Ecotoxicological studies of environmental samples from Buenos Aires area using a standardized amphibian embryo toxicity test (AMPHITOX).

The toxicity of 34 environmental samples from potentially polluted and reference stations were evaluated by means of the AMPHITOX test from acute to chronic exposure according to the toxicity found in each sample. The samples were obtained from surface and ground water, leaches, industrial effluents and soils. The data, expressed in acute, short-term chronic and chronic Toxicity Units (TUa, TUstc and TUc) resulted in a maximal value of 1000 TUc, found in a leach, while the lower toxicity value was 1.4 TUa corresponding to two surface water samples. In five samples (four providing from reference places) no toxicity was detected. The results point out the possibility of evaluating the toxicity of a wide diversity of samples by means of AMPHITOX as a customized toxicity test. The fact that almost all samples with suspected toxicity in rivers and streams from the Metropolitan area of Buenos Aires city resulted toxic, indicates the need of enhanced stewardship of chemical substances for environmental and human health protection purposes.     

Metallothioneins and cadmium uptake by the liver in Bufo arenarum

Bufo arenarum females were treated daily with 0.5 mg Cd kg(-1) during 10 days to evaluate the uptake of this heavy metal and the induction of metallothionein synthesis in the liver. The liver incorporated 26% of the Cd administered, about 6.5 times higher than the average uptake of the other tissues of B. arenarum. Three protein fractions from the B. arenarum liver bound Cd, and were induced by this xenobiotic up to approx. 24 times above the basal level of these proteins.     

温州市区内河水质毒性评价

采用分析水质理化指标及蚕豆根尖微核试验对市区内河水质进行监测,并结合现场调查,评价市区内河水污染状况,结果表明市区内河水污染较重,并具有一定遗传毒性.     

Species-specific responses to metals in organically enriched river water, with emphasis on effects of humic acids

Invertebrate communities in polluted rivers are often exposed to a wide variety of compounds. Due to complex interactions, 'pollution tolerant' species are not necessarily the most tolerant species to toxicants tested under standard laboratory conditions. It was hypothesized that the distribution of species in polluted rivers is not only dependent on the tolerance of species to toxicants, but also on species-specific capacities to modify or compensate for negative effects of toxicants. To test this hypothesis, species-specific responses to metals in organically enriched river water were studied under controlled conditions. The zebra mussel Dreissena polymorpha and the midge Chironomus riparius were exposed to metal-polluted water from the River Dommel. Additionally, the (interactive) effects of metals and humic acids (HA) on both species were evaluated. In spite of a lower tolerance of Chironomus riparius to metals in laboratory studies, the midge was the most tolerant of the two test species to metal-polluted site water. The results indicated that the sensitivities of the two test species determined in laboratory tests were inversely related to their sensitivities to polluted river water. In accordance with these results, midge larvae were protected from copper (Cu) toxicity by HA, while metal toxicity was not reduced (Cu) or even amplified (cadmium) by HA for the zebra mussel. Thus, the presence of (naturally occurring) HA in site water may partly account for discrepancies between responses of species to bioassays and toxicity tests. It is suggested that these differences in responses to metals in site water are strongly influenced by species-specific preferences for organic compounds (like HA). It is concluded that the response to organic compounds present in site water largely determines whether a species is classified as 'pollution tolerant' or 'pollution sensitive'.     

Antagonism and synergism between lead and zinc in amphibian larvae

Lead and zinc effects on Bufo arenarum larval survival were studied in single and combined treatments. On a weight basis, lead is about twice as toxic as zinc. The antagonism or synergism between these heavy metals is dose-dependent.     

