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Copyright of Revista Biológico Agropecuaria Tuxpan is the property of Revista Biologico Agropecuaria Tuxpan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of ESPOCH Congresses: The Ecuadorian Journal of S.T.E.A.M. is the property of Knowledge E DMCC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ants are very diverse hymenopterans with a wide geographical distribution. They are social insects and their communication is based on chemical signals. Within the group of semiochemicals that regulate the search for foods are the trail pheromones on the roads. The purpose of this review is to document the main tracking pheromones on the trails that guide ants to feeding sources. A systematic review was carried out based on the guidelines of the PRISMA statement of research found in PubMed, Web of Science and Google Scholar of the pheromones trails. Reported 26 chemical compounds were reported in 14 species of ants, the main sources of obtaining were extracts of the whole body, abdomen and glands. The detection of the semiochemicals were electrophysiological responses of Hymenoptera and chromatographic methods, recording short and long-chain organic compounds (C05-C18). The study of trial chemical compounds has been carried out on a small number of species, this type of research has great potential for the control of invasive ants, since their distribution has had negative repercussions on ecosystems and economic damage to man. [ABSTRACT FROM AUTHOR]

Microalgae are unicellular photosynthetic microorganisms that can grow autotrophically or heterotrophically. They are considered a source of biomolecules and metabolites of nutritional, pharmaceutical and industrial importance since they can be used for the production of biofuels, biofertilizers, food for consumption and wastewater treatment. In the present work, the cultivation potential of four native microalgae from the department of Bolívar from different bodies of water was evaluated. After their isolation and identification, the microalgae were cultivated following the Batch-type scaling system and once the exponential phase was reached, 100 mL of each species was inoculated in triplicate, measuring up to 1 liter. The bioassays were carried out using the modified Conway culture medium and under controlled conditions of temperature, aeration, light intensity and photoperiod. Cell growth and kinetic parameters were determined by cell quantification using a Neubauer chamber. In addition, a Kruskal-Wallis statistical analysis and the post-hoc multiple range test were performed.It was found that Dunaliella salina reached the highest cell density (12,957,500 cell/mL) compared to Cyclotella meneghiniana (225,000 cell/mL), Nitzschia palea (367,500 cell/mL) and Navicula tripunctata (1,107,500 cell/mL). In the exponential phase, N. palea presented the highest growth rate, the highest divisions per day and the shortest generation time. On the contrary, D. salina presented a lower growth rate, lower divisions per day and longer generation time. Statistical tests indicated significant differences between the cultures and the multiple range a posteriori test showed that D. salina was the species with different population growth, making it suitable for mass cultivation for commercial purposes to obtain bioproducts [ABSTRACT FROM AUTHOR]

Copyright of Revista de Toxicología is the property of Asociacion Espanola de Toxicologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: the bioassay with the bioindicator species Daphnia magna Strauss, 1820 makes it possible to obtain the individual acute ecotoxicological effect and in a mixture of various chemical toxics by means of the mean lethal concentration (LC50). Objective: to determine the ecotoxicological effect of the mixture of aroclor 1254 and lead (Pb2+) on D. magna. Materials and Methods: LC50 was measured with arochlor 1254> Pb2+, and subsequently the concentration without ecological effect (PNEC) for the individual effect and as a mixture. PNEC values were contrasted with category 4-E1 (lagoons and lakes) and E2 (rivers) of the Peruvian Environmental Quality Standard (Supreme Decree No. 004 2017-MINAM-Peru). Results: LC50 values gradually decreased after 48 h of exposure for both compounds individually and as a mixture. The proportion-synergy (PS) was calculated in ratios of 1:1, 3:2 and 4:1 (arochlor 1254: Pb2+), obtaining higher PS values in 3:2 and 4:1 in contrast to 1:1. Conclusions: the PNEC estimated arochlor 1254 concentration is similar to the conservation value of the aquatic environment category 4-E1 and E2, and the maximum concentration for Pb2+ is not adequate and should be reduced to strengthen the conservation of aquatic biota. Finally, the bioindicator D. magna ideally determined the mixture of aroclor 1254 and Pb2+. [ABSTRACT FROM AUTHOR]

