Ecotoxicity assessment of the aquatic environment around Lake Kojima,Japan

To reduce the impact of chemical substances on the aquatic ecosystem, it is essential to understand their ecotoxicological properties in the natural aquatic environment. Consequently, we conducted an ecotoxicological study on the aquatic environment around Lake Kojima, a man-made lake located in the southwest of Japan. Lake Kojima receives its chemical inputs mainly from two rivers that flow through various agricultural and industrial areas. For ecotoxicity screening, surface water and sediment samples were collected 4 times in 1993 from 16 preselected sites. Then, the solutes in the filtered surface water were concentrated by ODS resin, and the organic chemicals in the suspended solids (SS) and sediments were extracted by acetone. A battery of five ecotoxicity tests (agar plate test using bacteria and yeast, algal growth inhibition test, Daphnia magna immobilization test, and root elongation test using lettuce seeds) was used to assess these extracts. The results show that the surface water extracts had a lethal effect on D. magna, the SS extracts suppressed algal growth, and the sediment extracts were inhibitory to the growth of yeast. A significant inhibitory effect by the sediment extracts from 4 lake sites and 3 river sites was detected by these ecotoxicity tests. Attempts also were made to identify the putative ecotoxic chemicals in the collected samples. Elementary sulfur was identified as one of the major toxicants in the sediment extracts that were inhibitory to the yeast growth. Moreover, samples of surface water around Lake Kojima, collected weekly from June to September in 1994, were found to contain three pesticides and were toxic to D. magna. But the concentration of the pesticides detected was too low to cause daphnia immobilization. It is believed that the toxicity of the water extracts was mainly due to the combined toxic effect of natural and man-made components. © 1996 by John Wiley & Sons, Inc.     

Effects of phenanthrene on lemna minor in a sediment-water system and the impacts of UVB

The objective of this study was to evaluate if the Lemna -bioassay is appropriate to test contaminated sediments. A mixture of sand was spiked with phenanthrene to investigate whether sediment-bound pollutants can affect the plants via direct contact of the roots or the underside of the leaves. After 24 h of equilibration for sorption/desorption processes, the test was carried out in the sediment–water mixture, and another test was performed with the aqueous phase which was separated from the sediment. The growth inhibition of Lemna was nearly the same in both tests. Hence it follows that the toxicant is adsorbed from the aqueous phase via the underside of the leaves and sediment bound phenanthrene is not bioavailable. Polycyclic aromatic hydrocarbons are known to show photoinduced toxicity to plants in the presence of UV which is a result of photosensitization reactions in the plant and photomodification to more toxic and better soluble photoproducts. Photoinduced toxicity could be observed in the water phase during UVB treatment, whereas the presence of suspended sediment probably lowered the UV intensity, resulting in a lower growth inhibition.     

Use of four microbial tests to assess the ecotoxicological hazard of contaminated sediments

Three single-species bioassays (Microtox, Selenastrum capricornutum, and Panagrellus redivivus) and a test using microbial communities developed on artificial substrates were used in a series of in situ and laboratory tests evaluating the ecotoxicological hazard of contaminated sediments at two sites on Lake Michigan: Waukegan (Illinois) Harbor and The Chicago Area Confined Disposal Facility Study. In the single-species tests, exposure to elutriates of contaminated sediments significantly inhibited bacterial luminescence, algal photosynthesis, and nematode survival and growth at polluted stations, while elutriates from control stations did not. The battery of three tests is a promising screening tool for in-place pollutants. Protozoan species richness and protozoan phototroph abundance were inhibited by elutriates from contaminated sites, but the abundance of heterotrophic protozoans was enhanced by sediment elutriates from some stations. Microbial community photosynthesis was significantly inhibited by most sediment elutriates, while community respiration was often stimulated; thus, functional responses paralleled the structural changes. Overall, the results of the microbial community tests were consistent with expected patterns of toxicity at the two sites on Lake Michigan. In general, single-species test results agreed with the community bioassays. Although community tests may be more realistic than single-species bioassays in predicting the impact of sediment contamination on actual ecosystems, caution must be exercised in interpreting the results.     

