Toxicity of water and sediment from stormwater retarding basins to Hydra hexactinella

Hydra hexactinella was used to assess the toxicity of stormwater and sediment samples from three retarding basins in Melbourne, Australia, using an acute test, a sublethal test, and a pulse test. Stormwater from the Avoca St retarding basins resulted in a LC50 of 613 ml/L, NOEC and LOEC values of 50 ml/L and 100 ml/L, while the 7 h pulse exposure caused a significant increase in the mean population growth rate compared to the control. Water samples from the two other retarding basins were found non-toxic to H. hexactinella. This is the first study to employ sediment tests with Hydra spp. on stormwater sediments and a lower population growth rate was observed for organisms exposed to sediment from the Avoca St retarding basins. The behavioral study showed that H. hexactinella tended to avoid the sediment-water interface when exposed to sediment from all retarding basins, compared to the reference sediment. Further work is needed to determine the long-term effects of stormwater polluted sediments and acute effects due to organism exposure to short-term high concentrations during rain events.     

Field validation of a battery of biomarkers to assess sediment quality in Spanish ports

Two marine invertebrates, the crab Carcinus maenas and the clam Ruditapes philippinarum, were used as bioindicator species to assess contamination when exposed in situ to sediment from different sites from four Spanish ports Cadiz (SW Spain), Huelva (SW Spain), Bilbao (NE Spain) and Pasajes (NE Spain). In an attempt to determine sediments toxicity, a combination of exposure biomarkers was analyzed in both species: metallothionein-like-proteins (MTLPs), ethoxyresorufin O-deethylase (EROD), glutathione S-transferase activity (GST), glutathione peroxidase (GPX) and glutathione reductase (GR). In parallel, physical and chemical characterization of the different sediments was performed and biological responses related to the contaminants. Significant induction of MTLPs was observed when organisms were exposed to metal contaminated sediments (port of Huelva), and EROD and GPX activities after exposure to sediments containing organic compounds (port of Bilbao and Pasajes). No significant interspecies differences were observed in biomarker responses except for the GST and GR.     

The interactive effects of low pH, toxic metals, and DOC on a simulated temporary pond community

The effects of pH, potentially toxic metals, and dissolved organic carbon (DOC) on a freshwater, palustrine wetland assemblage (three amphibian species, one mosquito genus, and 18 genera of algae) were examined in 500 liter outdoor mesocosms. The design was fully factorial and exposure levels were set to represent concentrations that occur naturally in temporary ponds in central Pennsylvania, an acid-impacted region of the USA. Water chemistry was precisely regulated by use of an artificial pond water rather than using stream water or well water with partially unknown composition. Jefferson (Ambystoma jeffersonianum) and spotted salamanders (A. maculatum) were negatively impacted by low pH and high metal concentrations. Wood frogs (Rana sylvatica) were negatively impacted by high DOC and low pH. These negative effects included increased time to metamorphosis and decreased survival and wet body mass at metamorphosis. Mosquito emergence was unaffected by pH, metals, or DOC. All three abiotic factors (metals, pH, and DOC) interacted to determine algal taxonomic composition. Hence, abiotic conditions may determine amphibian reproductive success both directly and indirectly, via effects on algae, since a primary food source of salamanders, zooplankton, are affected by changes in algal composition. These complex interactions should be considered in evaluating the possible toxicity of pond waters to fauna and flora. Until now, pH alone has been considered the primary limiting factor for amphibians breeding in temporary ponds.     

Laboratory study highlights the key influences of stormwater sediment thickness and bioturbation by tubificid worms on dynamics of nutrients and pollutants in stormwater retention systems

In urban area, the accumulation of polluted stormwater sediments (SWS) in retention ponds may be a source of dissolved pollutants and nutrients for the aquatic ecosystems. Our objective was to quantify the influence of the thickness of SWS layer and the occurrence of tubificid worms on organic matter processing (O(2) uptake and fluxes of NH(4)(+), NO(3)(-), PO(4)(3-), and dissolved organic carbon between sediment and water), releases of 17 PAHs and 4 heavy metals, and microbial characteristics. Results showed that oxidation of SWS organic matter (O(2) and NO(3)(-) uptakes) and releases of nutrients were significantly increased by the quantity of accumulated SWS and the worm bioturbation. Releases of acenaphtene and naphthalene from sediments were significantly increased by the thickness of the SWS layer. In contrast, tubificid worms did not promote the mobilization of pollutants. In conclusion, biological activities and stormwater sediment characteristics need to be assessed to quantify the fate of pollutants and nutrients in stormwater retention ponds.     

