Showing papers on "Bioaccumulation published in 1995"

Bioaccumulation of Polycyclic Aromatic Hydrocarbons by Marine Organisms

Abstract: Polycyclic aromatic hydrocarbons (PAHs) appear in most urbanized coastal areas of the world, accumulating in sediments and biota that are unable to efficiently eliminate them. This review focuses specifically on the mechanisms of bioavailability, uptake, and elimination, which determine the extent of accumulation and retention of PAHs in invertebrates and fish in marine ecosystems. We review here the literature on the mechanisms and factors that control these processes which ultimately determine the concentration of PAHs in marine organisms. Understanding both the temporal and spatial characteristics of bioaccumulation of the environmentally important PAHs is crucial for determining the impact that this class of compounds may have on marine populations. To provide a complete assessment of these potential impacts, scientists require knowledge about the distribution of these compounds in different environmental matrices, their uptake and partitioning in different tissues, their rates of elimination, and their potential for persistence in certain species. The combined information on these mechanisms and the environmental factors that control accumulation will help scientists develop predictive models of contaminant accumulation both for acute events, such as oil spills, and for long-term, chronic exposure as is found in many urban areas in our coastal ecosystems.

Bioaccumulation of mercury and methylmercury

Abstract: The factors controlling the accumulation of mercury in fish are poorly understood. The oft invoked lipid solubility of MMHg is an inadequate explanation because inorganic Hg complexes, which are not bioaccumulated, are as lipid soluble as their MMHg analogs and, unlike other hydrophobic compounds, MMHg in fish resides in protein rather than fat tissue. We show that passive uptake of the lipophilic complexes (primarily HgCl2 and CH3HgCl) results in high concentrations of both inorganic and MMHg in phytoplankton. However, differences in partitioning within phytoplankton cells between inorganic mercury — which is principally membrane bound — and MMHg — which accumulates in the cytoplasm — lead to a greater assimilation of MMHg during Zooplankton grazing. Most of the discrimination between inorganic and MMHg thus occurs during trophic transfer while the major enrichment factor is between water and phytoplankton. As a result, MMHg concentrations in fish are ultimately determined by water chemistry which controls MMHg speciation and uptake at the base of the food chain.

A review of the effects of heavy metals on freshwater mussels.

Abstract: The widespread recent decline in the species diversity and population density of freshwater mussels in North America may be partly related to chronic, low-level exposure to toxic metals. As benthic filter-feeding organisms, freshwater mussels are exposed to metals that are dissolved in water, associated with suspended particles and deposited in bottom sediments. Thus, freshwater mussels can bioaccumulate certain metals to concentrations that greatly exceed those dissolved in water. In adult mussels, the most common site of metal uptake is the gill, followed by the mantle and the kidney. The toxic effects of metals on freshwater mussels have been examined in a few acute toxicity tests, but the sublethal effects of long-term exposure to low environmental concentrations are little understood. Sublethal exposure to metals can alter growth, filtration efficiency, enzyme activity and behaviour. Sublethal effects are frequently observed at concentrations that are only half the lethal concentrations. However, few toxicity tests have used environmentally realistic exposure concentrations. Total concentrations of Cd, Cu, Hg and Zn in many oxic surface waters are in the ngl(-1) range, yet many toxicity studies have exposed mussels to concentrations in the μgl(-1) or even the mgl(-1) range. An understanding of the processes by which metals affect freshwater mussels would provide insights on the ecotoxicological significance of metal contamination to natural mussel populations and aid in the development of water-quality criteria that adequately protect mussels.

Bioaccumulation of mercury and methylmercury

Abstract: The factors controlling the accumulation of mercury in fish are poorly understood. The oil invoked lipid solubility of MMHg is an inadequate explanation because inorganic Hg complexes, which are not bioaccumulated, are as lipid soluble as their MMHg analogs and, unlike other hydrophobic compounds, MMHg in fish resides in protein rather than fat tissue. We show that passive uptake of the lipophilic complexes (primarily HgCl2 and CH3HgCl) results in high concentrations of both inorganic and MMHg in phytoplankton. However, differences in partitioning within phytoplankton cells between inorganic mercury — which is principally membrane bound — and MMHg — which accumulates in the cytoplasm — lead to a greater assimilation of MMHg during zooplankton grazing. Most of the discrimination between inorganic and MMHg thus occurs during trophic transfer while the major enrichment factor is between water and phytoplankton. As a result, MMHg concentrations in fish are ultimately determined by water chemistry which controls MMHg speciation and uptake at the base of the food chain.

