Boron originating from produced water discharged to Brazilian coastal waters: Ecological risk assessment with marine organisms.

Deterministic and probabilistic ecological risk assessments were performed for the boron present in coastal waters in the region of the São Sebastião channel (coast of São Paulo State, Brazil) surrounding the outfall of the São Sebastião waterway terminal (TEBAR) and in reference areas far from the outfall. A set of ecotoxicity tests with 9 marine organisms (Lytechinus variegatus, Arbacia lixula, Skeletonema costatum, Asterionellopsis glacialis, Parablenius pilicornis, Artemia salina, Megabalanus coccopoma, Mysidopsis juniae and Hypnea musciformes) was performed in the laboratory. Ecotoxicity tests confirmed that boron presents low ecotoxicity, with Lytechinus variegatus being the most sensitive species studied, with an EC50 of 14.6 mg L-1 and a no-observed effect concentration (NOEC) of 6.75 mg L-1. According to the deterministic ecological risk assessment, no significant environmental impact is expected if we consider the most sensitive of the organisms tested and the highest concentration of boron found in the coastal waters (5.82 mg L-1).

Saxitoxins from the freshwater cyanobacterium Raphidiopsis raciborskii can contaminate marine mussels.

Raphidiopsis raciborskii (formerly Cylindrospermopsis raciborskii) is a freshwater cyanobacterium potentially producing saxitoxins (STX) and cylindrospermopsin. Its ecophysiological versatility enables it to form blooms in the most diverse types of environments, from tropical to temperate, and from relatively pristine to polluted. In Peri Lake, located in the subtropical south of Brazil, growing populations of STX-producing R. raciborskii have been detected since 1994, posing risks to the use of its waters that supply a population of about 100,000 inhabitants. Despite the existence of a monitoring system for the presence and toxicity of cyanobacteria in Peri Lake water, no assessment has been made in the coastal region, downstream of outflowing lake water, thereby potentially making available a toxic biomass to natural and cultivated shellfish populations in the salt water ecosystem. To address this problem, the present study evaluated environmental variables and STX concentration by profiling the outflowing waters between Peri Lake and the adjacent coastal zone. Laboratory experiments were carried out with three strains of R. raciborskii in order to confirm the effect of salinity on STX production and verify if Perna Perna mussels fed with R. raciborskii cultures would absorb and accumulate STX. Results showed that environmental concentrations of STX reach high levels (up to 6.31 µg L-1 STX eq.), especially in the warmer months, reaching the coastal zone. In laboratory tests, it was found that the strains tolerate salinities between 4 and 6 and that salinity influences the production of STX. In addition, mussels fed with R. raciborskii effectively absorb and accumulate STX, even in typically marine salinities (22 to 30), suggesting that R. raciborskii biomass remains available and toxic despite salinity shock. These results draw attention to the ecological and health risk associated with R. raciborskii blooms, both in the lake environment and in the adjacent marine environment, calling attention to the need to improve the monitoring and management systems for water and shellfish toxicity in the region of interest, as well as other places where toxic cyanobacteria of limnic origin can reach the coastal zone.

Colorimetric method for determining viability of sea urchin sperm applied in toxicity tests.

The aim of this study was to improve the methodological procedure for the evaluation of sea urchin (Lytechinus variegatus) sperm sensitivity in MTT (3-(4,5-dimethylthiazol-2yl)-2,5 diphenyltetrazolium bromide) enzyme reduction assays with the formation of formazan (purple color) in the interior of viable cells. Assays were carried out with the reference toxicants sodium dodecyl sulfate (SDS), copper, zinc, cadmium and ammonium, using a sperm solution previously activated in sea water and a sperm solution prepared in sea water containing 400 µg L-1 verapamil, which enabled activation of the sperm to occur only when exposed to the toxicants. The assays performed with sperm in verapamil presented similar sensitivity to that shown in the fertilization tests with copper, zinc and SDS, while the assays carried out with the pre-activated sperm solution presented greater resistance to the action of the toxicants. It appears that the action of verapamil involves an intracellular effect on the distribution of Ca2+ ions and that the toxicants used prevent the metabolic reactivation of the sperm.

