Effects of 4-Nonylphenol on Benthic Macroinvertebrates and Insect Emergence in Littoral Enclosures

Abstract

The effect of 4-nonylphenol (NP) on benthic, freshwater macroinvertebrates in littoral enclosures was evaluated over a 2-year period. Enclosures received 11 NP applications, 48 h apart, with nominal rates of 3, 30, 100, and 300 g/L. Mean measured peak concentrations in integrated water column samples over the 20-d application period were 5 Ϯ 4, 23 Ϯ 11, 76 Ϯ 21, and 243 Ϯ 41 g/L NP. Concentrations of NP in the water column decreased rapidly after the last application. Maximum NP concentrations measured in sediments, pore water, and macrophytes of a 300-g/L enclosure were 27.4 mg/kg, 29.9 g/L, and 89.6 mg/kg, respectively. The most abundant macroinvertebrate groups, Chironomidae, Oligochaeta, and Mollusca, decreased in abundance after application. Effects on Mollusca were the most severe. Their numbers were significantly reduced at the highest treatment (243 Ϯ 41 g/L NP) throughout most of the study. Oligochaetes (Naididae, Tubificidae) and chironomids (Tanytarsini, Chironomini) were also significantly reduced at the highest treatment, but populations recovered within 6 weeks. Snails and naidid oligochaetes were slightly affected at the second highest treatment (76 Ϯ 21 g/L NP). Insect emergence was reduced during and immediately postapplication, but the effects were likely caused or compounded by a surfactant sheen on the surface of the water that interfered with emergence and/or oviposition. The observed effects on the benthic community were most likely due to exposure from the water, although more persistent macrophyte-associated residues may have contributed to effects on Gastropoda, Naididae, and Tanytarsini. Macrophyte-associated NP residues may pose a small risk to benthic organisms, but it is probably minor compared to water exposures. The no-observed and lowest-observed-effect concentration for the benthic community was 23 Ϯ 11 and 76 Ϯ 21 g/ L NP, respectively.

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

“…None of the assessed populations were affected at 3‐ and 30‐μg/L treatments. Total benthic macroinvertebrate abundance was only affected at the highest treatment, 243 ± 41 μg/L [3].…”

“…Effects on zooplankton, benthic macroinvertebrates, and fish were monitored regularly during the first field season (six to nine times each between June and October 1993) and for benthic macroinvertebrates twice more during the second field season (May and August 1994). Zooplankton was sampled with funnel traps [2] and benthic macroinvertebrates with a handheld corer [3]. Abundances of taxa within both groups were expressed as numbers/m 2 .…”

Evaluation of the Efficacy of Extrapolation Population Modeling to Predict the Dynamics of Americamysis Bahia Populations in the Laboratory

“…357-400), a series of papers describes the results from a comprehensive littoral enclosure study of NP in a freshwater system [31][32][33][34][35]. 357-400), a series of papers describes the results from a comprehensive littoral enclosure study of NP in a freshwater system [31][32][33][34][35].…”

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

“…Most copepods, however, are predators as adults (and late copepodite stages), and their preferred forage items include immature copepods, cladocerans, rotifers, chironomids, and oligochaetes [23,32]. This forage base was dramatically reduced between days 7 and 28 [33], which could have delayed recovery. Although switching to algal food sources may have occurred, primarily herbivore diets have been shown to reduce survival and reproductive success in larger cyclopoid copepods [34].…”