Showing papers on "Bioaccumulation published in 1996"

Kinetic determinations of trace element bioaccumulation in the mussel, Mytilus edulis

Abstract: Laboratory experiments employing radiotracer methodology were conducted to determine the assimilation efficiencies from ingested natural seston, the influx rates from the dissolved phase and the efflux rates of 6 trace elements (Ag, Am, Cd, Co. Se and Zn) in the mussel Mytilus edulis. A kinetic model was then employed to predict trace element concentration in mussel tissues in 2 locations for which mussel and environmental data are well described: South San Francisco Bay (California, USA) and Long Island Sound [New York, USA). Assimilation efficiencies from natural seston ranged from 5 to 18": for Ag, 0.6 to 1% for Am, 8 to 20% for Cd, 12 to 16% for CO, 28 to 34% for Se, and 32 to 41 ':, for Zn. Differences in chlorophyll a concentration in ingested natural seston did not have significant impact on the assimilation of Am, CO, Se and Zn. The influx rate of elements from the dissolved phase increased with the dissolved concentration, conforming to Freundlich adsorption isotherms. The calculated dissolved uptake rate constant was greatest for Ag, followed by Zn > Am -; Cd > CO > Se. The estimated absorption efficiency from the d~ssolved phase was 1.53 % for Ag, 0.34 % for Am, 0.31 X for Cd, 0.11 % for CO, 0.03"' for Se and 0.89% for Zn. Salinity had an inverse effect on the influx rate from the dissolved phase and dissolved organic carbon concentration had no significant effect on trace element uptake. The calculated efflux rate constants for all elements ranged from 1.0 to 3.0% d-' The route of trace element uptake (food vs dissolved) and the duration of exposure to dissolved trace elements (12 h vs 6 d) did not significantly influence trace element efflux rates. A model which used the experimentally determined influx and efflux rates for each of the trace elements, following exposure from ingested food and from water, predicted concentrations of Ag. Cd, Se and Zn in mussels that were directly comparable to actual tissue concentrations independently measured in the 2 reference sites in national monitoring programs. Sensitivity analysis indicated that the total suspended solids load, which can affect mussel feeding activity, assimilation, and trace element concentration in the dissolved and particulate phases, can significantly influence metal bioaccumulation for particlereactive elements such as Ag and Am. For all metals, concentrations in mussels are proportionately related to total metal load in the water column and their assimilation efficiency from ingested particles. Further, the model predicted that over 96% of Se in mussels is obtained from ingested food, under conditions typical of coastal waters. For Ag, Am, Cd, CO and Zn, the relative contribution from the dissolved phase decreases significantly with increasing trace element parhtion coefficients for suspended particles and the assimilation efficiency in mussels of ingested trace elements, values range between 33 and 67% for Ag, 5 and 1 7 % for Am, 47 and 82% for Cd, 4 and 30% for CO, and 17 and 51 ?h for Zn.

Bioaccumulation of hydrophobic chemicals in agricultural food chains

Abstract: The bioaccumulation of polychlorinated biphenyls, dibenzo-p-dioxins, dibenzofurans, and hexachlorobenzene in an air−plant/soil−cow−human food chain was examined using field data collected in southe...

Accumulation and Retention of Metals in Mussels from Food and Water: A Comparison under Field and Laboratory Conditions

Abstract: Mussels are used as bioindicator organisms to assess bioavailable contaminant concentrations in coastal waters. This study used radiotracer methodologies to examine the bioaccumulation and efflux rates of six metals (Ag, Am, Cd, inorganic Co, organic Co [as cobalamine], Pb, and Zn) in the mussel Mytilus galloprovincialis, in which the dissolved phase and ingested phytoplankton food were compared quantitatively as sources. Mussels maintained in the laboratory in running seawater and caged in the field for up to 4 months generally displayed similar metal absorption efficiencies (AEs) and efflux rates from their soft parts. AEs from food were typically lower than radioisotope retention efficiencies from the dissolved phase and ranged from 4% for Am to about 60% for Pb; values were comparable to those reported for the common blue mussel, Mytilus edulis. Efflux rate constants from mussel soft parts (1−5% daily) were comparable to M. edulis values from short-term depurations; biological half-lives of all metals...