Toxicity and bioaccumulation of sediment-associated contaminants using freshwater invertebrates: A review of methods and applications

Abstract: This paper reviews recent developments in methods for evaluating the toxicity and bioaccumulation of contaminants associated with freshwater sediments and summarizes example case studies demonstrating the application of these methods. Over the past decade, research has emphasized development of more specific testing procedures for conducting 10-d toxicity tests with the amphipod Hyalella azteca and the midge Chironomus tentans. Toxicity endpoints measured in these tests are survival for H. azteca and survival and growth for C. tentans. Guidance has also been developed for conducting 28-d bioaccumulation tests with the oligochaete Lumbriculus variegatus, including determination of bioaccumulation kinetics for different compound classes. These methods have been applied to a variety of sediments to address issues ranging from site assessments to bioavailability of organic and inorganic contaminants using field-collected and laboratory-spiked samples. Survival and growth of controls routinely meet or exceed test acceptability criteria. Results of laboratory bioaccumulation studies with L. variegatus have been confirmed with comparisons to residues (PCBs, PAHs, DDT) present from synoptically collected field populations of oligochaetes. Additional method development is currently underway to develop chronic toxicity tests and to provide additional data-confirming responses observed in laboratory sediment tests with natural benthic populations.

Size-dependent bioconcentration kinetics of hydrophobic organic chemicals in fish based on diffusive mass transfer and allometric relationships.

Abstract: In a series of size classes of fathead minnow, bioconcentration kinetics and bioconcentration factors of five polychlorinated benzenes and biphenyls are weight related. A simple bioaccumulation model for hydrophobic chemicals in fish is presented that is based on diffusive mass transfer. The model contains physical-chemical and size-related parameters. The model calculations are in good agreement with experimental values from the literature for uptake and elimination rate constants. The model, however, partly explains the observed size and octanol/water partition coefficient (K ow ) related uptake and elimination rate constants in the present study with juvenile fathead minnow. Physiological factors other than size-related parameters, such as uptake by skin, are suggested to be important as well. The main fish-related parameters are (gill) exchange surface area and lipid content ; the main physical-chemical parameters are K ow and molecular weight.

Bioaccumulation of Methylmercury and Transformation of Inorganic Mercury by Macrofungi

Abstract: The terrestrial biogeochemical cycle of mercury between humus and fungi was investigated in a mercury-contaminated former mining area of Germany. We used a variable volume extraction procedure and aqueous sodium boron tetraethyl derivatization to determine accurately and precisely methylmercury bioconcentration factors for fungi. The methylmercury and total mercury content for fungi carpophores ranged from 0.08 to 7.94 μg/g of Hg as methylmercury and from 6.2 to 144.0 μg/g of inorganic Hg, respectively. The levels in humus material were between 0.01 and 0.09 μg/g of Hg as methylmercury and 15.8 and 140.2 μg/g of inorganic Hg, respectively. The bioconcentration factors obtained are generally lower than 1 for total mercury and between 3.0 and 199.0 for methylmercury. By an in vitro methylation experiment with two axenic cultures of Coprinus comatus and Coprinus radians, we could show for the first time that these saprophytic macromycetes are able to methyl ate mercury.

Heavy metal bioaccumulation in different tissues of two fish species with regards to their feeding habits and trophic levels.

Abstract: Heavy metals residues (i.e. Cu, Zn, Mn, and Pb) were determined in seven chosen tissues of two fish species (Esox lucius and Carassius auratus) from Anzali wetland. The impact of feeding habit on metal accumulations in different tissues as well as the respective contribution of water and food to matel uptake by fishes were considered. No tendency for bioamplification was observed for the metals along the wetland trophic levels. Generally, there was no statistically significant relationship between the metal content of the tissues and the fish length for both species. In all cases, except for lead, the mean amounts of the metals in the flesh of the species were higher than those in commercially important fishes from the Caspian sea. However, they were below the recommended levels for human consumption.

