RESUMEN
In a world where pristine water is becoming scarcer, the need to reuse water becomes imperative. In this context explaining the water quality, purpose fitness and the parameters or conditions of the water body to adjust so as to improve its quality, are of great relevance. The goal of the present study was the use of water, riverine, and biodiversity quality indices to assess the condition of the studied urban wetland, since no single index can provide a complete health assessment of a water body. Decision trees were also used to elucidate the best water parameters to mend in order to recover the overall health of the urban wetland. The decision trees identified relevant physicochemical parameters as well as their approximate concentration at which a healthy water environment can be sustained for zooplankton and proved to be a powerful and simple alternative to customary approaches. Suspended particles and phosphates proved to be important parameters with concentrations approximately lower than 88 mg L-1 and 11 mg L-1, respectively, for a good biodiversity index of zooplankton. Ammonia, total coliforms, BOD, nitrates, and sodium were the main parameters that affected the water quality index. The vegetation coverage and its structure were the driving factors in the riverine quality index of the wetland.
Asunto(s)
Monitoreo del Ambiente , Humedales , Animales , Biodiversidad , Árboles de Decisión , Calidad del AguaRESUMEN
In the present work, we quantified the harmful effects of Cd(+ 2) to Brachionus macracanthus using both acute (median lethal) and chronic (population growth) toxicity tests. Chronic toxicity tests were conducted under 4 different concentrations (0.000625-0.005 mg L(- 1)) of cadmium chloride at 23 degrees C under 3 food (Chlorella vulgaris) levels (0.5 x 10(6), 1.0 x 10(6) and 2.0 x 10(6) cells mL(- 1)) using static renewal system for three weeks. The median lethal concentration bioassayed at 24 h (LC(50)) for B. macracanthus was 0.19 mg L(- 1) of CdCl(2). Cadmium adversely affected the population growth of B. macracanthus at all tested concentrations. Increase in algal food had a positive effect on the rotifer growth in controls; with increase in Cd levels, the population growth of B. macracanthus decreased even under the highest food level tested. The peak population abundance of B. macracanthus in controls at the highest food level of 2.0 x 10(6) cells mL(- 1) was 40 ind. mL(- 1). Depending on the heavy metal concentration and the algal level, the population growth rate (r) of B. macracanthus varied from 0.02 to 0.28 day(- 1). The relatively higher sensitivity of B. macracanthus to cadmium toxicity is discussed in relation to other species of the same genus.