Mercury concentrations in prey fish indicate enhanced bioaccumulation in mesopelagic environments

Abstract: The detection of high concentrations of methylmercury in the sub-thermocline low oxy- gen seawater indicates a potential for enhanced bioaccumulation of mercury in such environments not yet explored. Here we present mercury concentrations in 8 fish species of lo w trophic level in relation to their vertical distribution. Fish specie s were selected to cover a wide range of vertical distributions, from epipelagic ( 300 m) environments in the sub-tropical mid-North Atlantic. Mean mercury concentrations in the study species ranged fro m 57 to 377 ppb dry wt and were significantly and positively correlated with median daytime depth. Concentration s increased by 4-fold from epipelagic to mesopelagic species with no further increases with depth among mesopelagic spe- cies down to about 1200 m. Such enhanced mercury bioaccumulation in the marine mesopelagic com- partment seems to be determined proximately by levels in food and ultimately by water chemistry that controls mercury speciation and uptake at the base of the food chain. We conclude that this is the best explanation for high and yet poorly understood mercury concentration s found in deep-sea predators.

Development and verification of a bioaccumulation model for organic contaminants in benthic invertebrates

Abstract: A novel nonequilibrium, steady-state model is presented to predict the bioaccumulation of organic chemicals by filter feeding and detritivorous benthic invertebrates. This model accounts for chemical disequilibria between overlying water, diet and sediment, biomagnification, and benthic invertebrate feeding preferences and strategies. The results of a field study of PCB congener bioaccumulation in various benthic invertebrate species in western Lake Erie are reported to verify the model. A comparison of model-predicted and field data demonstrate that the predictability of this model is better than that of the widely used equilibrium partitioning model for as sessing bioaccumulation in benthic organisms and for developing sediment quality criteria.

Effect of bioturbation on metal-sulfide oxidation in surficial freshwater sediments

Abstract: Recent studies have demonstrated the role of acid-volatile sulfide (AVS) in controlling the bioavailability of several cationic metals in anoxic sediments. However, metal-sulfide complexes can be relatively labile with respect to oxidation associated with factors such as seasonal changes in rates of oxidation/production of AVS. Another potentially important mechanism of AVS oxidation in surficial sediments is bioturbation. We used different densities of the burrowing oligochaete Lumbriculus variegatus in a series of laboratory experiments to evaluate the effect of bioturbation on oxidation of AVS and subsequent bioavailability of cadmium and zinc spiked into freshwater sediments. Metal bioavailability was determined directly by bioaccumulation in the test organisms and indirectly through analysis of interstitial (pore) water metal concentrations. In our studies, horizon-specific sediment analyses were conducted to assess spatial differences in AVS and pore-water metal concentrations specifically related to organism activity. Burrowing activity of the oligochaete significantly reduced AVS concentrations in surficial sediments in a density-dependent manner and resulted in elevated interstitial water concentrations of cadmium but not zinc. Concentrations of cadmium in pore water from deeper horizons (below the zone of active burrowing) were consistently lower than those in the surficial sediments. The bioaccumulation of cadmium and zinc by L. variegatus was reflective of pore-water concentrations of the two metals, i.e., there was significant accumulation of cadmium, but not zinc, by the oligochaetes. Overall, our results indicate that bioturbation can enhance the bioavailability of some cationic metals in surficial sediments, via oxidation of AVS, and demonstrate the importance of analyzing surficial sediments when assessing bioavailability of metals in sediments.

Determination of organotin compounds in the foodweb of a shallow freshwater lake in the Netherlands.

Abstract: An extensive study on the presence of nine organotin compounds (OTs) in a freshwater foodweb was made, using newly developed analytical procedures in order to obtain insight in accumulation and degradation processes. Tributyltin (TBT), Triphenyltin (TPT) and their degradation products were detected. Zebra mussels, eel, roach, bream, pike, perch, and pike perch and cormorant showed high OT body concentrations. At the lower trophic levels, phenyltin concentrations were higher in benthic species while butyltin concentrations were higher in pelagic species. This indicates that TBT is passed on primarily via the water, while TPT is passed on to a larger extent via the sediment. At the higher trophic levels, net bioaccumulation of TPT was greater than that of TBT, resulting in relatively higher TPT concentrations. High concentrations of biodegradation products of TBT, but not of TPT, were found in the livers of fish and birds, which indicates that TBT is more easily metabolized than TPT. A comparison with literature data of fish lethal body concentrations revealed that fish in the field may be endangered. With birds, the highest concentrations of OTs were present in liver and kidney and not in subcutaneous fat, which confirms that OTs accumulate via different mechanisms than traditional lipophilic compounds. As a whole the OT concentrations found in the foodweb may be considered to be quite alarming.