Influence of sediment on the fate and toxicity of a polyethoxylated tallowamine surfactant system (MON 0818) in aquatic microcosms

The fate and toxicity of a polyethoxylated tallowamine (POEA) surfactant system, MON 0818, was evaluated in water-sediment microcosms during a 4-d laboratory study. A surfactant solution of 8 mg l(-1) nominal concentration was added to each of nine 72-l aquaria with or without a 3-cm layer of one of two natural sediments (total organic carbon (TOC) 1.5% or 3.0%). Control well water was added to each of nine additional 72-l aquaria with or without sediment. Water samples were collected from the microcosms after 2, 6, 24, 48, 72, and 96 h of aging to conduct 48-h toxicity tests with Daphnia magna and to determine surfactant concentrations. Elevated mortality of D. magna (43-83%) was observed in overlying water sampled from water-only microcosms throughout the 96-h aging period, whereas elevated mortality (23-97%) was only observed in overlying water sampled from water-sediment microcosms during the first 24h of aging. Measured concentrations of MON 0818 in water-only microcosms remained relatively constant (4-6 mg l(-1)) during the 96-h period, whereas the concentrations in overlying water from microcosms containing either of the two types of sediment dissipated rapidly, with half-lives of 13 h in the 3.0% TOC sediment and 18 h in the 1.5% TOC sediment. Both toxicity and the concentration of MON 0818 in overlying water decreased more rapidly in microcosms containing sediment with the higher percent TOC and clay and with a higher microbial biomass. Mortality of D. magna was significantly correlated with surfactant concentrations in the overlying water. These results indicate that the toxicity of the POEA surfactant in water rapidly declines in the presence of sediment due to a reduction in the surfactant concentration in the overlying water above the sediment.     

Metallothionein induction and cadmium uptake in Bufo arenarum embryos following an acclimation protocol

Bufo arenarum embryos at the end of their embryonic development were acclimated to cadmium (Cd) by means of a 10-day treatment protocol. Embryos were processed for metallothionein (Mt) isolation and Cd and zinc (Zn) contents were measured. The results showed that: (1) the uptake of Cd in the experimental embryos was 7 microg/g embryo (wet weight) representing a bioaccumulation of Cd 255 times higher than in the maintaining medium; (2) a major Mt-like fraction was Cd-induced 7.8 times that in control embryos; two other protein fractions also bound Cd and Zn but were induced by Cd only about 2 and 1.4 times; (3) the Zn concentration was about 44 microg Zn/g embryo (wet weight) and did not change significantly (p>0.01) in the experimental embryos with respect to controls, but in acclimated embryos the essential metal was released from the Mts. The enhanced Mt synthesis and release of Zn from the native Mts are discussed in relation to the acclimation phenomenon.     

Stage dependent susceptibility to lead in Bufo arenarum embryos

The stage dependent susceptibility to lead in amphibian development was studied by exposing Bufo arenarum embryos during neurulae, neuromuscular activity and gill circulation stages for twenty hours to 1 ppm Pb(2+). Survival, malformations and behavioral disorders were evaluated. The embryonic susceptibility to lead was markedly stage dependent. The survival at the neuromuscular activity stage was approximately half that of the other two periods; concerning malformations, the gill circulation stage was the least sensitive. The observed malformations consisted of failed closure of neural tube, hydropsy, small and cylindrical tails, reduced body size and incurvations in the body axis. Some alterations occurred in all experimental groups and therefore were considered non-dependent on the period of treatment. In all experimental embryos, neurological disorders such as trembles and loss of equilibrium were observed.     

The mutagenic potentials of tap water samples in Shanghai

The tap water samples were collected from the users' ends in several areas of Shanghai, which is located in Taihu Lake basin, Eastern China. Source water samples were also collected from two municipal source water facilities at the same time. Samples were assayed by three different short-term mutagenicity test systems: Salmonella/microsome assay (Ames test), the Arabinose resistance test (Ara test) and the SOS/umu test. The data showed that two source water samples did not display direct mutagenic potentials. Two tap water samples from city north, which were directly from Yangtze River, were also not mutagenic. Water samples from city south and middle which used source water originating from Taihu Lake were proved to be contaminated with mutagenic potentials by three different assay techniques. The boiled water displayed an even stronger mutagenic potential compared to its original tap water. The molecular mechanism of mutagenicity was associated with a reading frame-shifting potential. GC-MS analysis of tap water extracts from city middle and corresponding source water was compared. Qualitatively similar spectra were observed except for the peaks of three chlorinated aromatic hydrocarbon compounds, which existed only in the tap water. Since the water source has been polluted, raw water was heavily chlorinated in order to sterilize. More toxic compounds, including mutagens, might form during the multi-chlorination. Caution about the possibility of elevated cancer risks in the population that consumes heavily chlorinated water should be kept in mind. A cohort study in the residents of Shanghai is required.     

