Nitocra Spinipes Research Articles

Effects of four synthetic musks on the life cycle of the harpacticoid copepod Nitocra spinipes

A full life-cycle (≤26 days exposure) toxicity test with the harpacticoid copepod Nitocra spinipes was used to study the effects of one nitro musk (musk ketone) as well as three polycyclic musks (Tonalide™, Celestolide™ and Galaxolide™). A subchronic individual life-table endpoint, the larval development rate, was recorded after 7–8 days exposure of juveniles and was significantly decreased in copepods exposed to sublethal concentrations of musk ketone, Celestolide™ and Galaxolide™. However, none of the Tonalide™ concentrations had any effect on larval development. The lowest Galaxolide™ concentration (0.02 mg/l), which affected juvenile development, was about 100 times below the adult 96-h-LC 50-value of 1.9 mg/l (95% confidence interval: 1.4–2.7 mg/l). However, none of the four musks had any agonistic or antagonistic activity in the ecdysteroid-sensitive Drosophila melanogaster B II-cell line. This indicates that the decrease in larval development rate was due to pharmacological effects rather than steroid receptor-mediated endocrine disruption. A modified Euler–Lotka equation was used to calculate a population-level endpoint, the intrinsic rate of natural increase ( r m), from individual life-table endpoints, i.e. mortality rate, time of release of first brood, sex ratio, the fraction of ovigerous females among all females as well as the number of nauplii per ovigerous female. The second highest musk ketone concentration (0.1 mg/l) was the only treatment, which significantly affected r m (*** P<0.001). At the highest musk ketone (0.3 mg/l) and Celestolide™ (0.3 mg/l) concentrations, all copepods were dead at the end of the exposures. This shows that a sensitive individual life-table endpoint is protective over the population-level endpoint r m. Though we think that it is necessary to obtain population-level endpoints from standardised toxicity test, for ecologically successful risk characterisation of synthetic musks as well as other chemicals. The results from the present study show that it is possible to obtain population-level data from the full life-cycle test with N. spinipes. However, there seems to be little risk that synthetic musks are harmful to copepods at present environmental concentrations.

Oestrogens have no Hormonal Effect on the Development and Reproduction of the Harpacticoid Copepod Nitocra spinipes

In recent years, reports have described endocrine-disruptive effects of environmental oestrogens in fish, but little is known about similar effects in crustaceans. The objective of the present study was therefore to examine whether the oestrogens 17-β-oestradiol, 17-α-ethynylestradiol and diethylstilbestrol (DES), could affect mortality, larval development rate, fecundity and sex ratio in the sexually reproducing harpacticoid copepod Nitocra spinipes. Newly released nauplii (<24-h old) were exposed to 1/1000, 1/100 and 1/10 (nominal concentrations) of each oestrogen's 96 h-LC 50 value for ≤18 days at 22±1°C. The percentage of gravid females and the number of developed copepodites were both reduced at 0.03 mg l −1 DES, although the latter response was not significant. None of the other two oestrogens induced any measurable effects. Since the only observed significant response appeared at a DES concentration no more than 10 times below the 96 h-LC 50 value, there is no evidence of endocrine-disruptive activity in N. spinipes exposed to oestrogens.

Patterns of community variability depend on habitat variability and habitat generalists in natural aquatic microcosms