Enhancement of toxicant release from sediment by sonication and sodium ligninsulfonate

Organic solvents are commonly used in many sediment toxicity bioassays to facilitate the extraction and concentration of adsorbed contaminants from sediment samples. However, the inherent biotoxicity of most solvents to the bioassay organism may complicate greatly the interpretation of the toxicity test results. To alleviate this problem, a solvent-less extraction procedure was developed for use in the assessment of sediment toxicity. Basically, it involves the use of sonication and sodium ligninsulfonate to enhance the release of the adsorbed contaminants from the sediment. The procedure was applied to sediment samples collected from the St. Clair River at a site approximately 25 m offshore of Dow Chemicals (Sarnia, Ontario). Test results indicate that the most toxic components of the St. Clair River system near Dow Chemicals were associated mainly with the sediment fraction, and there appeared to be very little or no biotoxicity in the overlaying water column. Several of the major contaminants were identified as chlorinated hydrocarbons. The impact of these chemicals on the aquatic environment is discussed. © 1996 by John Wiley & Sons, Inc.     

Sediment‐contact and survival of fingernail clams: Implications for conducting short‐term laboratory tests

Porewater toxicity tests have been used as indicators of whole sediment toxicity. However, many species commonly tested in porewater predominately reside in the water column and otherwise have little to no direct contact with sediment and associated porewater. We assessed the feasibility of porewater toxicity tests with fingernail clams Musculium transversum, a benthic macroinvertebrate that inhabits soft bottom sediments and feeds by filtering surface and porewater. Fingernail clams were exposed to water or sediment in a 96 h laboratory test with a 5×2 factorial experimental design. The five treatments included sediments from four sites in the Mississippi River and one sediment‐free control (well water). In all treatments, clams were exposed to the sediments or water either directly (no enclosure) or indirectly (enclosure, suspended above the sediment surface). There were three replicates for each of the ten treatment combinations. Overall, survival of fingernail clams did not vary among the five treatments (p=0.36). In treatments without enclosures, survival of clams in the sediment‐free control was not significantly different (p=0.34) from the sediment‐containing treatments. Survival of clams in the sediment‐free control averaged 85%—suggesting that direct sediment contact is not necessary for survival in short‐term tests. In contrast, survival of clams in the sediment‐containing treatments differed significantly (p=0.03) between exposures with (mean, 77%) and without (mean, 89%) enclosures. Thus, fingernail clams may provide an alternative species for evaluating benthic macroinvertebrates in short‐term laboratory porewater tests. However, more information on their physiological requirements and the development of sublethal endpoints is recommended before their use in tests of longer duration. ©2000 John Wiley & Sons, Inc. Environ Toxicol 15: 23–27, 2000     

A marine bioassay test set to assess marine water and sediment quality-its need,the approach and first results

There is a need for establishing a marine bioassay test set to assess marine water and sediment samples in Germany. The selected marine bioassay test set, two tests for the water phase (with the luminescence bacteria Vibrio fischeri and the algae Phaeodactylum tricornutum Bohlin) and a whole sediment test with the marine amphipod Corophium volutator (Pallas) is described and first results are shown.     

Evidence of genotoxic substances in the Niagara river watershed

The SOS chromotest was used to detect genotoxicity of sediment samples from seven locations in the Welland River, Ontario, Canada, in December 1986 and April 1987. DMSO extracts of sediment samples from one location situated directly below the discharge pipe of a polyvinyl chloride plant showed a statistically significant (p < 0.01) genotoxic effect. It was concluded that genotoxic contaminants were associated with vinyl chloride contaminated sediments from this location. At a distance of 5 m downstream of the polyvinyl chloride plant's discharge, the mean SOS induction factor was 2.05, while 100 m further downstream the SOS induction factor had dropped to 1.54. The Ames test was used to detect genotoxicity of samples that gave positive responses in the SOS chromotest. The results of the Ames test were negative. This may suggest that the SOS chromotest is more sensitive than the Ames test for testing genotoxicity in these types of samples.     

