Toxic effects of zinc from trout farm sediments on ATP, protein, and hemoglobin concentrations of Limnodrilus hoffmeisteri.

Zinc (Zn) is a nutritionally essential metal, and deficiency results in severe health consequences to aquatic organisms. In this study toxicity data for Limnodrilus hoffmeisteri produced by Zn in systems using three natural sediments (trout farms: El Oyamel, El Truchón, and El Potrero) are presented. Hemoglobin, adenosine triphosphate (ATP), and protein concentrations were measured in L. hoffmeisteri exposed to spiked sediments, as indicators of exposure. Physicochemical characteristics of water and sediments were also considered. Zn concentrations were measured in water and sediment. El Oyamel, El Truchón, and El Potrero pond sediments did not have similar physicochemical characteristics. Zn concentrations of water obtained from the rustic ponds were near 0.4575 mg/L; however, this metal was always found to be higher in the sediments (0.0271-0.9754 mg/kg). The bioassay with worms demonstrated that pond sediments from El Oyamel, El Potrero, and El Truchón produced toxicity since ATP and protein concentrations were low compared to controls (organisms without metal). All spiked sediments had a significant reduction effect on ATP, protein, and hemoglobin concentrations. This investigation clearly shows that sediments of El Truchón, El Oyamel, and El Potrero possess toxicity potential. These results suggest the usefulness of these bioassays to evaluate the toxicity of sediments polluted with heavy metals.

[Effect of carbaryl and lead on phenols, chlorophyll and proteins of the microalga Ankistrodesmus falcatus]. / Efecto del carbaril y del plomo sobre fenoles, clorofila y proteínas de la microalga Ankistrodesmus falcatus.

Considering that Ankistrodesmus falcatus is very sensitive to different pollutants, in this work the effect of lead, carbaryl and a mixture of both pollutants on protein, chlorophyll and phenols concentration in this microalga have been studied. At different lots of Ankistrodesmus falcatus in the middle of the log growth phase, different concentrations of lead, carbaryl and a mixture of both pollutants were added, during 24, 48 and 72 h. Chlorophyll, proteins and phenols concentration was measured. The results show that the mixture of lead-carbaryl produces a major toxic effect than the xenobiotics by themselves, so it has been suggested that to establish permissible limits it is necessary to consider the synergism presented in simultaneous exposure to both xenobiotics. It is suggested to use phenols determination as a primary indicator of environmental impact in an aquatic ecosystem.

Hemoglobin concentration and acetylcholinesterase activity of oligochaetes in relation to lead concentration in spiked sediments from Ignacio Ramirez reservoir.

This paper presents toxicity and uptake data of Limnodrilus hoffmeisteri generated by lead in systems using natural sediments from Ignacio Ramírez reservoir. Lead uptake, hemoglobin concentration, and acetylcholinesterase activity were studied in L. hoffmeisteri exposed to spiked sediments. All assays of lead uptake were conducted using whole sediments. Sediment texture was also considered. Acetylcholinesterase activity and hemoglobin concentration decreased after treatment with lead. Acetylcholinesterase activity and hemoglobin concentration tests indicated a response to the concentration of lead. These results suggest the usefulness of a diversity of bioassays to evaluate the toxicity of sediments polluted with heavy metals.