Habitat variability is largely an external mechanism influencing community variability by affecting abundances and precipitating other community changes but the nature of this influence is poorly understood. The absence of systematic quantitative studies appears to be a major reason for this deficiency. To address the problem, we have evaluated community and population variability in invertebrate communities collected from 49 coastal Jamaican rock pools with contrasting levels of habitat variability. We calculated a multivariate index of habitat variability based on temporal changes in physicochemical variables. Variability in diversity indices (Simpson.s and Shannon-Wiener), evenness (2 measures), and species richness represented community variability while species rank correlations and community constancy represented changes in community structure. Additionally, we analyzed the impact of three habitat generalists (harpacticoid copepod (Nitocra spinipes Boeck), cyclopoid copepod (Orthocyclops modestus Herrick), and the ostracod (Potamocypris sp.)) on overall community variability. As habitat variability increased, both community and population variability increased. Community structure (ranked abundances) was more variable in variable habitats compared to non-variable habitats but communities in these variable habitats retained greater constancy of composition suggesting that highly variable habitats are dominated by a few species with good dispersal abilities. Rare species may come and go, but the dominant species persist in these habitats. Habitat generalists influenced temporal community variability differently, especially evenness (based on the Shannon-Wiener index). Positive relationships were found between the variability in evenness and population variability of the ostracod and cyclopoid copepod. A negative relationship was found between the variability in evenness and the variability of harpacticoid copepods. Our study suggests that individual communities or assemblages respond independently and asynchronously to environmental factors, a view originally proposed by Gleason (1917).We conclude that the form of community structure in variable habitats remains constant. The species composition and relative abundances can change over time but the relative abundance of the dominant species stays high and the remaining species, regardless of their numbers,make relatively small contributions to the overall community variability pattern.

Sediment and water phase toxicity and UV-activation of six chemicals used in military explosives

Explosives used in ammunition have been dumped in both lakes and oceans before the potential environmental effects of these chemicals were understood. Growing environmental concern in society and in the Swedish military resulted in a project dealing with the aquatic toxicology of explosives. The aim of the present study was to assess the hazard of six explosives by determining the acute sediment and water phase toxicity for two crustaceans ( Daphnia magna and Nitocra spinipes). Detoxification during storage was used as an indication of degradability (hydrolysis and biodegradation). The effect of ultraviolet light on the toxicity of these compounds was determined by post-exposure to ultraviolet light and determination of toxicity enhancement. The explosives were picric acid, trinitrotoluene, (2,4-dinitrotoluene), hexahydro-1,3,5-trinitro-1,3,5-trazine, nitroguanidine, and pentyl. The stabilising agent diphenylamine was tested in the same way. For the major explosive, trinitrotoluene, the water-phase EC/LC 50s were between 5 and 20 mg l −1 and the toxicity was not significantly affected by storage of test solutions for 30 days, indicating hydrolytic stability. The toxicity was not affected by addition of sediment, indicating that trinitrotoluene was not bound appreciably to sediment, but toxicity decreased after storage for 30 days in the presence of sediment, indicating biological degradation or slow adsorption of the chemical. The toxicity of the other explosives was similar or lower than for trinitrotoluene, but the stabilising agent diphenylamine was slightly more toxic with EC/LC 50s between 0.5 and 5 mg l −1. Photoinduced toxicity by ultraviolet light is known for many chemicals including polycyclic aromatic hydrocarbons and trinitrotoluene. The latter was confirmed in this study and especially for degraded trinitrotoluene. 2,4-Dinitrotoluene, which is one degradation product of trinitrotoluene was also activated by ultraviolet light. The toxicity of diphenylamine decreased after storage in water (hydrolysis) and with sediment (biodegradation), but both diphenylamine and its degradation products exhibited photoinduced toxicity.

Assessing pollution and UV-enhanced toxicity in Torsviken, Sweden, a shallow bay exposed to contaminated dredged harbor sediment and hazardous waste leachate