Nickel tissue residue as a biomarker of sub-toxic exposure and susceptibility in amphibian embryos

Although low level exposure to physicochemical agents is the most common environmental scenario, their effects on living organisms are very controversial. However, there is an increasing need to integrate low level exposures from risk assessment to remediation purposes. This study focus on the possibility to employ Ni tissue residue values as biomarkers of sub-toxic exposure and susceptibility to this metal in a range of almost pristine to sub-toxic concentrations for Rhinella arenarum embryos. For that purpose, three batches of amphibian embryos were pretreated during 10 days with three increasing concentrations of Ni starting in 2, 8 and 20 microg Ni(2+) L(-1) and ending in 16, 64 and 160 microg Ni(2+) L(-1) (in natural fresh waters this value ranges from 2 to 10 microgL(-1); the LC(50)-24h for R. arenarum is 26.2mg Ni(2+) L(-1)). For the experimental conditions, the Ni tissue residue values at 360 h post exposure were 0.5, 2.1 and 3.6 microg Ni g(-1) embryo w/w, respectively, corresponding to BCFs of 31, 33 and 23. The susceptibility to Ni in those experimental embryos was evaluated by means of challenge exposures to three lethal concentrations of this metal (10, 20 and 30 mg Ni(2+) L(-1)), registering survival during the following 10 days of treatment. As a general pattern, the lower, intermediate and higher pretreatments with Ni resulted in enhanced, neutral and adverse effects on embryonic survival, respectively. Thus, sub-toxic exposure to Ni could modify the resistance of the amphibian embryo to this metal and Ni tissue residue values could be considered as biomarkers of both, exposure and susceptibility.     

Deriving freshwater quality criteria for 2,4,6-trichlorophenol for protection of aquatic life in China

Freshwater quality criteria of 2,4,6-trichlorophenol (2,4,6-TCP) were developed with particular reference to the aquatic biota in China, and based on USEPA's guidelines. Acute toxicity tests were performed on nine different domestic species indigenous to China to determine 48 h LC(50) and 96 h LC(50) values for 2,4,6-TCP. In addition, 21 d survival-reproduction test with Daphnia magna, 30 d embryo-larval test with Carassius auratus, 60 d fry-juvenile test with Ctenopharyngodon idellus, 30 d early life stage test with Bufo bufo gargarizans and 96 h growth inhibition test with Scenedesmus obliqaus were also conducted to estimate lower chronic limit and upper chronic limit values. The final acute value (FAV) was 2.01 mg/l 2,4,6-TCP. Acute-to-chronic ratios ranged from 5.01 to 12.2. The final chronic value (FCV) and the final plant value (FPV) of 2,4,6-TCP were 0.226 and 2.24 mg/l respectively. Based on FAV, FCV and FPV for 2,4,6-TCP, a criteria maximum concentration of 1.01 mg/l and a criterion continuous concentration of 0.226 mg/l were derived. The results of this study provide useful data for deriving national or local water quality criteria for 2,4,6-TCP based on aquatic biota in China.     

