ISSN:0730-7268    

DOI:10.1002/etc.5620151201

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractIn developing sediment quality criteria (SQC) for metals, it is essential that bioavailability be a prime consideration. Different studies have shown that while dry weight metal concentrations in sediments are not predictive of bioavailability, metal concentrations in interstitial (pore) water are correlated with observed biological effects. A key partitioning phase controlling cationic metal activity and toxicity in the sediment‐interstitial water system is acid‐volatile sulfide (AVS). Acid‐volatile sulfide binds, on a mole‐to‐mole basis, a number of cationic metals of environmental concern (cadmium, copper, nickel, lead, zinc) forming insoluble sulfide complexes with minimal biological availability. Short‐term (10‐d) laboratory studies with a variety of marine and freshwater benthic organisms have demonstrated that when AVS concentrations in spiked or field‐collected sediments exceed those of metals simultaneously extracted with the AVS, interstitial water metal concentrations remain below those predicted to cause effects, and toxicity does not occur. Similar observations have been made in life‐cycle laboratory toxicity tests with amphipods and chironomids in marine and freshwater sediments spiked with cadmium and zinc, respectively. In addition, field colonization experiments, varying in length from several months to more than 1 year, with cadmium‐ or zinc‐spiked freshwater and marine sediments, have demonstrated a lack of biological effects when there is sufficient AVS to limit interstitial water metal concentrations. These studies on metal bioavailability and toxicity in sediments serve as the basis for proposed SQC for the metals cadmium, copper, nickel, lead, and zinc. Specifically, four approaches for deriving criteria are described: (a) comparison of molar AVS concentrations to the summed molar concentration of the five metals simultaneously extracted with the AVS; (b) measurement of interstitial water metal concentrations and calculation of summed interstitial water criteria toxic units (IWCTU) for the five metals, based upon final chronic values from water quality criteria documents; (c) calculation of summed IWCTU based upon sediment AVS concentrations and metal‐specific partitioning of the metals to organic carbon; and (d) calculation of summed IWCTU based upon partitioning of the metals to a minimum binding phase sorbent (chromatographic sand). For a number of reasons, SQC derived using these approaches generally should be considered “no effect” values, i.e., with these techniques it is possible to predict when sediment metals will not be toxic, but not necessarily when metal toxicity will be manifested. Currently, approaches (a) and (b) are the most useful in terms of predicting metal bioavailability and deriving SQC. Further research is required, however, to fully implement approaches (c) and (d). Additional research also is required to thoroughly understand processes controlling bioaccumulation of metals from sediments by benthic organisms, as well as accumulation of metals by pelagic species that ingest

ISSN:0730-7268    

DOI:10.1002/etc.5620151202

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractNumerous studies have shown that dry weight concentrations of metals in sediments cannot be used to predict toxicity across sediments. However, several studies using sediments from both freshwater and saltwater have shown that interstitial water concentration or normalizations involving acid‐volatile sulfide (AVS) can be used to predict toxicity in sediments contaminated with cadmium, copper, nickel, lead, or zinc across a wide range of sediment types. Six separate experiments were conducted in which two or three sediments of varying AVS concentration were spiked with a series of concentrations of cadmium, copper, lead, nickel, or zinc or a mixture of four of these metals. The amphipodAmpelisca abditawas then exposed to the sediments in 10‐d toxicity tests. Amphipod mortality was sediment dependent when plotted against dry weight metals concentration but was not sediment dependent when plotted against simultaneously extracted metal (SEM)/AVS or interstitial water toxic units (IWTUs). Sediments with SEM/AVS ratios<1.0 were seldom (2.3%) toxic (i.e., caused1.0 were frequently (80%) toxic. Similarly, sediments with0.5 IWTU were toxic 94.4% of the time. These results, coupled with results from related studies, demonstrate that an understanding of the fundamental chemical reactions which control the availability of cadmium, copper, lead, nickel, and zinc in sediments can be used to explain observed biological responses. We believe that using SEM/AVS ratios and IWTUs allows for more accurate predictions of acute mortality, with better causal linkage to metal concentration, than is possible with sediment evaluation tools which rely on dry weight metal concentrati

