Walter J. Berry

Predicting sediment metal toxicity using a sediment biotic ligand model: methodology and initial application

An extension of the simultaneously extracted metals/acid-volatile sulfide (SEM/AVS) procedure is presented that predicts the acute and chronic sediment metals effects concentrations. A biotic ligand model (BLM) and a pore water-sediment partitioning model are used to predict the sediment concentration that is in equilibrium with the biotic ligand effects concentration. This initial application considers only partitioning to sediment particulate organic carbon. This procedure bypasses the need to compute the details of the pore-water chemistry. Remarkably, the median lethal concentration on a sediment organic carbon (OC)-normalized basis, SEM*(x,OC), is essentially unchanged over a wide range of concentrations of pore-water hardness, salinity, dissolved organic carbon, and any other complexing or competing ligands. Only the pore-water pH is important. Both acute and chronic exposures in fresh- and saltwater sediments are compared to predictions for cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) based on the Daphnia magna BLM. The SEM*(x,OC) concentrations are similar for all the metals except cadmium. For pH = 8, the approximate values (micromol/gOC) are Cd-SEM*(xOC) approximately equal to 100, Cu-SEM*(x,OC) approximately equal to 900, Ni-SEMoc approximately equal to 1,100, Zn-SEM*(x,OC) approximately equal to 1,400, and Pb-SEM*(x,OC) approximately equal to 2,700. This similarity is the explanation for an empirically observed dose-response relationship between SEM and acute and chronic effects concentrations that had been observed previously. This initial application clearly demonstrates that BLMs can be used to predict toxic sediment concentrations without modeling the pore-water chemistry.

Mechanistic sediment quality guidelines based on contaminant bioavailability: Equilibrium partitioning sediment benchmarks

Globally, estimated costs to manage (i.e., remediate and monitor) contaminated sediments are in the billions of U.S. dollars. Biologically based approaches for assessing the contaminated sediments which pose the greatest ecological risk range from toxicity testing to benthic community analysis. In addition, chemically based sediment quality guidelines (SQGs) provide a relatively inexpensive line of evidence for supporting these assessments. The present study summarizes a mechanistic SQG based on equilibrium partitioning (EqP), which uses the dissolved concentrations of contaminants in sediment interstitial waters as a surrogate for bioavailable contaminant concentrations. The EqP-based mechanistic SQGs are called equilibrium partitioning sediment benchmarks (ESBs). Sediment concentrations less than or equal to the ESB values are not expected to result in adverse effects and benthic organisms should be protected, while sediment concentrations above the ESB values may result in adverse effects to benthic organisms. In the present study, ESB values are reported for 34 polycyclic aromatic hydrocarbon, 32 other organic contaminants, and seven metals (cadmium, chromium, copper, nickel, lead, silver, zinc). Also included is an overview of EqP theory, ESB derivation, examples of applying ESB values, and considerations when using ESBs. The ESBs are intended as a complement to existing sediment-assessment tools, to assist in determining the extent of sediment contamination, to help identify chemicals causing toxicity, and to serve as targets for pollutant loading control measures.

Predicting the toxicity of chromium in sediments

Chromium exists in sediments in two oxidation states: Cr(III), which is relatively insoluble and nontoxic, and Cr(VI), which is much more soluble and toxic. Chromium(VI) is thermodynamically unstable in anoxic sediments, and acid-volatile sulfide (AVS) is formed only in anoxic sediments; therefore sediments with measurable AVS concentrations should not contain toxic Cr(VI). If this hypothesis holds true, measuring AVS could form the basis for a theoretically based guideline for Cr in sediments. Ten-day water-only and spiked sediment toxicity tests with the amphipod Ampelisca abdita were performed with Cr(VI) and Cr(III), along with sediments collected from a site contaminated with high concentrations of Cr. In sediments where AVS exceeded analytical detection limits, Cr concentrations in interstitial water were very low (<100 microg/L) and no significant toxicity to A. abdita was observed. In sediments in which AVS was not significantly greater than zero, Cr concentrations in interstitial waters increased significantly, with greater than 90% of the Cr present as Cr(VI), and mortality of A. abdita was elevated. These results demonstrate that measurements of AVS and interstitial water chromium can be useful in predicting the absence of acute effects from Cr contamination in sediments.

