Impacts on water quality by in situ induced ozone‑oxygen oxidation in a polluted urban reservoir.

The results of the successful implementation of a treatment based on the injection of ozone (O) and oxygen (O) into a contaminated body of water are reported for the first time. Three decontaminating units (SCAVENGER™), which have the capacity to inject up to 120 g O/h and 250 Kg O/h in the form of microbubbles (90 ± 10 μm in diameter), were placed in the contaminated Valsequillo reservoir, Central Mexico. In order to evaluate the efficacy of the treatment, 20 physicochemical parameters, 18 organic compounds, 66 inorganic compounds and 11 biological indicators were measured before, during and after the treatment; all of them in several representative sites of the east side of the Valsequillo reservoir.

Effect of benomile fungicide in the demographics parameters of Ceriodaphnia reticulata Jurine, 1820 (Crustacea: Cladocera).

Benomile is one of the most used fungicides in the growing fields. In the rainy season brings benomilo with the planktonic communities. The effect of nominal concentrations of benomile under acute and chronic exposure was tested in the cladoceran Ceriodaphnia reticulata that were used.

Effects of copper and cadmium on cholinesterase and glutathione S-transferase activities of two marine gastropods (Monodonta lineata and Nucella lapillus).

With the view of using Nucella lapillus and Monodonta lineata as bioindicators in biomonitoring programs in the NW coast of Portugal, the sensitivity to copper and cadmium of these two common species in Atlantic coasts of Europe was investigated. Assays based on mortality and on the activity of the enzymes cholinesterases (ChE) and glutathione S-transferases (GST) were used, as these biomarkers have been used in biomonitoring studies in the area. ChEs present in foot muscle of both species were characterised and found to show properties of both typical acetylcholinesterase and pseudocholinesterase.

Effect of ammonia toxicity on the competition among three species of cladocerans (Crustacea: Cladocera).

Among the natural abiotic variables affecting the species density and composition of cladocerans, ammonia is important. Using population growth data as tool, we studied the competitive outcome of three cladoceran species (Ceriodaphnia dubia, Daphnia pulex, and Moina macrocopa) grown alone and together at three different concentrations (0, 25, and 100 mg L(-1)) of ammonia at one density (1 x 10(6)cells ml(-1)) of the microalga Chlorella vulgaris. Regardless of the presence or absence of competing species, C.

Combined effects of algal (Chlorella vulgaris) density and ammonia concentration on the population dynamics of Ceriodaphnia dubia and Moina macrocopa (Cladocera).

Ammonia is a natural variable in ponds and lakes. Although an important source of nitrogen for microalgae, at high concentrations ammonia can affect the density and diversity of cladocerans. Using the cladocerans Ceriodaphnia dubia, and Moina macrocopa, the effect of nominal concentrations of ammonium chloride under acute and chronic exposures at different levels of algal food was tested.