Nonionic Surfactants in Perspective

Abstract-Responses of aquatic invertebrates to a C 14-15 linear alcohol ethoxylate (LAE) nonionic surfactant with an average of seven ethylene oxide units per mole of alcohol were evaluated in outdoor stream mesocosms. Two experiments were carried out to evaluate responses of aquatic invertebrates to 28-and 30-d exposures in eight stream mesocosms. Changes in benthic invertebrate densities and in invertebrate drift were monitored during pretreatment, treatment, and posttreatment periods. In Experiment 1, mean measured concentrations of surfactant were 0.08, 0.16, and 0.33 mg LAE/L. In Experiment 2, mean measured concentrations were 0.11, 0.28, and 0.55 mg LAE/L. In each experiment, there were two treated streams at each surfactant concentration and two untreated streams that served as controls. No significant effects (p Ͼ 0.05) on population densities of Copepoda, Cladocera, Chironomidae, Nematoda, or Annelida were observed in either experiment. Moreover, no effects were detected on the numbers of any of these organisms collected in drift nets. However, there was a significant decrease (p Յ 0.05) in the densities of Simuliidae at surfactant concentrations Ն0.16 mg LAE/L. This was accompanied by an increase in the numbers of Simuliidae collected in drift nets. Based on these results, the no-observed-effect concentration for aquatic invertebrates was 0.08 mg LAE/L, and the lowest-observed-effect concentration was 0.16 mg LAE/L.

Section: Resultsmentioning

confidence: 99%

“…Large volumes of surfactants are produced annually, with over 15.2 million metric tons of surfactants used worldwide in 1987 [1,2]. These compounds constitute a large portion of a variety of cleaning products, including detergents, personal care products, and household cleaning agents [3].…”

Section: Introductionmentioning

confidence: 99%

Effects of a nonionic surfactant (C_14–15AE‐7) on aquatic invertebrates in outdoor stream mesocosms

Gillespie

Rodgers

Crossland

1996

“…These compounds are routinely discharged in industrial wastewaters as a result of their widespread usage in cleaning products and industrial processing [1]. The NPEs are usually degraded during wastewater treatment, but NP that is liberated in the process is more recalcitrant and is often detected in wastewater treatment discharges and receiving waters [2,3]. A recent monitoring study detected NP in 13 of 30 U.S. rivers, albeit at concentrations ≤0.64 μg/L [4], but concentrations of 100 to 300 μg/L have been measured in effluent from activated sludge treatment plants [2].…”

Section: Introductionmentioning

confidence: 99%

Effects of repeated exposure to 4‐nonylphenol on the zooplankton community in littoral enclosures

O'Halloran

Liber

Gangl

et al. 1999

The effects of 4‐nonylphenol (NP) on freshwater zooplankton were evaluated in 18 littoral enclosure mesocosms in northeastern Minnesota. The 18 enclosures were allocated to three blocks of six units with each block including two untreated control enclosures and one enclosure for each of four NP treatments (3, 30, 100, and 300 μg/L). Treated enclosures received 11 applications of NP over a 20‐d period between July 8 and 28, 1993. Maximum NP concentrations measured in the water column 2 h after each application averaged (±SD) 5 ± 4, 23 ± 11, 76 ± 21, and 243 ± 41 μg/L over the 11 applications. Nonylphenol dissipated rapidly from the water column but was more persistent in sediments and in/on macrophytes. All cladoceran and copepod taxa were significantly reduced in abundance at 243 ± 41 μg/L; some sensitive taxa were also affected at 76 ± 21 and 23 ± 11 μg/L. While many rotifer taxa were unaffected at any of the test concentrations, several were affected at ≥76 ± 21 μg/L. Ostracods were only affected at 243 ± 41 μg/L. No zooplankton taxon was affected at 5 ± 4 μg/L. The period of maximum impact usually occurred within 1 to 7 d of the last NP application, and recovery to control abundance levels generally occurred within 7 to 28 d of the last NP application. Two sensitive taxa, Acroperus and Calanoida, did not recover at ≥76 ± 21 μg/L by the end of the study. The maximum acceptable toxicant concentration for protection of all zooplankton taxa was estimated at ˜10 μg/L, although overall community diversity was unaffected at 23 ± 11. The water was the most probable route of NP exposure, but the greater persistence of NP residues in/on macropyhtes may have contributed to the lack of recovery of some macrophyte‐associated taxa.

“…The study described here was designed to provide field data on NP persistence in water and sediments and data on NP toxicity to aquatic biota under semicontrolled conditions. Although previous studies had documented the presence of NP in aquatic environments [5,10], none had attempted to link chemical measurements with biological effects measured under field conditions. Previous toxicological assessments had been limited to laboratory experiments [9,11–13].…”

Section: Introductionmentioning

confidence: 99%

An integrated evaluation of the persistence and effects of 4‐nonylphenol in an experimental littoral ecosystem

Liber

Knuth

Stay

1999

Abstract-A comprehensive littoral enclosure study was conducted to assess the persistence and distribution of 4-nonylphenol (NP) in a littoral ecosystem, and to evaluate the compound's effects on resident aquatic biota. Enclosures with a mean (ϮSD) surface area and volume of 31.4 Ϯ 3.3 m 2 and 32.0 Ϯ 6.4 m 3 , respectively, received eleven applications at 48-h intervals with one of four different rates of NP. This created a 20-d application period which was followed by a three to fourteen month observation period, depending on the endpoint measured. Mean Ϯ SD NP concentrations in the water column measured 2 h after each application averaged 5 Ϯ 4, 23 Ϯ 11, 76 Ϯ 21, and 243 Ϯ 41 g/L at nominal treatments of 3, 30, 100, and 300 g/L, respectively. Persistence in the water column was relatively short, with a dissipation half-life estimated at Յ1.2 d. Persistence of NP in sediment and on macrophytes was substantially longer, with estimated half-lives of 28 to 104 d and 8 to 13 d, respectively. Zooplankton was the most sensitive group of organisms evaluated, with significant reductions in population abundances of some copepod taxa observed at the 23 Ϯ 11-g/L treatment. Fish survival was affected at 243 Ϯ 41 g/L. The most sensitive benthic macroinvertebrate taxon, Pisidium (Bivalvia) was affected at 76 Ϯ 21 g/L, but most taxa were only affected at the 243 Ϯ 41-g/L treatment. None of the assessed populations were affected at the 5 Ϯ 4-g/L treatment. Macrophytes and periphyton were not adversely affected by any of the treatments. Overall community composition, assessed at the family level or higher, was not affected at or below the 23 Ϯ 11-g/L treatment, but did exhibit substantial changes at the 243 Ϯ 41-g/L treatment. Some minor changes were observed at the 76 Ϯ 21-g/L treatment. The maximum acceptable toxicant concentration in the water column, based on protection of the most sensitive taxa in the test system, was estimated at ϳ10 g/L. Details on NP persistence and distribution within the enclosures, and detailed effects on zooplankton, benthic macroinvertebrates, and fish are described in four separate papers immediately following this overview.