further action.

Animals↗
PubMed1991

Benzo-a-pyrene: environmental partitioning and human exposure.

A multimedia transport model was used to evaluate the environmental partitioning of benzo-a-pyrene (BaP). Measured and predicted environmental concentrations were used to estimate the accumulation of BaP in the food chain and the subsequent extent of human exposure from inhalation and ingestion. Results show that BaP partitions mainly into soil (82%) and sediment (17%) and that the food chain is the dominant pathway of human exposure, accounting for about 97% of the total daily intake of BaP. Inhalation and consumption of contaminated water are only minor pathways of human exposure. The long-term average daily intake of BaP by the general population of the U.S. is estimated to be 2.2 micrograms (micrograms) per day. Cigarette smoking and indoor activities do not substantially increase human exposure to BaP relative to exposures to background levels of BaP present in the environment. Since the increased lifetime risk associated with human exposure to background levels of BaP is 3.5 x 10(-4), we conclude that ingestion of food items contaminated with BaP may pose a serious health threat to the U.S. population.

Animals↗
PubMed2006

Neighbourhood fast food environment and area deprivation-substitution or concentration?

It has been hypothesised that deprived neighbourhoods have poorer quality food environments which may promote the development of obesity. We investigated associations between area deprivation and the location of the four largest fast-food chains in Scotland and England. We found statistically significant increases in density of outlets from more affluent to more deprived areas for each individual fast-food chain and all chains combined. These results provide support for a 'concentration' effect whereby plausible health-damaging environmental risk factors for obesity appear to be 'concentrated' in more deprived areas of England and Scotland.

Diet↗
PubMed2002

Potential mechanisms of increased disease in humans from antimicrobial resistance in food animals.

There are at least 5 potential mechanisms by which antimicrobial resistance can have adverse effects on human health. The first, called the "attributable fraction," relates to individuals who become infected only because they are taking an antimicrobial agent (for unrelated reasons) to which the pathogen is resistant: the antimicrobial agent, by suppressing their normal microbiota, renders them more vulnerable to infection. A second mechanism involves the linkage of virulence traits to resistance traits so that resistant organisms may be more virulent than susceptible organisms. A third mechanism is that treatment may be rendered ineffective by the choice of a drug to which the pathogens are resistant or may be complicated by the need to use an agent with less desirable attributes than would otherwise be the case. A fourth mechanism is the animal equivalent of the attributable fraction: resistant pathogens acquired by this mechanism in food animals may then be transmitted through the food chain to humans. Last, resistance traits can be acquired by the commensal flora of animals; from this reservoir, resistance traits could find their way through the food chain to commensals and pathogens of humans.

Animals↗
PubMed2005

Exposure to metal mixtures and human health impacts in a contaminated area in Nanning, China.

Cadmium and lead have been identified as very toxic metals, which are widely present in the environment due to natural and anthropogenic emissions. Many studies have shown that the food chain is the main pathway of cadmium and lead transfer from the environment to humans. It is well documented that many factors will affect their transfer through food chains. Previous investigations on heavy metals were mostly concentrated on one contaminant in isolation. However, in real environments, exposure to mixtures of metals is ubiquitous such that cadmium pollution is invariably being associated with lead and zinc, etc. This study focuses on the contamination and health effects of the metal mixtures. For this purpose, a dietary survey was taken for 3 groups in Nanning in October 2002. Samples of soils, plants (vegetables), urine and blood of humans were measured for Cd, Fe, Cu, Zn, Ca and Pb, in addition, the urinary indicators of renal dysfunction Albumin (ALB), N-acetyl-beta-D-glucosaminidase (NAG), Beta-2-microglobulin (beta2-MG) and Retinol-binding protein (RBP) in urine were also measured. Results showed that soil contamination with metal mixtures had caused significant renal dysfunction of the local residents living in the contaminated area, and the dose-response curve was somewhat altered by the mixed contamination of Cd and Pb as well as the intake of other minerals. The importance of mixtures of metal contamination and human health are also discussed in this paper.

