Effects of Cr III and Pb on the bioaccumulation and toxicity of Cd in tropical periphyton communities: Implications of pulsed metal exposures

• Published in: Environmental pollution (1987) 2012-04, Vol.163, p.184-191
• Main Authors: Bere, Taurai, Chia, Mathias Ahii, Tundisi, José Galizia
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Animal, plant and microbial ecology; Applied ecology; Archaea - drug effects; Archaea - growth & development; Archaea - physiology; Bacteria - drug effects; Bacteria - growth & development; Bioaccumulation; Biological and medical sciences; cadmium; Cadmium - metabolism; Cadmium - toxicity; chlorophyll; Chlorophyll - analysis; Chromium; Chromium - metabolism; Chromium - toxicity; Communities; Cr III; Ecotoxicology, biological effects of pollution; Environmental Monitoring; Exposure; Fundamental and applied biological sciences. Psychology; General aspects; lead; Lead (metal); Lead - metabolism; Lead - toxicity; lotic systems; Metal mixtures; Metal pulses; Microalgae - drug effects; Microalgae - growth & development; Microalgae - physiology; periphyton; Periphyton community; Rivers - chemistry; Rivers - microbiology; streams; Time measurements; Toxic; Toxicity; Toxicology; Water Pollutants, Chemical - metabolism; Water Pollutants, Chemical - toxicity
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2011.12.028

Metal exposure pattern, timing, frequency, duration, recovery period, metal type and interactions, has obscured effects on periphyton communities in lotic systems. The objective of this study was to investigate the effects of intermittent exposures of Cr III and Pb on Cd toxicity and bioaccumulation in tropical periphyton communities. Natural periphyton communities were transferred to artificial stream chambers and exposed to metal mixtures at different pulse timing, duration, frequency and recovery periods. Chlorophyll a, dry mass and metal accumulation kinetics were recorded. Cr and Pb decrease the toxic effects of Cd on periphyton communities. Periphyton has high Cd, Cr and Pb accumulation capacity. Cr and Pb reduced the levels of Cd sequestrated by periphyton communities. The closer the frequency and duration of the pulse is to a continuous exposure, the greater the effects of the contaminant on periphyton growth and metal bioaccumulation. Light increased toxic and accumulative effects of metals on the periphyton community. ► We investigated toxicity effects of pulsed metal exposures on bioaccumulation and toxicity in periphyton. ► High frequency of short duration pulses has effects equal to long duration exposures. ► Important role of light in modulating metal toxicity on periphyton demonstrated. ► Factors other than magnitude and duration must be considered in water quality criteria. ► Accurate prediction of metal effects on biofilms requires data on effluent variability. The study highlights the importance of pulse timing, frequency, duration, recovery period and chemical type on aquatic life.