Evaluation of metal/acid-volatile sulfide relationships in the prediction of metal bioaccumulation by benthic macroinvertebrates

Abstract: Recent studies have demonstrated that the toxicity of divalent cationic metals (cadmium, copper, lead, nickel, and zinc) in sediments can be controlled through binding to acid-volatile sulfide (AVS). When the molar concentration of AVS exceeds that of the metals (i.e., the metal/AVS ratio is less than unity), they exist predominantly as insoluble metal sulfides, which presumably are not biologically available. Thus, at metal/AVS ratios less than 1, toxicity of sediment-associated metals to benthic macroin-vertebrates has not been observed. However, bioaccumulation may provide a more direct assessment of contaminant bioavailability than the presence or absence of toxicity. The purpose of this report is to comprehensively review available literature on metal bioaccumulation versus sediment metal/AVS relationships to further examine the tenet that AVS controls metal bioavailability. In all, 12 studies were evaluated; these ranged from short-term (10-d) laboratory experiments with metal-spiked or field-collected sediments containing cadmium, copper, lead, nickel, and/or zinc to long-term (> 1-year) field studies with sediments spiked with cadmium or zinc. Test organisms included mollusks, oligochaetes, polychaetes, amphipods, and midges. The preponderance of studies indicated reduced accumulation of metals at sediment metal/AVS ratios of less than 1. However, there were exceptions to this general observation, two of which occurred in short-term laboratory experiments with cadmium- or nickel-spiked sediments. In these studies there appeared to be a linear accumulation of metals with increasing sediment metal concentrations irrespective of the metal/AVS ratio. Although there is experimental evidence suggesting that significant bioaccumulation of metals does not occur when there is sufficient AVS available to bind them, the existence of at least some data to the contrary indicates the need for further research relative to factors controlling the bioaccumulation of metals from sediments.

Organochlorine dynamics in the pelagic food web of lake baikal

Abstract: In July and August 1993, samples were collected from Lake Baikal both to document organochlorine concentrations and to relate the contaminant levels to trophic position and lipid concentration. High-volume water samples and representatives of the major organisms in the food web, including zooplankton, fish, and seals, were collected. Dissolved and particulate water samples were analyzed for polychlorinated biphenyls (PCBs; 74 congeners) and hexachlorobenzene. Biota samples were analyzed for PCBs, hexachlorocyclohexanes, chlordane and related compounds, dieldrin, dichlorodiphenyltrichloroethane (plus metabolites), and toxaphene. Specific lipid classes were measured in fish since these were postulated to affect organochlorine concentrations. Stable nitrogen (815N) and carbon (813C) isotopic compositions were determined in all samples except seal blubber as a measure of trophic position. Total PCBs in surface water ranged from 130 pg/L in the lake's northern basin to 1,900 pg/L in the southern basin. Total PCBs in fish ranged from 60 to 710 ng/g (wet weight), with differences mostly attributed to total lipid content rather than to specific lipid classes. The PCB bioaccumulation factor was significantly correlated with log Kow, whereas the PCB bioconcentration factor was not. The transfer of contaminants through the food web was likely at steady state, whereas the uptake of PCBs from the water was not. This indicates recent PCB contamination.

Cadmium uptake and bioaccumulation in selected cultivars of durum wheat and flax as affected by soil type

Abstract: Accumulation of cadmium (Cd) in crop plants is of great concern due to the potential for food chain contamination through the soil-root interface. Although Cd uptake varies considerably with plant species, the processes which determine the accumulation of Cd in plant tissues are affected by soil factors. The influence of soil type on Cd uptake by durum wheat (Triticum turgidum var. durum L.) and flax (Linum usitatissimum L.) was studied in a pot experiment under environmentally controlled growth chamber conditions. Four cultivars/lines of durum wheat (Kyle, Sceptre, DT 627, and DT 637) and three cultivars/lines of flax (Flanders, AC Emerson, and YSED 2) were grown in two Saskatchewan soils: an Orthic Gray Luvisol (low background Cd concentration; total/ABDTPA extractable Cd: 0.12/0.03 mg kg-1, respectively) and a Dark Brown Chernozem (relatively high background Cd concentration; total/ABDTPA Cd: 0.34/0.17 mg kg-1 respectively). Plant roots, stems, newly developed heads, and grain/seeds were analyzed for Cd concentration at three stages of plant growth: two and seven weeks after germination, and at plant maturity. The results showed that Cd bioaccumulation and distribution within the plants were strongly affected by both soil type and plant cultivar/line. The Cd concentration in roots leaves and stems varied at different stages of plant growth. However, all cultivars of both plant species grown in the Chernozemic soil accumulated more Cd in grain/seeds than plants grown in the Orthic Gray Luvisol soil. The different Cd accumulation pattern also corresponded to the levels of ABDTPA extractable and metal-organic complex bound soil Cd found in both soils. Large differences were found in grain Cd among the durum wheat cultivars grown in the same soil type, suggesting the importance of rhizosphere processes in Cd bioaccumulation and/or Cd transport processes within the plant. Distribution of Cd in parts of mature plants showed that durum grain contained up to 21 and 36% of the total amount of Cd taken up by the plants for the Orthic Gray Luvisol and Chernozemic soils, respectively. These results indicate the importance of studying Cd speciation, bioaccumulation and cycling in the environment for the management of agricultural soils and crops.