Levels,distribution pattern and ecological risk assessment of organochlorines pesticides (OCPs) in water and sediments from two tributaries of the Chenab River,Pakistan

Residue levels, distribution patterns and ecological risk assessment of OCPs in water and sediment samples collected from two upstream feeding tributaries of the River Chenab, Pakistan were monitored. ΣOCPs levels in water and sediment ranged between 8 and 76 ng L^?1 and 17 and 224 ng g^?1, respectively. The mean concentration of ΣHCH (hexachlorocyclohexane) was 3.3 ± 3.2 ng L^?1 and 8.4 ± 9 ng g^?1 for water and sediment samples, respectively, while ΣDDT (dichlorodiphenyltrichloroethane) exhibited the average concentration of 9.07 ± 6.15 ng L^?1 and 40.3 ± 26.2 ng g^?1 for water and sediment samples, respectively. The concentration of DDT and HCHs in both water and sediment samples were about 80 % of total OCPs and DDTs were the predominant organochlorines in the investigated matrix. DDTs and HCHs in sediment samples posed higher ecotoxicological risk and results were significant when compared with the quality guidelines. Results of the present study should be taken seriously by higher authorities as there is a serious threat to ecological integrities by OCPs exposure.     

Ecotoxicological evaluation for the screening of areas polluted by mining activities

The aim of this study was to evaluate the applicability of three bioassays representing multiple trophic levels, for the preliminary ecotoxicological screening of sediments from sites contaminated by mining activities. Of the bioassays used in this study, the ostracod test was the most responsive. Vibrio fischeri luminiscence inhibition assay was less sensitive to the toxicants in the sediments than the phytotoxicity assays. The general trend observed was an increase in toxicity values measured by the bioassays with increasing metal mobilization in sediment samples. Therefore, the test battery can be used as a rapid and sensitive tool to evaluate the heavy metal contamination in sediments.     

ATP-TOX system—a new,rapid, sensitive bacterial toxicity screening system based on the determination of ATP

A new toxicity screening test, based on the inhibition of bacterial growth and luciferase activity by toxicants was developed. In the ATP-TOX System, chemical toxicity was found to be time-dependent and increased with increasing exposure time up to 5 hours. Three organisms were evaluated in this study: E. coli K-12 PQ37, Pseudomonas fluorescens and Salmonella typhimurium. E. coli K-12 PQ37 was found to be the most sensitive organism. It was also shown that P. fluorescens was more sensitive to toxicants when grown in minimal medium than in nutrient broth, suggesting that nutrients may have a protective effect on the bacterium. In comparative studies using selected toxic chemicals the ATP-TOX System was found to be more sensitive than the Spirillum volutans test and comparable to the Microtox test. Toxicant activity in sediment samples was found to be time dependent and increased with increasing exposure time in both ATP-TOX (E. coli) System and Microtox. The ATP-TOX System is complementary to the Microtox test as it also provides indications of low grade toxicant activity which is only manifested in actively growing cells over several life cycles. Thus, the ATP-TOX System appears to be an ideal screening test for sediment toxicity. The data indicate that the ATP-TOX System is sensitive, rapid, reproducible, economical and has great potential in applied studies.     

Investigation of the fate and effects of acetyl cedrene on <Emphasis Type="Italic">Capitella teleta</Emphasis> and sediment bacterial community

The fate of the fragrance material, acetyl cedrene (AC), in sediment was examined in a 16 day laboratory experiment using the sediment microbial community subjected to the following treatments: AC (nominal concentration; 0 and 50 μg g⁻¹ dw sediment) and macrofaunal worms (with/without Capitella teleta (formerly Capitella sp. I)). Furthermore effects of AC on microbial respiration in the system were determined by examining CO₂ flux. T-RFLP (terminal restriction fragment length polymorphism) was used to analyze PCR (polymerase chain reaction) amplified 16S DNA gene fragments from the sediments to detect changes in the structure and diversity of the bacterial community. In addition, survival of C. teleta in sediment was determined. Lastly, we examined how the interactions between microbes and C. teleta in the sediment affected the above-mentioned parameters. The results showed that there was an interaction between worm treatment and time of sampling on the loss of AC from the sediment. This was caused by AC loss initially being fastest in the sediment with C. teleta present, but at experimental termination there was no significant difference between the two treatments (i.e., with/without worms) in the amount of AC remaining in the sediment. Survival of C. teleta was significantly reduced by AC at experimental termination, but neither microbial respiration nor structure and diversity of the bacterial community were significantly affected.     

