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Elevated levels of chromium, partly attributable to historical disposal of chromite ore processing residue, are present in sediment along the eastern shore of the lower Hackensack River near the confluence with Newark Bay. Due to anaerobic conditions in the sediment, the chromium is in the form of Cr(III), which poses no unacceptable risks to human health or to the river ecology. However, as water quality conditions have improved since the 1970s, aerobic conditions have become increasingly prevalent in the overlying water column. If these conditions result in oxidation of Cr(III) to Cr(VI), either under quiescent conditions or during severe weather or anthropogenic scouring events, the potential for adverse ecological effects due to biological exposures to Cr(VI) is possible, though the reaction kinetics associated with oxidation of Cr(III) to Cr(VI) are unfavorable. To investigate the stability of Cr(III) in Hackensack River sediments exposed to oxic conditions, sediment suspension and oxidation experiments and intertidal sediment exposure experiments that exposed the sediments to oxic conditions were conducted. Results revealed no detectable concentrations of Cr(VI), and thus no measurable potential for total chromium oxidation to Cr(VI). Furthermore, total chromium released from sediment to elutriate water in the oxidation and suspension experiments ranged from below detection (

Total and hexavalent chromium [Cr(VI)] were measured in sediment and sediment porewater in the lower Hackensack River (NJ) to assess the relationship between sediment geochemistry and chromium speciation, which in turn controls the mobility, bioavailability, and toxicity of chromium. Between 2003 and 2005, >100 surface (0 to 15 cm) sediment samples were tested for total chromium and Cr(VI), acid-volatile sulfides (AVS), ferrous iron (Fe(II)), divalent manganese (Mn(II)), ammonia, and organic carbon. Sediment porewater samples were collected by centrifugation or using in situ samplers colocated with the collection of sediments. In whole sediments, total chromium and Cr(VI) concentrations ranged from 5 to 9190 mg/kg dry weight (dw) and from

Persistent organic pollutants (POPs) are environmental contaminants characterized by their persistence, long-range transport and biomagnification in food chains, and bioaccumulation in humans and wildlife. The presence of POPs in the aquatic environment is not a new phenomenon; it has only become more widely evident in the last decade because continually improving chemical analysis methods have lowered the limits of detection for a wide array of chemicals tested in surface waters, sediment, and biota. Advances in analytical techniques, statistical methods, and monitoring technologies for freshwater and marine environments are capable of tracing sources and fate of several newly emerging POPs. This chapter examines the challenges associated with five emerging POPs, including the perfluorinated chemicals, certain brominated flame retardants, active ingredients in pharmaceuticals and personal care products, engineered nanomaterials, and polyaromatic hydrocarbons from oil sands. Despite advances in forensic methods, the full magnitude and significance of POPs in the aquatic environment is largely unknown. Environmental risk assessment of POPs remains particularly challenging in freshwater and marine ecosystems; exposure and effects data relevant to the aquatic environment are critical limitations, and continual releases via land runoff, precipitation, plastic litter, industrial accidents, and treated or untreated wastewaters increasingly confound the understanding environmental impacts relative to so-called background, or uncontaminated, conditions.

The effect of pentachlorophenol (PCP) combined with salinity stress on specific aspects of cellular immunity was examined in two species of abalone. Chemotactic and phagocytic ability (percent phagocytosis, %P; and phagocytic index, PI), as well as gross morphological characteristics, of hemocytes withdrawn from red (Haliotis rufescens) and black abalone (H. cracherodii) after in vivo exposure to 25, 35, or 45 per thousand seawater salinity plus 1.2 mg/l PCP were determined. Abalone exposures of 3.5 and 6.5 h, respectively, were based on species-specific metabolic endpoints (MEPs) derived from previous NMR data. Hemocyte chemotaxis was found to be augmented by low salinity in red but not black abalone, while high salinity seemed to reduce chemotactic ability in both species. PCP did not potentiate the effects demonstrated by salinity variations alone in red abalone, although chemotaxis was further compromised in black abalone exposed to high salinity stress combined with PCP. Although chemotactic ability was similar among both species, both %P and PI was greater among black abalone. Low salinity may offset the effects of PCP in red but not black abalone. Whereas red abalone demonstrated a reduction in phagocytic ability upon exposure to high salinity alone, black abalone appeared more resilient to high salinity stress alone. Furthermore, while the effect of high salinity plus PCP is subadditive among red abalone, high salinity seems to potentiate the effect of PCP on black abalone. Finally, hemocytes exposed to acute salinity variations plus PCP showed varying morphological characteristics when compared to controls. Over 30% of hemocytes of high salinity plus PCP exposed abalone remained rounded and generally unattached to glass slides with only a few pseudopod extensions. Hemocyte preparations incubated in rhodamine-conjugated phalloidin were observed with fluorescence microscopy and reveal an altered actin filament pattern. Overall, black abalone demonstrate greater phagocytic ability than red abalone both in the presence and absence of PCP. Furthermore, increases in salinity are accompanied with reduced phagocytic ability with red abalone demonstrating particular sensitivity to salinity variations. While PCP inhibits ATP synthesis, salinity variations may impose an additional stress on intertidal animals exposed to transient or seasonal environmental changes.

