Investigation of the sublethal effects of some petroleum refinery effluents

In Canada, environmental regulations for protection of the biota from the adverse effects of effluents from petroleum refineries have tended to focus on acute toxicity. There is concern those effluents may have other subtle, but still deleterious, long-term effects on aquatic ecosystems. We have used a battery of toxicity tests to assess the acute toxicity, genotoxicity, and chronic toxicity of effluent samples from two Ontario refineries. The test organisms included representatives of the bacterial, algal, plant, cladoceran, and fish communities. The results of our preliminary study indicate that the effluent samples had little acute toxicity to the test organisms. There were indications of some sublethal toxicity to Ceriodaphnia dubia, Panagrellus redivivus, and Pimephales promelas. One of the effluents inhibited the growth of Selanastrum capricornutum (IC₅₀ of 59.9%) and Lemna gibba (IC₂₅ of 73.3%) and also caused a 15 percent reduction in the germination of Lactuca sativa seeds. The SOS-Chromotest, a commercially available test that measures the activity of a bacterial DNA repair system, detected genotoxic effects in a single effluent that had been concentrated ten fold. There was no apparent relationship between several chemical parameters and the observed sublethal effects. Further research is needed to establish whether or not the observed toxic effects are typical of effluents from Ontario refineries.     

Sublethal Toxicity Testing of Canadian Metal Mining Effluents: National Trends and Site-Specific Uses

As part of the Canadian Environmental Effects Monitoring program under the National Metal Mining Effluent Regulation, there is a requirement to conduct sublethal toxicity tests twice per year for the first three years. These first three years (2003 to 2005) were considered a period of initial monitoring and resulted in test endpoints for each of the required standardized methods on a fish, an aquatic plant, an invertebrate, and an algal species. On a national level (based on 1648 valid results), the test from most to least sensitive was: the inhibition of reproduction with Ceriodaphnia dubia, the growth inhibition (frond number) with Lemna minor, the inhibition of cell yield with Pseudokirchneriella subcapitata, the growth inhibition (dry weight) with Lemna minor, the growth inhibition of fathead minnows, and the effect on embryo viability with rainbow trout. This sensitivity ranking changed when tests were further evaluated on a geographical region and mine-type basis (e.g., base metal, precious metal, uranium, iron ore). Site-specific examples show how sublethal toxicity data are being used to track changes in effluent quality, choosing a final discharge point, monitoring multiple discharges to the same watercourse, and to identify study design weaknesses by comparing laboratory results to field survey conclusions.     

Hyperthermal effluent Effects on heleoplanktonic Cladocera and the influence of submerged macrophytes

In July and August, 1974, measurements were made of the standing crops of Cladocera in the littoral zone of Par Pond (Savannah River Plant, Aiken, South Carolina, U.S.A.), which receives hyperthermal effluent from a nuclear reactor. Crops of Ceriodaphnia spp. and Diaphanosoma brachyurum were greater in the heated than in the ambient area, while Bosmina longirostris maintained higher standing crops in the ambient area than in the area receiving hyperthermal effluent. In August, 1974, exclosures were placed in the effluent-affected area to test the hypothesis that the high density of rooted aquatic macrophytes in the effluent-affected area influences the standing crop of these Cladocera. The effects of changes in reactor effluent temperature were also determined in the exclosure experiments. The results of the exclosure study support two generalizations: 1) the presence of dense rooted vegetation allows higher standing crops of Ceriodaphnia spp. and D. brachyurum; and 2) lower temperatures than those usually found at the heated station would favor B. longirostris standing crops, while the higher effluent temperatures favor Ceriodaphnia spp. and D. brachyurum.     

Oligochaete respiration as a measure of sediment toxicity in Puget Sound,Washington

Respiration rate measurements were conducted with the marine oligochaete Monopylephorus cuticulatus Baker and Brinkhurst to determine the sublethal toxicity of sediments collected from Puget Sound, Washington. Worms were exposed to elutriates prepared from centrifuged sediment slurries. Standard respiration rates were measured at high dissolved oxygen levels for each sample tested and were compared with control and other test results. A total of 97 sediment samples were tested; 40 samples demonstrated significant respiration effects (elevation or depression). Comparison with results of other tests conducted at the same stations or geographic locations (genotoxicity to fish cells, lethality to sensitive species, reproductive impairment tests) indicated very good agreement on broad scale toxicity patterns at different geographical areas, and that respiration measurements effectively determined sublethal toxicity of sediments. This study represents the first application of respiration measurements as a sublethal toxicity test for field-collected sediments.     

