Showing papers on "Bioaccumulation published in 2002"

Algal blooms reduce the uptake of toxic methylmercury in freshwater food webs

Abstract: Mercury accumulation in fish is a global public health concern, because fish are the primary source of toxic methylmercury to humans. Fish from all lakes do not pose the same level of risk to consumers. One of the most intriguing patterns is that potentially dangerous mercury concentrations can be found in fish from clear, oligotrophic lakes whereas fish from greener, eutrophic lakes often carry less mercury. In this study, we experimentally tested the hypothesis that increasing algal biomass reduces mercury accumulation at higher trophic levels through the dilution of mercury in consumed algal cells. Under bloom dilution, as algal biomass increases, the concentration of mercury per cell decreases, resulting in a lower dietary input to grazers and reduced bioaccumulation in algal-rich eutrophic systems. To test this hypothesis, we added enriched stable isotopes of Hg to experimental mesocosms and measured the uptake of toxic methylmercury (CH3200Hg+) and inorganic 201Hg2+ by biota at several algal concentrations. We reduced absolute spike detection limits by 50–100 times compared with previous techniques, which allowed us to conduct experiments at the extremely low aqueous Hg concentrations that are typical of natural systems. We found that increasing algae reduced CH3Hg+ concentrations in zooplankton 2–3-fold. Bloom dilution may provide a mechanistic explanation for lower CH3Hg+ accumulation by zooplankton and fish in algal-rich relative to algal-poor systems.

Synthetic musks in the environment. Part 1: Species-dependent bioaccumulation of polycyclic and nitro musk fragrances in freshwater fish and mussels.

Abstract: Bioaccumulation of polycyclic musks (HHCB, AHTN) and nitro musks (musk xylene, musk ketone, and their amino metabolites) in aquatic biota was investigated by analyzing 18 fish samples (rudd, tench, crucian carp, eel) and 1 pooled zebra mussel sample from the pond of a municipal sewage treatment plant. Furthermore, water samples taken at the effluent of the sewage plant as well as water samples and two series of semipermeable membrane devices (SPMDs) from the pond were included. This comprehensive data set allowed the determination of species-dependent bioaccumulation factors on a lipid basis (BAFL), e.g., for HHCB the BAFL in tench were more than 20 times higher than in eel. The BAFL for HHCB and AHTN in biota were lower than the partition coefficients KSPMD/W obtained from SPMD samples, which are assumed to represent model bioconcentration values. This stresses that metabolism of these compounds in fish must not be neglected.

Exposure and potential food chain transfer factor of Cd, Se and Zn in marine fish Lutjanus argentimaculatus

Abstract: Radiotracer techniques were employed to quantify the rates of uptake from aqueous and dietary sources, and rates of elimination of Cd, Se and Zn by a marine predatory fish, the mangrove snapper Lutjanus argentimaculatus. The relative significance of bioaccumulation of metals by fish from water and food and the food chain transfer factor were then assessed using a kinetic modeling approach. Cd and Zn in the aqueous phase exhibited an approximately linear uptake pattern over a 1 to 2 d exposure, whereas Se exhibited a 2-compartmental uptake at a low ambient concentration, with a slow initial uptake followed by a rapid increase in Se influx. Most of the accumulated aqueous Se and Zn were incorporated into the muscles, whereas Cd was evenly distributed in the viscera and the remaining tissue, with a lower proportion in the gills. The influx rates were dependent on the ambient metal concentration and were tissue-specific for each metal. The assimilation efficiency of trace metals in fish ingesting different prey (copepods, Artemia sp. and clam tissue) ranged from 6 to 24% for Cd, 32 to 68% for Se and 15 to 46% for Zn, and decreased with an increase in ingestion rate. The efflux rate constant of Cd in fish following uptake from the dietary phase (0.047 d -1 ) was higher than that following aqueous uptake (0.025 d -1 ), whereas the efflux rate constants of Se and Zn were comparable between these 2 exposure pathways. Our modeling calculations indicate that dietary uptake of Cd and Zn dominates their accumulation in fish when zooplankton are the main prey, whereas aqueous uptake may be the dominant pathway when planktivorous fish are the dominant prey for the predatory fish. Dietary uptake always dominates Se accumulation in these fish. The modeling results also indicated that the food chain transfer factor of Cd was <0.5 in the fish regard- less of the ingestion rate and the assimilation efficiency, consistent with the results of field studies. However, Se and Zn may potentially be biomagnified when the ingestion rate and assimilation effi- ciency are at the high end of the range possibly encountered by the predatory fish.