Acetylglucosaminidase↗
PubMed1992

Bioaccumulation processes in ecosystems.

The fate of environmental pollutants--the various isotopes of elements, and inorganic or organic compounds--is a fundamental aspect of ecology and ecotoxicology, and bioaccumulation is a phenomenon often discussed in this context. Human activities have drastically altered natural concentrations of many substances in the environment and added numerous new chemicals. An understanding of the processes of bioaccumulation is important for several reasons. 1) Bioaccumulation in organisms may enhance the persistence of industrial chemicals in the ecosystem as a whole, since they can be fixed in the tissues of organisms. 2) Stored chemicals are not exposed to direct physical, chemical, or biochemical degradation. 3) Stored chemicals can directly affect an individual's health. 4) Predators of those organisms that have bioaccumulated harmful substances may be endangered by food chain effects. While former theories on the processes of bioaccumulation focused on single aspects that affect the extent of accumulation (such as the trophic level within the food chain or the lipophilicity of the chemical), modern theories are based on compartmental kinetics and the integration of various environmental interactions. Concepts include results from quantitative structure-activity relationships (QSAR), pharmacokinetics, ecophysiology and general biology, molecular genetic aspects and selection, and finally the structure of communities and man-made alterations in them.

Animal Population Groups↗
PubMedDate not supplied

Pentachlorophenol: environmental partitioning and human exposure.

This paper uses a six compartment environmental partitioning model to explore the transport and accumulation of pentachlorophenol (PCP) within and between various environmental media. Environmental concentrations were then used to estimate the amount of PCP entering the food chain and the long-term, average daily intake of PCP by the general population of the U.S. Results show that PCP partitions mainly into soil (96.5%) and that the food chain, especially fruits, vegetables, and grains, accounts for 99.9% of human exposure to PCP. The long-term, average daily intake of PCP is estimated to be 16 micrograms/day, which agrees well with a previous estimate of 19 micrograms/day (Geyer et al. 1987).

Chlorophenols↗
PubMed2004

Cassava cyanogens and fish mercury are high but safely consumed in the diet of native Amazonians.

The two most important staple foods (cassava and fish) in the diet of native Amazonians contain neurotoxins (linamarin and monomethyl mercury, MMHg). These same neurotoxins are public health issues in other parts of the world. Factors such as chemistry, environment, and human ecology determine the endemism of neuropathies caused by consumption of cassava (Manihot esculenta Crantz) and fish. Linamarin is a natural component of cassava tubers that can be destroyed before consumption by proper processing. Furthermore, small amounts of the toxin absorbed by people consuming cassava can be effectively metabolized if the diet contains adequate protein-containing sulfur amino acids. Naturally occurring Hg in the waters of the Amazonian rain forest is methylated to MMHg by microorganisms and bioconcentrated in the aquatic food chain. There is no effective method for MMHg removal from fish. Despite high concentrations of naturally occurring neurotoxins in cassava (linamarin) and fish (MMHg), daily consumption of these foods in large amounts over the course of a lifetime poses no health hazards for Amazonians.

Amino Acids↗
PubMed1986

Synergistic neurotoxicity of carbon tetrachloride/carbon disulfide (80/20 fumigants) and other pesticides in grain storage workers.