Potential re-colonisation by cladocerans of an acidic tropical pond

To predict how re-colonisation of acidified lakes will proceed, at least two approaches are possible: (i) to compare the life history traits of candidate species and determine which one has the highest fitness, and (ii) to simulate a more realistic scenario carrying out experiments with the grouping of the candidate species, so that the intrinsic rate of natural increase of each species is integrated with its sensitivity to low pH and its ability to compete with the other candidate populations. The objective of the present study was to investigate the future re-colonisation of such acidified systems, taking as case-study a tropical pond (Lagoa das Dunas, Camaçari, BA, Brazil) and four species of cladocerans occurring in nearby water bodies (Ceriodaphniacornuta, Ceriodaphniasilvestrii, Latonopsisaustralis and Macrothrix elegans), by comparing the two above mentioned approaches. The second approach included two sets of in situ microcosms experiments, one simulating the re-colonisation by immigrating ephippia, thus using neonates of each species as colonisers, and another simulating the immigration of adults. Both these simulations followed nearly the same trends. The integration of the effects of a higher temperature, a different photoperiod and species competition determined differences in the species densities ranking between the two approaches: life history versus microcosms. The densities of C.cornuta in the microcosms matched the biphasic concentration/response hormetic model, in the simultaneous presence of two increasingly intense stressors (interspecific competition and acidity), with a low-dose stimulation and a high-dose inhibition. The present study provided, thus, a further support to the acceptance of hormesis in ecotoxicology, also at the population level in multispecies experiments.     

Distribution and bioaccumulation of selenium in aquatic microcosms

Closed-system microcosms were used to study factors affecting the fate of selenium (Se) in aquatic systems. Distribution and bioaccumulation of Se varied among sediment types and Se species. A mixture of dissolved (75)Se species (selenate, selenite and selenomethionine) was sorbed more rapidly to fine-textured, highly organic pond sediments than to sandy riverine sediments. Sulfate did not affect the distribution and bioaccumulation of (75)Se over the range 80-180 mg SO(4) liter(-1). When each Se species was labeled separately, selenomethionine was lost from the water column more rapidly than selenate or selenite. Selenium lost from the water column accumulated primarily in sediments, but volatilization was also an important pathway for loss of Se added as selenomethionine. Loss rates of dissolved Se residues were more rapid than rates reported from mesocosm and field studies, suggesting that sediment: water interactions are more important in microcosms than in larger test systems. Daphnids accumulated highest concentrations of Se, followed by periphyton and macrophytes. Selenium added as selenomethionine was bioaccumulated preferentially compared to that added as selenite or selenate. Organoselenium compounds such as selenomethione may thus contribute disproportionately to Se bioaccumulation and toxicity in aquatic organisms.     

Chemical status of selenium in evaporation basins for disposal of agricultural drainage

Evaporation basins (or ponds) are the most commonly used facilities for disposal of selenium-laden saline agricultural drainage in the closed hydrologic basin portion of the San Joaquin Valley, California. However concerns remain for potential risk from selenium (Se) toxicity to water fowl in these evaporation basins. In this study, we examined the chemical status of Se in both waters and sediments in two currently operating evaporation pond facilities in the Tulare Lake Drainage District. Some of the saline ponds have been colonized by brine-shrimp (Artemia), which have been harvested since 2001. We evaluated Se concentration and speciation, including selenate [Se(VI)], selenite [Se(IV)], and organic Se [org-Se or Se(-II)] in waters and sediment extracts, and fractionation (soluble, adsorbed, organic matter (OM)-associated, and Se(0) and other resistant forms) in sediments and organic-rich surface detrital layers from the decay of algal blooms. Selenium in ponds without vascular plants exhibited similar behavior to wetlands with vascular plant present, indicating that similar Se transformation processes and mechanisms had resulted in Se immobilization and an increase of reduced Se species [Se(IV), org-Se, and Se(0)] from Se(VI)-dominated input waters. Selenium concentrations in most pond waters were significantly lower than the influent drainage water. This decrease of dissolved Se concentration was accompanied by the increase of reduced Se species. Selenium accumulated preferentially in sediments of the initial pond cell receiving drainage water. Brine-shrimp harvesting activities did not affect Se speciation but may have reduced Se accumulation in surface detrital and sediments.     