Ecotoxicology of Selenium

Abstract: Selenium is a naturally occurring semimetallic (also referred to as a metalloid) trace element that is essential for animal nutrition in small quantities but becomes toxic at dietary concentrations that are not much higher than the required levels for good health. Thus, dietary selenium concentrations that are either below or above the optimal range are of concern. This chapter summarizes the ecotoxicology of excessive selenium exposure for animals, especially as reported during the last 15 years. It focuses primarily on freshwater fish and aquatic birds because fish and birds are the groups of animals for which most toxic effects have been reported in the wild. However, information related to bioaccumulation by plants and animals as well as effects in invertebrates, amphibians, reptiles, and mammals also are presented.

Peer Reviewed: Contaminant Amplification in the Environment

Abstract: A new approach suggests that phenomena, such as bioconcentration, biomagnification, and bioaccumulation, result from two fundamental processes.

Metal concentrations in Clarias gariepinus and Labeo umbratus from the Olifants and Klein Olifants River, Mpumalanga, South Africa: zinc, copper, manganese, lead, chromium, nickel, aluminium and iron

Abstract: The upper catchment of the Olifants River, from its origin near Bethal to its confluence with the Wilge River, north of Witbank, and its tributaries are being subjected to increasing afforestation, mining, power generation, irrigation, domestic and industrial activities. These activities have a profound effect on the water quality. The major point sources of pollution in the study area include mines, industries and very importantly, combined sewage purification works that are located alongside the river. In addition to oxidizable material, these sources contain detergents, nutrients and metals. It was therefore necessary to determine the extent to which these activities affect the water quality of the system. The bioaccumulation of zinc (Zn), copper(Cu), manganese (Mn), lead (Pb), chromium (Cr), nickel (Ni), aluminium (Al) and iron (Fe) in the skin, muscle, liver and gill tissues of Clarias gariepinus and Labeo umbratus from the Upper Olifants River and Klein Olifants River was investigated over the period February 1994 to May 1995. The highest concentrations of these metals were found in the gill and liver tissues of both species, with lower concentrations in the skin and muscle tissues. Bioaccumulation patterns were found to vary according to the species of the fish, mainly according to their different feeding habits and the routes of metal uptake. It also varied as a function of the different localities. Accumulation was size specific, with higher concentrations of metals found in smaller fish.

Bioaccumulation of chlorpyrifos through an experimental food chain: study of protein HSP70 as biomarker of sublethal stress in fish.

Abstract: The accumulation and transfer of the organophosphorus pesticide chlorpyrifos has been studied in an experimental aquatic two-level food chain using two species of the crustacean Artemia (A. franciscana and A. parthenogenetica) and the small fish Aphanius iberus. Artemia adults contaminated by exposure to the pesticide in water were used as live prey for Aphanius, the next trophic level. During the experimental bioaccumulation phase, fish were fed chlorpyrifos-contaminated Artemia pools with concentrations between 6.5 and 14.5 ng/g fresh weight for 32 days. Both concentrations accumulated in fish, and biomagnification factor (BMF) values showed a continuous decrease during the bioaccumulation phase, probably due to the physicochemical characteristics of the organophosphorus pesticide, to the biotransformation ability of fish and to the progressive adaptation of fish metabolism to toxic exposure. The first day that fish were fed uncontaminated preys, the pesticide accumulated via food was rapidly eliminated and was not detected. The effect of chlorpyrifos exposure through the food chain on stress protein (HSP70) synthesis was measured as a general biochemical response of stress in the fish (A. iberus). The levels of HSP70 were significantly higher in fish fed on contaminated Artemia than in the control fish fed on uncontaminated Artemia. Results showed that the HSP70 induction in fish could be associated to exposure of chlorpyrifos via food.

