Biotreatment of wastewater using aquatic invertebrates, Daphnia magna and Paramecium caudatum.

A number of major changes have occurred over the past few years, which give cause for a re-examination of conventional wastewater treatment methods. Among these are growing problems of worldwide energy and food shortages and nutrients not removed by conventional secondary processes causing algal blooms and other problems in the receiving waters. The global increase in wastewater calls for innovative low cost technology approaches to its recycling. Biotreatment systems, utilizing living organisms are receiving growing attention since they are ecologically sound, cheap and applicable in areas without land constraints. Filter feeders (both invertebrates and vertebrates) are promising in this area since they can remove suspended organic matter and bacteria, even in the size range of microns. In the present study biological treatment of municipal wastewater using two invertebrates--Paramecium caudatum, a protozoan and Daphnia magna, a cladoceran was investigated. Analysis at pre-experimental and post-experimental stages revealed the potential of these species in abatement of water pollution. D. magna was more efficient than P. caudatum in laboratory-scale studies.

Removal of chromium by two aquatic pteridophytes.

In the recent years, the use of phytoremediation for ameliorating metal pollution has been gaining ground. This study explores the. possibility of utilising two common aquatic ferns, Salvinia molesta Mitchell and Azolla rubra R.Br. for scavenging chromium from solutions. Chromium removal from spiked solutions ranged from 40-99% during the seven day exposure. Results reveal their bioremoval capabilities and potentialfor use in wastewater decontaminant

Negative inotropic response to cerium in ventricular papillary muscle is mediated by reactive oxygen species.

This study was performed with the objective of assessing the mechanical response of the myocardium to different levels of cerium and delineation of the mechanism underlying the mediation of the functional changes. Rat ventricular papillary muscle was used as the experimental model. Isolated papillary muscles were exposed to different concentrations of CeCl3 and the force of contraction was measured using a force transducer. Experiments have revealed that the negative inotropic response to CeCl3 was proportional to its concentration. The inotropic changes were found to be completely reversible at concentrations < or =5 microM, and partially reversible at higher concentrations. Neutralization of cerium-induced inotropic changes by the superoxide anion scavenger superoxide dismutase (SOD) at concentrations < or =5 microM indicates that the mechanical changes are mediated by reactive oxygen species. At higher concentrations of Ce3+, SOD partially reversed the contractile changes. The beneficial effect of SOD was seen only if the muscles were pretreated with the scavenger prior to the addition of cerium chloride.