Chemical fractionation of Cu and Zn in stormwater, roadway dust and stormwater pond sediments

This study evaluated the chemical fractionation of Cu and Zn from source to deposition in a stormwater system. Cu and Zn concentrations and chemical fractionation were determined for roadway dust, roadway runoff and pond sediments. Stormwater Cu and Zn concentrations were used to generate cumulative frequency distributions to characterize potential exposure to pond-dwelling organisms. Dissolved stormwater Zn exceeded USEPA acute and chronic water quality criteria in approximately 20% of storm samples and 20% of the storm duration sampled. Dissolved Cu exceeded the previously published chronic criterion in 75% of storm samples and duration and exceeded the acute criterion in 45% of samples and duration. The majority of sediment Cu (92-98%) occurred in the most recalcitrant phase, suggesting low bioavailability; Zn was substantially more available (39-62% recalcitrant). Most sediment concentrations for Cu and Zn exceeded published threshold effect concentrations and Zn often exceeded probable effect concentrations in surface sediments.     

北运河表层沉积物对重金属Cu、Pb、Zn的吸附

首先分析了北运河6个采样点表层沉积物中重金属含量及相关基本特征。通过实验室模拟实验,利用分配系数Kd评价沉积物对重金属Cu、Pb、Zn的吸附特性,进一步考察了水体pH变化和有机质对重金属在北运河沉积物上吸附的影响。结果表明,沉积物中重金属的含量顺序为Zn>Cu>Pb,去除有机质后,沉积物对重金属的吸附能力显著降低,但各采样点中的重金属含量,沉积物对重金属吸附能力,以及沉积物中的有机质含量并没有明显相关性,这可能是因为不同采样点中有机质种类与结构不同导致的。总之,北运河沉积物对Pb有很强的吸附能力,其次是Cu和Zn,而且,Cu、Zn、Pb的吸附量随着pH的升高逐渐增大,水体pH值对于Zn的吸附影响更大。     

Characterisation of esterases as potential biomarkers of pesticide exposure in the lugworm Arenicola marina (Annelida: Polychaeta)

Here, we identify and characterise cholinesterase (ChE) and carboxylesterase (CbE) activities in the body tissues of the sediment dwelling worm Arenicola marina. Exposure to the organophosphorus pesticide azamethiphos yielded an in vitro IC50 of 5 microg l(-1) for propionylcholinesterase (PChE). PChE was significantly inhibited in vivo after a 10 day exposure to 100 microg l(-1) azamethiphos, equivalent to the recommended aquatic application rate (ANOVA; F=2.75, P=0.033). To determine sensitivity to environmental conditions, A. marina were exposed for 10 days to field collected sediments. PChE activity was significantly lower in worms exposed to sediments from an estuary classified to be at high risk from point source pollution by the UK Environment Agency (ANOVA; F=15.33, P<0.001). Whilst causality cannot be directly attributed from these latter exposures, they provide an important illustration of the potential utility of esterase activity as a biomarker of environmental quality in this ecologically relevant sentinel species.     