Antecedentes: las larvas de Dermatobia hominis causan miasis subcutáneas en animales y humanos de las zonas neotropicales. Esto obliga a buscar alternativas eficientes y sostenibles para su control. Dentro de estas‚ destacan los productos tópicos‚ que presentan ventajas sobre los sistémicos. Para las investigaciones con estos productos tópicos se requieren ensayos in vivo‚ pues se carece de pruebas in vitro. Objetivo: diseñar y estandarizar una prueba in vitro para la evaluación de productos tópicos para el control de D. hominis. Métodos: se colectaron 112 larvas procedentes de una miasis natural en bovinos; se lavaron con solución salina fisiológica y Gentamicina (80 mg/mL); posteriormente cada larva se depositó en viales estériles que contenían MEM Eagle y se transportaron al laboratorio de parasitología de la Universidad de Ciencias Aplicadas y Ambientales. Las larvas se distribuyeron de manera homogénea en cuatro grupos y se agregó a cada vial un tratamiento diferente: T1-Diclorvos 10 %; T2- Ivermectina 1 %; T3-Dimetil sulfoxido y T4- Solución salina fisiológica. Se estableció como tiempo de evaluación de muerte larvaria los minutos: 1‚ 60‚ 240‚ 1440‚ 2880 y 4320 postratamiento. Se realizó un análisis de supervivencia de Kaplan-Meier utilizando el programa GraphPad Prism‚ seguido de una prueba de rango logarítmico con comparaciones por pares para determinar las diferencias en la supervivencia de las larvas entre los tratamientos. Así mismo‚ se analizó la mortalidad bruta y mortalidad ajustada de Abbott. Resultados: se encontró que los tratamientos T1 y T2‚ tienen una mortalidad del 50 % alrededor de los 240 minutos de iniciado el ensayo‚ mientras que los tratamientos T3 y T4 alcanzan el 50 % de mortalidad cerca de los 1440 minutos. Por otro lado‚ los tratamientos T1 y T2 comparados con T3 y T4‚ tuvieron diferencias significativas (p < 0‚0001)‚ mostrando efecto en la probabilidad de supervivencia. Conclusión: el bioensayo larvicida demostró ser una herramienta útil para evaluar la eficacia de los diferentes preparados de uso tópico empleados. Este bioensayo fue rápido‚ sencillo y confiable para monitorear la eficacia de los productos evaluados. [ABSTRACT FROM AUTHOR]

The marine-estuarine polychaete Capitella capitata is an endobenthic species which is considered as a cosmopolitan organism. The laboratory culture of this species-complex allows its use as a test species in toxicity bioassays and reproduction studies. Objective: It is pretended to observe mortality under two temperature and salinity ranges as optimal conditions to culture Capitella sp. in the laboratory. Metodology: Polychaetes were collected in Callao Province, Peru, during November 2016 and January 2017. A bioassay was carried out to observe mortality under different temperature and salinity ranges using two treatments: treatment 1, with polychaetes collected during January 2017, which were subjected to conditions similar to the collection site (temperature: 20-22° C, salinity: 30-32 psu); treatment 2, with the organisms collected during November 2016, with temperature (24-26 °C) and salinity (32 a 34 ups) selected according to bibliographic data. Results: The increase of temperature and time significantly influenced polychaete mortality of the two treatments (Spearman correlation), while salinity and dissolved oxygen did not show correlation with mortality. Significant effect of time was observed on mortality, with more deaths from the second half of the experiment. Organisms from treatment 1, with environmental conditions similar to those of their habitat survived more than worms from treatment 2. These results were also observed in the porcentual varibility of the variation coefficient among days in each treatment. The cumulative mortality curve did not show differences between treatments. Conclusion: The optimal ranges to culture Capitella sp. in the laboratory are those from their habitat. In addition to temperature and time, other posible causes of the observed mortality can be worms age, health or maturity, and probably the bad quality of the water used during the bioassay. [ABSTRACT FROM AUTHOR]

