Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Food Chain”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources
PubMed2003

Natural specific radioactivity in different soils. Transfer in the soil plant food chain.

In order to warrant customer's health we must pay attention to the quality of the environment and production processes; that means look all over alimentary chain. Media speak often about this topics, because of the interest of the public opinion regarding agribusiness; Nether the less much is know about soil radioactivity, but often scant attention is directed to the knowledge of the amount what remains in food and arrives to the man who is the last and main user of the product. As a consequence of that, we have done some originals studies concerning specific radioactivity in alimentary chain: soil-plant-food. These studies have been made in relation with geopedologic position of fields in volcanic, clayey, sandy soils of Latium. We have measured radioactive activity over some alimentary chains both annual (like turnip and garden cress) and pluriannual (such as vine). We made comparisons on the same soils studying the following natural markers: K40, Pb214, and Bi214; and Cs137, one of the main natural markers.

Food Chain↗
PubMed2003

Dynamics of PCDDs/DFs and coplanar-PCBs in an aquatic food chain of Tokyo Bay.

Concentrations and accumulation profiles of PCDDs/DFs and coplanar-PCBs (co-PCBs) in aquatic biota (e.g., plankton, shellfish, benthic invertebrate, and fish) and sediment from Tokyo Bay were examined to elucidate the relationship between bioaccumulation and trophic level in the food web as determined by the stable nitrogen isotope analysis. Bioaccumulation patterns of PCDDs/DFs and co-PCBs varied greatly among congeners. Accumulation patterns of PCDDs/DFs and co-PCBs are not solely explained by their physicochemical properties. Biota-sediment accumulation factors (BSAFs) for co-PCBs in biota from Tokyo Bay were significantly greater than those of PCDDs/DFs. Furthermore, the slopes of the plots of delta15N and BSAF values and water solubility of 2,3,7,8-substituted PCDDs/DFs and co-PCBs were highly correlated. The results of our study would provide the valuable information to understand the accumulation properties of PCDDs/DFs and co-PCBs that can be used as a scientific basis to determine the sediment quality criteria of PCDDs/DFs and co-PCBs.

Animals↗
PubMed2001

Metal dynamics in an Antarctic food chain.

The concentrations of copper, zinc, cadmium, selenium and mercury were determined in eggs, muscle, liver, kidney and stomach content of nestilings and adults of the Antarctic petrel, Thalassoica antarctica, and its predator, the south polar skua, Chataracta maccormicki, from Svarthamaren, Dronning Maud Land, Antarctica. The dominant food of the petrels is krill, Euphausia superba. The results show relatively high levels of cadmium in krill, which is assumed to be the main reason for the high levels of cadmium in petrels and skuas. Cadmium is almost absent in eggs, but accumulates very rapidly with age in nestlings. The copper concentrations in livers of nestling petrels reach very high levels during growth. This may be seen in connection with physiological development processes. Mercury seems to be accumulated with age and between trophic levels. Among the nestlings, the mercury levels decrease with increasing age, which may be accomplished by the excretion of mercury through the growth of feathers and as a dilution effect during growth. Selenium and mercury are inversely correlated in nestlings. The levels of zinc were similar for different nestling stages and between nestlings and adults in skuas and petrels.

Age Factors↗
PubMed2005

Accumulation, metabolism, and food-chain transfer of chlorinated and brominated contaminants in subadult white whales (Delphinapterus leucas) and narwhals (Monodon monoceros) from Svalbard, Norway.

The concentrations and patterns of polychlorinated biphenyls (PCBs), chlorinated pesticides, and polybrominated diphenyl ethers (PBDEs) were studied in white whales (Delphinapterus leucas) and narwhals (Monodon monoceros) from Svalbard, Norway. In addition, their main food items were included in the study. In the whales, a broad range of pollutants was found in relatively high concentrations. PCBs and pesticides were approximately 3000 and 8000 ng/g lipid, respectively, for white whales and three times higher for narwhals. PBDEs 47 were approximately 70 ng/g lipid for white whales and 170 ng/g lipid for narwhals. Compared with other marine mammals from the same area, contaminant levels are among the highest levels ever measured. These high levels are likely in part because of a decreased capacity to metabolize contaminants. Metabolic indices indicated that most compounds accumulate to the same degree in white whales and narwhals, but for some toxaphenes and chlordanes, narwhals might have a decreased metabolism and consequently a higher accumulation. The three-times-higher contaminant levels in blubber of narwhals was further explained by substantially higher contaminant levels in their more benthic diet. The high levels and broad pattern of accumulating pollutants make white whales and narwhals excellent indicators for a wide range of contaminants in the Arctic.