Effects of ultraviolet radiation on toad early life stages

Background  Exposure to harmful levels of ultraviolet-B radiation (UVB), a component of solar radiation, has been suggested as a potential cause of amphibian declines. Methods  We measured solar radiation (UVB, ultraviolet-A, and visible) wavebands in breeding ponds of Bufo boreas (boreal toad, a montane species that has undergone severe population declines) and Bufo woodhousii (Woodhouse’s toad, a plains toad that has not experienced declines) and examined tolerances of these species to simulated solar UVB exposures in the laboratory. Results  We found larvae of both species to be tolerant of simulated solar UVB in excess of solar UVB levels observed in their breeding ponds. B. boreas tadpoles were more tolerant of simulated solar UVB exposure than B. woodhousii tadpoles, possibly because of greater amounts of photoprotective melanin in B. boreas skin. Conclusions  UVB levels observed in B. boreas habitats do not currently appear to constitute a threat to the survival of these animals; however, long-term (>1 month) exposure to UVB levels comparable to levels associated with the water interface appears to reduce survival in B. woodhousii tadpoles. Therefore, future increases in surface and water column UVB radiation in bufonid habitats might pose significant survival risks to B. boreas or B. woodhousii populations.     

From wetland to farm and back again: phosphorus dynamics of a proposed restoration project

We studied the phosphorus dynamics in a former wetland, which had been converted to a celery farm, and now consists of two shallow, flooded ponds that are being proposed for aquatic habitat restoration. However, like many agricultural areas, this site is plagued by phosphorus legacy issues. Proposed restoration includes hydrologic reconnection of these ponds to its adjacent stream, which are now isolated from one another by an earthen berm, to create a wetland complex. One of the two flooded ponds was partially dredged, whereas the other one has remained undredged. Water column, sediment pore water, and sediment total phosphorus concentrations were significantly greater in the undredged pond compared to the dredged pond, but in both cases phosphorus levels in the water columns (mean TP 929 vs. 133 μg/L in undredged vs. dredged ponds, respectively) would exacerbate downstream water quality issues if hydrologic reconnection occurred without first addressing the phosphorus issue. Sediment isotherm and maximum sorption data indicated that the sediments are close to phosphorus saturation in the undredged pond; simulated dredging of the cores revealed that exposure of deeper sediment layers would increase sorption capacity. Pore water SRP concentrations increased with sediment depth and were significantly greater in the undredged vs. dredged pond at both the 1–4-cm depth (2249 vs. 112 μg/L) and 14–17-cm depth (5506 vs. 222 μg/L). This study provides a framework for other projects that need to balance the competing demands of habitat restoration vs. water quality when restoring wetlands that have been converted to agricultural production.

     

Mercury species of sediment and fish in freshwater fish ponds around the Pearl River Delta, PR China: human health risk assessment

This study investigated total mercury (THg) and methylmercury (MeHg) concentrations in five species of freshwater fish and their associated fish pond sediments collected from 18 freshwater fish ponds around the Pearl River Delta (PRD). The concentrations of THg and MeHg in fish pond surface sediments were 33.1-386 ng g(-1) dry wt and 0.18-1.25 ng g(-1) dry wt, respectively. The age of ponds affected the surface sediment MeHg concentration. The vertical distribution of MeHg in sediment cores showed that MeHg concentrations decreased with increasing depth in the top 10 cm. In addition, a significant correlation was observed between %MeHg and DNA from Desulfovibrionacaea or Desulfobulbus (p<0.05) in sediment cores. Concentrations of THg and MeHg in fish muscles ranged from 7.43-76.7 to 5.93-76.1 ng g(-1) wet wt, respectively, with significant linear relationships (r=0.97, p<0.01, n=122) observed between THg and MeHg levels in fish. A significant correlation between THg concentrations in fish (herbivorous: r=0.71, p<0.05, n=7; carnivorous: r=0.77, p<0.05, n=11) and corresponding sediments was also obtained. Risk assessment indicated that the consumption of largemouth bass and mandarin fish would result in higher estimated daily intakes (EDIs) of MeHg than reference dose (RfD) for both adults and children.     

