Stimulatory and toxic effects of acid, pentachlorophenol or zinc on the mineralization of acetate in acid or calcareous soils and subsoils

Beelen, Patrick van; Fleuren-Kemilä, Arja K.; Mil, C.H.A.M. van

doi:10.1080/10934529409376118

Cited by 4 publications

(10 citation statements)

References 15 publications

(21 reference statements)

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“…Given that the concentration of Zn in soil solution increases between two-and eight-fold for each unit decrease in pH [13], the lack of any clear relationship between soil pH and Zn toxicity to indigenous microorganisms (expressed on a total soil concentration basis) is surprising. Our results provide one hypothesis to explain this apparent lack of effect of pH on Zn toxicity noted by several authors [5,6,[16][17][18][19][20]. Experimental verification of the concept is needed by assessing the Zn toxicity response of microorganisms adapted to both low and high background Zn concentrations in soil.…”

Section: Application To a Metalloregion Approachmentioning

confidence: 56%

“…However, no differences were noted in the inhibition of N-mineralization by 330 mg Zn/kg in four soils with pH values between 5.8 and 7.8 [15]. Acetate mineralization was even less sensitive to Zn in two acid soils (pH 3.8-4.5) than in two calcareous soils (pH 8.2-8.3 [19]). The toxicity of Zn salts was not consistently reduced with increasing soil pH.…”

Section: Introductionmentioning

confidence: 75%

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Background Zinc Concentrations in Soil Affect the Zinc Sensitivity of Soil Microbial Processes—a Rationale for a Metalloregion Approach to Risk Assessments

McLaughlin¹,

Smolders²

2001

Environ Toxicol Chem

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Soil microbial processes are particularly sensitive to Zn, but great difficulty exists in deriving soil standards based on laboratory toxicity tests. Zinc toxicity data for soil microbial processes were collated from the literature, and their variability with soil properties was assessed. Data were screened for quality and reliability, and analysis was based on the highest metal dose at which no adverse effect was found (HNOAED). The HNOAED values were expressed on a pore-water basis and were found to be positively related to background concentrations of Zn in soil, also expressed on a pore-water basis. This suggests that soil microorganisms acclimate to indigenous concentrations of Zn in soil pore water, and this acclimation affects the subsequent response to Zn added as a pollutant. Thus, regions having low background Zn concentrations in soil pore water will be much more sensitive to Zn pollution than others having high background concentrations. A method to account for effects of background Zn on assessments of Zn toxicity is suggested where metalloregions are defined having common sets of abiotic and biotic factors that affect the toxicity of Zn. This approach could markedly improve regional or continental risk assessments for metals in the environment.

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Section: Application To a Metalloregion Approachmentioning

confidence: 56%

Section: Introductionmentioning

confidence: 75%

Background Zinc Concentrations in Soil Affect the Zinc Sensitivity of Soil Microbial Processes—a Rationale for a Metalloregion Approach to Risk Assessments

McLaughlin¹,

Smolders²

2001

Environ Toxicol Chem

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“…This may not be the case for microorganisms, however, because the toxicity of 500 mg Zn/kg soil on the dehydrogenase enzyme is lower in acid soils compared to soils with a high pH [3]. Moreover, acetate mineralization in acid soils seems to be resistant to concentrations as high as 1,000 mg Zn/kg [4], whereas the same process is inhibited by 10% at 60 to 300 mg Zn/kg in soils with pH 8 [5]. Hence, at lower pH the toxic effect of metals seems to increase for earthworms and to decrease for soil microbial processes.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The PCP concentration that inhibits 10% of the acetate mineralization rate in 10 soils (EC10) varies from 5 to 800 mg/kg [5]. Variations in sorption due to pH and organic carbon content cannot explain these differences in EC10 concentrations [5]. The variations in toxic effects of pollutants like PCP and zinc on microbial processes in soils with different pH are not easy to explain in complex soil systems because each soil sample has different microflora and its own sensitivity.…”

Section: Introductionmentioning

confidence: 99%

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Influence of pH on the toxic effects of zinc, cadmium, and pentachlorophenol on pure cultures of soil microorganisms