Biokinetics of zinc and cadmium accumulation and depuration at different stages in the life cycle of the cuttlefish Sepia officinalis

Abstract: Bioaccumulation of 65 Zn and 109 Cd by the cuttlefish Sepia officinalis L. was studied at dif- ferent stages of its life cycle, i.e. in embryos, juveniles and adults, following exposures via sea water, sediments and food. Cuttlefish eggs efficiently accumulated both elements from seawater with bio- concentration factors of 79 for 65 Zn and 46 for 109 Cd after 11 d exposure. Most of the radiotracers were found in the capsule membrane of the eggs, demonstrating that the capsule acts as a shield to protect embryos against metals. Juveniles and adults efficiently bioconcentrated both radiotracers from sea- water, with the muscular tissues containing 84% of the total 65 Zn and 62% of the total 109 Cd. Loss ki- netics followed a single exponential function for 65 Zn, while for 109 Cd loss was best described by a double exponential model. Biological half-lives for elimination were ca. 2 mo for both elements. After 29 d depuration in uncontaminated seawater, 76 to 87% of the radiotracers were found in the digestive gland. For both elements, the dissolved phase can be considered as a significant source of accumula- tion. In an experiment with radiolabelled sediments, transfer factors were very low, even after 29 d ex- posure. Food-chain transfer experiments demonstrated that both juveniles and adults assimilated 65 Zn and 109 Cd very efficiently. Moreover, loss of ingested radiotracers was much slower than elimination of 65 Zn and 109 Cd taken up from seawater, indicating a very strong retention of dietary Cd and Zn by juvenile as well as by adult cuttlefish. As with direct uptake from seawater, ingested radiotracers were mainly found in the digestive gland, with fractions reaching 82% for 65 Zn and 97% for 109 Cd after 29 d depuration. These tracer experiments indicate that (1) food is the likely primary pathway for Zn and Cd bioaccumulation in S. officinalis, and (2) the digestive gland plays a major role in the subsequent storage and presumed detoxification of these elements regardless of the uptake pathway.

Biological availability of traffic-related platinum-group elements (palladium, platinum, and rhodium) and other metals to the zebra mussel (Dreissena polymorpha) in water containing road dust.

Abstract: The uptake and bioaccumulation of 15 road dust metals by the zebra mussel (Dreissena polymorpha) were investigated in laboratory exposure studies with emphasis on the traffic-related platinum-group elements (PGEs) palladium (Pd), platinum (Pt), and rhodium (Rh). The biological availability of the metals may depend on water characteristics, so the mussels were maintained in two types of water: nonchlorinated tap water and humic water of a bog lake, both of which contained dust of a moderately frequented road. After an exposure period of 26 weeks, soft tissues of the mussels were freeze-dried and analyzed for the metals. The metal concentrations in the mussel soft tissue ranged from several hundred micrograms per gram (e.g., for iron [Fe]) to less than 10 ng/g (for PGEs). Metal uptake from the road dust by the mussels was found for the PGEs and silver (Ag), bismuth (Bi), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), Fe, lead (Pb), and antimony (Sb). After maintenance of mussels in road dust-contaminated tap water, bioaccumulation factors (BAF = (c e x p o s e d m u s s e l s - c c o n t r o l m u s s e l s )/c t o t a l m e t a l , w a t e r ; where c is concentration) decreased in the following order: Cu > Cd > Ag > Pd > Sb > Pb > Fe > Pt > Rh. The biological availability of most metals was enhanced by humic water as compared to tap water. Our results show a hitherto unrecognized high availability of Pd for the mussels. Thus, this metal should be monitored more intensively in the environment to assess its distribution in the biosphere.

Remediation of heavy metal-contaminated soils using phosphorus: evaluation of bioavailability using an earthworm bioassay.

Abstract: This study investigated the effectiveness of phosphorus (P) as an in situ remediation technique in site soils collected from the Tri-State mining area. The site soils were treated with two different types (KH2PO4 and Super Triple Phosphate fertilizer) and levels (600 and 5,000 mg/kg) of phosphorus. A toxicokinetic approach was used to determine whether phosphorus amendments reduced heavy metal bioavailability to the earthworm Eisenia fetida. Bioaccumulation factors were used as a measure of bioavailability. Depuration patterns of lead, zinc, and cadmium also were studied after removing earthworms from contaminated soils and then placing them in noncontaminated artificial soil. Results showed that the high phosphorus treatments significantly reduced lead, zinc, and cadmium bioavailability to the earthworms, probably due to formation of metal-phosphate complexes in the soils. Results also indicated that other soil characteristics in addition to amended phosphorus have an affect on bioavailability. Depuration experiments showed a biphasic elimination pattern for each metal. The current results indicate that phosphorus soil amendments may reduce ecological risk to soil-inhabiting invertebrates exposed to heavy metal-contaminated soils.