The coexistence of Bosmina and Ceriodaphnia in a south Andes lake

1. The coexistence of Bosmina and Ceriodaphnia was studied in relation to phytoplankton succession in a small lake (Laguna Ezquerra) in the araucanian region of Argentina. 2. The study involved field sampling and single species cultures of each of the two cladocerans in lake water under laboratory conditions. 3. Ceriodaphnia showed a unimodal cycle while Bosmina had a bimodal pattern during 4 months of coexistence. Ceriodaphnia exhibited a direct relationship between clutch size and biovolume of edible algae, whereas Bosmina's fecundity was related to the density of flagellates. 4. We found that the fecundity of these species responded differently to laboratory and field conditions. The fecundity of Ceriodaphnia followed the same pattern in both the field and laboratory, whereas Bosmina showed higher fecundity values in laboratory experiments. 5. Our results are in good agreement with predictions derived from Northern Hemisphere studies, indicating that food-limited populations of daphnids and Bosmina can coexist for extended periods in spatially homogeneous environments. 6. The variation in food availability, measured as biovolume of edible algae, determines the loss of Ceriodaphnia and the persistence of Bosmina.     

Recent advances in the use of meiofaunal polychaetes for ecotoxicological assessments

While whole sediment toxicity tests with macrofaunal polychaetes are well developed and standardized, they are oftentimes not very sensitive to environmental contaminants. Meiofaunal polychaetes, however, are sensitive to contaminants, easy to culture, and representative of the interstitial habitat. These are desirable attributes for ecotoxicological assessments of marine and estuarine sediments. The meiofaunal polychaete, Dinophilus gyrociliatus Schmidt, 1857, is a cosmopolitan species that has become a useful tool for ecotoxicological assessments, particularly for its use in toxicity testing with sediment pore waters. Due to its short life cycle it is suitable for sublethal toxicity tests, with egg production by the females as a sensitive endpoint, which can be assessed in a 7-day exposure period. Toxicity assessments of pore waters from an industrialized bay in Texas, U.S.A., and of pore waters from sediments spiked with nitroaromatic explosives, demonstrated that the D. gyrociliatus reproduction endpoint was consistently among the most sensitive, when compared to early-life stage tests with several other marine species, including macro-algae, sea urchins and fish. There was also excellent agreement among the results of porewater tests with D. gyrociliatus, nauplii of the meiofaunal copepod, Longipedia americana, and embryos of the sea urchin, Arbacia punctulata in a survey with pore waters extracted from sediments collected in the vicinity of an oil platform in the Gulf of Mexico, where metals were the primary contaminants of concern.     

Residual effects of 3,4-dichloroaniline on offspring born to Ceriodaphnia cf. dubia exposed for multiple generations

One of the acknowledged limitations ofconventional toxicity tests is their inabilityto evaluate the impact of toxicants onsubsequent generations. Given their relativelyshort lifespan, cladocerans in the field may beexposed to toxicants for several generations.However, it is unclear what effect such anexposure regime could have on the cladoceranfitness after removal of the toxicant. Thispaper aimed to determine the offspring fitnessof juveniles produced by adult Ceriodaphnia cf. dubia exposed toresidual levels of 3,4-dichloroaniline overfour generations. Mass cultures of Ceriodaphnia cf. dubia were maintainedfor several generations in variousconcentrations of 3,4-dichoroaniline (0, 2.5,5, 10, 15 and 20 µg/L). The mass cultureswere re-established every generation using4th brood neonates <24 h old. Eachgeneration, 4th brood neonates <24 h oldwere also transferred individually intotoxicant-free water and examined until theproduction of their 3rd brood. F1offspring of mothers exposed to 15 and20 µg/L 3,4-dichloroaniline showedsignificantly (p < 0.05) reducedreproduction compared to the controls. Nosignificant (p > 0.05) changes inreproduction due to 3,4-dichloroaniline wereobserved for the F2 and F3 offspring. However,F4 offspring of mothers exposed to all3,4-dichloroaniline concentrations showedsignificantly (p < 0.05) increasedreproduction compared to the controls. Possibleexplanations for the varying influence ofmaternal 3,4-dichloroaniline exposure on thereproductive output of the offspring arediscussed.     