ISSN:0730-7268    

DOI:10.1002/etc.5620151203

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractWe investigated the utility of interstitial water concentrations of metals and simultaneously extracted metal/acid‐volatile sulfide (SEM/AVS) ratios to explain the biological availability of sediment‐associated divalent metals to benthic organisms exposed in the laboratory to sediments from five saltwater and four freshwater locations in the United States, Canada, and China. The amphipodAmpelisca abditaor the polychaeteNeanthes arenaceodentatawere exposed to 70 sediments from the five saltwater locations, and the amphipodHyalella aztecaor the oligochaeteLumbriculus variegatuswere exposed to 55 sediments from four freshwater locations in 10‐d lethality tests. Sediment toxicity was not related to dry weight metals concentrations. Almost complete absence of toxicity in spiked sediments and field sediments where metals were the only known source of contamination and where interstitial water toxic units (IWTUs) were<0.5 indicates that toxicity associated with sediments having SEM/AVS ratios<1.0 from two saltwater locations in industrial harbors was not metals‐related as these sediments contained0.5 and SEM/AVS ratios0.5 (55%) were used alone. The difference between the molar concentrations of SEM and AVS (SEM – AVS) can provide important insight into the extent of additional available binding capacity, the magnitude by which AVS binding has been exceeded, and, when organism response is considered, the potential magnitude of importance of other metal binding phases. For these reasons, SEM – AVS should be used instead of SEM/AVS ratios as a measure of metals availability. Over all published experiments with both metal‐spiked and field sediments, SEM – AVS and IWTUs accurately (99.2%) identified absence of sediment toxicity and with less accuracy (79.1%) identified the

ISSN:0730-7268    

DOI:10.1002/etc.5620151204

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractNumerous studies have demonstrated the efficacy of interstitial water metal concentrations and simultaneously extracted metals/acid‐volatile sulfide (SEM/AVS) ratios in explaining the acute toxicity of sediment‐associated metals to benthic organisms. However, no full life‐cycle chronic marine or estuarine tests have been conducted for this purpose. In this study, cohorts of newborn amphipods,Leptocheirus plumulosus, were exposed to cadmium‐spiked estuarine sediment for 28 d to determine effects on mortality, growth, and reproduction relative to interstitial water and SEM/AVS normalization. Seven treatments of cadmium were tested: 0 (control), 0.34, 0.74, 1.31, 1.55, 2.23, and 4.82 M SEMcd/AVS ratios (measured concentrations). Interstitial water cadmium (IWcd) and sediment concentrations of SEMcdand AVS were monitored periodically and by depth during the exposure. When sediment SEMcd/AVS ratios were ≤1.55, mean IWcdconcentrations were less than the 96‐h water‐only cadmium LC50 for juvenile and subadultL. plumulosus, and mortality, growth, and reproduction were not affected. When SEMcd/AVS ratios were ≥2.23, IWcdconcentrations were more than 100 times greater than the 96‐h water‐only cadmium LC50, and all amphipods died. These results are consistent with predictions of metal bioavailability from acute tests with metal‐spiked sediments, i.e., that sediments with SEMcd/AVS ratios<1 are not toxic, while sediments with SEMcd/AVS

ISSN:0730-7268    

DOI:10.1002/etc.5620151205

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractThe development of sediment quality criteria for the cationic metals cadmium, copper, lead, nickel, and zinc has focused on the use of acid‐volatile sulfide (AVS) as the primary normalization phase for predicting interstitial pore‐water concentrations and bioavailability of the metals. To date, most of the research in support of AVS in this context has utilized short‐term laboratory exposures, with a relative paucity of information pertaining to long‐term exposures. The purpose of this study, therefore, was to investigate the use of AVS as a predictor of metal toxicity to a benthic organism in a long‐term laboratory exposure. Clean sediment was spiked with zinc to obtain nominal treatments ranging from −2.34 to 58.5 μg/g dry weight with respect to the molar difference between simultaneously extracted metal (SEM) and AVS. The test was initiated with newly hatched larvae of the midgeChironomus tentansand carried through one complete generation (56 d) during which survival, growth, emergence, and reproduction were monitored. When the molar difference between SEM and AVS (i.e., SEM – AVS) was<0, the concentration of zinc in the sediment interstitial water was low and no adverse effects were observed for any of the biological endpoints measured. Conversely, when SEM – AVS exceeded 0, a dose‐dependent increase in the relative concentration of zinc in the pore water was detected. However, the absolute concentration of pore‐water zinc at each treatment declined over the course of the study, corresponding to an increase in sediment AVS and to a loss of zinc due to diffusion into the overlying water, which was renewed twice daily. Only when SEM – AVS exceeded 0 were significant reductions in survival, growth, emergence, and reproduction observed. Together, the chemical and biological data from this study compare favorably with observations made in short‐term exposures and thus support the use of AVS as a normalization phase for predicting toxicity in meta