Comparative bioaccumulation of polycyclic aromatic hydrocarbons from sediment by two infaunal invertebrates

Abstract: Bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) from field-contaminated sediments by 2 infaunal invertebrates, Rhepoxynius abronius (a non-deposit feeding amphipod) and Armandia brevis (a non-selective, deposit-feeding polychaete), was examined. Sediments were selected over a large geographical area of the Hudson-Raritan estuary (New York, USA) to assess the potential for bioaccumulation from a typical urban estuary. Assessment of bioaccumulation in these invertebrates is important because of the need to understand their health and role in ecosystem functioning and because they are vectors of sediment-associated contaminants to demersal fish. Our study compared the response of these 2 species over a wide range of PAH concentrations to learn how feeding mode may affect contaminant accumulation. After 10 d of exposure to sedirnents, we assessed the tissue concentrations of 24 PAHs and found no significant differences for the low molecular weight PAHs (LPAHs) between R. abronius and A. brevis. There was, however, a large differential observed between species for bioaccumulated high molecular weight PAHs (HPAHs). Because we assumed that the amphipod was not feeding and most of its tissue burden was received through ventilation of interstitial water (IW), we concluded that IW was probably the major route of uptake for the LPAHs for both species and that sediment ingestion was a much more important uptake route of HPAHs for the polychaete. Analysis of correlations between amphipod and polychaete tissue burdens found that the species were responding similarly to a gradient of PAH concentrations in sediment; however, when the associations between concentrations in tissue and exposure matrix (e.g. sediment, IW) were examined the interpretations were less clear. Concentrations of PAHs in IW and sediment indicated that the partition coefficient (&,) was generally 2 orders of magnitude higher than expected for LPAHs and highly variable between sites for HPAHs. When K,, was re-calculated using free PAH, i t became much less variable and was uniformly elevated above the predicted values. The BAF,,, (lipid/organic carbon normalized bioaccumulat~on factor) in the polychaete was generally consistent over the series of PAHs, as expected, and when metabolism and pre-steady state conditions were considered, partitioning of PAHs between tissue and sediment was relatively close to the theoretical maximum. Despite much lower than predicted 1W concentrations, the LPAH bioconcentration factors (BCF) for the amphipod were close to expected, but the HPAH BCFs were close to the predicted values only when expressed in terms of the free PAH. From these data, and previous studies, we conclude that there was a significant reduction in bioavailability of HPAHs to R. abronius due to partitioning of HPAHs to dissolved organic carbon.

Differential Bioaccumulation of Non-ortho-Substituted and Other PCB Congeners in Coastal Arctic Invertebrates and Fish.

Abstract: The composition of 47 ortho- and seven non-ortho-substituted PCBs in sediment, water, invertebrates, and fish collected from Cambridge Bay, Northwest Territories, Canada, is presented. The congener composition in sea urchins (Strongylocentrotus droebachiensis) was attributed to differences in the log K OW of individual congeners during uptake from ingested sediment and aqueous solubility during secondary uptake from the water column. Four-horn and short-horn sculpins exhibited selective bioaccumulation of the recalcitrant congeners : those lacking two non-chlorinated carbons in adjacent meta and para positions on the biphenyl ring. The presence of methyl sulfone PCBs in four-horn sculpin liver provided direct evidence for metabolism. The percent composition of total PCB levels in four-horn sculpin livers, contributed by non-ortho-substituted PCBs 77 and 126 (those with potential for dioxin-like toxicity), was relatively constant regardless of total PCB concentration, suggesting that for a given species increased exposure to PCBs does not lead to increased relative concentrations of non-ortho-substituted congeners. Limited data on congeners 77 and 126 in sediment, sea urchins, or four-horn sculpins suggests that, with increasing trophic status, these congeners were diminished rather than enriched relative to the total PCB concentration.

PCB congeners and hexachlorobenzene biota sediment accumulation factors for Macoma nasuta exposed to sediments with different total organic carbon contents

Abstract: Deposit-feeding marine clams (Macoma nasuta) were exposed for 119 d to three sediment types that varied in total organic carbon (TOC) from 0.8 to 2.5%. Sediments were spiked with equal concentrations of 13 polychlorinated biphenyl congeners and hexachlorobenzene. Tissue residues were measured, and steady-state bioaccumulation factors (BAFs), the corresponding lipid, and TOC-normalized biota sediment accumulation factors (BSAFs) were determined. The BSAFs were less variable than were the BAFs with the exception of compounds with log K[sub ow] > 7. Many of the BSAFs exceeded 1.7, which is a calculated maximum value based on partitioning alone. Although BSAFs varied with sediment type and compound, the use of a BSAF of 4 as a screening level for neutral organic compounds in assessing dredge materials is supported by the present study.