Use of tissue and sediment-based threshold concentrations of polychlorinated biphenyls (PCBs) to protect juvenile salmonids listed under the US Endangered Species Act

Abstract: Under the Endangered Species Act, the National Marine Fisheries Service has authority to protect listed species from any adverse actions that may jeopardize the population's ability to recover and increase to sustainable levels. Listed salmon species in the northwest United States are known to travel through urban areas in their migration from river to ocean. Species such as the chinook salmon (Oncorhynchus tshawytscha) often spend several weeks in these urban estuaries where they can be highly exposed to urban-related contaminants that reside in the sediments and accumulate in their prey species. The concern is that these contaminants are bioaccumulated to levels that may impact the ability of individual salmon to grow and mature normally. This paper provides a framework for determining the tissue and sediment concentrations of polychlorinated biphenyls (PCBs) that are likely protective against adverse effects in listed salmonid species. 2. The relevant ecotoxicological literature was examined and 15 studies were selected that met the pre-established criteria outlined here. For each study, the lowest tissue concentration (residue) of total PCBs associated with a biological response was selected. The tissue concentration associated with the 10th percentile of these 15 studies was chosen to represent the residue effect threshold (RET) above which wild juvenile salmonids would be expected to exhibit adverse sublethal effects from accumulated PCBs. This value (2.4mg PCBs g � 1 lipid) is expressed in terms of the lipid-normalized concentration because of the large effect lipid can have on the expressed toxicity and the substantial variability in lipid content observed in salmonids over their life cycle. 3. A sediment concentration that is expected to produce the RET was then determined using the biota-sediment accumulation factor approach. The sediment effect threshold, which varies with the total organic carbon content in sediment, is the level above which adverse effects may be expected in juvenile salmonids due to accumulation of PCBs from environmental exposure. Bioaccumulation of PCBs was examined in one river system as a model for determining an appropriate bioaccumulation factor for wild juvenile chinook salmon. 4. Evaluation of exposure to potentially deleterious concentrations of PCBs based on tissue residues is the preferred approach; however, the sediment effect threshold may also be used in cases where bioaccumulation has been characterized in an estuary. The threshold values presented here are intended as interim guidelines that should be modified as more data become available. Additionally, because of the uncertainty around many of the factors and assumptions that comprise the single

Relevance and analysis of traffic related platinum group metals (Pt, Pd, Rh) in the aquatic biosphere, with emphasis on palladium.

Abstract: Following the introduction of automobile catalysts in the middle of the Eighties in Germany there is an increasing emission of the platinum-group-metals (PGM) platinum (Pt), palladium (Pd) and rhodium (Rh). Still, it remains unclear if these metals are bioavailable for aquatic animals and to which extent they accumulate in the aquatic biosphere. Zebra mussels (Dreissena polymorpha ) were maintained in water containing road dust at a concentration of 1 kg/10 l. Following an exposure period of 26 weeks, soft tissues of the mussels were analysed applying adsorptive cathodic stripping voltammetry (ACSV) for the determination of Pt and Rh and total-reflection X-ray fluorescence analysis after co-precipitation of Pd with mercury. This experiment revealed for the first time that all the three catalyst emitted metals were accumulated by mussels. The bioaccumulation increased in the following manner: Rh

Bioaccumulation of metals in the East Calcutta wetland ecosystem

Abstract: This study was initiated to examine the extent of toxic metal contamination of the east Calcutta wetland ecosystem. Biological oxygen demand, chemical oxygen demand, total dissolved solids, conductivity, total suspended solids, total hardness, and pH were recorded from six different locations on the sewage carrying canals including an industrial effluent-fed fish pond in the eastern Calcutta (lat. 22°33´-22°40´ N;long. 88°25´-88°35´E). Concentrations of metals such as Pb, Cu, Cr, Zn, Fe, Mg, and Mn in wastewater, and water of adjacent sewage-fed fish tank were also determined. Concentrations of these metals in soil/sludge and accumulation of these metals in plant and fish tissues were also studied. The concentrations of heavy metals in wastewater, namely Pb, Zn, Cu, Mn, and Fe, were reduced by 25 to 45% and total Cr was reduced by 95%, on the course of the 40 km long journey of the composite wastewater from the sources to river mouth via the wastewater carrying canal and the stabilization pond. Reductions...