Spawning and multiple end points of the embryo-larval bioassay of the blue mussel Mytilus galloprovincialis (Lmk).

Since the 1960s, little has been done to improve and simulate the use of short-duration chronic bioassays of bivalve embryos, particularly in mussels. However, these test organisms offer great advantages in relation to other groups, due to the ease of obtaining breeders in cultivation systems, in the environment and any time, and due to their high sensitivity to chemicals or contaminants. To contribute some methodological aspects, this study uses techniques to stimulate spawning or improve the obtaining of gametes for use in bioassays with the mussel Mytilus galloprovincialis. It also evaluates different criteria for determining the effect on the larvae, for estimation of EC50 and NOEC values, based on morphological analysis of developmental delay and the biometrics of the larvae. KCl proved to be a reliable inducer of spawning, with positive responses in 10 of the 12 months of the year tested. Moreover, this chemical, in association with NH4Cl, demonstrated the capacity to activate immature oocytes obtained from extirpated gonads, enabling an improvement in fertilization rates. The different criteria adopted to determine the effects on the larvae in the assays with reference toxicants (SDS and K2Cr2O7) resulted in EC50 and NOEC values without significant differences, indicating reliability in the results and freedom in the choice of criteria of effect to be adopted in the trials.

Ecological risk analysis of pesticides used on irrigated rice crops in southern Brazil.

Based on studies conducted in the past decade in the southern region of Brazil to determine residue levels of the pesticides normally used on irrigated rice crops, changes can be observed in relation to the presence of pesticides in the waters of the main river basins in Santa Catarina State. In previous harvests, the presence of residues of 7 pesticides was determined, with the herbicide bentazon and the insecticide carbofuran being the products showing highest frequency. Following toxicological tests conducted with 8 different test organisms, deterministic and probabilistic risk analysis was performed to assess the situation of the river basins in areas used for the production of irrigated rice. Of the species tested, the herbicide bentazon showed greatest toxicity toward plants, but did not present an ecological risk because in the worst-case scenario the highest concentration of this pesticide in the environment is 37 times lower than the lowest EC50/LC50 value obtained in the tests. The insecticide carbofuran, which had the highest toxicity toward the organisms used in the tests, presented an ecological risk in the deterministic analysis, but without any associated probability. The results highlight the need for increased efforts in training farmers in crop management practices and for the continual monitor of water bodies for the presence of pesticide residues.

EXTENDING THE VIABILITY OF SPERMATOZOA AND EGGS OF THE SEA URCHIN LYTECHINUS VARIEGATUS.

BACKGROUND: The storage of spermatozoa and eggs of the sea urchin Lytecninus variegatus can meet the demand of different human activities. OBJECTIVE: To develop a protocol easy to reproduce for spermatozoa cryopreservation and cooling of the eggs of the sea urchin. MATERIALS AND METHODS: Different formulations of artificial sea water were tested for their effectiveness in the freezing of sea urchin spermatozoa and storage of the eggs. RESULTS: Protocol for freezing of spermatozoa in liquid nitrogen presented the positive results when the cryoprotectant solution was diluted in artificial seawater free of calcium and magnesium. For the conservation of the eggs by cooling, the calcium-free artificial sea water, the calcium- and magnesium-free sea water, and the low-sodium water proved more efficient in preserving the integrity of the eggs. CONCLUSION: The results showed success in the freezing protocol of spermatozoa and cooling of the eggs mainly in artificial calcium- and magnesium-free sea water.

Seabather's eruption: report of fourteen cases.

Seabather's eruption is a papulo-pruritic dermatitis caused by the nematocysts of the larvae of the jellyfish Linuche unguiculata retained in the clothing fibers. Previously reported in Brazil, this work describes fourteen cases that occurred in the State of Santa Catarina, in southern Brazil. The new cases observed over a short period of time (the first half of January, 2012), at the height of the summer season, should alert health teams to possible epidemics on the coast of the state of Santa Catarina.

Identification of the toxic constituents of sediments in a Brazilian subtropical estuary.