Beelen

Fleuren-Kemilä

1997

Enviro Toxic and Chemistry

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Abstract-In this study the effect of the acidification of soil pore water on the uptake and toxicity of cationic and anionic pollutants was measured in an experimental model system. The influence of pH on the toxic effects of zinc, cadmium, and pentachlorophenol was studied in buffered suspensions of pure cultures of soil microorganisms. In this system the speciation of the toxicant, the pH, and the biomass are defined, constant, and thus easier to study than in a system with the solid soil matrix and pore water. The mineralization of [ 14 C]acetate to 14 CO 2 was used to measure the toxic effects of pollutants on a fungus (Aspergillus niger CBS 121.49), an actinomycete (Streptomyces lividans 66), two Gram-negative Pseudomonas putida strains (MT-2 and DSM 50026), and a Gram-positive strain (Rhodococcus erythropolis A177). Large differences in sensitivity were observed between the species. For pentachlorophenol the highest EC50 was 81 mg/L for Pseudomonas putida at pH 8, whereas the lowest was 0.13 mg/L for Aspergillus niger at pH 6. Aspergillus niger was not sensitive to 1,000 mg Zn/L, whereas Pseudomonas putida at pH 7.8 showed the lowest EC50, 0.14 mg Zn/L. When pH was increased, pentachlorophenol became less toxic and showed less sorption to the biomass, whereas zinc and cadmium became more toxic and showed more sorption to the biomass. The results indicate that higher pore-water concentrations due to acidification of zinc-and cadmium-polluted soils may not be accompanied by increased toxic effects on microorganisms because of the relatively low toxicity of these metals in pore water at low pH.

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The relation between extrapolated risk, expressed as potentially affected fraction, and community effects, expressed as pollution‐induced community tolerance

Beelen

Fleuren-Kemilä

Aldenberg

2001

Enviro Toxic and Chemistry

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The results of toxicity tests can be used to calculate the potentially affected fraction (PAF) of species in an ecosystem at a given pollutant concentration using statistical extrapolation methods. The PAF curve indicates the fraction of species from the original community that may become inhibited at each elevated pollutant concentration and is a measure of the ecotoxicological risk. Pollution-induced community tolerance (PICT) is a true community response that is measured under controlled conditions in the laboratory, using organisms from contaminated field sites. Microorganisms from experimental field plots with added Zn were exposed to various concentrations of Zn in the laboratory and the mineralization of 14C acetate was monitored. Microorganisms from plots with Zn concentrations above 124 mg/kg showed a significant increase in the effect concentration 10% (EC10) and, therefore, had a significant PICT. The pore-water concentrations of Zn in these field soils were in the same magnitude as the EC10 of the microorganisms from these soils. The PAF curve was calculated from previously reported toxicity tests with five different microbial species using the average and the standard deviation of the logarithmically transformed EC10 values. The average sensitivity of this PAF curve was similar to the EC50 of the acetate mineralization curve from the field plot without added Zn2+, but the PAF curve was less steep. Our experiments indicated that 27 to 84% of the original microbial species were inhibited at Zn concentrations from 334 to 1,858 mg/kg soil, respectively. Our results suggest that the PICT method can now also be used to quantify the fraction of the original species composition that is inhibited at a specific pollutant concentration.

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Stimulatory and toxic effects of acid, pentachlorophenol or zinc on the mineralization of acetate in acid or calcareous soils and subsoils

Abstract: The toxic effects of pollutants on the soil microflora was studied as part of a research program aimed at the setting of soil quality standards.

Cited by 4 publications

References 15 publications

Background Zinc Concentrations in Soil Affect the Zinc Sensitivity of Soil Microbial Processes—a Rationale for a Metalloregion Approach to Risk Assessments

Background Zinc Concentrations in Soil Affect the Zinc Sensitivity of Soil Microbial Processes—a Rationale for a Metalloregion Approach to Risk Assessments

Influence of pH on the toxic effects of zinc, cadmium, and pentachlorophenol on pure cultures of soil microorganisms

The relation between extrapolated risk, expressed as potentially affected fraction, and community effects, expressed as pollution‐induced community tolerance

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