The actions of pentachlorophenol (PCP) under various water salinities was investigated in live, intact red ( Haliotis rufescens ) and black abalone ( H. cracherodii ) by in vivo 31 P nuclear magnetic resonance (NMR) spectroscopy. Based on PCP toxicity in red abalone (6 h LC 50 1.6 mg l −1 ; 6 h NOEL=0.8 mg l −1 ), animals were exposed in flowing seawater (14°C) to a sublethal PCP concentration of 1.2 mg l −1 and a water salinity of either 25, 35 or 45 ‰. Phosphagen changes in foot muscle were monitored by surface-probe localized 31 P NMR. Upon PCP exposure, phosphoarginine (PA) levels declined and inorganic phosphate (Pi) levels concurrently increased. Dosing was terminated at a standard metabolic endpoint (MEP), defined as the time for the spectral peak height for Pi to reach one-half that of PA. This was on average 3.3±0.2 and 6.8±0.7 h at ambient salinity; 5.3±0.7 and 7.1±0.7 h for high salinity; and 4.0±0.5 and 6.5±1.0 h at low salinity, for red and black abalone, respectively. During recovery, all biochemical endpoints returned to normal; however, both onset and intensity of effects were influenced by changes in seawater salinity. Disposition of [U- 14 C]PCP in both species was also examined to determine if the effects observed with NMR had a kinetic basis. Three sets of abalone ( n =3) from each species were exposed to each salinity (25, 35 and 45 ‰), plus 1.2 mg l −1 of [U- 14 C]PCP. Red abalone were exposed for 3.5 h and black abalone for both 3.5 and 6.5 h (they represent the lowest average MEP for both species). Residues were quantified via tissue digestion and liquid scintillation counting. The 3.5 h total concentration factors (TCFs) for red abalone were not significantly different among the three salinities ( P >0.05) and ranged from 104 to 133. However, low salinity seemed to deter the uptake of [U- 14 C]PCP in black abalone, as the TCF was over three times lower for abalone exposed to 25 ‰ at both 3.5 h (TCF=19±11) and 6.5 h (TCF=38±8) than at 35 ‰ (3.5 h TCF=62±6; 6.5 h TCF=119±11) and 45 ‰ (3.5 h TCF=67±14, 6.5 h TCF=115±8). Furthermore, the 3.5 h TCF for red abalone exposed to PCP at all salinities was similar to the 6.5 h TCF for black abalone exposed at 35 and 45 ‰. Thus, black abalone appear to have greater resistance to the combined effects of PCP and salinity variations, which appears to be due to slower uptake of the biocide. While PCP is a potent uncoupler of mitochondrial oxidative phosphorylation, use of varying water salinities simulated an additional stress imposed on intertidal animals by transient or seasonal environmental changes.

Application of nuclear magnetic resonance spectroscopy (NMR) for elucidating the sublethal actions of toxicants in intact aquatic organisms, and the influence of natural stress factors, has recently been demonstrated. Using a flow-through chamber, red abalones ( Haliotis rufescens ) were exposed (at 14 °C) to ambient (35%.), hyposaline (25%.), or hyper saline (4 5 %.) seawater, with and without a sublethal concentration (1.2 mg l −1 ) of pentachlorophenol (PCP). They were then maintained in clean seawater (at the same salinity) to check both rate and degree of recovery; phosphagen changes in foot muscle were monitored by surface-probe localized 31 P NMR. Whereas different water salinities alone did not produce measurable effects, upon PCP exposure phosphoarginine levels declined, inorganic monophosphate levels increased, and intracellular pH decreased. Whereas during recovery all biochemical endpoints returned to normal, both onset and intensity of effects were significantly influenced in an unexpected manner by changes in seawater salinity. Application of 31 P NMR represents a powerful new tool for elucidating the influence of natural stress factors on pollutant actions in vivo , providing a more accurate assessment of environmental effects.

