Bacterial interference in whole‐effluent toxicity tests

Grothe, Donald R.; Johnson, Daniel E.

doi:10.1002/etc.5620150523

Cited by 7 publications

(8 citation statements)

References 1 publication

(1 reference statement)

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“…Large variation in survival of fathead minnow larvae among replicates has been observed by others (T. Norberg-King, U.S. Environment Protection Agency [EPA] Environmental Research Laboratory, Duluth, MN, USA, and P. Downey, TRAC Laboratories, Inc., Denton, TX, USA, personal communication) and bacterial interferences in whole-effluent acute toxicity tests with fathead minnows have been previously observed in samples of cooling water [6]. An anomaly that confounds interpretation of the C. dubia test in ambient applications has also been documented; C. dubia frequently have higher fecundity in ambient waters than they do in control water (reconstituted or laboratory water) [7].…”

Section: Introductionmentioning

confidence: 69%

Evidence that variability in ambient fathead minnow short‐term chronic tests is due to pathogenic infection

Kszos

Stewart

Sumner³

1997

Enviro Toxic and Chemistry

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Abstract-An examination of results from ambient fathead minnow subchronic toxicity tests identified a common characteristic of the tests, which manifests itself as a large among-replicate and between-test variance in survival. The unusual replicate-specific mortality in tests with ambient water appears to be due to pathogenic bacteria or fungi. This finding is based on the following facts: a comparison of survival among replicates in effluents and ambient waters showed that when mean survival was low (40-70%), among-replicate variation for ambient tests was greater than it was for the effluent tests; in 63 tests conducted at three locations over nearly 3 years, treating the water with ultraviolet (UV) light improved survival; a seasonal pattern to survival was present at ambient sites; survival was higher when minnows were separated by using 1 minnow/beaker rather than the standard system of 10 minnows/beaker; and survival tended to be higher in ambient sites contaminated with low levels of chlorine. The existence of the pathogen(s) does not mean that the test cannot be used effectively to assess toxicity of ambient waters; instead, it indicates that factors other than toxicity may need to be taken into consideration when interpreting the results.

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Section: Introductionmentioning

confidence: 69%

Evidence that variability in ambient fathead minnow short‐term chronic tests is due to pathogenic infection

Kszos

Stewart

Sumner³

1997

Enviro Toxic and Chemistry

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“…Other investigators also reported anomalous test results using P. promelas that were believed to be due to a naturally occurring biological interference characterized by filamentous growths on the larvae. That study also indicated UV exposure because filtration was effective for controlling the effects of the pathogens [4]. In data compiled by the Wisconsin Department of Natural Department of Natural Resources, Madison, Wisconsin, USA, 26% of chronic P. promelas WET tests (n ϭ 1,496 tests) showed unacceptable survival (Ͻ80%) in receiving water controls as compared with laboratory-water controls (2.9%).…”

Section: Introductionmentioning

confidence: 84%

Sporadic Mortality in Chronic Toxicity Tests Using Pimephales Promelas (Rafinesque): Cases of Characterization and Control

Downey¹,

Fleming²,

Guinn³

et al. 2000

Environ Toxicol Chem

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Abstract-In whole effluent toxicity tests, organisms are exposed to various effluent concentrations for a specific time period to estimate the potential effects of an effluent on a receiving stream. Laboratories typically have good success performing valid chronic toxicity tests. However, some difficulty in conducting valid chronic whole effluent toxicity tests with Pimephales promelas (fathead minnow) has been encountered as a result of sporadic control mortality. Some investigators report an interference that causes anomalous patterns of survival in chronic fathead minnow tests. This interference has been termed sporadic mortality phenomenon. Characteristics of sporadic mortality phenomenon include high variability among replicates, nonmonotonic dose responses, mortality beginning on or about day 4 of the test, and fungal growths often observed on the larvae. Histopathologic examinations often indicate bacterial and/or fungal infections on fish exhibiting symptoms of sporadic mortality phenomenon. The most plausible explanation of sporadic mortality phenomenon is a naturally occurring pathogen or pathogens that interfere with the test method. This interference may invalidate tests or falsely indicate toxicity. Sporadic mortality phenomenon can be reduced or eliminated by sample treatments intended to inactivate (heating, antibiotics, or ultraviolet light) or remove (filtration) pathogenic microorganisms. These methods must be used with forethought because of their potential to alter the toxicity of a sample.

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“…For instance, increased hardness is a feature of some effluents, which can have an adverse effect on daphnids irrespective of contaminant concentrations [6]. Variations in salinity and total dissolved solids concentrations can significantly affect WET test organisms [71–73]. So too can the presence of other biota in the effluent ([72]; Table 1).…”

Section: Level Of Protectionmentioning

confidence: 99%

Whole effluent toxicity testing—usefulness, level of protection, and risk assessment

Chapman¹

2000

Enviro Toxic and Chemistry

165

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The general status of whole effluent toxicity (WET) tests is assessed relative to their generally accepted purpose of identifying, characterizing, and eliminating toxic effects of effluents on aquatic resources. Although WET tests are useful, they are not perfect tools (no perfect tools exist). Imperfections include the innate variability of these tests, due both to biotic and anthropogenic factors; the reality of species differences both between the laboratory and the field and within the field; and differences between the laboratory and the receiving environment. Whole effluent toxicity tests may be overprotective (because of their conservative nature, the absence of environmental and ecological processes that could ameliorate exposure, and sensitivity to noncontaminant effects), underprotective (because the most sensitive species cannot be tested, multiple stresses tend to be present in the receiving environment, and failure to account for food chain effects or all possible endpoints), or offer an uncertain level of protection (intermittent doses and mixtures in the environment, adaptations, and hormesis). The implication of hormesis and inverted U‐shaped dose responses for WET testing are reviewed in particular detail. Comparisons to field conditions indicate that WET tests are not reliable predictors of effects or lack of effects in the receiving environment. Whole effluent toxicity tests are only the first stage in a risk assessment and as such identify hazard, not risk. Identification of risk requires discarding the concept of independent applicability. The appropriate use of WET tests is identified in the context of their advantages and disadvantages.

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Bacterial interference in whole‐effluent toxicity tests

Cited by 7 publications

References 1 publication

Evidence that variability in ambient fathead minnow short‐term chronic tests is due to pathogenic infection

Evidence that variability in ambient fathead minnow short‐term chronic tests is due to pathogenic infection

Sporadic Mortality in Chronic Toxicity Tests Using Pimephales Promelas (Rafinesque): Cases of Characterization and Control

Whole effluent toxicity testing—usefulness, level of protection, and risk assessment

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