Uptake, disposition, and persistence of nonylphenol from water in rainbow trout (Oncorhynchus mykiss)

Abstract: 1. Nonylphenol is an environmental estrogenic compound. Little is known about its interaction with aquatic species since most of the work on oestrogenic alkylphenols has been done in vitro using cells in culture. 2. Rainbow trout (Oncorhynchus mykiss) were exposed to 14C-nonylphenol at 18 and 36 ppb in water to study its distribution, persistence, and bioaccumulation. 3. Nonylphenol, or its metabolites, were distributed through the body of rainbow trout including the edible tissues of dorsal muscle and fat. 4. Nonylphenol was rapidly taken up into most tissues and had an apparent half-life of 19-20 +/- 4 SE hours in the muscle and fat. 5. The apparent bioaccumulation factor in viscera and carcass ranged from 40 in carcass to 100 in viscera. 6. Three glucuronide metabolites were separated by thin-layer chromatography following treatment of bile with beta-glucuronidase.

Evaluation of bioaccumulation factors in regulating metals

Abstract: Regulating metals on the basis of simple measures of bioaccumulation in aquatic organisms gives misleading results. Simple bioaccumulation factors are useful in characterizing the hazard posed by hydrophobic organic compounds, but the bioaccumulation of metals is more complex. For metals that are essential for health, many organisms have the ability to control and maintain internal metal concentrations in the presence of significant variations in external concentrations. Hence bioaccumulation factors expressed as the ratio of wet tissue concentration and water concentration must vary according to external concentration. Regulations that specify a single generic accumulation factor are thus inappropriate.

Trace Metals in Mesozooplankton of the North Sea: Concentrations in Different Taxa and Preliminary Results on Bioaccumulation in Copepod Collectives (Calanus finmarchicus/C. helgolandicus)

Abstract: Trace metals (Cd, Cu, Zn, Pb, Ni) were determined in different zooplankton taxa to assess their role in the biogeochemical cycle in the North Sea. Results of semi-static bioaccumulation experiments on board ship using collectives of Calanus finmarchicus/C. helgolandicus were in agreement with a net accumulation strategy, thus meeting an inevitable precondition for their utilization as biomonitors. Cd, Cu and Zn concentrations in field samples of zooplankton displayed a pronounced variability between taxa, with Cd ranging from 0.13 mg kg -1 (d.w.) in fish larvae to 51 mg kg -1 in hyperiid amphipods. Almost no information is available about metal requirements of copepods. However, most of our and worldwide reported Cu concentrations in calanoid copepods (6-22 mg kg -1 ) coincided with estimates of enzymatic requirements of decapod crustaceans. Cd levels in Calanus collectives increased significantly from 0.68 mg kg -1 in the German Bight to 11 mg kg -1 at some stations around Scotland above 59° N, in line with literature data reported for benthic decapod crustaceans.

Effects of spatial and temporal variation of acid-volatile sulfide on the bioavailability of copper and zinc in freshwater sediments