Comparisons between microscale and whole-sediment assays for freshwater sediment toxicity assessment

The use of several microscale assays for evaluating freshwater sediment toxicity was investigated to develop a representative and cost-effective test battery. The bioassays evaluated (18 assays total) included microscale assays performed on solid-phase, pore water, and organic extracts as well as conventional standardized whole-sediment assays with Chironomus riparius and Hyalella azteca on 10 sediment samples collected in the St. Lawrence/Great Lakes system. Selected sediment physical and chemical characteristics were also conducted to aid in the interpretation of results. Benthic invertebrate assays such as C. riparius and H. azteca endpoints were found to correlate well to contaminant levels. Microscale assays such as ATP (adenosine triphosphate) measurement of sediment microbial biomass gave promising results to predict whole-sediment toxicity to benthic invertebrates. Most assays on pore water did not adequately represent whole-sediment toxicity, whereas organic extracts appeared to be more representative, alleviating some potential confounding factors such as interference due to toxicity caused by ammonia. © 1998 John Wiley & Sons, Inc. Environ Toxicol Water Qual 13 : 93–110, 1998     

A caridean grass shrimp (Palaemonetes pugio Holthius) as an indicator of sediment quality in Florida coastal areas affected by point and nonpoint source contamination

Grass shrimp are one of the more widely distributed estuarine benthic organisms along the Gulf of Mexico and Atlantic coasts, but they were used infrequently in contaminated sediment assessments. Early‐life stages of caridean grass shrimp, Palaemonetes pugio (Holthius), were used in this baseline survey as indicators of sediment pore water quality for several Florida coastal areas affected by nonpoint and point sources of contamination. Static toxicity tests were conducted using 24 well culture plates assessing embryo and larval survival after 12 days exposure to pore water (interstitial water). Acute toxicity was observed in 28% of pore waters (15 of 53 samples) suggesting that sediment contamination was not widespread in the study area based on the response of this species. When toxicity was observed, grass shrimp pore water toxicity test was usually a more sensitive indicator of contamination than solid‐phase tests conducted with the epibenthic invertebrate, Mysidopsis bahia. P. pugio embryos were more sensitive than larval form and response of different brood stocks usually were similar (P>0.05) when exposed to same pore waters. Based on all considerations, this early‐life stage toxicity test shows promise being useful detecting pore water toxicity. This conclusion is based on availability of a test methodology which requires minimal space and effort, and the test species widespread geographical distribution. However, there are several remaining research needs, including the important issue of its sensitivity relative to that for other pore water test species as well as for species used in solid‐phase toxicity tests. © 2000 John Wiley & Sons, Inc. Environ Toxicol 15: 234–242, 2000     

Assessment of sediment quality of Yangtze River estuary using zebrafish (Danio rerio) embryos

Yangtze River estuary is one of the largest estuaries worldwide. In this study, the sediment quality of Yangtze River estuary was evaluated using zebrafish (Danio rerio) embryos. Freshly fertilized zebrafish eggs (2 h after fertilization) were exposed to the whole sediment and its organic phase of extract, respectively. The parameters, including survival rate, abnormality, hatching rate, and heart rate of the zebrafish embryos, were recorded during the 96‐h exposure. The results demonstrated that the concentrations of heavy metals (Zn, Cu, Cd, Ni, Cr, and As) and low‐molecular weight PAHs (Fluorene) in the sediment of Yangtze River estuary exceeded their corresponding effects range low values. The maximum concentrations of Zn and Fluorene in the sediment samples were 239.6 μg/g and 45.9 ng/g, respectively. In both whole sediment test and organic extract test, the survival rate and heart rate of zebrafish embryos were reduced, as well as abnormalities and delayed hatching were induced. For example, the highest mortality of the embryos was 39% in the whole sediment exposure. Overall, the occurrence of toxic compounds in the sediment of Yangtze River estuary may have potentially teratogenic effect on biota. The sediment from the upstream of Yangtze River estuary have more observed toxic effects on zebrafish embryos than that form the downstream. Therefore, more attention should be paid to control these pollutants, especially heavy metals in the Yangtze River estuary. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2010.     