Impacts of weathered tire debris on the development of Rana sylvatica larvae

Highway runoff has the potential to negatively impact receiving systems including stormwater retention ponds where highway particulate matter can accumulate following runoff events. Tire wear particles, which contain about 1% Zn by mass, make up approximately one-third of the vehicle derived particulates in highway runoff and therefore may serve as a stressor to organisms utilizing retention ponds as habitat. In this study, we focused on the potential contribution of tire debris to Zn accumulation by Rana sylvatica larvae and possible lethal or sublethal impacts resulting from exposure to weathered tire debris during development. Eggs and larvae were exposed to aged sediments (containing either ZnCl2 or tire particulate matter, both providing nominal concentrations of 1000 mg Zn kg(-1)) through metamorphosis. Water column Zn was elevated in both the ZnCl2 and tire treatments relative to the control treatment, indicating that aging allowed Zn leaching from tire debris to occur. Tissue Zn was also elevated for the ZnCl2 and tire treatments indicating that Zn in the treatments was available for uptake by the amphibians. Exposure to both ZnCl2 and tire treatments increased the time for larvae to complete metamorphosis in comparison with controls. We also observed that the longer the organisms took to complete metamorphosis, the smaller their mass at metamorphosis. Our results indicate that Zn leached from aged tire debris is bioavailable to developing R. sylvatica larvae and that exposure to tire debris amended sediments can result in measurable physiological outcomes to wood frogs that may influence population dynamics.     

Relationship between copper speciation in sediments and bioaccumulation by marine bivalves of Taiwan

This paper evaluates the relationships between copper species in sediments and accumulation by the purple clam (Hiatula diphos) and venus clam (Gomphina aeguilatera) collected from the field and culture (aquaculture) ponds in the polluted coastal area of Lukang, Taiwan. Sediment was sampled along with the molluscs, including oysters (Crassostrea gigas), purple clams (Hiatula diphos), rock-shells (Thais clavigera), venus clams (Gomphina aeguilatera), and hard clams (Meretrix lusoria), from two unique environments of Lukang during the period from August 1993 to July 1994. The data indicate that the total copper concentrations in sediments from culture ponds (185 microg g(-1)) was higher than those of the field (44.0 microg g(-1)). Copper species in sediments were analyzed by a sequential leaching technique. Results show that concentrations of various copper species in the sediments are in the range of 1.14 +/- 0.59 to 13.2 +/- 22.4 microg g(-1) and 0.36 +/- 0.24 to 133 +/- 36.7 microg g(-1) for the two environments, respectively. Also the exchangeable copper in sediment from culture ponds was 15 times higher than that from the field. In addition, the sum of exchangeable and copper carbonates had the highest percentages of copper in both the pond sediment (86.6 %) and the field sediment (50.7 %). Maximum copper concentrations (309 +/- 35.1 microg g(-1)) in oysters were much higher than those in the other benthic organisms by about 4-127 times. Similarly, the data also showed that copper concentrations in Thais clavigera were 12-32 times higher than those in other benthic organisms. Copper concentrations in various benthic organisms differed significantly (p < 0.05) from that in Thais clavigera. This capacity makes Thais clavigera a potential candidate for monitoring copper in marine sediments. In terms of copper species, the best correlation was generally obtained between copper carbonates in sediments and copper concentrations in Hiatula diphos (r = 0.886*). A strong multiple regression correlation (p < 0.05, r2 = 0.7894) also indicates that the copper carbonates may dominate as the available form of copper to Hiatula diphos from various environments in the Lukang coastal area under natural physicochemical conditions.     

Foraminiferal proxies for pollution monitoring in moderately polluted harbors

Benthic foraminifera are increasingly used as environmental bio-indicators, especially in polluted environments where their sensitivity to pollutants may be expressed by a modification of the assemblages. Eighteen sediment samples were collected in September 2000 in five harbors located in moderately polluted estuaries on the coast of Vendée (France) for the study of foraminiferal assemblages. Ten heavy metals and 13 PAH have been analyzed from the sediments. The marine to continental estuarine gradient has a prevalent influence on the foraminiferal distribution. However, the results show that foraminiferal density and species richness of the assemblages decrease with an increase in heavy metal and PAH concentration, and therefore may be used as pollution indicators. Moreover, the more polluted areas are dominated by the tolerant pioneer species Haynesina germanica that may be used as bio-indicator of pollution, mainly in the uppermost areas.     