Torsviken is a small bay close to the city of Gothenburg, Sweden. Part of the bay has been used for disposal of dredged harbor sediment since the 1970s. Other potential sources of contamination are a deposit site and treatment facility for hazardous waste. The area has been classified as ecologically sensitive and is of great ornithological interest. Birds are abundant and several rare species have been observed. In this study, pollution was assessed by analyzing concentrations of polycyclic aromatic hydrocarbons, polychlorinated biphenyls and heavy metals and by measuring toxicity of sediment samples to Daphnia magna, Nitocra spinipes, Chironomus riparius and Hyalella azteca. The combined exposure to several contaminants and solar light can enhance toxic effects, and since Torsviken is a shallow bay (maximum depth 2 m), organisms surviving the bioassays were exposed to simulated ultraviolet (UV) light of site-relevant intensity for 2 h to detect potential UV-enhanced toxicity. Torsviken is subdivided into three basins and the concentrations of most investigated contaminants, especially polycyclic aromatic hydrocarbons and polychlorinated biphenyls, were 2–5 times higher in the inner (western) area compared to the outer (eastern) areas. Acute sediment toxicity was found primarily in Nitocra, but there was no clear difference between the two areas of Torsviken. Ultraviolet-induced toxicity also occurred especially in Nitocra but only in the western area where organic pollutants are elevated in concentration. In the same sediment sampling site that caused the highest increase in mortality in Nitocra, there was also a significant response by Daphnia after UV treatment. Correlations between the toxicity enhancement (measured as % of surviving Nitocra from the bioassays that died after subsequent exposure to UV light) and chemical concentrations were found for several of the pollutants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, mercury and lead, indicating that some of these substances were bioavailable and induced toxicity with UV irradiation. The results support the need to develop special sediment quality guidelines for shallow sites, where the phototoxic properties of pollutants should be accounted for.

Assessing pollution and UV-enhanced toxicity in Torsviken, Sweden, a shallow bay exposed to contaminated dredged harbor sediment and hazardous waste leachate

Abstract Torsviken is a small bay close to the city of Gothenburg, Sweden. Part of the bay has been used for disposal of dredged harbor sediment since the 1970s. Other potential sources of contamination are a deposit site and treatment facility for hazardous waste. The area has been classified as ecologically sensitive and is of great ornithological interest. Birds are abundant and several rare species have been observed. In this study, pollution was assessed by analyzing concentrations of polycyclic aromatic hydrocarbons, polychlorinated biphenyls and heavy metals and by measuring toxicity of sediment samples to Daphnia magna, Nitocra spinipes, Chironomus riparius and Hyalella azteca. The combined exposure to several contaminants and solar light can enhance toxic effects, and since Torsviken is a shallow bay (maximum depth 2 m), organisms surviving the bioassays were exposed to simulated ultraviolet (UV) light of site-relevant intensity for 2 h to detect potential UV-enhanced toxicity. Torsviken is subdivided into three basins and the concentrations of most investigated contaminants, especially polycyclic aromatic hydrocarbons and polychlorinated biphenyls, were 2–5 times higher in the inner (western) area compared to the outer (eastern) areas. Acute sediment toxicity was found primarily in Nitocra, but there was no clear difference between the two areas of Torsviken. Ultraviolet-induced toxicity also occurred especially in Nitocra but only in the western area where organic pollutants are elevated in concentration. In the same sediment sampling site that caused the highest increase in mortality in Nitocra, there was also a significant response by Daphnia after UV treatment. Correlations between the toxicity enhancement (measured as % of surviving Nitocra from the bioassays that died after subsequent exposure to UV light) and chemical concentrations were found for several of the pollutants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, mercury and lead, indicating that some of these substances were bioavailable and induced toxicity with UV irradiation. The results support the need to develop special sediment quality guidelines for shallow sites, where the phototoxic properties of pollutants should be accounted for.

Sediment and water phase toxicity and UV-activation of six chemicals used in military explosives