Using field data and weight of evidence to develop water quality criteria

ABSTRACT In the United States, ambient aquatic life water quality criteria are derived using guidelines developed in 1985 that include a clear and consistent methodology using data from standard toxicity tests. The methodology from these guidelines has been successful, but a broader methodology is needed because some effects of pollutants do not lend themselves to conventional toxicity testing. Criterion assessment is proposed as that methodology. In criterion assessment, a specific environmental goal is translated into a measurable benchmark of effect that is used together with a modeled exposure–response relationship to estimate a range of exposures that will achieve the specific goal. The model of the exposure–response relationships and the benchmark effect are developed from field data and laboratory data using multiple analytical methods. Then the model is solved for the effect, thereby estimating the criterion, an upper threshold for acceptable exposures. The resulting candidate criteria are synthesized to select criteria and other benchmark values, such as remedial goals. The criterion assessment process is illustrated using the US Environmental Protection Agency Framework for Developing for Suspended and Bedded Sediments Water Quality Criteria, which recommends developing alternative candidate criterion values and then evaluating them to select a final criterion. Candidate criteria may be derived from models of field observations, field manipulations, laboratory tests, or empirical and theoretical models. Final selection of a criterion uses a weight-of-evidence comparison that engenders confidence because causal associations are confirmed on the basis of different assumptions, independent data sets, and varied statistical methods, thereby compensating for the concerns raised by individual studies and methods. Thus, it becomes possible to specify criteria for agents with biological or physical modes of action, as well as those with chemical modes of action, to best achieve environmental goals.

Toxicity testing, risk assessment, and options for dredged material management.

Programs for evaluating proposed discharges of dredged material into waters of the United States specify a tiered testing and evaluation protocol that includes performance of acute and chronic bioassays to assess toxicity of the dredged sediments. Although these evaluations reflect the toxicological risks associated with disposal activities to some degree, analysis activities are limited to the sediments of each dredging project separately. Cumulative risks to water column and benthic organisms at and near the designated disposal site are therefore difficult to assess. An alternate approach is to focus attention on the disposal site, with the goal of understanding more directly the risks of multiple disposal events to receiving ecosystems. Here we review current US toxicity testing and evaluation protocols, and describe an application of ecological risk assessment that allows consideration of the temporal and spatial components of risk to receiving aquatic ecosystems. When expanded to include other disposal options, this approach can provide the basis for holistic management of dredged material disposal.

Ecological Indicators in Risk Assessment: Workshop Summary

ABSTRACT Ecological indicators can be defined as relatively simple measurements that relay scientific information about complex ecosystems. Such indicators are used to characterize risk in ecological risk assessment (ERA) and to mark progress toward resource management goals. In late 1997, scientists from the U.S. Environmental Protection Agency and from the Chemical Manufacturers Association (CMA) held a workshop to explore opportunities for collaborative research and scientific exchange on the development and application of ecological indicators. Several scientific challenges were identified as they relate to problem formulation, exposure and effects assessment, and risk characterization. Chief among these were a better understanding of multiple stressors (both chemical and non-chemical), characterization of reference sites and natural variability, extrapolation of measures to ecologically relevant scales, development of comprehensive, ecosystem-based models that incorporate multiple stressors and receptors, and a consistent system for evaluating ecological indicators.

International study on Artemia. XVI. Survival, growth and reproductive potential of the mysid, Mysidopsis bahia Molenock fed various geographical strains of the brine shrimp, Artemia☆

Abstract Newly-hatched Artemia nauplii from different geographic locations were fed to Mysidopsis bahia Molenock to test their suitability as a food source for laboratory populations of the mysid. In one experiment, In a second experiment, These results are in marked contrast to those from a number of studies using other crustaceans which have found brine shrimp from either California or Brazil to be superior to those from GSL. Differences in the response to the various Artemia sources may be linked to the type of metamorphosis occurring during development. Those species which undergo a pronounced metamorphosis typically do not survive well on GSL Artemia while those in which metamorphosis is gradual or absent usually do.