Toxicity of acid-sulphate soil leachate and aluminium to the embryos and larvae of Australian bass (Macquaria novemaculeata) in estuarine water

The toxicity of leachate water from acid-sulphate soil to the early life stages of Australian bass, Macquaria novemaculeata, incubated in seawater was evaluated. Acid-sulphate soil leachate water (pH> or =6.8) delayed the hatching of fertilised eggs, but after 48 h the per cent hatching was normal. In comparison, acidic saline water (25 per thousand salinity) at pH 4.0 or less prevented embryos from hatching. The survival of yolk-sac larvae exposed to acid-sulphate soil leachate water at a concentration of 32% in seawater and an initial pH of 7.2, was significantly different to controls after 96 hours. In corresponding tests with only acidified saline water (20 per thousand salinity), pH levels equal to or below 5.0 killed yolk-sac larvae after 96 h exposure. Aluminum showed a pH dependent toxicity to yolk-sac larvae, with added aluminium as low as 200 microg litre(-1) having a significant effect on larval survival at pH 5.5, and concentrations of 600-800 microg litre(-1) having a significant effect on larval survival at an initial pH range of 6.0 < pH < 6.8. It was concluded that significant mortality of the early life stages of Australian bass would occur if they are exposed to acid-sulphate soil leachate that results in a pH in the receiving estuarine water below 5.5, or when the pH is below 6.8 and aluminium is present at a total concentration of 800 microg litre(-1) or greater.     

An assessment of the potential toxicity of runoff from an urban roadscape during rain events

Goal, Scope and Background

The potential negative impact of urban storm water on aquatic freshwater ecosystems has been demonstrated in various studies with different types of biological methods. There are a number of factors that influence the amount and bioavailability of contaminants in storm water even if it is derived from an area with a fairly homogenous land use such as a roadscape where a variation in toxicity during rain events might be expected. There are only a few previous investigations on the toxicity of highway runoff and they have not explored these issues extensively. The main objective of this study is therefore to characterize the potential toxicity of highway runoff during several rain events before it enters a detention pond in VästerOas, Sweden, using laboratory bioassays with test organisms representing various functional groups in an aquatic ecosystem. The results are to be used for developing a monitoring program, including biological methods.

Materials and Methods

The storm water was sampled before the entrance to a detention pond, which receives run-off from a highway with approximately 20,000 vehicles a day. The drainage area, including the roadscape and vegetated areas, is 4.3 ha in size. Samples for toxicity tests were taken with an automatic sampler or manually during storm events. In total, the potential toxicity of 65 samples representing 15 different storm events was determined. The toxicity was assessed with 4 different test organisms; Vibrio fischeri using the Microtox® comparison test, Daphnia magna using Daphtoxkit-F?agna, Thamnocephalus platyurus using the ThamnotoxkitF? and Lemna minor, duckweed using SS 028313.

Results and Discussion

Of the 65 samples, 58 samples were tested with DaphniatoxkitF?agna, 57 samples with the Microtox® comparison test, 48 samples with ThamnotoxkitF? and 20 samples with Lemna minor, duckweed. None of the storm water samples were toxic.No toxicity was detected with the Lemna minor test, but in 5 of the 23 samples tested in comparison to the control a growth stimulation of 22–46% was observed. This is in accordance with the chemical analysis of the storm water, which indicated rather large concentrations of tot-N and tot-P. In addition to the growth stimulation, morphological changes were observed in all the 5 samples from the winter event that was sampled. The lack of toxicity observed in our study might be due to a lower traffic intensity (20,000 vehicles/day) at the site and the trapping of pollutants in the vegetated areas of the roadscape, resulting in much smaller loads of pollutants in the storm water than in some previous studies.

Conclusions

Ecotoxicological evaluations of storm water including run off from rain events from urban roadscape studies clearly reveal that toxicity may or may not be detected depending upon site, storm condition and the test organism chosen. However, storm water might not be as polluted as previously reported nor may the first flush be such a widespread phenomenon as we originally expected. In this study, there was also a good correlation between pollutant load measured and the lack of toxicity. The test organisms chosen in this study are commonly used in effluent control programs in Sweden and other countries, which makes it possible to compare the results with those from other effluents. In this study, only acute toxicity tests were used and further studies using chronic toxicity tests, assays for genotoxic compounds or in situ bioassays might reveal biological effects at this site. Furthermore, most of the samples were taken in spring, summer or fall and it is possible that winter conditions might alter the constituents in the storm water and, thus, the toxicity of the samples.