This chapter summarizes knowledge on tissue residues and ecotoxicological effects typically observed in aquatic organisms exposed to dioxins, polychlorinated biphenyls (PCBs), and Polybrominated diphenyl ethers (PBDEs). It also summarizes the physical and chemical properties of compounds that are important to understanding environmental fate, bioaccumulation, distribution in the environment, and the significance of tissue residues in aquatic organisms. The chapter discusses what is understood about the environmental fate of these compounds, with an emphasis on factors that influence exposure and toxicity. It includes an overview of toxic equivalency factors (TEFs) assigned to different dioxins and certain dioxin-like PCBs used to evaluate the significance of environmental exposures, and a discussion of recent TEF schemes proposed to aid PBDE risk assessment. Although scientific interest regarding the ecological effects of dioxins, PCBs, and PBDEs stems from our knowledge of human health, much work remains regarding assessing risks to aquatic organisms.

As part of a comprehensive ecological risk assessment on a broad range of species, the potential for adverse effects in birds was evaluated at a chromate ore processing residue disposal site, Study Area 7, located at the confluence of the Lower Hackensack River, Passaic River, and Upper Newark Bay. Although detection of elevated concentrations of total chromium in sediment prompted the study, it was also necessary to consider potential risks related to other chemicals present in elevated concentrations due to widespread anthropogenic activities in Upper Newark Bay and its watershed. U.S. Army Corps of Engineers' TrophicTrace ® software was used to predict exposure to avian receptors using measured concentrations of chemicals in sediment, measured concentrations of chemicals in benthic invertebrates, and measured site physicochemical parameters. The TrophicTrace ® model was improved as part of the Study Area 7 ecological risk assessment to account for (1) incidental ingestion of sediment by dabbling and diving birds, (2) area use factors for spatial overlap of wide-ranging fish species and piscivorous birds, (3) spatially-explicit utilization of the site by birds with a variety of foraging strategies, and (4) temporal patterns of site utilization by migratory species. The ecological risk assessment demonstrated that chromium in sediment does not pose unacceptable hazards to avian receptors. Potentially unacceptable hazards were indicated for several organic chemicals (i.e., pesticides, polychlorinated biphenyls, and dioxins/furans), with hazard quotients highest for Upper Newark Bay reference conditions, reflecting potential widespread chemical impacts to the estuary. The modifications to TrophicTrace ® conducted for this assessment may be prudent and applicable for improving the accuracy and realism of other assessments involving avian receptors exposed to chemicals via contaminated sediment and transfer through the food web.

A Sediment Quality Triad (SQT) study consisting of chemical characterization in sediment, sediment toxicity and bioaccumulation testing, and benthic community assessments was performed in the Lower Hackensack River, New Jersey. Chemistry data in sediment and porewater were evaluated based on the equilibrium partitioning approach and other published information to investigate the potential for chemical effects on benthic organisms and communities. Relationships were supported by laboratory toxicity and bioaccumulation experiments to characterize chemical effects and bioavailability. Benthic community results were evaluated using a regional, multimetric benthic index of biotic integrity and four heterogeneity indices. Evidence of slight benthic community impairment was observed in five of nine sediment sample stations. Severe lethal toxicity to amphipods (Leptocheirus plumulosus) occurred in four of these five stations. Although elevated total chromium concentrations in sediment (as high as 1900 mg/kg) were the rationale for conducting the investigation, toxicity was strongly associated with concentrations of polycyclic aromatic hydrocarbons (PAHs) rather than total chromium. PAH toxic units (SigmaPAH TU) in sediment and SigmaPAH concentrations in laboratory organisms from the bioaccumulation experiment showed a clear dose-response relationship with toxicity, with 0% survival observed in sediments in which SigmaPAH TU1-2 and SigmaPAH concentrations in Macoma nasuta were2 micromol/g, lipid weight. Metals detected in sediment and porewater, with the possible exception of copper, did not correlate with either toxicity or levels in tissue, likely because acid-volatile sulfide levels exceeded concentrations of simultaneous extracted metals at all sample locations. The study reinforces the value of using multiple lines of evidence approaches such as the SQT and the importance of augmenting chemical and biological analyses with modeling and/or other approaches to evaluate chemical bioavailability and toxicity of sediments.