Mercury Contamination in Diamondback Terrapins in New Jersey.

Mercury contamination in consumed foods poses a significant threat to human health globally. The consumption of mercury-contaminated turtle meat is of special concern due to mercury's capability to bioaccumulate and biomagnify in organisms. Turtles are long-lived predators, allowing for a high degree of bioaccumulation and biomagnification of contaminants. In the U.S., diamondback terrapins (Malaclemys terrapin) are legally harvested in several states throughout their range. Harvested turtles are usually sold to both local and global markets mainly for human consumption, which results in a human consumption threat. The objective of this study was to analyze mercury concentrations to determine if the consumption of terrapins poses a threat to human health. Diamondback terrapins were collected from two study sites: Cape May and Hackensack Meadowlands, New Jersey, relatively pristine and contaminated estuaries, respectively. Turtle carapace, blood, and muscle samples were analyzed for total mercury concentrations. Results showed significant difference between study sites and females' and males' blood mercury concentrations. Similarly, results showed blood mercury correlated with carapace length. Results also showed that 50% of Cape May muscle samples and 72.7% Meadowlands muscles samples surpassed the New Jersey sensitive threshold of 0.18 ppm. Furthermore, 27.3% of Cape May muscle samples and 45.5% of Meadowlands muscles samples surpassed the U.S. Environmental Protection Agency's mercury threshold of 0.3 ppm for seafood consumption for the general public. Overall, the harvest of terrapins could pose a threat to consumers, and terrapins should be monitored closely or possibly banned for human consumption, especially in areas with known contamination history.

Bioaccumulation and depuration of metals in blue crabs (Callinectes sapidus Rathbun) from a contaminated and clean estuary.

Blue crabs from a contaminated estuary (Hackensack Meadowlands-HM) and a cleaner reference site (Tuckerton-TK) were analyzed for Cr, Cu, Hg, Pb, and Zn in muscle and hepatopancreas. Crabs from each site were taken into the laboratory and fed food from the other site, or in another experiment, transplanted to the other site for eight weeks. All crabs were analyzed for metals. Overall, tissue concentrations reflected environmental conditions. Tissue differences were found for Cu, Pb and Zn (all higher in hepatopancreas), and Hg (higher in muscle). HM muscle had more Hg than TK muscle, but did not decrease after transplanting or consuming clean food. HM crabs lost Cu, Pb and Zn in hepatopancreas after being fed clean food or transplanted. TK crabs increased Hg in muscle and Cr and Zn in hepatopancreas after transplantation or being fed contaminated (HM) food. Concentrations were variable, suggesting that blue crabs may not be fully reliable bioindicators of polluted systems.

Soil metal concentrations and productivity of Betula populifolia (gray birch) as measured by field spectrometry and incremental annual growth in an abandoned urban Brownfield in New Jersey.

A forested brownfield within Liberty State Park, Jersey City, New Jersey, USA, has soils with arsenic, chromium, lead, zinc and vanadium at concentrations above those considered ambient for the area. Using both satellite imagery and field spectral measurements, this study examines plant productivity at the assemblage and individual specimen level. Longer term growth trends (basal area increase in tree cores) were also studied. Leaf chlorophyll content within the hardwood assemblage showed a threshold model for metal tolerance, decreasing significantly beyond a soil total metal load (TML) of 3.0. Biomass production (calculated with RG-Red/Green Ratio Index) in Betula populifolia (gray birch), the co-dominant tree species, had an inverse relationship with the Zn concentration in leaf tissue during the growing season. Growth of B. populifolia exhibited a significant relationship with TML. Assemblage level NDVI and individual tree NDVI also had significant decreases with increasing TML. Ecosystem function measured as plant production is impaired at a critical soil metal load.

Soil metal concentrations and vegetative assemblage structure in an urban brownfield.

Anthropogenic sources of toxic elements have had serious ecological and human health impacts. Analysis of the soil samples from a brownfield within Liberty State Park, Jersey City, NJ, USA, showed that arsenic, chromium, lead, zinc and vanadium exist at concentrations above those considered ambient for the area. Accumulation and translocation features were characterized for the dominant plant species of four vegetative assemblages. The trees Betula populifolia and Populus deltoides were found to be accumulating Zn in leaf tissue at extremely high levels. B. populifolia, P. deltoides and Rhus copallinum accumulated Cr primarily in the root tissue. A comparison of soil metal maps and vegetative assemblage maps indicates that areas of increasing total soil metal load were dominated by successional northern hardwoods while semi-emergent marshes consisting mostly of endemic species were restricted primarily to areas of low soil metal load.