Mechanism and prediction for contamination of freshwater bivalves (Unionidae) with the cyanobacterial toxin microcystin in hypereutrophic Lake Suwa, Japan

Abstract: Seasonal changes of microcystin (MC) bioaccumulation in three freshwater Unionid bivalves, Anodonta woodiana, Cristaria plicata, and Unio douglasiae, were investigated in the hypereutrophic Lake Suwa. Total MC concentrations (MC-RR and -LR) as determined by reverse-phase high-performance liquid chromatography were at high levels in the hepatopancreas of C. plicata and U. douglasiae, with maxima at 297 and 420 g/g dry weight, respectively. The amounts and seasonal changes in the accumulated MC concentration differed in all species. The total MC concentration of A. woodiana was always less than that of other species (maximum concentration of 12.6 g/g dry weight). The toxin concentration of C. plicata remained very low in summer, when the Microcystis bloom occurred, but increased rapidly in autumn, when the toxic bloom disappeared. For U. douglasiae, simple regression analyses were performed to clarify the relationship between MC bioaccumulation and environmental parameters such as water temperature, chlorophyll a, suspended solids (SS), intracellular MC per unit volume of lake water and per-unit weight of SS and extracellular MC. The toxin concentration of U. douglasiae correlated more closely with qualitative factors, with intracellular toxin per SS (p 0.001, R 2 0.72) than with quantitative factors such as chlorophyll a and intracellular toxin per unit volume of lake water. No correlation could be found between MC in the tissues and extracellular MC. These results indicate that a long-term survey is needed to assess the safety of bivalves. The study should take into consideration both interspecific differences in toxin content and what is the optimal monitoring parameter. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 424 - 433, 2002; Published online in Wiley InterScience (www.interscience.

Methods for toxicity assessment of contaminated soil by oral or dermal uptake in land snails: Metal bioavailability and bioaccumulation

Abstract: Using two biological characteristics of the land snail (subspecies Helix aspersa aspersa and Helix aspersa maxima), i.e., soil eating and crawling on wet surfaces, methods were developed to assess the bioavailability of heavy metals (Cd, Cr, Pb, and Zn) from soil and aqueous leachates of soil. Measurement of heavy-metal concentrations in soil, leachates, and soft tissues of snails showed that contamination from ingested soil is the major route for metal uptake. Generally, the concentrations of metals were greater in the viscera than in the foot and rose with the proportion of spiked soil (S1) in the diet. After ingestion of soil, bioaccumulation factors in the viscera were over two for Cd (3.5–27) and Zn (1.7–4.4) for both subspecies but were below one for Cr(0.04–0.6, exceptfor H. aspersa maxima: 1.21) and Pb(0.02–0.23). Contamination by leachate S1 mainly caused accumulation of Cr in the tissues. Determining the metal burden per snail enables an estimation to be made of the risk of secondary poisoning encountered by predators. The present study provides data on the bioavailability of metals in soils and on the relationships between bioaccumulation and sublethal effects.

Spatial trends and bioaccumulation of organochlorine pollutants in marine zooplankton from the Alaskan and Canadian Arctic

Abstract: Planktonic copepods (Calanus glacialis and C. hyperboreus; n = 37) and water (n = 19) were collected to examine the spatial distribution and bioaccumulation of organochlorine contaminants (OCs) in the Alaskan and Canadian Arctic. The rank order of total OC (σ OC) group concentrations in Calanus samples was toxaphene ≥ σ polychlorinated biphenyls (PCBs) > σ hexachlorcyclohexane (HCH). σ DDT > σ chlordane-related compounds (CHLOR) > σ chlorobenzenes (ClBz). The dominant analyte was α-HCH in all water and zooplankton samples. The most abundant toxaphene congener in water and zooplankton samples was the hexachlorobornane B6-923. Organochlorine contaminant group concentrations in Alaskan zooplankton and water samples were lower than those in samples collected from sites in the eastern Canadian Arctic. Comparison of PCB and toxaphene congener profiles in zooplankton and water samples suggests that biotransformation by cytochrome P-4502B isozymes is low in Calanus, and limited phase I metabolism may occur. The log relationship of bioaccumulation factor (log BAF) versus octanol-water partition coefficient (log Kow) relationship was near 1: 1 for OCs within the log Kow range of 3 to 6. A curvilinear model provided a better relationship between these two variables when OC compounds with log Kow > 6 were included. These results suggest that hydrophobic OCs (log Kow 3-6) in Calanus species are at equilibrium with the water concentrations and that physical partitioning, rather than biotransformation, is the major factor governing OC profiles in marine zooplankton.