Neurophysiologic, neurobehavioral, and neuropsychologic profiles in 17 grain storage workers, 1 grain inspector, and 4 malting laboratory workers are described. The effects of CS2 toxicity as seen in viscose rayon workers as well as in experimental animals is remarkably similar to the clinical profile of our grain storage workers. CS2 use explains the dysfunction of peripheral axons, auditory nerve, the optic nerve, and the extrapyramidal system, as well as altered behavior and cognition changes. The signs and symptoms in these workers seem to be dose-related and we note that workers separated out from the areas where fumigation took place reported improvement not seen by fellow workers who continued the fumigant treatment routine. Likewise, malting laboratory workers exposed only to the grain dust from 3 to 7 years showed only minimal symptoms. Though a number of mechanism have been suggested for the alteration of neuropsychological function, the chelating ability of DDC derived from CS2 and its ability to markedly increase copper and zinc within the central nervous system suggests a mechanism of toxicity analogous to copper intoxication as in Wilson's Disease and may explain the production of extrapyramidal symptoms in these patients. Chelation of copper might prove therapeutic in CS2 poisoning. It is obvious that both basic and clinical research will be necessary to sort out the questions raised. We applaud the EPA's decision to ban the use of 80/20 fumigants and also methyl bromide, and trust that similar toxic substances be carefully studied before their selection for replacing these previous toxic agents. We further decry the technique of re-introducing grain dust into the food chain rather than destroying it, since the dust contains very high residues of fumigant material. We speculate on the possible role of CS2 and other pesticides in the food chain and the incidence of Parkinsonian symptoms in these patients and the general public.

Adult↗
PubMedDate not supplied

Fish and shellfish poisoning.

OBJECTIVE: To review history, biology, and medical aspects associated with fish and shellfish poisoning. DATA SOURCES: Current literature, various Web sites, and Halstead's Volume II of Poisonous and Venomous Marine Animals. STUDY SELECTION: Determined by author. DATA SELECTION: Determined by author. DATA SYNTHESIS: Fish and shellfish poisoning occur through the natural event of the food chain. Fish and shellfish consume algae that contain toxin-producing dinoflagellates. As a result they become contaminated and the toxin is concentrated as it moves up the food chain. Fish and shellfish can tolerate high levels of toxins, thereby appearing healthy while posing a significant danger to man. The toxin cannot be detected by sight, smell, or taste and is not destroyed by cooking or freezing. Thus man becomes an unsuspecting victim. There are several types of poisoning that occur through fish and shellfish consumption. They are ciguatera and scombroid fish poisoning; and paralytic, diarrheic, neurotoxic, and amnesic shellfish poisoning. A different toxin produces each of these poisonings; however, sources and symptoms may be similar among these poisonings making them difficult to diagnose. These intoxications can vary in severity from mild to fatal depending on the type and amount of toxin ingested. Age and underlying illnesses may also contribute to the outcome of these poisonings. CONCLUSION: Though people are aware of health warnings and may think they are important, it is human nature to think that "this could not possibly happen to me". Therefore, they fail to make the necessary changes required to reduce the incidence of fish and shellfish poisoning.

Animals↗
PubMed1994

[Integrated quality assurance].

The definition of terms and connotation of "Quality", "Quality Assurance" and "Integration" lead to an analysis and understanding of inhibiting and fostering factors of the "Health Triad" of people, animals and environment. Although "Quality" is largely or ultimately determined by the consumer, there are considerable differences as this term is applied by (a) the individual consumer, (b) the dynamic producer defending or gaining markets, (c) those engaged in traditional product manufacturing, or (d) governments setting (minimum) requirements for the sake of free trade. "Quality Assurance" offers cooperation of partners all along the food chain from "pasture to table". The managerial process turned into a continuum of responsibility and agreement on processes and product characteristics. This overcomes the disadvantages of strategies stressing distinct defense barriers. In practice this philosophy of a predominant role of defence barriers proved largely partnership destructive, in that it permitted to shift responsibilities for failures and to claim administrative competence according to momentary situations and interests. "Integrated Quality Assurance" means mutual agreement of two or more partners along the food chain (e. g. feed producers, farmers, animal health industry, veterinarians and food processors) on product characteristics and production methods. It involves essential system elements including facilities, materials, manpower, information, transport, management etc. Different principles and procedures of quality assurance have been introduced in practice, including agriculture and food processing. These different approaches are not mutually exclusive but largely of complementary nature.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