Contaminants in fish of the Hackensack Meadowlands, New Jersey: size, sex, and seasonal relationships as related to health risks.

The trace metal content and related safety (health risk) of Hackensack River fish were assessed within the Hackensack Meadowlands of New Jersey, USA. Eight elements were analyzed in the edible portion (i.e., muscle) of species commonly taken by anglers in the area. The white perch collection (Morone americana) was large enough (n = 168) to enable statistically significant inferences, but there were too few brown bullheads and carp to reach definite conclusions. Of the eight elements analyzed, the one that accumulates to the point of being a health risk in white perch is mercury (Hg). Relationships between mercury concentrations and size and with collection season were observed; correlation with lipid content, total polychlorinated biphenyl (PCB) content, or collection site were very weak. Only 18% of the Hg was methylated in October (n = 8), whereas June and July fish (n = 12) had 100% methylation of Hg. White perch should not be considered edible because the Hg level exceeded the "one meal per month" action level of 0.47 microg/g wet weight (ppm) in 32% of our catch and 2.5% exceeded the "no consumption at all" level of 1 microg/g. The larger fish represent greater risk for Hg. Furthermore, the warmer months, when more recreational fishing takes place, might present greater risk. A more significant reason for avoiding white perch is the PCB contamination because 40% of these fish exceeded the US Food and Drug Administration (FDA) action level of 2000 ng/g for PCBs and all white perch exceeded the US Environmental Protection Agency cancer/health guideline (49 ng/g) of no more than one meal/month. In fact, nearly all were 10 times that advisory level. There were differences between male and female white perch PCB levels, with nearly all of those above the US FDA action level being male. Forage fish (mummichogs and Atlantic silversides) were similarly analyzed, but no correlations were found with any other parameters. The relationship of collection site to contaminants cannot be demonstrated because sufficient numbers of game fish could not be collected at many sites at all seasons.

Studies of a contaminated brackish marsh in the Hackensack Meadowlands of northeastern New Jersey: an assessment of natural recovery.

Eight-Day Swamp is known to be contaminated with heavy metals, especially mercury. Sediment cores were collected to approximately 32 cm at 17 sites on four transects and analyzed at 1 or 2 cm intervals for seven metals and organic matter. Very high metal levels were found throughout the site. Long and Morgan's "effects range-median" (ER-M) was exceeded in more than 50% of slices for all elements except As. Hg had the highest concentration relative to ER-M; median Hg concentration was 72 times its ER-M. On the marsh plain, all metals showed enrichment at 14-20 cm depth of 10-40X over surficial sediments. 137Cs analysis showed sedimentation rates ranging from 0.33 to 0.50 cm yr(-1) over the last approximately 40 yr. These rates indicate that metal contamination peaks occurred in sediments deposited in the early 1960s. Thus, newer, less contaminated sediments are burying older, more contaminated layers and peak levels of contaminants are becoming less available to benthos.

Dissolved oxygen and dietary phosphorus modulate utilization and effluent partitioning of phosphorus in rainbow trout (Oncorhynchus mykiss) aquaculture.

Phosphorus (P) is the limiting nutrient in freshwater primary production, and excessive levels cause premature eutrophication. P levels in aquaculture effluents are now tightly regulated. Increasing our understanding of waste P partitioning into soluble, particulate, and settleable fractions is important in the management of effluent P. When water supply is limited, dissolved oxygen concentration (DO) decreases below the optimum levels. Therefore, we studied effects of DO (6 and 10mg/L) and dietary P (0.7 and 1.0% P) on rainbow trout growth, P utilization, and effluent P partitioning. Biomass increased by 40% after 3 weeks. DO at 10mg/L significantly increased fish growth and feed efficiency, and increased the amount of P in the soluble fraction of the effluent. Soluble effluent P was greater in fish fed 1.0% P. DO increases fish growth and modulates P partitioning in aquaculture effluent.

Studies of a contaminated brackish marsh in the Hackensack Meadowlands of Northeastern New Jersey: benthic communities and metal contamination.