Acute toxicity of industrial and municipal effluents in the state of Maryland,USA: results from one year of toxicity testing

In July, 1986 the Johns Hopkins University Applied Physics Laboratory's Aquatic Ecology Section established a bioassay facility for conducting an effluent biomonitoring program for the State of Maryland. Acute toxicity test procedures were developed and implemented for testing freshwater (Pimephales promelas, Daphnia magna and Ceriodaphnia sp.) and estuarine (Cyprinodon variegatus and Mysidopsis bahia) invertebrates and fish. Procedures and test species are similar to those used by the U.S. Environmental Protection Agency (EPA) except that low salinity testing ( 15) is conducted with the sheepshead minnow and an estuarine mysid found in the Chesapeake Bay.Results from the first year of the program involving acute screening bioassays of major industrial and municipal dischargers are presented. Over 90 dischargers were tested during the first full year of operation. The frequency of toxicity was 36% and 14% for industrial and municipal dischargers, respectively. Reference toxicity test results are also summarized. Results from these tests are presented by outfall type. A number of examples are presented concerning the use of these data for regulating toxic discharges by the State of Maryland's Department of the Environment. These results indicate the importance of implementing a biomonitoring program with proven, easily managed methods that can be readily understood by both regulators and permit holders.     

Selection of a suitable cladoceran species for toxicity testing in turbid waters

Abstract Two Australian cladocerans, Moina australiensis Sars and a species of Ceriodaphnia, were evaluated as possible biological indicator organisms to assess the toxicity of irrigation supply and drainage water of the Murrumbidgee and Coleambally Irrigation Areas. M. australiensis, being large (～2000 μm) and orange, was initially chosen to overcome visibility problems in highly turbid Australian inland waters. However, the organism responded erratically in culture. Mortality was high and neonate production was unpredictable when cultured under recommended United States Environmental Protection Agency protocols. Attempts to improve culture performance by optimizing food (quality and quantity), water (control source, hardness, volume) and temperature were only marginally successful. Similar difficulties were not evident when Ceriodaphnia sp. was used as the test organism. Although Ceriodaphnia sp. is small (～1000 μm), grey and more difficult to see in turbid water its responses were more predictable and reliable than those of M. australiensis. Results of initial trials comparing the two organisms suggest that Ceriodaphnia sp. was a better test organism and more suited to local requirements.     

Measurement of chronic toxicity using the opossum shrimpMysidopsis bahia

The chronic toxicity of silver and endosulfan to the opossum shrimpMysidopsis bahia was determined using continuous-flow bioassays. The 28-day bioassays measured survival, fecundity, and growth (length and weight measurements). Maximum acceptable toxicant concentrations (MATC) were estimated from measured toxicant concentrations. MATC values were similar using either brood size or growth as a criterion for sublethal effects. As an alternative to the determination of fecundity impairment, measurement of growth reduction in response to exposure to toxicants may provide a useful tool in the assessment of chronic toxicity inMysidopsis life-cycle bioassays.     

Sensitive biomarker of polycyclic aromatic hydrocarbons (PAHs): urinary 1-hydroxyprene glucuronide in relation to smoking and low ambient levels of exposure

The lysosomal neutral red retention time (NRRT) assay, a biomarker for lysosomal membrane stability, and the total immune activity (TIA) assay, a measure of non-specific immune system activity, were used in laboratory studies to assess the toxic effects of 2,4,6-trinitrotoluene (TNT) on earthworms (Eisenia andrei) in vivo. The results were compared with the concentration of TNT and its metabolites in earthworm tissue, as well as standard sublethal toxicity endpoints including growth (i.e. weight change) and reproduction effects from previously published studies. Filter paper experiments indicated a significant decrease in NRRT at ≥1.8 μg TNT cm^-2, whereas sublethal (weight loss) and lethal effects to earthworms were detected at ≥3.5 and 7.1 μg TNT cm^-2, respectively. Experiments in artificial soil showed that NRRT effects could be detected at lower TNT concentrations (≥55 mg TNT kg^-1 soil dry weight) compared with other sublethal endpoints (effects on growth and reproduction). The TIA biomarker did not significantly respond to TNT. Copper (as CuSO₄, filter paper contact tests) and 2-chloroacetamide (soil tests), which were used as reference toxicants, also decreased the NRRT. The use of the NRRT assay linked with tissue concentrations of TNT metabolites in earthworms was identified as a potentially appropriate biomarker approach for TNT exposure assessment under laboratory conditions and a novel tool for effects-based risk assessment.     