Recommendations and Perspectives

Considering the complex nature of run off from urban roadscapes, it will be virtually impossible to evaluate properly the potential hazard of particular storm water and the efficiency of a particular treatment strategy from only physical and chemical characterizations of the effluent. Therefore, despite the lack of toxicity detected in this study, it is recommended that toxicity tests or other biological methods should be included in evaluations of the effects of runoff from roadscapes.

     

Estimation of ambient chronic toxicity in a polluted creek system

Ambient water toxicity estimations were conducted in Piles Creek as part of an ecological risk assessment study. This creek is part of a highly polluted estuarine system located near Linden, New Jersey. An upstream and a downstream site in the creek were evaluated for effects on survival, growth and sexual maturity of the estuarine mysid, Mysidopsis bahia. Manasquan Inlet, Manasquan, New Jersey, served as the reference site. Seven-day screening toxicity tests were conducted once a month over a three month period. Results indicate that survival of mysids was not affected in any toxicity test. Mysid growth was significantly reduced at both of the test sites, in two out of three trials. Sexual maturity was shown to be adversely affected in mysids exposed to ambient waters from both test sites throughout the duration of the study.     

The acute toxicity of agricultural surfactants to the tadpoles of four Australian and two exotic frogs

Nonionic surfactants are frequently incorporated into pesticide formulations, and are therefore a group of chemicals to which amphibians may be exposed in agricultural or urban landscapes. However, little is known about the effects of surfactant exposure in amphibians. Feeding stage tadpoles of Bufo marinus, Xenopus laevis and four species of Australian frogs (Crinia insignifera, Heleioporus eyrei, Limnodynastes dorsalis and Litoria moorei) were exposed to nonylphenol ethoxylate (NPE) and alcohol alkoxylate in static-renewal acute toxicity tests. All species exhibited nonspecific narcosis following exposure to both these surfactants. The 48-h EC50 values for NPE ranged between 1.1 mg/l (mild narcosis) and 12.1 mg/l (full narcosis). The 48-h EC50 values for alcohol alkoxylate ranged between 5.3 mg/l (mild narcosis) and 25.4 mg/l (full narcosis). Replicate acute toxicity tests with B. narinus exposed to NPE at 30 degrees C over 96 h indicated that the narcotic effects were not particularly time dependant. The mean 24, 48, 72, and 96-h EC50 (mild narcosis) values were 3.6, 3.7, 3.5 and 3.5 mg/l, respectively. The mean 24, 48, 72 and 96-h EC50 (full narcosis) were 4.0, 4.1, 4.2 and 4.0, respectively. Acute toxicity tests with B. marinus exposed to NPE at 30 degrees C under conditions of low dissolved oxygen (0.8-2.3 mg/l) produced a two to threefold increase in toxicity.     

Effects of heavy metals on sea urchin embryo development. 1. Tracing the cause by the effects

The toxicity of the polluted waters originating from a disused lead mine was evaluated using both sea urchin bioassays and heavy metal analysis. Samples from three polluted waters (a seawater and two freshwaters) were collected from the mine area and one seawater sample was taken from a non-contaminated reference site. The test waters contained higher concentrations of heavy metals such as manganese, lead, cadmium, zinc, chromium, nickel, iron, and copper than did ambient seawater. The three test waters had inhibitory effects, in a dose-dependent manner, on the first cleavage of sea urchin embryos and on pluteus formation during the development. Some malformations, such as a radialized pluteus, exo-gastrula, and spaceship Apollo-like embryos were induced by the test waters without dilution. Zinc alone also induced the same anomaly. Zinc in the test seawater was ascertained as one of the metals that caused the anomalies, but not all of the toxicity was caused by zinc. It was speculated that interactive effects, involving zinc and possibly manganese and nickel, were occurring.     