ISSN:0730-7268    

DOI:10.1002/etc.5620151206

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractAcid‐volatile sulfide (AVS) has been proposed as the primary normalization phase for the development of sediment quality criteria for certain cationic metals. This study was designed to assist in this development by providing necessary field data on the relationships among season, AVS concentrations, and zinc bioavailability and toxicity in freshwater sediments. Zinc was spiked into uncontaminated sediments collected from a local pond, creating five simultaneously extracted metal (SEM) concentrations ranging from 0.8 to 12.0 μmol/g dry weight. The spiked sediments were transferred to 4‐L plastic trays, returned to the bottom of the pond, and sampled on five dates during 1993‐1994. Results revealed a pronounced increase in AVS concentration with increasing zinc concentration. Acid‐volatile sulfide concentrations in zinc‐spiked sediments displayed only minor seasonal variation but were lowest in surficial (0‐2 cm) sediments. Acid‐volatile sulfide concentrations always exceeded SEM concentrations at ≤6.0 μmol SEM/g; only at 12.0 μmol SEM/g did SEM/AVS ratios exceed 1.0. Zinc was rarely detected in pore water at any treatment and never at concentrations which should have posed a hazard to benthic macroinvertebrates. No substantial effect on colonization of zinc‐spiked sediments by benthic macroinvertebrates was observed. Only oligochaetes (Naididae) were significantly reduced in abundance at the high zinc treatment, although reductions were occasionally evident for other taxa. Lack of noteworthy pore‐water zinc concentrations and lack of associated, ecologically meaningful effects were attributed to the increase in AVS levels observed with increasing SEM zinc sediment concentration. The increases in AVS theoretically resulted from a replacement of natural iron and manganese sulfides with the more stabl

ISSN:0730-7268    

DOI:10.1002/etc.5620151207

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractThe role of interstitial cadmium and acid‐volatile sulfide (AVS) in controlling the bioavailability of sediment‐associated metal was examined using the chronic saltwater benthic colonization test. Sediments were spiked to achieve nominal cadmium/ AVS molar ratios of 0.0 (control), 0.1, 0.8, and 3.0 in this 118‐d test. Oxidation of AVS in the surficial 2.4 cm within 2 to 4 weeks resulted in sulfide profiles similar to those occurring naturally in local sediments. In the nominal 0.1 cadmium/AVS treatment, measured simultaneously extracted metal (SEMcd) was always less than AVS. Interstitial cadmium concentrations (<3‐10 μg/L) were less than those likely to cause biological effects. No significant biological effects were detected. In the nominal 0.8 cadmium/ AVS treatment, measured SEMcdcommonly exceeded AVS in the surficial 2.4 cm of sediment. Interstitial cadmium concentrations (24‐157 μg/L) were of likely toxicological significance to highly sensitive species. Shifts in the presence or absence over all taxa, and fewer macrobenthic polychaetes(Mediomastus ambiseta, Streblospio benedicti, andPodarke obscurd)and unidentified meio‐faunal nematodes, were observed. In the nominal 3.0 cadmium/AVS treatment, concentrations of SEMcdwere always greater than AVS throughout the sediment column. Interstitial cadmium ranged from 28,000 to 174,000 μg/L. In addition to the effects above, these sediments were colonized by fewer macrobenthic species, polychaete species, and harpacticoids; had lower densities of diatoms; lacked bivalve molluscs; and exhibited other impacts. Over all treatments, the observed biological responses were consistent with SEMcd/AVS ratios in surficial sediments and interstitial water cadmium

ISSN:0730-7268    

DOI:10.1002/etc.5620151208

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractRecent 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 o

ISSN:0730-7268    

DOI:10.1002/etc.5620151209

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractRecent 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 oligochaeteLumbriculus variegatusin 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 byL. variegatuswas 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 i

ISSN:0730-7268    

DOI:10.1002/etc.5620151210

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY