Toxicity Assessment of Diazinon in a Constructed Wetland Using Hyalella azteca

Abstract

The goal of this study was to examine the use of a constructed wetland to mitigate the ecological impacts of simulated diazinon runoff from agricultural fields into receiving waters, via 48 h aqueous and sediment bioassays using Hyalella azteca. Aqueous animal 48 h survival varied temporally and spatially in conjunction with measured diazinon concentrations. Sediment H. azteca survival varied temporally and spatially in conjunction with measured diazinon concentrations, but less than aqueous exposures, confirming that sediment bound diazinon was less bioavailable than aqueous diazinon.

Efficacy of Constructed Wetlands in Pesticide Removal from Tailwaters in the Central Valley, California

“…While sediments from the sediment basin contained 43% sand on the average, the sand fraction was only 19% in the sediments at the inlets of the CWs. This observation was similar to the finding of Smith et al (24), who showed that under high flow conditions, pesticides were not found in the sediment from a retention basin, although they were detected downstream.Gan et al (25) observed that in a drainage ditch, the sand fraction of the sediment deposit decreased from 87% at the start of the channel to 21% at 145 m downstream, while the clay fraction increased concurrently from 5 to 23%, and organic matter content from 0.65 to 6.37%. This observation also suggests that pyrethroids in the input tailwater were likely associated predominantly with lowdensity or fine particles that traveled unretained through the sediment basin into the wetlands.…”

Cost of reproduction. Changes in metabolism and endosulfan lethality caused by reproductive behavior in Hyalella curvispina (Crustacea: Amphipoda)

“…Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/ecoenv Amphipods, mainly H. azteca, are generally used in laboratory tests and in situ bioassays to evaluate rural and urban pollution, because of their easy maintenance and high abundance in aquatic environments (Wang et al, 2004;Wan et al, 2005;You et al, 2004;Smith et al, 2007;Ding et al, 2011). However, there is a global trend to evaluate the impact of pollutants with native species, as they are adapted to particular aquatic system conditions and may provide more realistic results than those obtained from exotic species (Jergentz et al, 2004;Giusto et al, 2012;Mugni et al, 2012a,b;Paracampo et al, 2012).…”

Effects of Vegetation in Mitigating the Toxicity of Pesticide Mixtures in Sediments of a Wetland Mesocosm

“…These components could have less of a role in sediment toxicity as diazinon and permethrin are compartmentalized among macrophytes, sediment particles, and sediment organic carbon within the first week when toxicity was observed. Few studies have directly assessed organophosphate sediment toxicity and, specifically, diazinon sediment toxicity (Bouldin et al 2007;Smith et al 2007). This is likely due to physicochemical properties of diazinon as the compound sorbs less readily to and desorbs more rapidly from sediments than pyrethroids (Bondarenko and Gan 2006;Gan et al 2005).…”

“…Bulk sediment bioassays were 48-h static nonrenewed exposures assessing H. azteca survival according to modified protocols from Smith et al (2007) and USEPA (2000) for H. azteca reference toxicity tests and acute sediment toxicity tests. H. azteca approximately 1 to 2 weeks old were collected by passing mixed-age animals through a 600-μm stainless steel mesh sieve and using only those retained by a 425-μm stainless steel mesh sieve for the bioassays.…”