Abstract Explosives used in ammunition have been dumped in both lakes and oceans before the potential environmental effects of these chemicals were understood. Growing environmental concern in society and in the Swedish military resulted in a project dealing with the aquatic toxicology of explosives. The aim of the present study was to assess the hazard of six explosives by determining the acute sediment and water phase toxicity for two crustaceans (Daphnia magna and Nitocra spinipes). Detoxification during storage was used as an indication of degradability (hydrolysis and biodegradation). The effect of ultraviolet light on the toxicity of these compounds was determined by post-exposure to ultraviolet light and determination of toxicity enhancement. The explosives were picric acid, trinitrotoluene, (2,4-dinitrotoluene), hexahydro-1,3,5-trinitro-1,3,5-trazine, nitroguanidine, and pentyl. The stabilising agent diphenylamine was tested in the same way. For the major explosive, trinitrotoluene, the water-phase EC/LC50s were between 5 and 20 mg l−1 and the toxicity was not significantly affected by storage of test solutions for 30 days, indicating hydrolytic stability. The toxicity was not affected by addition of sediment, indicating that trinitrotoluene was not bound appreciably to sediment, but toxicity decreased after storage for 30 days in the presence of sediment, indicating biological degradation or slow adsorption of the chemical. The toxicity of the other explosives was similar or lower than for trinitrotoluene, but the stabilising agent diphenylamine was slightly more toxic with EC/LC50s between 0.5 and 5 mg l−1. Photoinduced toxicity by ultraviolet light is known for many chemicals including polycyclic aromatic hydrocarbons and trinitrotoluene. The latter was confirmed in this study and especially for degraded trinitrotoluene. 2,4-Dinitrotoluene, which is one degradation product of trinitrotoluene was also activated by ultraviolet light. The toxicity of diphenylamine decreased after storage in water (hydrolysis) and with sediment (biodegradation), but both diphenylamine and its degradation products exhibited photoinduced toxicity.

Combining sediment quality criteria and sediment bioassays with photoactivation for assessing sediment quality along the Swedish West Coast

Sediments from 48 sites along the Swedish West Coast were sampled for determination of priority pollutants (metals, polycyclic aromatic hydrocarbons and chlorinated hydrocarbons). Toxicity to two crustaceans ( Daphnia magna and Nitocra spinipes) were also determined within 2 weeks and after 12 months of storage at 4°C. Since, according to earlier studies, polycyclic aromatic hydrocarbons may exhibit photoinduced toxicity, all test vessels (including exposed test organisms) were subjected to ultraviolet irradiation after immobility/lethality was recorded. Thereafter, the vessels were recorded again for immobility/lethality and the data were compared with phototoxicity data of analyzed substances, in order to estimate the bioavailability of phototoxic hydrocarbons in these sediments. Immobility of Daphnia exposed to 16% sediment (wet weight) ranged from 0 to 80% both before and after photo treatment. Nitocra 96-h LC 50s (% wet weight of sediment) ranged from 1.9 to >32% before, and from 1.0 to >32% after ultraviolet treatment. The sensitivity to the different sediments as well as the photo-activation was species dependent and differed between fresh and stored sediments. Photoactivation in Daphnia was generally low but significant in an analysis of variance test. Compared with two different sediment quality guidelines it was found that some sediments would be classified as moderately or strongly polluted. These values did not always coincide with toxicity to any of the two species. The guidelines were thus of no value in predicting sediment toxicity. Correlations between toxicity and chemicals measured in the sediments were also highly variable and inconsistent. Photo-induced toxicity in Nitocra did not correlate (p<0.01) to any of the analyzed substances, and a clear pattern between ultraviolet-induced toxicity to Daphnia and polycyclic aromatic hydrocarbon concentrations in the sediments was not obtained, possibly because most sediments contained relatively low amounts of bioavailable material. However, the sediment sample with the highest concentrations of photoactive PAHS such as pyrene did demonstrate the greatest increase in toxicity (39%) following ultraviolet irradiation.