Phase 1 of the TIE method was applied to samples of elutriates from sediments of the Itajaí-Açu estuary and adjacent coastal region in southern Brazil. Embryo-larval toxicity assays were used with the sea urchin Arbacia lixula in samples of raw elutriate, and treated with Ulva fasciata, EDTA and sodium thiosulfate. Inside the estuary, ammonia was responsible for more than 40% of the toxicity in both the dredged and undredged regions. A toxicity gradient was observed, between the estuary and the coastal region, with an increase in the importance of metals for the latter. Temporally, there is strong evidence of the influence of dredging and disposal of sediments in the contamination of the coastal dumping site. The results indicating that this area presents limitations in its saturation capacity. Chemical analysis indicated the metal Cu is probably responsible for the toxicity of the sediments observed, without the interference of ammonia.

Evaluation of mysids and sea urchins exposed to saxitoxins.

Saxitoxins are neurotoxins produced by dinoflagellates and cyanobacteria that form toxic blooms in waters. The impact of saxitoxins to the most vulnerable taxa and environment are not well understood. The experimental model was based on the use of toxic cell extracts containing saxitoxins. This extract was utilized for acute and chronic tests with Mysidopsis juniae. Chronic tests were also done with Lytechinus variegatus and Arbacia lixula larvae. Acute test with mysids had a LC50=2.34 µg/L. The chronic test with sea urchins showed morphological abnormalities resulting in malformation of larval appendices at low concentrations of the toxin (EC50=2.96 µg/L for L. variegatus and 2.06 µg/L for A. lixula). Although saxitoxins are considered neurotoxins, both species of sea urchins showed symptoms not related to nerve cells. A. lixula was more sensitive than L. variegatus, proving that its sensitivity should be taken in consideration to be another option to toxicological tests.

Arsenate (As V) in water: quantitative sensitivity relationships among biomarker, ecotoxicity and genotoxicity endpoints.

It is useful to test ecotoxicity and genotoxicity endpoints in the environmental impact assessment. Here, we compare and discuss ecotoxicity and genotoxicity effects in organisms in response to exposure to arsenate (As V) in solution. Eco(geno)toxicity responses in Aliivibrio fischeri, Lytechinus variegatus, Daphnia magna, Skeletonema costatum and Vicia faba were analyzed by assessing different endpoints: biomass growth, peroxidase activity, mitotic index, micronucleus frequency, and lethality in accordance with the international protocols. Quantitative sensitivity relationships (QSR) between these endpoints were established in order to rank endpoint sensitivity. The results for the QSR values based on the lowest observed effect concentration (LOEC) ratios varied from 2 (for ratio of root peroxidase activity to leaf peroxidase activity) to 2286 (for ratio of higher plant biomass growth to root peroxidase activity). The QSR values allowed the following sensitivity ranking to be established: higher plant enzymatic activity>daphnids≈echinoderms>bacteria≈algae>higher plant biomass growth. The LOEC values for the mitotic index and micronucleus frequency (LOEC=0.25mgAsL(-1)) were similar to the lowest LOEC values observed in aquatic organisms. This approach to the QSR of different endpoints could form the basis for monitoring and predicting early effects of pollutants before they give rise to significant changes in natural community structures.

The holoplankton of the Santa Catarina coast, southern Brazil.

This paper presents information from different sampling surveys carried out along the Santa Catarina coast in order to outline the biogeographical characteristics of the zooplankton in this region and identify species or groups of species with potential use as bioindicators. Based on a checklist of species of the zooplankton community in the state, it was observed that, in the warmer months of the year, the fauna is similar to that of the states of Paraná and São Paulo (e.g. Creseis virgula f. virgula, Penilia avirostris; Acartia lilljeborgi and Oithona oswaldocruzi), while in the colder months there are coastal representatives of the fauna of Rio Grande do Sul (e.g. Acartia tonsa). However, the zooplankton consists predominantly of warm water species for most of the year, which is typical of Tropical Shelf Waters. Various species of zooplankton can be used as hydrological indicators, enabling a distinction to be made between coastal waters which are influenced by continental inputs (e.g. Paracalanus quasimodo and Parvocalanus crassirostris), common in the north of the state, and processes of upwelling (e.g. Podon intermedius) and the influence of the Subtropical Shelf Front (e.g. Pleopis polyphemoides), coming from the south. The different environments investigated present a zooplankton abundance that depends on the influence of continental inputs and the possibility of their retaining and contribution for the coastal enrichment, which varies seasonally.