Cores taken from 16 stations within Eight Day Swamp, a highly contaminated marsh in the Hackensack Meadowlands, were analyzed for metal concentrations and for benthic community structure. Metal levels were compared with the benchmark ERM values, and expressed in terms of toxic units. Mercury was the most important metal in all the samples in terms of its contribution to the total toxic units. The overall abundance and taxa richness in the benthic community were associated with the height of the location relative to the tidal cycle, but were generally not significantly correlated with metal concentrations at the sites. Ordination of the communities showed that the communities that were low-lying (on the mudflat) were most similar to one another, and those that were higher up on the marsh were most similar to one another. However, diversity indices (Shannon-Wiener H' and Simpson's) were significantly associated with concentrations of the metals (except As) and with the sum of the toxic units at a station.

Metal dynamics of plant litter of Spartina alterniflora and Phragmites australis in metal-contaminated salt marshes. Part 1: Patterns of decomposition and metal uptake.

To investigate the decay rate and metal uptake in litter from two species of wetland plants, leaves and stems of senescent Spartina alterniflora and Phragmites australis (P) were obtained from the Hackensack Meadowlands (NJ, USA) in October 1998, and their initial metal contents were determined. Two types of S. alterniflora were obtained, one set from a natural site (NS) and one from a restored site (RS). Leaves and stems were placed in separate litterbags, and samples of each type were reciprocally transplanted into each of the three collection sites (NS, RS, and P) as well as in the laboratory, where they were alternately dried and wetted. Litterbags were retrieved from the field at four six-month intervals and after one year from the laboratory. Annual decay coefficients were greater for leaves than for stems. Stems of P. australis initially decomposed more slowly (37-63% remaining) than those of S. alterniflora (23-53 % remaining), but after two years, decay was comparable (8-40% remaining for both species). Decomposition was slower at the RS site than at the other field sites, and it was slowest in the laboratory. Metal concentrations initially were lower in stems than in leaves, and Cr, Pb, and Zn were lower in P. australis than in S. alterniflora. In the field, large increases (10- to 100-fold) in metal concentrations rapidly obliterated any initial differences between plant species. Metal concentrations in leaves rose more quickly and remained greater than in stems. For example, Cu approached 300 microg/g in leaves but was less than 200 microg/g in stems. In contrast to the modest rise in metal concentrations in the leaf tissue at the more contaminated RS site (Zn rose to approximately 200 microg/g in sediments containing approximately 400 microg/g), Cu and Zn concentrations in leaf litter at the P and NS sites increased to levels exceeding those in the surrounding sediment (Zn rose to approximately 500 microg/g in sediments containing approximately 200 microg/g). Temporal changes in metal pools (grams of metal per litterbag) were not discernable because of the negative correlation of mass remaining and metal concentrations as well as because of the great variability of metal concentrations within each treatment. Decomposition and the accumulation of metals may be influenced more by differences between tissue types than by species or sediment metal concentrations.

Interactions of metals affect their distribution in tissues of Phragmites australis.

Culms of Phragmites australis were grown in vermiculite in a greenhouse. Some plants were exposed to 1000 microg/g Cu or Pb or Zn, or combinations of two or three of those metals. When plants reached senescence, they were harvested and analyzed for metal concentrations in upper leaves, lower leaves, stems and roots. While all metals accumulated in highest concentrations in the roots, Zn accumulated in aboveground tissues far more than the other metals. Furthermore, the concentration of any one metal in the different tissues was affected by the presence of other metals. The amount of copper in upper leaves increased when Zn was also present with the Cu. The amount of Cu in roots was increased in the presence of Pb and/or Zn. The amount of Zn in lower leaves was reduced when Cu was also present along with Zn. Thus, when combinations of metals were present, the distribution of metals was altered. The most important interactions appeared to be of Cu and Zn, which may reflect competition for binding sites on metal-binding proteins.

Metal uptake, transport and release by wetland plants: implications for phytoremediation and restoration.

Marshes have been proposed as sites for phytoremediation of metals. The fate of metals within plant tissues is a critical issue for effectiveness of this process. In this paper we review studies that investigate the effects of plants on metals in wetlands. While most of these marsh plant species are similar in metal uptake patterns and in concentrating metals primarily in roots, some species retain more of their metal burden in below ground structures than other species, which redistribute a greater proportion of metals into above ground tissues, especially leaves. Storage in roots is most beneficial for phytostabilization of the metal contaminants, which are least available when concentrated below ground. Plants may alter the speciation of metals and may also suffer toxic effects as a result of accumulating them. Metals in leaves may be excreted through salt glands and thereby returned to the marsh environment. Metal concentrations of leaf and stem litter may become enriched in metals over time, due in part to cation adsorption or to incorporation of fine particles with adsorbed metals. Several studies suggest that metals in litter are available to deposit feeders and, thus, can enter estuarine food webs. Marshes, therefore, can be sources and well as sinks for metal contaminants. Phragmites australis, an invasive species in the northeast U.S. sequesters more metals below ground than the native Spartina alterniflora, which also releases more via leaf excretion. This information is important for the siting and use of wetlands for phytoremediation as well as for marsh restoration efforts.