Sediment toxicity and contaminants in the Kattegat and Skagerrak

Sediment bioassays have usually been applied to sediments from sites close to known sources of pollution such as harbours or major industrial sites. In this study sediment bioassays were conducted on samples from 120 sites in the Kattegat and Skagerrak (North Sea) at water depths ranging from 4 to 682 m. Sediment toxicity to Daphnia magna, expressed as immobility after 48 h exposure to 16% sediment (wet weight) ranged from 0 to 95%. Sediment toxicity to Nitocra spinipes, expressed as the 96 h LC 50 for sediment in water, ranged from 0.61 to 88% dry weight. The responses obtained in duplicate bioassay test vessels showed good correlation ( r=0.7–0.8), but toxicity to Daphnia was not correlated with toxicity to Nitocra. High sediment toxicity was not restricted to areas close to industrial sites and harbours, but was found also in open sea areas. Analysed sediment concentrations of contaminants (heavy metals, organochlorines and polyaromatic hydrocarbons) at 25 of these 120 sites were tested for correlation with sediment toxicity, but no correlations, or rather weak ones, were found. Further, the concentrations of single contaminants were usually below those, which are considered harmful to aquatic organisms (tentative sediment quality criteria). Therefore, none of the single analysed contaminants seems to cause the observed sediment toxicity. No improvement in correlation was achieved when using an additive model of joint toxicity between different groups of contaminants and the combined toxicity to Daphnia and Nitocra. Therefore, the cause of the sediment toxicity is so far unknown, and no hazard assessment based on the analysed contaminants was warranted. The average immobility of Daphnia after exposure to 16% sediment (wet weight) for 48 h was 29%, and the average 96 h LC 50 for Nitocra exposed to various concentrations of sediment was 11.4% (dry weight) of sediment in dilution water. A tentative hazard assessment based on these average results from both bioassays suggested that sediment toxicity in the Kattegat and Skagerrak must be reduced by on average four times to approach a Predicted Effect Level (PEL) allowing 50% survival.

Toxicity of conventional, elemental chlorine‐free, and totally chlorine‐free kraft‐pulp bleaching effluents assessed by shortterm lethal and sublethal bioassays

AbstractThe toxicity of nine effluents from Swedish kraft‐pulp mills using conventional, elemental chlorine‐free (ECF) and totally chlorine‐free (TCF) bleaching processes was studied. Effluents represented six different processes: conventional‐softwood 30% ClO2; ECF‐softwood; TCF‐hardwood, for which all the samples were taken before and after secondary treatment; conventional‐softwood 8% ClO2; TCF‐softwood O3/H2O2; and TCF‐softwood H2O2. Comparison of effluents, which had not undergone secondary treatment, suggested that those from mills using conventional bleached pulp were the most toxic, with toxic emission factors (TEF) ≈ 1,000 according to the Microtox® test (AZUR Environmental, Carlsbad, CA, USA). In the acuteNitocra spinipestest, the conventional‐softwood 8% ClO2and the ECF‐softwood effluents before secondary treatment were the most toxic, with TEF ≈ 700. In the reproduction test,N. spinipeswas two to three times more sensitive than in the lethal test. The species most sensitive to the effluents investigated was the macroalgaCeramium strictum, with TEF values up to 3,000. The conventional effluent using a substitution of 8% ClO2was the most toxic, and the TCF effluents were the least toxic. Degradation treatment of the ECF and TCF effluents for 28 d in the laboratory did not eliminate acute lethal effects onN. spinipesand the Microtox bacterium.

Combining sediment quality criteria and sediment bioassays with photoactivation for assessing sediment quality along the Swedish West Coast