Selective grazing on Cryptomonas by Ceriodaphnia quadrangula fed a natural phytoplankton assemblage

Grazing of C. quadrangula from a Siberian forest pond on natural phytoplankton assemblages was studied in a modified flow-through system. Ceriodaphniastrongly selected subdominant Cryptomonas erosarather than the dominant diatoms of comparable size. Using Cryptomonas as the sole microalgae food, Ceriodaphnia demonstrated significant somatic and population growth. Seasonal biomass maximum of Ceriodaphnia and Cryptomonas coincidedin the pond. Although bacterial component cannot be excluded, it was concluded that Cryptomonaswas the principal algal food source for Ceriodaphnia.     

Relative effects of Daphnia and Ceriodaphnia on phosphorus-chlorophyll relationships in small urban lakes

Empirical models based on zooplankton biomass were used to predict mean summer chlorophyll a (Chl a) and to examine how zooplankton influenced the total phosphorus (TP) - Chl a relationship. Four years of data were analyzed for three lakes having similar TP concentrations but varied abundances of Daphnia and Ceriodaphnia. Mean TP did not correlate significantly with mean Chl a during the study period, although mean Daphnia density was a good predictor of Chl a concentration (p > 0.001). Both residuals from the TP - Chl a relationship (p > 0.001) and Secchi depth (p > 0.007) were negatively correlated with Daphnia abundance. Ceriodaphnia abundance was positively correlated with Chl a (p > 0.002) and Secchi depth (p > 0.001). Mean size of Daphnia during spring was the best predictor of the Daphnia-Ceriodaphnia shift in mid-summer. Early establishment of a large-sized Daphnia cohort may prevent their summer elimination by Chaoborus and intensify competition with Ceriodaphnia. These results imply an important link between Daphnia and Ceriodaphnia thereby limiting the utility of Chl a - TP model predictions in these small, urban lakes. This linkage and the differential effect of these two zooplankton species on planktonic algae deserve further consideration in similar lakes where phytoplankton and zooplankton tend to be tightly coupled.     

Phosphorus acquisition and competitive abilities of two herbivorous zooplankton, <Emphasis Type="Italic">Daphnia pulex</Emphasis> and <Emphasis Type="Italic">Ceriodaphnia quadrangula</Emphasis>

Contrary to an expectation from the size-efficiency hypothesis, small herbivore zooplankton such as Ceriodaphnia often competitively predominate against large species such as Daphnia. However, little is known about critical feeding conditions favoring Ceriodaphnia over Daphnia. To elucidate these conditions, a series of growth experiments was performed with various types of foods in terms of phosphorus (P) contents and composition (algae and bacteria). An experiment with P-rich algae showed that the threshold food level, at which an individual’s growth rate equals zero, was not significantly different between the two species. However, the food P:C ratio, at which the growth rate becomes zero, was lower for Daphnia than for Ceriodaphnia, suggesting that the latter species is rather disfavored by P-poor algae. Ceriodaphnia showed a higher growth rate than Daphnia only when a substantial amount of bacteria was supplied together with a low amount of P-poor algae as food. These results suggest that an abundance of bacteria relative to algae plays a crucial role in favoring Ceriodaphnia over Daphnia because these are an important food resource for the former species but not for the latter.     