Copyright of Archivos Latinoamericanos de Nutrición is the property of Sociedad Latinoamericana de Nutricion and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Veterinaria is the property of Universidad Nacional del Nordeste and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de Toxicología is the property of Asociacion Espanola de Toxicologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de Toxicología is the property of Asociacion Espanola de Toxicologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Agro Productividad is the property of Colegio de Postgraduados and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Vitrofural® is an additive used for the chemical sterilization of plant culture media in the in vitro propagation of plants. At the end of its use, it becomes a waste of the biotechnological process and is dumped into confined terrestrial environments. Nevertheless, the possible ecotoxicological impacts that could occur are unknown. The aim of this work was to determine the acute toxicity of earthworms (Eisenia foetida) by exposure to Vitrofural® residues on agar. The toxic potential of the waste was evaluated by single exposure to earthworms for 14 days. Worms were exposed by contact and ingestion at a concentration corresponding to the maximum possible to be obtained from lixiviate of the solid residue of Vitrofural® on agar, after 7 and 21 days of preparation. The number of dead animals and the loss of body mass were quantified, and the sublethal toxic signs were described. In the experimental groups there was no mortality, only slight morphological and physiological alterations were observed with a tendency to decrease in frequency in the group exposed to the lixiviates with 21 days of preparation. Similar response was observed in the evolution of body mass. The lixiviated of Vitrofural® in agarized medium induce slight sublethal effects in earthworms a function of the preparation time and demonstrate the absence of ecotoxicological risk due to exposure in this specie. [ABSTRACT FROM AUTHOR]

Copyright of BIOAGRO is the property of Revista BIOAGRO and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This research evaluated the ability of the life suspended microalgae Chlorella sp. to remove the color from the effluent of a textile company in the department of Atlantic (Colombia). The microalgae was cultured in a bioreactor of 2,5 L of effective capacity, using a commercial fertilizer as growth medium under continued aeration at laboratory temperature, in light/dark photoperiods of 12 hours each. Then the wastewater was treated using different concentrations of microalgae equivalent to 0,10, 0,20 and 0,30 absorbance units, with their respective controls. The results show that at the absorbance 0,30 bio-test, it was removed 97,2% of the dye originally present, COD decreased by 94,6% and DBO5 by 95,4%. These results suggest that the biological treatment with microalgae Chlorella sp. in wastewater is an efficient method. [ABSTRACT FROM AUTHOR]

This research evaluated the insecticidal activity of various native isolates of Bacillus thuringiensis against Spodoptera frugiperda, From Soils of Funza and Silvania (Cundinamarca) Tunja (Boyacá) in crops of beans, peas, maize and orange compared with a commercial witness HD1 (subsp. Kurstaki) against S. frugiperda. LC50 lethal concentration average was initially determined by the "probit" method, which was 5.88 E-4 mg ai / ml of diet, strain HD1 with different doses (0.0; 6.8 E-2; 3.4E-2 ; 6.8E-3; 6.8E-4; 6.8E-5 6.8E-6 and ai mg / ml diet) in first instar larvae S. frugiperda. In addition to qualitative observations mortality was measured at 96 and 120 hours. Subsequently the determined median lethal concentration (LC50) with strain HD1 proceeded to use this concentration in each native B. thuringiensis isolates to be compared with the commercial control CL50. Design was completely randomized with 7 treatments (each with 25 first instar larvae) and 3 replications. For the second test determining promissory isolates of Bt, a completely randomized design with 11 treatments (each with 20 first instar larvae) and 3 replications was arranged. Results indicated that M3008 and M4001 native isolates have higher mortality averages, which were 75% and 71.65% respectively in first instar larvae in purified diet, compared with mortality LC50 of commercial control. [ABSTRACT FROM AUTHOR]

Glyphosate is an herbicide that is widely used in Colombia not only for farming, but also for illicit crop eradication. Wind drift in air spraying and the lixiviation of this product can contaminate water bodies and for this reason, it is important to measure its toxic effect. Fish such as the Poecilla reticulata were submitted to concentrations of 0; 2.3; 5.5; 8.3; 11.0; 13.8 mg of glyphosate/L in the commercial formula Roundup® 747 SG/L to determine the mortality of treated individuals and the lethal concentration 50 (LC50-96) in lab conditions. Mortality was tested at 24, 48, 72, and 96 hours, and we were able to find that it increased as the herbicide concentration and the time elapsed increased. We also noticed a variation in the swimming pattern of the fish studied. The value of the 50-lethal concentration glyphosate over P. reticulata during the first 96 hours that the treatment was applied was of 3.14 mg/L, which suggests an ecological impact in natural ecosystems and a potential use of this type of fish as a contamination bioindicator for this herbicide in extreme toxicity tests. [ABSTRACT FROM AUTHOR]