Toxicity of urban highway runoff in Shanghai to Zebrafish (Danio rerio) embryos and luminous bacteria (Vibrio qinghaiensis.Q67)

Pollution from urban highway runoff has been identified as one of the major causes of the deterioration of receiving water quality. The purpose of this study is to assess the toxicity of urban storm water samples in Shanghai using the zebrafish (Danio rerio) embryo test and the bacterial luminescence (Vibrio qinghaiensis) assay. The toxicity of highway runoff from seventeen storm events was investigated in both grab and composite samples. Zebrafish embryos were exposed to the runoff samples and development parameters including lethality, spontaneous movements in 20 s, heart beat rate, hatching rate, and abnormality of zebrafish embryos were observed after 24, 48, 72, and 96 h of exposure. Inhibition rates of luminescence intensity were also recorded. The results showed that in the zebrafish embryo toxicity tests, both grab and composite samples increased the lethality, reduced the percentage with spontaneous movements and heart beats, inhibited the hatching of embryos, and induced morphological abnormalities. In the Vibrio qinghaiensis toxicity test, all the grab samples inhibited the luminescence, while some of the composite samples promoted it, which indicated that different types of toxicants might have been affecting the species. The multivariate statistics analysis indicated that heavy metal (zinc, manganese, and copper) and PAHs might mainly contribute to the toxicity of runoff samples.     

Deriving freshwater quality criteria for 2,4-dichlorophenol for protection of aquatic life in China

Freshwater quality criteria for 2,4-dichlorophenol (2,4-DCP) were developed with particular reference to the aquatic biota in China, and based on USEPA's guidelines. Acute toxicity tests were performed on nine different domestic species indigenous to China to determine 48-h LC50 and 96-h LC50 values for 2,4-DCP. In addition, 21 day survival-reproduction tests with Daphnia magna, 30-day embryo-larval tests with Carassius auratus, 60 day fry-juvenile test with Ctenopharyngodon idellus, 30 d early life stage tests with Bufo bufo gargarizans and 96 h growth inhibition tests with Scenedesms obliqaus were conducted, to estimate lower chronic limit (LCL) and upper chronic limit (UCL) values. The final acute value (FAV) was 2.49 mg/l 2,4-DCP. Acute-to-chronic ratios (ACR) ranged from 3.74 to 22.5. The final chronic value (FCV) and the final plant value (FPV) of 2.4-DCP were 0.212 mg/l and 7.07 mg/l respectively. Based on FAV, FCV, and FPV, a criteria maximum concentration (CMC) of 1.25 mg/l and a criterion continuous concentration (CCC) of 0.212 mg/l were derived. The results of this study provide useful data for deriving national or local water quality criteria for 2,4-DCP based on aquatic biota in China.     

Residue levels of chlorinated hydrocarbon compounds in water and sediment samples from Nile branches in the Delta, Egypt.

Water and sediment samples were collected from eight different locations along the River Nile and its branches. Residues of hexachlorocyclohexane (HCH's), hexachlorobenzene (HCB), DDT's, cyclodienes and polychlorinated biphenyls (PCB's) were analyzed by GLC. Data on Grand Total (GT) concentration values pointed out that Rosetta Branch was more polluted with all components than Demietta Branch. Kafr El-Ziate was the most polluted location showing 1355.8 ng/L for water and 7396.9 ng/g for sediments, while Delta Barrage was the least polluted site. The concentrations of gamma-HCH were higher than the other isomers (alpha- and beta-HCH) in all studied sites. The results showed that HCB was the smallest pollutant at all locations on comparison with other chlorinated hydrocarbons. El-Mansoura, Rosetta and Kafr El-Ziate sites contained the highest concentrations of DDT's in both water and sediment samples. P,P'-DDE was dominate in all locations of water samples, but P,P'-DDT was in sediment samples. Also, the results showed the prominent presence of cyclodienes when compared with the other OC's compounds in sediment samples, especially Aldrin. Kafr El-Ziate was the most polluted location by PCB's, particularly the Ar1242. However, there were increasing levels of chlorinated hydrocarbons in the sediment samples parallel to percentage extractable organic matter (% EOM). Sediment/water ratios were calculated for all locations.