Bioaccumulation of polychlorinated biphenyls and chlorinated pesticides by the Asiatic clam Corbicula fluminea: its use as sentinel organism in the Rio de La Plata Estuary, Argentina

Abstract: Individual PCBs and chlorinated pesticides (CHLPs) were determined in water, suspended particles (SPM), sediments, and Asiatic clams to study their bioaccumulation kinetics and evaluate the usefulness of the clams as sentinel organisms. Bioaccumulation depended on the routes of uptake and bioavailability determined by compound hydrophobicity. CHLPs were mainly present in the dissolved phase, showed a positive correlation between the bivalve-water BAFs and K ow 's and reached steady-state levels before 70 days in a caging experience. These facts reflect an efficient water-gill partitioning process. In contrast, PCBs were only detected in the SPM, showed essentially K ow independent bivalve-sediment and bivalve-SPM BAFs with the lowest values for super-hydrophobic heptachlorobiphenyls 174, 180, and 170, and did not reach steady-state levels during a 140-day exposure period. This suggests that the uptake was hindered by their stronger affinity for SPM and the interference of steric factors during intestine absorption. Corbicula fluminea are reliable sentinel organisms and showed clear geographical trends along 150 km of the Rio de La Plata coast : a progressive decrease of PCB levels and more degraded patterns dominated by recalcitrant congeners, i.e., 153, were observed with increasing distance from the major La Plata-Buenos Aires urban center. A size-related trend overlapped with this spatial gradient : older clams usually showed higher levels and a more degraded PCB signature. CHLPs showed less clear geographical trends due to the presence of multiple sources. CHLP patterns showed a strong dominance of chlordane-related compounds, particularly trans-chlordane which was 2-5 times more abundant than the cis isomer. On a temporal scale, from 1986 to 1993, Asiatic clams presented sustained PCB levels but showed a significant decrease of chlordane and DDT, which suggests reduced inputs in recent years.

Bioavailability of polycyclic aromatic hydrocarbons from a historically contaminated sediment core

Abstract: To determine changes in bioavailability of selected polycyclic aromatic hydrocarbons (PAHs) with sediment aging, Lumbriculus variegatus were exposed for 4 weeks to sediment core sections taken from a contaminated lake. Core depths included surficial (0 to 4 cm), 4- to 8-, 12- to 16-, 28- to 32-, and 44- to 48-cm sections deposited from approximately 1899 to 1993, and were known to be historically contaminated with PAHs. Bioaccumulation was maximal at the 12- to 16-cm depth (circa 1967) where sediment PAH concentrations were greatest. Accumulation was generally below detection limits in the 0- to 4-cm depths, even though sediment concentrations of some compounds were comparable to those at the 12- to 16-cm depth where accumulation was great enough to generate accurate kinetics curves. Accumulation peaked at about 96 h, then declined over the remainder of the study for the lower-molecular-weight PAHs. For most higher-molecular-weight PAHs, accumulation peaked at about 2 weeks, then declined only slightly after 4 weeks. The differential bioavailability observed between surficial and at-depth core sections raises questions concerning the adequacy of results generated from toxicity and bioaccumulation tests routinely conducted with surficial sediments.

Manganese, lead and strontium bioaccumulation in the tissues of the yellowfish, Barbus marequensis from the lower Olifants River, Eastern Transvaal

Abstract: The bioaccumulation of manganese, lead and strontium in the freshwater fish (Barbus marequensis) from the lower Olifants River, E. Transvaal, was investigated. The highest concentrations of these metals were detected in the vertebrae and gills. The localities in the Kruger National Park did not differ significantly from each other and therefore no clear indication as to where the highest bioaccumulation had occurred, could be established. However,the highest manganese and strontium levels occurred in fish from the Selati River. For the future monitoring of manganese, lead and strontium levels in bony fish, it is suggested that bony tissues (e.g. vertebrae, opercular bone or scales), gills, liver and muscle tissue are used.