Copyright of Biomédica: Revista del Instituto Nacional de Salud is the property of Instituto Nacional de Salud of Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Biomédica: Revista del Instituto Nacional de Salud is the property of Instituto Nacional de Salud of Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Innotec is the property of Laboratorio Tecnologico del Uruguay and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fitosanidad is the property of Instituto de Investigaciones de Sanidad Vegetal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In Colombia, the vigilance of the Maximum Residue Limits MRLs of veterinary antimicrobials in cattle meat is limited, because the analytical capacity is insufficient to monitor a large number of samples and a wide range of antibiotics. The bioassay is a microbiological method developed by the health public agency (FSIS) of the United States Department of Agriculture (USDA) for the detection, identification and semiquantification of antimicrobial residues in cattle muscle. Objective: It was evaluated preliminary the bioassay for use as a test for the qualitative detection for monitoring and surveillance of four antimicrobials in cattle muscle, as contribution to the inocuity management system within the agreement framework about the application of Sanitary and Phytosanitary Measures; using some guidelines of the European Decision 2002/657/EC. Methods: The experimental protocol used fortified tissues with varying concentrations of penicillin G potassium, Oxytetracycline, erythromycin and streptomycin, as representatives of the four important families of veterinary antibiotics used in Colombia. To establish the performance criteria of the bioassay were prepared six replicates of each of the levels or concentrations tested for antimicrobial, including a level without fortification and five levels of lower antibiotic concentrations, equal and above MRL Maximum Residue Limit for each one of the tested antimicrobials. Results: The performance characteristics of method were preliminarily determined (specificity, detection limits and stability). The test showed excellent specificity (no false positive); detection limits were determined for the four antibiotics in relation to their respective Maximum Residue Limit MRLs: Beta-lactams (penicillin G =MRL), tetracyclines (Oxytetracycline =MRL), macrolides (erythromycin =MRL) and aminoglycosides (streptomycin >4 MRL); however, the sensitivity of bioassay for the streptomycin was unsatisfactory. Stability of the analytes in the matrix was adequate during the period evaluated. Conclusions: The preliminary bioassay method evaluated is applicable to the detection of a broad range of antimicrobial residues in bovine muscle at concentrations at the MRLs. [ABSTRACT FROM AUTHOR]

This research was conducted with the objective of evaluating a strategy agroecological management of fruit borer Neoleucinodes elegantalis. Homeopathic treatments were evaluated three CH4, CH7 and CH14, using the principle of isopathy. Bioassays weretested the three homeopathic solutions, the treatments CH4, CH7 presented a lower number of eggs and larvae per fruit, which showed statistically significant differences versus water control according to Duncan's test. For variable rate hatching of eggs showed no statistical differences between treatments. then in the field, compared homeopathic solution (CH4) with a absolute control. The results of this trial indicated that was presented fewer damaged fruits per plant using CH4, presenting significant differences with the control from the third tothe seventh evaluation.In the variable percentage of fruit losses caused by the pest were statistical differences from the third evaluation for the solution CH4 showing the least damage.Thisstudy allowed to recognize the effectiveness of homeopathic remedies Neoleucinodes elegantalis control, as well as base projectsfor agro-ecological studies and subsequent homeopathic management integrated pest management. [ABSTRACT FROM AUTHOR]