Use of the aquatic oligochaetes Lumbriculus variegatus and Tubifex tubifex for assessing the toxicity of copper and cadmium in a spiked-artificial-sediment toxicity test

A sediment toxicity test using the freshwater oligochaetes Lumbriculus variegatus and Tubifex tubifex was performed. We evaluated acute and chronic toxicity affects of copper and cadmium on reproduction in both species and the bioaccumulation of both metals by L. variegatus using artificial sediment. L. variegatus bioconcentrated copper 22-fold and cadmium 16-fold after a 14-day exposure to spiked artificial sediments with 0.02% organic content. The EC₅₀ for T. tubifex varied depending upon endpoint from 2.7 to 2.8 mg/L for cadmium and from 8.4 to 8.9 mg/L for copper. The EC₅₀ for L. variegatus was 2.2 mg/L for cadmium and 3.9 mg/L for copper. Based on these results, L. variegatus appears to be more sensitive to metal toxicity in artificial sediments than T. tubifex. ©1999 John Wiley & Sons, Inc. Environ Toxicol 14: 271–278, 1999     

Assessing Mercury Exposure and Effects to American Dippers in Headwater Streams near Mining Sites

To evaluate mercury (Hg) exposure and possible adverse effects of Hg on American dipper (Cinclus mexicanus) reproduction, we collected eggs and nestling feathers and the larval/nymph form of three Orders of aquatic macroinvertebrates (Ephemeroptera, Plecoptera and Trichoptera = EPT) important in their diet from three major headwater tributaries of the upper Willamette River, Oregon in 2002. The Coast Fork Willamette River is contaminated with Hg due to historical cinnabar (HgS) mining at the Black Butte Mine; the Row River is affected by past gold-mining operations located within the Bohemia Mining District, where Hg was used in the amalgamation process to recover gold; and the Middle Fork Willamette River is the reference area with no known mining. Methyl mercury (MeHg) concentrations (geometric mean) in composite EPT larvae (111.9 ng/g dry weight [dw] or 19.8 ng/g wet weight [ww]), dipper eggs (38.5 ng/g ww) and nestling feathers (1158 ng/g ww) collected from the Coast Fork Willamette were significantly higher than MeHg concentrations in EPT and dipper samples from other streams. Total mercury (THg) concentrations in surface sediments along the same Hg-impacted streams were investigated by others in 1999 (Row River tributaries) and 2002 (Coast Fork). The reported sediment THg concentrations paralleled our biological findings. Dipper breeding territories at higher elevations had fewer second clutches; however, dipper reproductive success along all streams (including the lower elevation and most Hg-contaminated Coast Fork), was judged excellent compared to other studies reviewed. Furthermore, MeHg concentrations in EPT samples from this study were well below dietary concentrations in other aquatic bird species, such as loons and ducks, reported to cause Hg-related reproductive problems. Our data suggest that either dipper feathers or EPT composites used to project MeHg concentrations in dipper feathers (with biomagnification factor of 10–20×) may be used, but with caution, to screen headwater streams for potential Hg-related effects on dippers. When actual feather concentrations or projected feather concentrations are equal to or lower than concentrations reported for the Coast Fork, dippers are expected to reproduce well (assuming adequate prey and suitable nest sites). When Hg concentrations are substantially higher, more detailed investigations may be required. Birds feeding almost exclusively on fish (e.g., osprey [Pandion haliaetus]) and usually found further downstream from the headwaters would not be adequately represented by dippers given the higher MeHg concentrations in fish resulting from biomagnification, compared to lower trophic level invertebrates.     

Hyalella azteca 10-day sediment toxicity test: Comparison of growth measurement endpoints

Hyalella azteca are presently used in toxicity tests designed to evaluate adverse biological effects associated with exposure to contaminated sediments. Biological endpoints examined in a sediment test include changes in survival, as well as sublethal effects such as changes in growth, and reproduction. Length and weight, two methods used routinely to measure growth, were compared using H. azteca recovered from a 10-day sediment toxicity test. Length of individual organisms was measured using an image analyzer and dry weight of organisms was determined using an electronic microbalance. Statistical analysis was conducted using one-way analysis of variance to compare treatment sites. Length measures were shown to have greater power, a small minimum detectable difference, and smaller amount of underlying variability. The results indicate that length, measured using an image analyzer, was a more sensitive means to detect significant changes in growth and can be conducted with a greater degree of statistical confidence than use of weight measures. © 1998 John Wiley & Sons, Inc. Environ Toxicol Water Qual 13: 243–248, 1998     