Abstract Sediments from 48 sites along the Swedish West Coast were sampled for determination of priority pollutants (metals, polycyclic aromatic hydrocarbons and chlorinated hydrocarbons). Toxicity to two crustaceans (Daphnia magna and Nitocra spinipes) were also determined within 2 weeks and after 12 months of storage at 4°C. Since, according to earlier studies, polycyclic aromatic hydrocarbons may exhibit photoinduced toxicity, all test vessels (including exposed test organisms) were subjected to ultraviolet irradiation after immobility/lethality was recorded. Thereafter, the vessels were recorded again for immobility/lethality and the data were compared with phototoxicity data of analyzed substances, in order to estimate the bioavailability of phototoxic hydrocarbons in these sediments. Immobility of Daphnia exposed to 16% sediment (wet weight) ranged from 0 to 80% both before and after photo treatment. Nitocra 96-h LC50s (% wet weight of sediment) ranged from 1.9 to &amp;gt; 32% before, and from 1.0 to &amp;gt; 32% after ultraviolet treatment. The sensitivity to the different sediments as well as the photoactivation was species dependent and differed between fresh and stored sediments. Photoactivation in Daphnia was generally low but significant in an analysis of variance test. Compared with two different sediment quality guidelines it was found that some sediments would be classified as moderately or strongly polluted. These values did not always coincide with toxicity to any of the two species. The guidelines were thus of no value in predicting sediment toxicity. Correlations between toxicity and chemicals measured in the sediments were also highly variable and inconsistent. Photo-induced toxicity in Nitocra did not correlate (p &amp;lt; 0.01) to any of the analyzed substances, and a clear pattern between ultraviolet-induced toxicity to Daphnia and polycyclic aromatic hydrocarbon concentrations in the sediments was not obtained, possibly because most sediments contained relatively low amounts of bioavailable material. However, the sediment sample with the highest concentrations of photoactive PAHS such as pyrene did demonstrate the greatest increase in toxicity (39%) following ultraviolet irradiation.

Sediment toxicity and contaminants in the Kattegat and Skagerrak

Abstract Sediment bioassays have usually been applied to sediments from sites close to known sources of pollution such as harbours or major industrial sites. In this study sediment bioassays were conducted on samples from 120 sites in the Kattegat and Skagerrak (North Sea) at water depths ranging from 4 to 682 m. Sediment toxicity to Daphnia magna, expressed as immobility after 48 h exposure to 16% sediment (wet weight) ranged from 0 to 95%. Sediment toxicty to Nitocra spinipes, expressed as the 96 h LC50 for sediment in water, ranged from 0.61 to 88% dry weight. The responses obtained in duplicate bioassay test vessels showed good correlation (r = 0.7–0.8), but toxicity to Daphnia was not correlated with toxicity to Nitocra. High sediment toxicity was not restricted to areas close to industrial sites and harbours, but was found also in open sea areas. Analysed sediment concentrations of contaminants (heavy metals, organochlorines and polyaromatic hydrocarbons) at 25 of these 120 sites were tested for correlation with sediment toxicity, but no correlations, or rather weak ones, were found. Further, the concentrations of single contaminants were usually below those, which are considered harmful to aquatic organisms (tentative sediment quality criteria). Therefore, none of the single analysed contaminants seems to cause the observed sediment toxicity. No improvement in correlation was achieved when using an additive model of joint toxicity between different groups of contaminants and the combined toxicity to Daphnia and Nitocra. Therefore, the cause of the sediment toxicity is so far unknown, and no hazard assessment based on the analysed contaminants was warranted. The average immobility of Daphnia after exposure to 16% sediment (wet weight) for 48 h was 29%, and the average 96 h LC50 for Nitocra exposed to various concentrations of sediment was 11.4% (dry weight) of sediment in dilution water. A tentative hazard assessment based on these average results from both bioassays suggested that sediment toxicity in the Kattegat and Skagerrak must be reduced by on average four times to approach a Predicted Effect Level (PEL) allowing 50% survival.