Abstract: Variation in concentrations of acid-volatile sulfide (AVS) in sediments from the upper Clark Fork River of Montana, USA, was associated with differences in bioaccumulation of Cu and Zn and growth of larvae of the midge, Chironomus tentans Growth of midge larvae was significantly greater and bioaccumulation of Cu was significantly less in surface sections (0-3 cm depth) of sediment cores, which had greater concentrations of AVS and lesser ratios of simultaneously extracted metals to AVS (SEM:AVS ratios) than in subsurface sediments (6-9 cm) Concentrations of AVS were significantly less in sediments incubated with oxic overlying water for 9 weeks than in the same sediments incubated under anoxic conditions Bioaccumulation of Cu differed significantly between incubation treatments, corresponding to differences in concentrations of AVS and SEM:AVS ratios, although midge growth did not Bioaccumulation of Zn did not differ significantly between depth strata of sediment cores or between incubation treatments When results from the two sets of bioassays were combined, bioaccumulation of Cu and Zn, but not growth, was significantly correlated with SEM:AVS ratios and other estimates of bioavailable metal fractions in sediments Growth of midge larvae was significantly correlated with bioaccumulation of Zn, but not Cu, suggesting that Zn was the greater contributor to the toxicity of these sediments Assessments of the toxicity of metal-contaminated freshwater sediments should consider the effects of spatial and temporal variation in AVS concentrations on metal bioavailability Keywords—Metals Bioavailability Chironomus tentans Sediment Acid-volatile sulfide

Gut content weight and clearance rate for three species of freshwater invertebrates

Abstract: There is concern for potential error in the accurate estimation of chemical bioaccumulation in benthic organisms due to chemicals associated with gut contents (sediments). In this study the benthic macroinvertebrates Hexagenia limbata, Chironomus tentans, and Lumbriculus variegatus were exposed to five sediments from the Lower Fox River/Green Bay area of Wisconsin to determine the percentage of their weight due to gut contents and the rate at which guts were emptied when the animals were held in clean water. Upon removal from the test sediments, inorganic gut contents in H. limbata, C. tentans, and L. variegatus represented approximately 9, 10, and 10% of their whole body dry weights, respectively. Depuration rates were relatively rapid, with mayflies, midges, and oligochaetes losing approximately 75, 90, and 100% of their gut contents during the first 12 h of depuration. This suggests that a 12–24-h holding period in clean water at the conclusion of sediment bioaccumulation tests with the three species should be sufficient to eliminate potential bias in tissue residue concentrations due to gut contents.

Toxicology of aquatic pollution : physiological, cellular and molecular approaches

Abstract: Preface 1. Water chemistry at the gill surface of fish and the uptake of xenobiotics D. J. Randall, C. Brauner, R. V. Thurston, and J. F. Neuman 2. Bioaccumulation of waterborne 1,2,4,5-tetrachlorobenzene in tissues of rainbow trout R. V. Thurston, J. F. Neuman, C. J. Brauner, and D. J. Randall 3. Dietary exposure to toxic metals in fish R. D. Handy 4. The physiology and toxicology of zinc in fish C. Hogstrand, and C. M. Wood 5. Lethal and sublethal effects of copper upon fish: a role for ammonia E. W. Taylor, M. W. Beaumont, P. J. Butler, J. Mair, and M. S. I. Mujallid 6. The physiology and status of brown trout exposed to aluminium in acidic soft waters J. A. Brown, and C. P. Waring 7. Physiological and metabolic costs of acclimation to chronic sublethal acid and aluminium R. W. Wilson 8. Physiological effects of nitrite in teleosts and crustaceans F. B. Jensen 9. Metallothioneins in fish: induction and use in environmental monitoring P.-E. Olsen 10. Oestrogenic substances in the aquatic environment and their potential impact on animals, particularly fish J. P Sumpter, S. Jobling, and C. R. Tyler 11. Effect of genetic toxicants in aquatic organisms J. W. Nunn, D. R. Livingstone, and J. K. Chapman 12. In vitro toxicology of aquatic pollutants: use of cultured fish cells S. G. George 13 Principles governing the use of cytochrome P4501A1 measurement as a pollution monitoring tool in the aquatic environment M. J. Leaver Index.

Cadmium and lead bioaccumulation in male chickens for high food concentrations

Abstract: Cadmium and lead bioaccumulation in broilers fed on rations containing high concentrations of Cd and Pb was studied. The degree of bioaccumulation was assessed by using klark of concentration (Kc). It was established that the 100 and 200 fold increase of lead and cadmium in the ration resulted in their increase in the muscles, the bones and the liver, but the degree of bioaccumulation was considerably lower than the increase of both of the heavy elements in the ration indicated by the lower Kc. A conclusion was drawn that the organism possesses adaptation mechanisms for limitation of cadmium and lead bioaccumulation through these mechanisms are not efficient enough for high ration doses of both elements. High ration doses resulted in bioaccumulation exceeding the safe for humans concentrations of lead in the bones and of cadmium in the muscles (for doses 200 fold higher than the highest Bulgarian State standard 13426–77 permissible concentrations /HPC/) and in the liver for doses 100 fold higher ...