Lethal and sublethal effects of abamectin, spinosad, methoxyfenozide and acetamiprid on the predaceous plant bug Deraeocoris brevis in the laboratory

Deraeocoris brevis (Uhler) (Hemiptera: Miridae), an important generalist predator in pome fruits in the western United States, was reared in the laboratory on frozen Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs and treated in a Potter spray tower to assess acute toxicity and chronic sublethal effects of abamectin, spinosad, methoxyfenozide, and acetamiprid. Acute toxicity was assessed using topical application. Sublethal effects were examined as the combined result of topical, residual and oral exposure. Two different dose rates, the full field rate and 10% rate of the full field rate, were compared to distilled water as the untreated check. Methoxyfenozide and spinosad had no acute toxicity to nymphs and adults at the 10% and full field rate, and no effect on egg hatch and nymph survival just after hatch. Acetamiprid and abamectin at the full field rate did not affect egg hatch, but the residue had moderate to high toxicity to hatched nymphs. Also, topically applied acetamiprid and abamectin had moderate to high acute toxicity to nymphs and adults at the full field rate, but moderate toxicity at the 10% rate. In sublethal bioassays, abamectin-treated adults (10% field rate) laid 80% fewer and less viable eggs compared with the untreated check. Spinosad-treated (full field rate) adults laid fewer and less viable eggs. Also, egg hatch in the subsequent generation was lower. Methoxyfenozide had no sublethal effects on adults at the full rate, but slowed development of 4th instars following treatment of 2nd instar nymphs, and lowered fecundity by 30% in the subsequent generation compared with the untreated check. Acetamiprid (10% rate) applied to nymphs or adults had no effects on development or reproduction. Results from this study suggest that the newer reduced risk insecticides, which have begun to replace organophosphate insecticides in pome fruits in the United States, are not as selective to natural enemies as initially thought. Their impact on D. brevis varied with chemistry and mode of action from primarily acute toxicity (i.e., acetamiprid) to reproductive and other sublethal effects (i.e., methoxyfenozide, spinosad) or a combination of both (i.e., abamectin). In addition to acute toxicity, sublethal effects need to be quantified in order to accurately predict the total impact of a pesticide on a natural enemy in the field.     

A Conceptual Framework for Using Mussels as Biomonitors in Whole Effluent Toxicity

As a main source of direct and continuous input of pollutants in the aquatic ecosystem, studying the effects of effluents on receiving ecosystems has a high ecological relevance. While ecological risk assessment procedures are usually based on a chemical-based single component approach, their application for complex mixtures and effluents is less straightforward. A chemical-based approach has to rely on the knowledge of what chemicals are present in effluents, their potential toxicity, how all of these individual chemicals interact and what their individual and combined contribution to the mixture is. Whole effluent toxicity (WET) testing, however, is an integrative tool that measures the toxic effect of an effluent as a whole and accounts for uncharacterized sources of toxicity and for interactions. This paper addresses the use of transplanted bivalves, i.e., caged mussels, as a biomonitoring tool in WET testing with special reference to field situations in both freshwater and marine environments. We indicate how endpoints at different levels of biological organization within exposed mussels can give an integrative overview of effects. Finally, we will provide a framework for future research using mussels and discuss a multitude of instream responses for routine, efficient and cost-effective active biomonitoring applications.     

Use of bioassay-based whole effluent toxicity (WET) tests to predict benthic community response to a complex industrial effluent

Whole effluent toxicity (WET) tests are a usefulmonitoring tool because they provide a rapid andreplicable measure of the potential ecotoxicologicaleffect of effluents. Although WET tests have beenincorporated into toxicity-based effluent limits toprotect receiving systems from adverse effects, fewstudies have attempted to quantitativelyfield-validate laboratory-derived toxicity thresholds.In this study, we examine the ability of WET tests topredict response thresholds of an invertebratecommunity to a paper mill effluent discharged into theNicolet-SW River, Québec, Canada. We quantifiedinvertebrate community structure and density in theriver and detrended for the effects ofphysical/chemical variables. This allowed examinationof direct correlation between invertebrate communitystructure and effluent concentration. There was asignificant decrease in taxonomic richness at aneffluent concentration of 16%, but significantchanges in the density of invertebrates occurredbetween 0% and 2% effluent. This suggests thatalthough most taxa returned to the river downstream ofthe effluent, they did so at lower densities.Calculated field thresholds were compared tolaboratory thresholds for the effluent using chronicWET tests with algae, cladocerans and fish. The WETtests produced a mean MATC of 3.6%. Thus, standardWET tests overestimated response thresholds of theinvertebrate community in the receiving environmentand impacts were observed in areas where no impact wasexpected.     