Survival of spotted salamander eggs in temporary woodland ponds of coastal Maryland

Temporary ponds on the Atlantic Coastal Plain in maryland were characterized according to water chemistry, rain input, phytoplankton, zooplankton and use by the spotted salamander Ambystoma maculatum during March-October 1983-1984. Neither the number of egg masses per unit of pond surface (abundance) nor the survival of spotted salamander embryos was significantly correlated (P>0.05) with pond pH. Rainfall during May-July significantly increased the hydrogen ion concentration of 5 of 11 ponds evaluated for the impact of rainfall during the previous 48h and the previous week. Survival of egg masses transferred among eight ponds with pH3.66-4.45 and one pond with pH5.18 was significantly reduced (P相似文献   

Effect of field exposure to 38-year-old residual petroleum hydrocarbons on growth, condition index, and filtration rate of the ribbed mussel, Geukensia demissa

In September 1969, the Florida barge spilled 700,000 L of No. 2 fuel oil into the salt marsh sediments of Wild Harbor, MA. Today a substantial amount, approximately 100 kg, of moderately degraded petroleum remains within the sediment and along eroding creek banks. The ribbed mussels, Geukensia demissa, which inhabit the salt marsh creek bank, are exposed to the spilled oil. Examination of short-term exposure was done with transplantation of G. demissa from a control site, Great Sippewissett marsh, into Wild Harbor. We also examined the effects of long-term exposure with transplantation of mussels from Wild Harbor into Great Sippewissett. Both the short- and long-term exposure transplants exhibited slower growth rates, shorter mean shell lengths, lower condition indices, and decreased filtration rates. The results add new knowledge about long-term consequences of spilled oil, a dimension that should be included when assessing oil-impacted areas and developing management plans designed to restore, rehabilitate, or replace impacted areas.     

The impact of vegetation on sedimentary organic matter composition and PAH desorption

Relationships between sedimentary organic matter (SOM) composition and PAH desorption behavior were determined for vegetated and non-vegetated refinery distillate waste sediments. Sediments were fractionated into size, density, and humin fractions and analyzed for their organic matter content. Bulk sediment and humin fractions differed more in organic matter composition than size/density fractions. Vegetated humin and bulk sediments contained more polar organic carbon, black carbon, and modern (plant) carbon than non-vegetated sediment fractions. Desorption kinetics of phenanthrene, pyrene, chrysene, and C₃-phenanthrene/anthracenes from humin and bulk sediments were investigated using Tenax^® beads and a two-compartment, first-order kinetic model. PAH desorption from distillate waste sediments appeared to be controlled by the slow desorbing fractions of sediment; rate constants were similar to literature values for k_slow and k_{very slow}. After several decades of plant colonization and growth (Phragmites australis), vegetated sediment fractions more extensively desorbed PAHs and had faster desorption kinetics than non-vegetated sediment fractions.     

The exposition of a calcareous Mediterranean soil to toxic concentrations of Cr, Cd and Pb produces changes in the microbiota mainly related to differential metal bioavailability

The involvement of the bacterial community of an agricultural Mediterranean calcareous soil in relation to several heavy metals has been studied in microcosms under controlled laboratory conditions. Soil samples were artificially polluted with Cr(VI), Cd(II) and Pb(II) at concentrations ranging from 0.1 to 5000 mg kg⁻¹ and incubated along 28 d. The lowest concentrations with significant effects in soil respirometry were 10 mg kg⁻¹ Cr and 1000 mg kg⁻¹ Cd and Pb. However, only treatments showing more than 40% inhibition of respirometric activity led to significant changes in bacterial composition, as indicated by PCR-DGGE analyses. Presumable Cr- and Cd-resistant bacteria were detected in polluted microcosms, but development of the microbiota was severely impaired at the highest amendments of both metals. Results also showed that bioavailability is an important factor determining the impact of the heavy metals assayed, and even an inverted potential toxicity ranking could be achieved if their soluble fraction is considered instead of the total concentration. Moreover, multiresistant bacteria were isolated from Cr-polluted soil microcosms, some of them showing the capacity to reduce Cr(VI) concentrations between 26% and 84% of the initial value. Potentially useful strains for bioremediation were related to Arthrobacter crystallopoietes, Stenotrophomonas maltophilia and several species of Bacillus.