Population Status of the Seaside Sparrow in Rhode Island: A 25-Year Assessment

Abstract To assess long-term changes in the population status of breeding Ammodramus maritimus (Seaside Sparrow) in Rhode Island, we repeated surveys conducted in 1982 by Stoll and Golet (1983). In June and July of 2007 and 2008, we surveyed 19 of Rhode Islands largest salt marshes. Seaside Sparrow abundance had declined at 9 of 11 marshes where the species was present in 1982, and we detected no sparrows at 4 smaller (<20 ha) marshes where they were present in 1982. Seaside Sparrow abundance increased at 3 marshes, including 1 at which the birds were not detected in 1982. We used aerial photographs to quantify changes in marsh size and human development within 150-m and 1-km buffers surrounding each marsh. From 1981 to 2008, the overall average number of structures within the 150-m and 1-km buffers increased by 37% and 66%, respectively. Concomitantly, salt-marsh area decreased by an overall average of 11%. Seaside Sparrow abundance was related to marsh size, but our analyses did not detect a statistical relationship of landscape or habitat-loss variables with the decline in sparrows. The Seaside Sparrow is currently classified as a species of concern in Rhode Island. However, given the population decline we documented, and the impending threat to salt-marsh habitats imposed by rising sea levels, we suggest that the classification be reassessed now and periodically in the future, and that monitoring efforts for the species be continued.

A Resilience Framework for Chronic Exposures: Water Quality and Ecosystem Services in Coastal Social-Ecological Systems

Abstract Water quality degradation is a chronic problem which influences the resilience of a social-ecological system differently than acute disturbances, such as disease or storms. Recognizing this, we developed a tailored resilience framework that applies ecosystem service concepts to coastal social-ecological systems affected by degraded water quality. We present the framework as a mechanism for coordinating interdisciplinary research to inform long-term community planning decisions pertaining to chronic challenges in coastal systems. The resulting framework connects the ecological system to the social system via ecological production functions and ecosystem services. The social system then feeds back to the ecological system via policies and interventions to address declining water quality. We apply our resilience framework to the coastal waters and communities of Cape Cod (Barnstable County, Massachusetts, USA) which are affected by nitrogen over-enrichment. This approach allowed us to design research to improve the understanding of the effectiveness and acceptance of water quality improvement efforts and their effect on the delivery of ecosystem services. This framework is intended to be transferable to other geographical settings and more generally applied to systems exposed to chronic disturbances in order to coordinate interdisciplinary research planning and inform coastal management.

Evaluating the Ecosystem Services and Benefits of Wetland Restoration using the Rapid Benefit Indicators Approach

Wetlands in urban and urbanizing areas are often smaller, more degraded, and subject to more stressors than those in undeveloped locations. Their restored level of functioning may never equal that of a site in an undisturbed landscape. Yet, the social benefits from restoring these wetlands may be significant because of the relative scarcity of wetlands and natural areas in urban settings and also the large number of people who may benefit. In this study, we have outlined a systematic approach to compiling nonmonetary indicators of wetlands restoration benefits: The Rapid Benefit Indicators (RBI) Approach. The RBI approach is grounded in economic theory and compatible with methods used by environmental economists to value ecosystem services. We illustrate the RBI approach with a comparison of 2 sites within the Woonasquatucket River Watershed in Rhode Island. As an urbanizing watershed, the Woonasquatucket illustrates how decisions may differ when based primarily on evaluations of ecological functioning versus those that incorporate benefits to people. It demonstrates how small urban sites with relatively low ecological function can provide large social benefits. Integr Environ Assess Manag 2019;15:148-159. Published 2018. This article is a US Government work and is in the public domain in the USA.