Accumulation of organic contaminants in two sediment-dwelling shellfish with contrasting feeding modes: Deposit- (Macomona liliana) and filter-feeding (Austrovenus stutchburyi)

Abstract: Bioaccumulation of four classes of contaminants (organochlorine pesticides, polychlorinated biphenyls (PCB), polynuclear aromatic hydrocarbons (PAH), and chlorophenols) was determined in two sediment-dwelling bivalves, the tellinid Macomona liliana and the venerid Austrovenus stutchburyi at five stations along a contaminant gradient in Manukau Harbour, New Zealand. The species were chosen because they provide contrasting exposure pathways for contaminant uptake: A. stutchburyi is a filter-feeder and M. liliana is a deposit-feeder. They are also important components of the estuarine ecosystem, and A. stutchburyi are used for food. Both shellfish showed marked gradients of contaminant concentrations from the inner-harbour to the entrance. Concentrations of contaminants were similar in the two species, with generally slightly higher PCB and PAH levels in M. liliana. On a dry tissue weight basis, the PAHs were the major contaminant class, with the highest concentration measured (203 ng/g DW). Mean bioaccumulation factors (BAF) were similar for the two species, with mean values in the range 20–30 for most contaminants with the exception of PAHs, which were less than 1. Mean accumulation factor (AF) values, the lipid normalized concentration in organisms divided by the organic carbon normalized sediment concentration, were mostly in the range 1–4, except for PAHs, which were 0.002 and 0.14. M. liliana showed significantly higher accumulation ratios than A. stutchburyi. The abundance and condition of M. liliana was reduced at the more contaminated sites. These results suggest that M. liliana are sensitive indicators of contaminant stress and may be usefully incorporated into chemical contaminant and biological effects monitoring programs.

Influence of gut content in immature aquatic insects on assessments of environmental metal contamination

Abstract: We evaluated the effect of metal associated with the gut content in immature aquatic insects (larvae and nymphs) on spatial and interspecific comparisons of whole-body metal concentrations. Four species, common to cobble-bottom rivers and streams, were collected along an established contamination gradient in the Clark Fork River, and from tributaries of the Clark Fork. Metal concentrations were determined in the gut and its content and in the insect body. Whole-body metal concentrations were higher and more variable as a result of gut content. The positive bias produced by the gut content did not alter interpretations of site contamination in most cases. Interspecific comparisons of metal bioaccumulation also were not greatly affected by the presence of gut content. The influence of gut content was specific for metal, species, and site. Feeding habit, gut size, and metal bioaccumulation in the body affected the relative contribution of the gut and its content to metal concentrations in the whole insect.

Cadmium and lead uptake by edible crops grown in a silt loam soil.

Abstract: There is increasing public concern about health effects resulting from ingestion of food containing toxic metals such as Cd and Pb. For example, a wide range of metabolic disorders and neuropsychological deficits in children have been noted, and chronic exposure to Cd has been linked to kidney failure and bone disease. The potential harm posed by the uptake of heavy metals such as Cd and Pb by plants is dependent on their abundance, mobility and bioaccumulation. Plant uptake of heavy metals was also influenced by soil pH. There is a linear relationship between soil concentrations of heavy metal and concentrations in vegetation around a zinc-lead tailing pond. The ability of the soil to retain metals depends on several factors; pH, cation exchange capacity (CEC), organic matter content, and their specific geochemical properties. Overall, the metal burden of a crop depends on: (a) uptake via the root system; (b) direct foliar uptake and translocation within the plant; and (c) surface deposition of particulate matter. Numerous studies have been conducted with agronomic crops regarding heavy metals in soils and plant uptake from sewage sludge, but only a few studies have dealt with the uptake of heavy metal mixtures in vegetables. This papermore » reports on germination/emergence, biomass and uptake of Cd and Pb in lettuce and radish grown in a loam soil spiked with known mixtures of CdCl{sub 2} and Pb(NO{sub 3}){sub 2}. Lettuce and radish have been used in this study because they are among the two groups of vegetable crops (leafy and root) consumed by humans. Also, earlier studies have reported that lettuce and radish bioaccumulate Cd and Pb from heavy metal polluted soils. 38 refs., 7 tabs.« less

Heavy metal bioaccumulation in lichens from Macedonia in northern Greece

Abstract: Research on lichens as biological monitoring indicators is described. The concentration of Pb, Cu, Zn and Cd in lichens from polluted and unpolluted areas of Greece were determined by atomic absorption spectrometry after acid digestion. The levels of the heavy metals in the tissues of different species are discussed. Although bioaccumulation of heavy metals depends on the degree of pollution of the given biotope, large variations were observed between different species collected from the same biotope. In areas with porphyry copper deposits, pendulous lichens hanging from trees and, to a lesser extent epiphytes, were less contaminated than epigeic or epilithic ones. Epilithic lichens accumulated larger concentrations of these metals than did epigeic lichens. Finally, the capacity of lichens to accumulate heavy metals, is compared to that of mosses and tree leaves.