Copyright of Archivos Latinoamericanos de Nutrición is the property of Sociedad Latinoamericana de Nutricion and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To estimate the metabolism of the food consumed by ruminants, various nutritional analysis techniques have been developed to provide valuable information for research into animal nutrition. Objectives include criteria to increase productive efficiency in tropical production systems, particularly when tropical forages are the nutritional basis for ruminants. Thus, the motivation to review and document different digestibility techniques to determine the best choice among national and international references. The aim was to review the literature about forage digestibility techniques developed for estimating the overall behavior of foods in ruminants. More than 50 references were reviewed, obtaining information on in vivo, in situ and in vitro digestibility techniques along with their limitations and advantages. It can thus be inferred that these techniques have become very important biotrial tools, given that they are easy to carry out, reduce costs and can be applied locally. They provide valuable information, particularly in view of the small number of studies on tropical forages. Based on the forage digestibility techniques findings, we may conclude that the in vitro gas production digestibility technique is the most versatile tool, with accessible and instructive procedures and at lower cost; it is also more compatible with animal welfare regulations carried out regarding the inoculums used, given the need for protocol standardization and because kinetic behavior in the trials has not produced the expected results. because it uses feces as inoculums. However, further studies need to be [ABSTRACT FROM AUTHOR]

Copyright of BIOAGRO is the property of Revista BIOAGRO and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper is aimed at divulging the fundamental notions related to the brine shrimp (Artemia spp.) bioassay among the researchers of our country. General biological characteristics of this organism, different experimental variants of the bioassay and their applications, as well as their advantages and disadvantages are summarized. Several examples about the advances achieved with the application of this bioassay are included promoting its use by ecolotoxicologists and specialists of natural products, mainly those concerned with the discovery and development of new natural pesticides. [ABSTRACT FROM AUTHOR]

This research evaluated the toxicity of ten pesticides used in the municipality of Popayan, Colombia, using bioassays with Bacillus subtillis, ATCC 6633, employing the disk diffusion method. For this study, was used the commercial formulation, because we want to know toxicity of these agrochemicals in the presentation used by farmer. Results showed that four groups of pesticides according to the magnitude of toxic effect, the first group is composed by Combo, Tamaron and Furadan, insecticides, which showed no toxicit~ The second group was lightly toxic, which was Lorsban insecticide with 42% of toxicity followed by moderately toxic, among those are Tordon, Gramoxone and Roundup herbicides, with a toxicity of 51.6%, 50.5% and 49.0% respectively. Finally the group of highly toxic, are Manzate, Curzate and Format fungicides, with a toxicity of 79. 3% 69.5% and 63.45% respectively. The analysis of variances, showed a significant differences between pesticides and between concentrations (p = 0.000). The differences depends of the type of pesticides and the concentration used, because the interaction pesticide - concentration was s#gnificant statistically (p = 0,000). [ABSTRACT FROM AUTHOR]

Chromium toxicity assessment of marine sediments in Peru is a topic of increasing interest. Mean lethal concentration of chromium (Cr+6) using the marine bivalve Donax obesulus Reeve 1854 (Pelecypoda: Donacidae) at 24 h, 48 h and 96 h of exposure was assessed, as well as its burying ability in a chromium (Cr+6) sediment. For D. obesulus acclimatization and rearing the marine microalga Dunaliella tertiolecta Butcher was employed. The assay was performed with 22.4 mm ± 1.5 mm D. obesulus adults. Mean lethal concentration (LC50) in chromium Cr+6 D. obesulus marine sediment was 410.4 mg·kg-1, 156.1 mg·kg-1 and 61.12 mg·kg-1 at 24 h, 48 h and 96 h of exposure, respectively. A guideline value proposed by Long et al. (1995) for chromium in an aquatic sediment is 370 mg·kg-1. The results obtained in terms of LC50 at 48 h and 96 h for D. obesulus, exposed to chromium, were 57.8% and 83.5%, lower than the guideline value, respectively. Chromium presented a notorious sublethal effect on D. obesulus burying ability at 48 h of exposure. The protocol using D. obesulus has advantages in terms of sensibility, easy use, simplicity of reading, low cost and ecological realism. [ABSTRACT FROM AUTHOR]