Animals↗
PubMed1983

Aluminum of acid soils in the food chain and senility.

Aluminum is liberated from aluminosilicates of soil clays and protracted Al intake by humans in food and medications has been shown to be a potential hazard to human health. Encephalopathology, senility, and lower statistical longevity were found to be geographically and geochemically linked to acid soil conditions. We examined the interrelation of soil environmental supply of Al3+(6H2O) to the food-plant-animal-human chain (e.g., in tea leaves, approximately 1000 mg L-1) and to identified health hazards. Because F forms a strong ligand with Al, we also analyzed the extent that F accumulation is associated with Al accumulation in plants such as tea. Food and medicinal intake of Al needs to be considered in relation to kidney weakness and Al accumulation in humans. Acid soil and plant management could be modified to reduce the hazard of Al in senile dementia (2 to 4 percent of persons age greater than 65 years) and in diseases of the central nervous system endemic in certain acid soil areas.

Aluminum↗
PubMed2004

Cadmium in food chain and health effects in sensitive population groups.

Even at the low exposure level of cadmium found in this study population living on farms in southern Sweden, there was an indication of effect on biochemical markers of renal function. Women had higher blood cadmium (BCd) and urinary cadmium (UCd) than men, which can be explained by higher absorption of Cd due to low iron status. In the present study, Cd in pig kidneys could not be used to predict human BCd or UCd even though cereals are a substantial part of both the human and the pig diet. The contribution of Cd from locally produced food to the total dietary intake in humans was relatively low and varied and the intake of Cd did not correlate with BCd or UCd. In contrast, Cd levels in pig kidney were significantly related to Cd levels in feed. However, there was no relationship between the locally produced cereals, constituting the main part of the feed, and Cd in pig kidneys. In pig feed, other non-locally produced ingredients contributed to a large part of the Cd in feed. The Cd in non-locally produced feed ingredients reaches the local circulation via excretion in faeces and application of manure to arable soils and will lead to increased levels in the crops. As indicated by experimental data from animals, neurochemical and neurobehavioral effects during development need to be further explored as sensitive endpoints for cadmium toxicity.

Animal Feed↗
PubMedDate not supplied

Bioavailability, bioaccumulation and tolerance of chromium: consequences in the food chain of freshwater ecosystems.

Many abiotic and biotic factors can influence the partitioning equilibrium of heavy metals, thus influencing metal impact on aquatic environments. Unicellular algal species release soluble organic substances able to complex metals. In our laboratory a Cr-tolerant strain was selected and isolated from a wild type strain of Scenedesmus acutus. The exudates released by the two strains counteracted the growth inhibition caused by Cr(VI) and the exudates of the Cr-tolerant strain were more effective. On the contrary, the exudates did not reduce chromium toxicity to the cladoceran Daphnia magna. The reduction of chromium effect on algae seems the consequence of an algae-specific interaction among Cr(VI), exudates and algal cells. Chromium uptake resulted to be energy-dependent since bioaccumulation rate in subdued light condition was lower than at high light intensity. The effect of Cr(VI) on algae changed depending on metabolism of the cells and in particular it seemed to be related to the bioaccumulation rate. Tolerance in the selected strain could not be ascribed to a lower uptake of chromium. The difference in sensitivity to chromium between the two strains was exploited to evaluate if tolerance acquired by algae could have consequences for Daphnia. After treatment with Cr(VI), the two strains of S. acutus were used as food source for D. magna. The results indicate that chromium is accumulated by algae in a form not available for daphnids and that Cr tolerance acquired by the algae can be of some advantage to the consumer organism.

Animals↗
PubMed2001

Model for food chain transfer and dose assessment in areas of the Slovak Republic.

The radio-ecological model ECOSYS-87 developed for German ecological conditions, has been adapted to the conditions of two sub-regions in the Slovak Republic. In particular, the selection of plant varieties used for animal feeding, the plants' growing cycles and harvests, the animal feeding practices and the human consumption rates were subjected to adaptation. Measurements of caesium and iodine radioactivity in soil, plants and animal products that have mainly been performed in the vicinity of the Bohunice nuclear power plant after the Chernobyl accident, are compared with the results of the adapted model. Data from various locations with dry, mixed or predominantly wet deposition show in general good agreement.

Animal Feed↗