Contamination and correlation with toxicity of sediment samples from the Skagerrak and Kattegat

The pollution state in the Skagerrak and Kattegat was investigated by determination of pollutant concentrations and toxicity of sediment samples from 11 stations in the area. A comparison was made with the sediment from a reference site near the Faroe Islands. Polycyclic aromatic hydrocarbons (PAH) and organochlorines were determined in whole sediment and heavy metals and ammonia were analysed in filtered pore water. Toxicity was bioassayed in whole sediment with Nitocra spinipes and Daphnia magna, in pore water with Mytilus edulis larvae and in solvent extracts from sediment with tests measuring etoxyresorufin-O-deethylase (EROD) activity in Oncorhyncus mykiss and rate of denitrification. Sites close to Göteborg and in an area from the Oslo fjord to the Norwegian Trench were most polluted. Sediment from the Faroe Islands was least polluted and also least toxic. Multivariate statistical analysis indicates that the different tests were sensitive to different kinds of pollutants. Effects on mussel larvae correlated strongest with the occurrence of ammonia, manganese, cadmium and PAHs, Nitocra with α-hexachlorocyclohexane (HCH) and p,p′-DDD, Daphnia with arsenic and γ-HCH, fish EROD activity with benzo[ghi]perylene and unknown compounds associated with organic carbon, and denitrification with chlordanes, dieldrin and a few PAHs. The results indicate that sampling sites close to Göteborg are so polluted that harmful effects on the ecosystem probably occur.

Development and lipid composition of the harpacticoid copepod Nitocra spinipes reared on different diets

Development and lipid composition of the harpacticoid copepod Nitocra spinipes reared on different diets

A 96‐h acute toxicity test with the brackish water crustacean Nitocra spinipes boeck: Assessment of chemicals, products, and effluents

A 96‐h acute toxicity test with the brackish water crustacean <i>Nitocra spinipes</i> boeck: Assessment of chemicals, products, and effluents

Occurrence and toxicity of persistent pollutants in surface microlayers near an incineration plant

Surface microlayers exposed to smoke plumes from an incineration plant were collected and their toxicity and content of anthropogenic compounds determined. The enriched levels of Al, Mn, Cu and Zn indicated an anthropogenic exposure, which was confirmed by increased levels of AOX and the presence of PCBs in the microlayers. AOX was enriched about twice the level found in the subsurface water (55 μg Cl L −1), which pointed to an airborne, local source. The mortality of the brine shrimp Artemia spp. changed in a dose-response manner after exposure to the microlayer. The crustacean Nitocra spinipes was not affected by the microlayer and no response was shown when the Microtox® method was used.

Sediment toxicity and heavy metals in the Kattegat and Skaggerak

Superficial (0 to 2 cm) sediments were sampled from 62 sites in Kattegat and Skagerrak during autumn 1989 and spring 1990, tested for toxicity to Daphnia magna and Nitocra spinipes (Crustacea) and analyzed for heavy metals (Cd, Cr, Cu, Hg, N, Pb, Zn), nutrients (N and P) and organic carbon. Whole sediment toxicity to Nitocra spinipes, expressed as 96-h LC50, ranged from 1.8 to > > 32 percent sediment (wet wt), which is equivalent to 0.63 to 53 percent dry wt. Sediment total metal concentrations (mg kg-1 dry wt) ranged from 0.01 to 0.32 for Cd, 8 to 57 for Cr, 3 to 40 for Cu, 0.03 to 0.86 for Hg, 3 to 43 for Ni, 6 to 37 for Pb and 21 to 156 for Zn. Analyzed concentrations of heavy metals were tested for correlation with whole sediment toxicity normalized to dry wt, and significant correlations (Spearman p<0.05) were found for Cd, Cr, Cu, Hg, and Ni. However, the analyzed concentrations of these metals were below the spiked sediment toxicity of these heavy metals to N. spinipes, except for Cr and Zn for which analyzed maximum concentrations approached the 96-h spiked sediment LC50s. There was no improvement in correlation between the sum of heavy metal concentrations normalized to their spiked toxic concentrations (Toxic Unit approach) and the whole sediment toxicity. Calculated heavy-metal-derived toxicity based on toxic units and whole sediment toxicity ranged from 0.1 to 24 (mean value 2.3 and SD 4.2). Theoretically, a value of 1.0 would explain whole sediment toxicity from measured metal concentrations using this approach. Thus, in spite of the fact that the total concentrations of the heavy metals were sufficient to cause toxicity based on an additive model for most of these sediments, the observed toxicity of the sediments from Kattegat and Skagerrak could not exclusively be explained by the concentrations of heavy metals, except for Cr and Zn at their maximum concentrations. Therefore, other pollutants than these heavy metals must also be considered as possible sediment toxicants.