Interlaboratory precision study of a whole sediment toxicity test with the bioluminescent bacterium Vibrio fischeri

The reproducibility of sediment toxicity bioassays using the Microtox® solid-phase test (SPT) with the luminescent bacterium Vibrio fischeri was estimated in an interlaboratory precision study. A preliminary study, with five labs testing six solid-phase samples, was used to evaluate proposed method modifications. As a result, it was recommended that the SPT protocol be revised to include whole sample testing with subsequent wet-weight to dry-weight correction, and the use of NaNO₃, rather than NaCl, as the diluent for freshwater sediment samples. The revised protocol was then examined in a definitive precision study, with 18 laboratories each testing eight samples. Coefficients of variation for the eight samples ranged from 35.8 to 78.0%. One possible source of error is the separate moisture content determination performed by each laboratory in order to calculate the wet-weight to dry-weight correction. Out of a total of 143 bioassays performed by the 18 labs, only two results (1.4%) exceeded the critical value of the interlaboratory consistency statistic h. With coefficients of variation comparable to other interlaboratory precision studies, and an extremely low number of results exceeding the critical value of h, it is concluded that the V. fischeri SPT has an acceptable level of precision and can be developed as a standardized test method. ©1999 John Wiley & Sons, Inc. Environ Toxicol 14: 339–345, 1999     

Impact of triphenyltin acetate in microcosms simulating floodplain lakes. I. Influence of sediment quality

Floodplain lakes in the Rhine–Meuse delta of the Netherlands vary considerably in levels of sediment-bound toxicants. Microcosm experiments were done to compare the ecological impact of the fungicide triphenyltin acetate (TPT) between test systems with clean or polluted sediments (10 microcosms each). Differences in sediment quality affected the structure of the aquatic communities that developed in the microcosms. Initially, a faster growth of the macrophyte Elodea nuttallii was observed on the polluted sediments, which contained not only toxicants but also higher organic matter and nutrient levels. Dynamics of TPT concentrations in the overlying water were very similar between the two types of test system. Higher levels of TPT, however, were found in the sediment compartment of the clean sediment systems containing a smaller macrophyte biomass. TPT was very persistent in the sediments. In both test systems representatives of several taxonomic groups showed clear responses to a single application of TPT, although benthic Nematoda were not affected. Although a few differences in the intensity and/or duration of TPT-related population responses were observed between the two types of test system, the background pollutants in the polluted sediment hardly affected the overall sensitivity of the aquatic community to the additional chemical stressor TPT.     

Integrated measures of ambient toxicity and fish community diversity in Chesapeake Bay tributaries

The goals of this study were to assess the results of a suite of sediment and water column bioassays in the framework of a toxicological risk ranking model and evaluate correlations of model output with fish community metrics. The test sites were located in four tributaries of Chesapeake Bay that are impacted on by industrial, urban and agricultural land use (Curtis Creek, Rock Creek, Fishing Bay and Wicomico River). The mortality, reproduction and growth rates in the water column assays indicated low-level chemical contamination impacts in Curtis Creek and Rock Creek. The results from the Wicomico River and Fishing Bay did not indicate contaminant impacts, but some borderline effects were seen. The sediment bioassays demonstrated greater toxicological responses than the water column assays. The sediments in the Curtis Creek and Rock Creek sites were contaminated with heavy metals and PAHs. The heavy metal concentrations were an order of magnitude lower in the Fishing Bay sediments and below detection in the Wicomico River sediments, except for zinc. The acid-volatile sulphides:simultaneously extractable metals (AVS:SEM) ratios were below 1 in all cases. All four systems had detectable petroleum hydrocarbon contamination. Organic contaminants were below detection for all analyses in the Wicomico River and Fishing Bay samples. The risk ranking model ranked Curtis Creek as the most toxicologically impacted site, followed by Rock Creek, Fishing Bay and Wicomico River, which were essentially equal. The diversity index for fish communities sampled by bottom trawl was significantly correlated with the toxicological risk scores for sediment. The toxicological results indicate sediment contamination effects on the deep water fish community in Curtis Creek and indicate that contaminant impacts are not likely to be a contributing factor to disturbed fish communities in Fishing Bay