Investigating The Sub-Acute Responses Of Lemna Minor, Pseudokirchneriella Subcapitata, Euglena Gracilis And Anodonta Grandis To Tributyltin-Hydride And Atrazine In Freshwater

Freshwater resources exist in limited quantities and are subject to increasing demands due to the consumption by residential, commercial and industrial uses. There are concerns that the widely used chemical analysis of drinking water does not deliver timely results. This study examines the efficacy of developing a holistic, multi-organism early-warning biomonitoring technology to assess aquatic toxicity. Sensitive indicator species such as Lemna minor, Pseudokirchneriella subcapitata, Euglena gracilis, and Anodonta grandis have been selected due to their specific behavioural and short-term biochemical responses in the identification of classes of contaminants in aquatic environments. Tributyltin, an antifouling agent in paints used on boats and atrazine, an herbicide widely used on agricultural crops, are evaluated in increasing concentrations to identify behavioural changes in these organisms. These graded responses, upon implementation in models, will warn water treatment operators of incoming contaminants and help identify the nature of the stressor. All organisms displayed some sensitivity to selected concentrations of the two test chemicals. The normal growth rate of L. minor dramatically declined with exposure to TBT (100.0 mg/L) and atrazine (500.0 g/L). Monitoring the biochemical changes, dissolved oxygen production, and also the growth rate, cell counts, of P. subcapitata showed significant effects to similar concentrations of TBT (100.00 g/L) and atrazine (500.00 g/L). The aquatic protest, E. gracilis, alters its cell morphology in the presence of low concentrations of TBT (10.0 g/L) and atrazine (50.0 g/L). Respiration patters of the bivalve, A. grandis, was directly influenced by the two chemicals, TBT (1.0 mg/L) and atrazine (50.0 mg/L). This study demonstrates that biological assessments of water samples deliver a rapid, realistic representation of the surrounding aquatic environment conditions.

Investigating The Sub-Acute Responses Of Lemna Minor, Pseudokirchneriella Subcapitata, Euglena Gracilis And Anodonta Grandis To Tributyltin-Hydride And Atrazine In Freshwater

Freshwater resources exist in limited quantities and are subject to increasing demands due to the consumption by residential, commercial and industrial uses. There are concerns that the widely used chemical analysis of drinking water does not deliver timely results. This study examines the efficacy of developing a holistic, multi-organism early-warning biomonitoring technology to assess aquatic toxicity. Sensitive indicator species such as Lemna minor, Pseudokirchneriella subcapitata, Euglena gracilis, and Anodonta grandis have been selected due to their specific behavioural and short-term biochemical responses in the identification of classes of contaminants in aquatic environments. Tributyltin, an antifouling agent in paints used on boats and atrazine, an herbicide widely used on agricultural crops, are evaluated in increasing concentrations to identify behavioural changes in these organisms. These graded responses, upon implementation in models, will warn water treatment operators of incoming contaminants and help identify the nature of the stressor. All organisms displayed some sensitivity to selected concentrations of the two test chemicals. The normal growth rate of L. minor dramatically declined with exposure to TBT (100.0 mg/L) and atrazine (500.0 g/L). Monitoring the biochemical changes, dissolved oxygen production, and also the growth rate, cell counts, of P. subcapitata showed significant effects to similar concentrations of TBT (100.00 g/L) and atrazine (500.00 g/L). The aquatic protest, E. gracilis, alters its cell morphology in the presence of low concentrations of TBT (10.0 g/L) and atrazine (50.0 g/L). Respiration patters of the bivalve, A. grandis, was directly influenced by the two chemicals, TBT (1.0 mg/L) and atrazine (50.0 mg/L). This study demonstrates that biological assessments of water samples deliver a rapid, realistic representation of the surrounding aquatic environment conditions.

Accumulation of Cd by a freshwater mussel (Pyganodon grandis) is reduced in the presence of Cu, Zn, Pb, and Ni

The effects of a metal mixture on Cd bioavailability and uptake in the freshwater mussel Pyganodon grandis (formerly Anodonta grandis grandis) were investigated in a limnocorral experiment in a Precambrian Shield lake during the summer of 1992. Differences in the partitioning of Cd in water, sediment, and mussels were identified between limnocorrals treated with Cd alone or with Cd and a mixture of metals (Cu, Zn, Pb, and Ni) at three concentration levels. Loss of Cd from the water column was slower in treatments with the metal mixture (22- to 34-day half-life) than in the treatment with Cd alone (11-day half-life). Despite the higher concentrations of Cd in the water column in treatments with the mixture of metals, the mussels accumulated proportionally less Cd as the metal concentrations increased. These relationships were observed in mussels exposed for 40 days ([Cd] <4.4 µg·L-1) and 80 days ([Cd] = 4-14 µg·L-1). The uncoupling of the effects of the metal mixture on Cd bioavailability and uptake suggests that laboratory studies may be appropriate for characterizing metal uptake in mussels exposed to mixtures of metals under nonequilibrium conditions. The significant deviation in the behavior of Cd in the presence of the metal mixture emphasizes the need to further investigate regulatory approaches that focus on individual contaminants.

Accumulation and elimination of cyanobacterial hepatotoxins by the freshwater clam Anodonta grandis simpsoniana

Freshwater clams (Anodonta grandis simpsoniana) exposed to 51-55 µg · L-1 of dissolved microcystin-LR (MC-LR) in the laboratory for 3 days did not accumulate MC-LR equivalents (MC-LReq). However, clams placed in three eutrophic lakes with phytoplankton containing MC-LR (concentrations from below detection to 8.3 µg · L-1 cellular toxin) for 12-28 days accumulated the toxin (24 ± 7 to 527 ± 330 ng · g-1 MC-LReq; mean ± SE). The relative MC-LReq concentrations in clams reflected MC-LR concentrations in lake phytoplankton, but individual variation was high. In individual clams exposed for 24 days, the average MC-LReq concentration was usually greater in the visceral mass than in gills and muscle, but average toxin concentrations in the three tissues were similar (587, 310, and 364 ng · g dry weight-1). In clams removed from the lake and placed in toxin-free water, MC-LReq concentrations in tissues declined rapidly for 6 days (by 69-88%) but remained relatively stable for the remaining 15 days. Analysis of clam tissues appears to be a more sensitive MC-LR indicator than analysis of phytoplankton. Accumulation of potent cyanobacterial toxins by this clam warrants further study as many are consumed by muskrats (Ondatra zibethicus), which in turn are consumed by terrestrial predators.