EFFECTS OF HARDNESS, ALKALINITY AND pH ON THE TOXICITY OF PENTACHLOROPHENOL TO SELENASTRUM CAPRICORNUTUM (PRINTZ)

Smith, P. D.; Brockway, D. L.; Stancil, F. E.

doi:10.1897/1552-8618(1987)6[891:eohaap]2.0.co;2

Cited by 10 publications

(7 citation statements)

References 21 publications

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“…The toxicity of 3,5‐DCP decreased with pH, similar to findings for pentachlorophenol (PCP) by Smith et al [23]. The initial pH of the different standard methods varies between pH 7.5 and 8.3.…”

Section: Discussionsupporting

confidence: 82%

Influence of growth conditions on the results obtained in algal toxicity tests

Mayer

Frickmann

Christensen

et al. 1998

Enviro Toxic and Chemistry

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The influence of test conditions on results from algal growth inhibition tests was investigated for the toxicants atrazine, 3,4‐dichloroaniline, 3,5‐dichlorophenol, and potassium dichromate. Emphasis was put on the following four main factors: light, temperature, nitrogen source, and pH. The green alga Selenastrum capricornutum was grown in batch cultures, and the toxic response was measured as reduction in average growth rate, relative to controls. Multifactor experiments were carried out to investigate the effects of the above four factors as well as the interactions between them: light intensity (44 and 198 μE/m2/s), temperature (16 and 26°C), nitrogen source (NH +4 and NO −3), and pH of the medium (7.5 and 8.6). Within the data set generated, the highest and lowest median effective concentration estimate differed by a factor of 3.8. The sensitivity of the test system to 3,4‐dichloroaniline, potassium dichromate, and 3,5‐dichlorophenol was less under light limitation than under light saturation. Conversely, with the photosynthetic inhibitor atrazine a reduced sensitivity was found at high light intensity, which, however, was high enough to cause slight photoinhibition. The inhibitory response to the weak organic acid 3,5‐dichlorophenol was less at the high than at the low pH level, which stems from the fact that neutral species of ionizable compounds are usually more toxic than charged species. No effect of the nitrogen source on inhibitory responses could be ascertained, and temperature influenced the results only indirectly by interacting with light (the saturation intensity increases with temperature). It is concluded that the light intensity in standardized algal toxicity tests could preferably be increased to achieve light‐saturated photosynthesis as this may potentially reduce test result variability.

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Section: Discussionsupporting

confidence: 82%

Influence of growth conditions on the results obtained in algal toxicity tests

Mayer

Frickmann

Christensen

et al. 1998

Enviro Toxic and Chemistry

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“…The toxicity of heavy metals can be influenced by external factors, such as pH and components of the media (Smith et al, 1987;Hall et al, 1989;Huebert et al, 1993;Dirilgen, 1998). The responses of L. paucicostata to six heavy metals were very rapid; in only 24 h the effect of the nutrients in the culture media could be overlooked.…”

Section: Discussionmentioning

confidence: 99%

A novel response of wild‐type duckweed (Lemna paucicostata Hegelm.) to heavy metals

Xiong

2004

Environmental Toxicology

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The responses of wild-type Lemna paucicostata, used as the experimental stock, to seven heavy metals were investigated with a hydroponic culture in a culture facility. The results showed that six of the metals could induce L. paucicostata to release daughter fronds from the mother frond before maturity, resulting in breakup of the colony. This phenomenon is novel and has not been reported before. Six of the heavy metals investigated-copper, cadmium, nickel, zinc, mercury, and chromium-could induce this response, but sensitivity and response of the plant varied. When Cu(2+) at a concentration of 0.2 micromol/L was added, the response was significantly different from that of the control after a 2-h exposure. The response to cadmium (0.8 micromol/L) was significantly different after a 6-h exposure; to zinc (10 micromol/L) and nickel (5 micromol/L), after 5 and 7 h, respectively. But for lead, even at a concentration of 80 micromol/L for 96 h, no colony breakup was induced. The response to heavy metals occurred within 24 h; increasing the exposure by another 24 h had nearly no additional effect on the colony breakup. When the response was over, the number of colonies with fronds varied with the inducement capacity of the metal. Nutrients could affect the sensitivity of L. paucicostata to some heavy metals, such as mercury, chromium, zinc, and nickel, but not to copper and cadmium. Sensitivity was also changed when CuCl(2) was used as the copper source instead of CuSO(4). These results indicate that some heavy metals could serve as a toxicant for inducing L. paucicostata to release daughter fronds in advance. This change might involve a stress response such as ethylene production. Also discussed is the possibility of this response as a biomarker in a bioassay.

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“…They are potent uncouplers of oxidative photophosphorylation [12]. Pentachlorophenol has several sites of action, including photophosphorylation, protein synthesis, and lipid biosynthesis [13].…”

Section: Mechanisms Of Pesticide Actionmentioning

confidence: 99%

Toxicity of pesticides to aquatic microorganisms: A review

DeLorenzo

Scott

Ross

2001

Enviro Toxic and Chemistry

452

173

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Microorganisms contribute significantly to primary production, nutrient cycling, and decomposition in estuarine eco-systems; therefore, detrimental effects of pesticides on microbial species may have subsequent impacts on higher trophic levels. Pesticides may affect estuarine microorganisms via spills, runoff, and drift. Both the structure and the function of microbial communities may be impaired by pesticide toxicity. Pesticides may also be metabolized or bioaccumulated by microorganisms. Mechanisms of toxicity vary, depending on the type of pesticide and the microbial species exposed. Herbicides are generally most toxic to phototrophic microorganisms, exhibiting toxicity by disrupting photosynthesis. Atrazine is the most widely used and most extensively studied herbicide. Toxic effects of organophosphate and organochlorine insecticides on microbial species have also been demonstrated, although their mechanisms of toxicity in such nontarget species remain unclear. There is a great deal of variability in the toxicity of even a single pesticide among microbial species. When attempting to predict the toxicity of pesticides in estuarine ecosystems, effects of pesticide mixtures and interactions with nutrients should be considered. The toxicity of pesticides to aquatic microorganisms, especially bacteria and protozoa, is an area of research requiring further study.

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EFFECTS OF HARDNESS, ALKALINITY AND pH ON THE TOXICITY OF PENTACHLOROPHENOL TO SELENASTRUM CAPRICORNUTUM (PRINTZ)

Cited by 10 publications

References 21 publications

Influence of growth conditions on the results obtained in algal toxicity tests

Influence of growth conditions on the results obtained in algal toxicity tests

A novel response of wild‐type duckweed (Lemna paucicostata Hegelm.) to heavy metals

Toxicity of pesticides to aquatic microorganisms: A review

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