Heavy metal concentrations in surficial sediments and benthic macroinvertebrates from Anzali wetland, Iran

Abstract: Lead, Copper, Zinc and Manganese were measured in surficial sediments, chironomid larvae, tubificid worms and two species of bivalve molluscs (Mytilaster lineatus and Corbicula fluminalis) from the Anzali wetland, Iran. No distinct relationship was observed between heavy metal levels and percentage fine fraction in sediments. The pattern of Mn accumulation was parallel to trends of organic matter variation. There were highly significant differences between sampling sites in contents of heavy metals but no significant differences between seasons. Significant differences were found in bioaccumulation of Lead and Zinc in three size categories of chironomid larvae. Lead was higher in smaller M. lineatus, while the reverse was observed for Copper.

Uptake and elimination of cadmium by Japanese eel, Anguilla japonica, at various temperatures

Abstract: There is no evidence that cadmium is biologically essential, but its toxicity to organisms is well known The so-called Itai-Itai disease in Japan, characterized by osteomalacia and renal tubular malfunction, has been attributed to cadmium poisoning in irrigation water The degree of contamination in aquatic environments is frequently assessed by comparing contaminant concentrations in associated biota Bioaccumulation, however, is influenced by environmental factors other than the degree of contamination, environmental factors such as salinity, temperature and pH The use of cadmium in the electroplating industry in Taiwan is intensive, but the wastewater used in this industry is seldom treated and has been a serious problem The Japanese eel (Anguilla japonica) is an important freshwater aquacultural fish in Taiwan; thus, it is important to know the accumulation and elimination of cadmium in the Japanese eel due to cadmium-polluted water at various temperatures in order to protect eel resources as well as human health 18 refs, 3 figs, 1 tab

Toxicity and bioaccumulation of selenium to a three-trophic level food chain

Abstract: Three species, Chlorella vulgaris, Brachionus calyciflorus, and Pimephales promelas, were exposed to selenate for 25 d in a three-trophic level test system. The organisms were linked in a continuous flow-through system in separate vessels, with each organism feeding on the trophic level below it. These organisms were continually exposed for 25 d to 0, 110.3, 207.7, and 396.1 μg/L total recoverable selenium (Se) from selenate in natural creek water supplemented with nutrients to sustain algal growth. In an initial algal screening test, growth rates were reduced at 81.7 and 1,053.7 μg/L, with no effect at 8.5 μg/L. In the trophic test, algal populations showed evidence of reduced growth rates at 207.7 and 386.1 μg/L, but not at 110.3 μg/L. Rotifer population standing crop (measured as dry weight) was significantly reduced at 207.7 and 396.1 μg/L by day 4, and declined to below detection by day 7 at these treatments. Fathead minnow growth was impaired after 7 d at the 207.7 and 396.1 μg/L levels, with 100% mortality by day 16. A reduction in rotifers and fish biomass was also apparent at the 110.3 μg/L level after day 20. The amount of Se in whole organisms was measured throughout the experiment. Bioconcentration factors were found to be dependent on the species, treatment level, and length of exposure period, and they ranged between 100 and 1,000.

Mussels as Bioindicators: Effects of TBT on Survival, Bioaccumulation, and Growth Under Natural Conditions

Abstract: During nine field-transplant experiments (1987–1990), juvenile mussels were exposed to mean tributyltin (TBT) concentrations from 2 to 530 ng l-1 for 12 weeks under natural conditions in San Diego Bay Mussels were used as biological indicators and monitored for survival, bioaccumulation, and growth Mussel growth was the primary biological response used to quantify TBT effects Chemical analyses were used to estimate TBT contamination in water and mussel tissues Integrating intensive measurements of chemical fate and biological effects increased the environmental significance of the data Multiple growth measurements on individuals increased the statistical power Size effects were minimized by restricting test animals to 10–12 mm in length, and methods were developed to minimize handling efffects This monitoring approach also permitted documenting temporal and spatial variability in TBT and its effects that have not been previously reported Survival, bioaccumulation, and growth were generally higher than predicted from laboratory studies Survival was not directly affected by seawater or tissue TBT concentrations Growth was significantly related to both seawater and tissue TBT, with the bioconcentration factor inversely proportional to seawater TBT concentration Threshold concentrations always causing significant reductions in juvenile mussel growth are estimated at 100 ng l-1 TBT for seawater and 15 µg g-1 TBT for tissue, but growth could be affected by much lower concentrations of TBT under the most adverse conditions Temperatures above 20°C were also found to reduce juvenile mussel growth rates