Determination of a tissue and sediment threshold for tributyltin to protect prey species of juvenile salmonids listed under the US Endangered Species Act

Abstract

ABSTRACT1. The purpose of this report is to determine the concentrations of tributyltin in sediments that would be protective against adverse effects on prey species of salmonids listed under the US Endangered Species Act.2. Two approaches for determining adverse sediment concentrations due to tributyltin (TBT) contamination are presented here. The first is the equilibrium partitioning (EqP) approach, which relies on a sediment-water partition coefficient and toxicological data for water exposures. The EqP approach utilizes the large water quality database that has been generated over the last two decades for TBT and provides strong evidence for adverse effects at low exposure concentrations.3. The second approach involves determination of a TBT tissue residue that is considered harmful for most species, which is then used to predict the sediment concentration that would likely produce this adverse tissue concentration.4. Both approaches are presented here because they generally support each other but based on the information presented below, and the inherent difficulty in measuring porewater concentrations, the tissue residue approach is the recommended method for determining adverse sediment concentrations.5. Using this analysis, the protective sediment concentration for TBT proposed here is 6000 ng g À1 organic carbon. Direct effects are not expected on salmonids at this sediment concentration because of their relatively short residence time in the estuary, general lack of interaction with sediment, and relatively high metabolic capacity. This concentration may ensure adequate abundance of salmonid prey species; however, it may not be low enough for the protection of sensitive benthic species.

Contaminants of Concern in Dutch Marine Harbor Sediments

“…The UCT values for metals, PCBs, PAHs, and OCPs were set pragmatically during the early 1990s, with dredged material management in the Netherlands in mind. A comparison with the MTC and PSDDA-Screening Levels suggests that most of these pass/fail criteria appear to be protective for the marine environment, However, we consider the UCT criteria for PCB (30 g/kg for individual congeners), for mineral oil (1250 mg/kg), and the omission of a TBT criterion to be too liberal, given the consensus-based guideline for PCBs (McDonald et al 2000) and the recent studies on the effects of mineral oil (Brils et al 2002) and TBT (Meador and Rice 2001;Meador et al 2002) on sediment-dwelling organisms.…”

“…For TBT we could not use the reported guidelines to assess our bulk sediment data because they had been set for interstitial water (PSSDA) or below the detection level (MTC). Instead, we used no-observed-effect concentrations (NOECs) from experiments with TBT spiked sediments conducted by Meador and Rice (2001) and Meador et al (2002). Chronic exposure of the marine polycheate Armandia brevis and estimates for prey species of salmonid fish to these sediments resulted in NOECs for sublethal effects of respectively 35 g TBT ϩ /kg dry sediment with 0.6% OC and 6000 g TBT ϩ /kg OC.…”

Baseline of butyltin contamination in sediments of Sundarban mangrove wetland and adjacent coastal regions, India

“…TBT concentrations in four stations (S 2 -S 3 , S 11 -S 12 ) exceeded this value (6,000 ng g -1 OC), and therefore effects in salmonoid prey species occurs. It should be mentioned that responses to TBT may occur at lower concentrations that those reported earlier (Meador and Rice 2001;Meador et al 2002) because of additive or synergistic effects produced by other contaminants bioaccumulated at the site.…”

“…Based on the tissue residue approach, protection against severe adverse sublethal effects for many salmonoid prey species should be achieved with a TBT sediment concentration of 6,000 ng g -1 OC. The tissue residue approach is based on tissue concentrations as an alternative method to those using water concentrations for generating SQG (Meador et al 2002). TBT concentrations in four stations (S 2 -S 3 , S 11 -S 12 ) exceeded this value (6,000 ng g -1 OC), and therefore effects in salmonoid prey species occurs.…”

Distribution of butyltin compounds in Brazil’s southern and southeastern estuarine ecosystems: assessment of spatial scale and compartments

“…In this context, fishes represent a crucial role as energy carriers from the lowest to higher trophic levels ( Van der Oost et al 2003). Fishes are able to bioaccumulate BTs at two or three levels of magnitudes (D'Agati et al 2006), even when exposed to low environmental concentrations (ng mL −1 or ng g −1 ) (Meador et al 2002). TBT toxicity is well described in the literature, mainly with regard to the effects on the endocrine system, where cytochrome P450 is inhibited and causes masculinization in gastropod females (Fernandez et al 2005;Leung et al 2006).…”