Precision of the nitocra spinipes acute toxicity test and the effect of salinity on toxicity of the reference toxicant potassium bichromate

AbstractThe precision of the 96‐h LC50 test with the eurohaline copepod Nitocra spinipes was evaluated from a data set containing 85 tests with the reference toxicant potassium bichromate conducted at 12 laboratories during a 12‐year period. The overall mean was 30 mg/L as K2Cr2O7 with a coefficient of variation (CV) of 47% (N = 85). Since salinity differed between tests (7–33 o/oo), it explained part of the variation (ca. 25%; Pearson two‐tailed test r = 0.49; p = 0.0000; N = 85). The effect of salinity on Cr(VI) toxicity was confirmed in an experiment with 4 salinities (3.4, 6.8, 14.6, and 27 o/oo) and was explained to 99% by the equation 96‐h LC50 (mg/L) = 2.58 + 1.79 × salinity (o/oo). Intralaboratory CVs for corresponding salinities ranged from 8 to 35% (repeatability). Interlaboratory CVs at two salinities were 42% (N = 11) at 7–9 o/oo and 47% (N = 4) at 15–16 o/oo. © 1993 John Wiley &amp; Sons, Inc.

A flowthrough fecundity test with Nitocra spinipes (harpacticoidea crustacea) for aquatic toxicity

A sublethal flowthrough fecundity test with the euryhaline harpacticoid copepod Nitocra spinipes has been developed as a complement to the acute toxicity test (for 48 or 96 hr LC 50) with the same species (B-E. Bengtsson, 1981, Mar. Pollut. Biol., 9, 238–241). Bacterial suspension as feed and test water are continuously fed by a peristaltic pump to the systeem. Newly fertilized females with ovigerous bands are harvested from laboratory cultures and put into the test vessels at the start of the experiment. They are then exposed to a series of concentrations of chemicals or industrial effluents for 13 days. The amount of live offspring (metanauplia and copepodids) are recorded and an EC 50 for fecundity is calculated. The report gives a detailed technical description of the test system and presents the results from 11 tests with pure chemicals (Zn, Cd, As, and pentachlorophenate) and six industrial effluents (pulp industry, textile industry, and refinery) in salinities ranging from 3 to 25‰

Bioaccumulation and effects of some technical triaryl phosphate products in fish and Nitocra Spinipes

AbstractThree commercial triaryl phosphates, Pliabrac 521, Reofos 95 and Reolub hyd 46, were tested for acute toxicity against the brackish‐water harpacticoid Nitocra spinipes Boeck (Crustacea) and the zebra fish, Brachydanio rerio Hamilton‐Buchanan. The 96‐h LC50 values ranged from 0.27 to 1.75 mg/L, with Pliabrac 521 as the most toxic and Reolub hyd 46 as the least toxic. The zebra fish was more than 10 times less sensitive to the tested compounds than was N. spinipes. Low to moderate accumulation of triaryl phosphates was observed. An accumulation factor (AF) of 100 to 2,000 was observed for Pliabrac 521 from water to bleak, Alburnus alburnus L. For the various triaryl phosphates, a dietary accumulation of 0.06 to 0.6 from food to minnow, Phoxinus phoxinus L., was observed. The most hydrophilic compounds were readily cleared from fish when the fish were placed in clean water, whereas the most lipophilic ones were still detectable, albeit in low concentrations, in the fish after a 2‐week depuration period. A rotatory‐flow behavioral study did not reveal any effects on swimming performance in the bleak, but reproduction was affected as a result of long‐term (163 d) exposure of minnows to subacute concentrations of Pliabrac 521.