Terrestrial short-term ecotoxicity of a green formicide.

When ants become annoying, large quantities of formicide are applied to terrestrial ecosystems in tropical regions, but awareness of the health and environmental impacts related to the use of synthetic pesticides has been increasing. The use of green pesticides to combat target organisms could reduce these impacts. In this regard, terrestrial ecotoxicity tests with higher plants (Brassica olaracea, Lactuca sativa and Mucuna aterrima), annelids (Eisenia foetida), Collembola (Folsomia candida) and soil enzyme activity analysis (diacetate fluorescein hydrolysis) were used to evaluate short-term terrestrial ecotoxicity of a green pesticide prepared from naturally-occurring organic compounds. At the highest formicide concentration tested in these experiments (i.e., 50 g kg(-1) soil) no toxicity toward terrestrial organisms was observed. The lack of short-term terrestrial ecotoxicity suggest that this green formicide can be classed as an environmentally friendly product as compared to the ecotoxicity of the most commonly used commercialized formicides.

Risk analysis of herbicide quinclorac residues in irrigated rice areas, Santa Catarina, Brazil.

Deterministic and probabilistic risk analyses were carried out for seven hydrographic basins in the State of Santa Catarina (Brazil), where irrigated rice is cultivated. Monitoring studies conducted in 1998/1999 and 1999/2000 had found that the herbicide quinclorac was the most frequently detected agrochemical residue, occurring in five of the seven hydrographic basins. In order to assess the ecological risk posed by quinclorac, median lethal concentration (LC(50)) and median effective concentration (EC(50)) data were obtained for quinclorac in toxicity tests with organisms routinely used in Brazil for this purpose. Experiments were carried out on microcosms associated with the irrigated rice crop to evaluate the effects of the herbicide on the natural plankton community. The deterministic analyses showed that the risk presented by the herbicide residues to the phytoplankton require mitigating action, while the probabilistic analysis revealed that the levels of risk for the aquatic community were acceptable. Field experiments showed that the recommended application concentration of the product directly affects phytoplankton and has an indirect, short-term effect on the zooplankton community.

[Seabathers eruption: report of the six cases in southern Brazil]. / Prurido do traje de banho: relato de seis casos no Sul do Brasil.

Seabathers eruption is an intensely pruriginous form of dermatitis that occurs after contact with the planula larvae of the cnidarian scyphozoan Linuche unguiculata, especially under the bathers clothes. They discharge their poisonous nematocysts from the cnidocytes, causing a typical eruption presenting papules, erythema and intense itching. The first five cases described in Brazil were published in 2001 and occurred on the southeastern coast (Ubatuba, State of São Paulo). Those cases were linked to larvae of Linuche unguiculata, because the occurrence and life cycle of this cnidarian had been studied in the São Sebastião Channel, State of São Paulo. The present authors report the six cases observed in southern Brazil (State of Santa Catarina), with a description of the typical clinical aspects and an investigation linking the cases to Linuche unguiculata in the local seawater.

Ecotoxicological evaluation of the short term effects of fresh and stabilized textile sludges before application in forest soil restoration.

The short term (eco)toxicity potential of fresh and stabilized textile sludges, as well as the short term (eco)toxicity of leachates obtained from both fresh and stabilized textile sludges, was evaluated by a battery of toxicity tests carried out with bacteria, algae, daphnids, fish, earthworms, and higher plants. The (eco)toxicological results showed that, after 120 d of stabilization, the experimental loading ratio of 25% sludge:75% soil (v/v) (equivalent to 64.4 ton/ha) did not significantly increase toxicity effects and increased significantly the biomass yield for earthworms and higher plants. The rank of biological sensitivity endpoints was: Algae approximately Plant biomass > Plant germination approximately Daphnids > Bacteria approximately Fish > Annelids. The lack of short term toxicity effects and the stimulant effect observed with higher plants and earthworms are good indications of the fertilizer/conditioner potential of this industrial waste, which after stabilization can be used in the restoration of a non-productive forest soil.