Copyright of Investigaciones ANDINA is the property of Fundacion Universitaria del Area Andina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The level of contamination in sediments from several sites on the coast of Galicia (Spain) diversely affected by the Prestige oil spill was evaluated 18 months after the accident. Data of metal and total hydrocarbon concentrations in sediments were integrated with data on the toxicity of these sediments on sea urchin embryos, obtained through bioassays using an aqueous sediment extract (elutriate) containing the soluble phase of fuel. The results of the chemical analyses show that significantly high levels of hydrocarbons and metals accumulate at some localities. Moreover, in some of these cases, they can enter the water column and become available to planktonic organisms, as shown by the results of the bioassays using the larval phases of a local species of sea urchin (Paracentrotus lividus). [ABSTRACT FROM AUTHOR]

Interlaboratory variability was studied for the bioassay using crustacean amphipods. Nine series of data were obtained from different laboratories using four different species (Ampelisca brevicornis, Corophium volutator, Corophium multisetosum and Microdeutopus gryllotalpa), all previously used for sediment toxicity assessment in Spain. Results were studied for interlaboratory variability and according to different confounding factors. The coefficients of variation were similar to those previously reported for this bioassay and sample classification was homogeneous among the laboratories that succesfully completed the exercise. No significant tendencies related to test species were identified and it seems that the factor most critically affecting test results and the classification of samples is storage time before testing. [ABSTRACT FROM AUTHOR]

In Peru, marine microalgaes Isochrysis galbana Parke and Chaetoceros gracilis Schütt, are employed as food source for many zoological species of the marine trophic chain. During culture conditions they prevent the use of yeasts, diminishing the acidification of culture media and in that way, avoiding injuries to the marine aquaculture. Chromium is a pollutant of anthropogenic importance in the aquatic ecosystem. In this research, the effect of Cr+6 in form of K2Cr2O7 was analyzed in ecotoxicity inhibition microbioassays with marine microalgae, I. galbana and C. gracilis using an estimator of specific population growth to quantify ecotoxicity responses. Bioassays were performed providing results related to the sensibility to K2Cr2O7 analysis, productivity, cost-efficiency and their potential application as tools for routine environmental monitoring. The values of medial Concentration of Inhibition (IC50) from 24 h to 120 h for I. galbana were: 11.55 mg L-1 (8.15 - 16.38) (24 h); 14.14 mg L-1 (11.60 - 17.24) (48 h); 4.47 mg L-1 (3.24 - 6.15) (72 h); 11.94 mg L-1 (8.14- 17.49) (96 h) and 19.20 mg L-1 (13.64- 27.26) (120 h). Conversely the values of IC50 from 24 h to 120 h for C. gracilis were: 9.21 mg L-1 (7.46 - 11.08) (24 h); 8.13 mg L-1 (2.09 - 15.24) (48 h); 12.51 mg L-1 (6.80 - 20.04) (72 h); 12.17 mg L-1 (2.23-34.32) (96 h) and 13.34 mg L-1 (1.19- 77.61) (120 h). Temperature and pH values were evaluated in all bioassays. The toxicity of chromium was compared with other aquatic microbioassays. Finally, perspectives of employing these ecotoxicological tools to evaluate environmental risk assessment of chromium in Peru are analyzed. [ABSTRACT FROM AUTHOR]

Environmental Risk Assessment (ERA) of freshwater environment in Peru needs the employment of standardized biological organisms such as the larval midge Ohironomus calligraphus Goeldi. The biological organisms to be employed as ecotoxicological tools should be easy, practical, sensitive and reproductible. The aim of this research was to evaluate Cd+2, Hg+2 and Pb+2 as cadmium chlorure (CdCl2), mercury chlorure (HgCl2) and lead nitrate (Pb3(NO)2) forms, on the mortality of first instar larva of diptera C. calligraphus at 48 h exposure and in this way determinate its variability. The species was acclimated and reared under standardized laboratory conditions. Six bioassays of acute static toxicity for each metal were done, in each one a randomized block experimental design (RBED) was used with four repetitions of five concentrations and employing 240 larvae for each bioassay. The median lethal concentration (LC50) in µg metal L-1 at 48 h exposure and the coefficient of variation (CV %) were: 132 µg L-1 and 45,45 % for Cd+2; 127 µg L-1 and 22,83 % for Hg2+; and finally 18.730 µg L-1 and 33 % for Pb2+. The variability of the essay of C. calligraphus is compared with other freshwater biological organisms all over the world. [ABSTRACT FROM AUTHOR]