microcystin-yr and microcystin

Photocatalysis has been shown to successfully remove microcystins (MC) in laboratory experiments. Most research to date has been performed under ideal conditions in pure or ultrapure water. In this investigation the efficiency of photocatalysis using titanium dioxide was examined in a complex matrix (waste stabilisation lagoon water). A flow-through photocatalytic reactor was used for the photocatalytic removal of four commonly occurring microcystin analogues (MC-YR, MC-RR, MC-LR, and MC-LA). Up to 51% removal for single MC analogues in waste lagoon water was observed. Similar removal rates were observed when a mixture of all four MC analogues was treated. Although treatment of MC-containing cyanobacterial cells of Microcystis aeruginosa resulted in no decline in cell numbers or viability with the current reactor design and treatment regime, the photocatalytic treatment did improve the overall quality of waste lagoon water. This study demonstrates that despite the presence of natural organic matter the microcystins could be successfully degraded in a complex environmental matrix.

Topics: Cyanobacteria; Marine Toxins; Microcystins; Microcystis; Titanium; Waste Disposal, Fluid; Wastewater; Water Pollutants, Chemical

Topics: China; Cyanobacteria; Environmental Monitoring; Humans; Lactuca; Lakes; Marine Toxins; Microcystins; Plant Leaves; Risk Assessment; Soil

Microcystin (MC) accumulation was determined in the liver and muscle of two omnivorous fish species which are consumed and are economically important, and in a planktivorous-carnivorous fish from Lake Eğirdir, Turkey. Free extractable MCs in fish tissue samples were detected by enzyme-linked immunosorbent assay (ELISA) with confirmation by high performance liquid chromatography with photodiode array detection (HPLC-PDA). MC-LA and -YR, were detected in both liver and muscle, followed by MCs -LY, -LF, -RR and -LR respectively. The MC concentrations varied between 0.043 and 1.72μg/g dry weight in liver and muscle tissues. MCs were also determined in samples of water, sediment and a bloom sample of Microcystis aeruginosa from the lake by HPLC-PDA. MC-LY and -YR were most commonly identified in water samples, with total MC concentrations ranging from 2.9±0.05 to 13.5±2.3μg/L. Sediment analyses, showed that MC-YR was present in samples between 7.0 and 17.6μg/g dw, especially in October, November and December when no MC-YR was recorded in water, followed by MC-LW. The findings indicate that water and sediment contained MCs, and more importantly that fish were contaminated with MCs that may pose an MC-associated human health risk.

Topics: Animals; Environmental Monitoring; Enzyme-Linked Immunosorbent Assay; Fishes; Harmful Algal Bloom; Humans; Lakes; Microcystins; Microcystis; Turkey; Water Microbiology; Water Pollutants; Water Supply

A water bloom of Planktothrix (Oscillatoria) rubescens was observed in a drinking water reservoir in central Spain in 2003. Microcystins where analysed by LC/ESI-MS in 21 samples collected from this reservoir in five different days between March and May. A demethylated variant of microcystin-RR was identified as the major microcystin in most samples. Trace levels of microcystin-LR, -RR and -YR were detected in some samples. Four less common microcystins, with [M+H]+ ions at m/z 960, 981, 1045 and 1053, were also found. Total extracellular microcystin concentration varied from 0.010 to 19.126 microg l(-1). Furthermore, anabaenopeptins B and F as well as Oscillamide Y were also identified in these samples.

Topics: Bacterial Toxins; Chromatography, Liquid; Cyanobacteria; Marine Toxins; Microcystins; Molecular Structure; Peptides, Cyclic; Spain; Spectrometry, Mass, Electrospray Ionization; Water; Water Microbiology