Spatial Analysis of Bifenthrin Sediment Concentrations in California Waterbodies from 2001 to 2010: Identification of Toxic and Non-Toxic Areas

The objective of this article is to summarize and map bifenthrin sediment measurements from California waterbodies from 2001 to 2010 to show sites where bifenthrin has been measured in sediment (including both detected and non-detected concentrations) and where corresponding toxicity or its lack has been reported or predicted. Bifenthrin measurements were available from depositional areas at 359 sites with concurrent total organic carbon (TOC) measurements in California waterbodies and values from approximately 37% of these sites were below the level of detection. Sediment toxicity data based on Hyalella azteca single species ambient toxicity tests were available for 268 sites with concurrent bifenthrin measurements and 62% of these sites showed no significant toxicity. Sixteen percent of the 140 California sites with non-detected bifenthrin concentrations had some significant sediment toxicity thus suggesting that toxicity at these sites is due to factors other than bifenthrin. One percent TOC normalized bifenthrin measurements reported from 268 sites showed no predicted significant toxicity at 83% of the sites based on a comparison with a Hyalella azteca acute value of 6.1 ng/g while 99.3% of the sites showed no predicted significant toxicity based on a Chironomus tentans acute toxicity value of 177.5 ng/g. The test species toxicity data (i.e., Hyalella or Chironomus) used to predict bifenthrin toxicity in the field is therefore critical as the use of Hyalella toxicity data (a highly sensitive species to bifenthrin) may be overprotective and this species is less representative of most California waterbodies when compared with Chironomids.     

An Evaluation of a Point Source Brine Discharge into a Riverine System and Implications for TDS Limitations

The North Fork Holston River (NFHR) below Saltville, Virginia, has been the subject of many studies due to years of contamination from a closed chloroalkali plant. In addition, a point source brine discharge high in total dissolved solids (TDS) may also be adversely affecting aquatic biota. This study assessed the toxicity of the brine discharge to selected test organisms, including two freshwater mussel species and also discusses implications for development of a TDS limit based on brine toxicity. Ceriodaphnia dubia was the most sensitive organism in acute and chronic brine toxicity tests. Bivariate analysis of the brine conductivity and C. dubia LC₅₀ values showed no relationship (p = .1756); however, LC₅₀ values were strongly related (r² = 0.8818) to sodium concentrations in the brine discharge. A comparison of the results from acute tests with the brine effluent and the reference toxicant sodium chloride (NaCl) demonstrated that organisms were more sensitive to NaCl. Brine discharge toxicity to C. dubia was variable during the study duration with toxicity determined to be dependent on specific TDS constituents rather than conductivity or TDS. These results suggest the need for site-specific development of TDS criteria that are based on the specific constituents in a discharge.     

Ecotoxicological effect of insecticides on Ooencyrtus nezarae (Hymenoptera: Encyrtidae) reared from refrigerated and unrefrigerated Riptortus pedestris (Hemiptera: Alydidae) host

Due to increased field occurrence of Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) on various crops including soybean, persimmon and apple in recent years in Korea, demand for insecticide applications to control the stink bug has increased. Acute toxicity of eight pesticides on Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae), a major egg parasitoid of R. pedestris, was compared in the laboratory. Fenitrothion, spinosad, cyfluthrin, etofenprox and carbosulfan caused 100% mortality of O. nezarae within 24 hours by topical application or exposure to residue. Fenitrothion was also highly toxic to the parasitoid when ingested orally. In a previous study, release of refrigerated inviable eggs of R. pedestris was found to increase field parasitism; therefore, we evaluated the sublethal effect of fenitrothion when O. nezarae parasitised refrigerated or unrefrigerated host eggs. Although parasitism rates on both kinds of eggs significantly decreased when O. nezarae were provided with host eggs sprayed with fenitrothion, no difference in parasitism rate, adult emergence, sex ratio, development time and longevity of O. nezarae was found between the refrigerated or unrefrigerated host eggs when the insecticide was treated either before or after oviposition. There was no significant sublethal effect when parasitised host eggs were treated with the insecticide. From these results, all the insecticides tested showed high, acute toxicity against O. nezarae with relatively lower sublethal effects. Refrigeration of host eggs did not affect the susceptibility of O. nezarae to insecticides.