Is the invasion of the common reed, Phragmites australis, into tidal marshes of the eastern US an ecological disaster?

Studies of effects of the invasive brackish marsh plant Phragmites australis (common reed) on estuarine biota are reviewed. With few exceptions, most field studies indicate that these P. australis-dominated marshes have diverse and abundant benthic biota, and are utilized by nekton, comparable to Spartina alterniflora marshes. However, larval mummichogs, Fundulus heteroclitus, appear to be reduced in P. australis marshes compared with S. alterniflora marshes. Small epifauna living on plant stems also appear to be denser on S. alterniflora than P. australis stems. Other studies indicate that the detritus produced by decaying P. australis litter provides food value comparable to that of S. alterniflora and that its production enters estuarine food webs. Therefore, the general assumption that these marshes are ecologically "useless" is untrue. This information should be considered by marsh managers when making decisions about restoration projects.

Evaluating prey capture by larval mummichogs (Fundulus heteroclitus) as a potential biomarker for contaminants.

We evaluated larval prey capture as a "behavioral biomarker" of contamination by examining feeding behavior of larval mummichogs (Fundulus heteroclitus) from many different sites, including a severely contaminated "Superfund" site, moderately contaminated sites, and reference areas. Prey capture ability was related to sediment contaminant levels. The levels of contaminants at a site were highly correlated with each other, so that the impact of individual contaminants was confounded. The number of captures of brine shrimp by mummichog larvae from all sites was highly variable, but significant negative correlations of prey capture were seen with mercury, lead, zinc, cadmium, and PCBs. As observed previously with adults, polyaromatic hydrocarbons (PAHs) did not appear to impair prey capture ability. The only site in which prey capture rates of 8-day old larvae were severely affected was the most highly contaminated Superfund site, Berry's Creek, NJ. This implies that larval prey capture is not as sensitive a behavioral biomarker for contamination as adult behavior studied previously.

Mercury uptake by the estuarine species Palaemonetes pugio and Fundulus heteroclitus compared with their parasites, Probopyrus pandalicola and Eustrongylides sp.

When exposed to methylmercury in the laboratory, grass shrimp, Palaemonetes pugio, parasitized by the isopod Probopyrus pandalicola, accumulated lower concentrations of mercury than their unparasitized counterparts. The parasitic isopod accumulated far less mercury than the grass shrimp. When exposed to mercury in a contaminated field site, mummichogs, Fundulus heteroclitus, parasitized with the nematode Eustrongylides, similarly accumulated lower concentrations of mercury than unparasitized fish, and the parasite similarly accumulated less than the host. The lower uptake by the parasites compared to their hosts is counter to the general view of biomagnification of methylmercury, since parasites are a trophic level above their hosts. The mechanism whereby parasitized animals accumulate less toxicant than unparasitized ones is unknown, but may be partially due to lower metabolic rate.

Contamination of saltmarsh sediments and biota by CCA treated wood walkways.

Sediments, marsh grasses, and ribbed mussels were collected under two CCA wood walkways (15 and 3 years old) and 1, 3, and 10 m out, in the high, middle and low marshes. These sediments, and samples from reference sites, were analyzed for Cu, Cr, and As by atomic absorption spectrophotometry. Metal concentrations were highly elevated under the walkways and up to 10 m away. Dispersal of contaminants near the old walkway was greatest in the low marsh, less in the middle, and least in the high marsh, corresponding to periods of tidal inundation. Accumulation under the walkway was generally greatest in the low marsh. Contamination was much higher in sediments under the new walkway than the old one, but metals had not dispersed as far. Accumulation patterns in plants were similar, but the contamination did not disperse as far and was not greater under the new vs the old walkway, despite differences in sediment concentrations. In mussels, bioaccumulation was seldom statistically significant, due largely to small sample sizes.