Field and Laboratory Studies of the Toxicity to Phytoplankton of Polychlorinated Biphenyls (PCBs) Desorbed from Fine Clays and Natural Suspended Particulates

Polychlorinated biphenyls (PCBs; Aroclor 1254) were adsorbed to natural (Hudson River and New York Bight) and commercial (illite) particles in the laboratory, then allowed to desorb for several hours into the surrounding aqueous medium in the presence of either of two laboratory strains of diatom species or a complete natural phytoplankton assemblage. Cell density, photosynthesis, and chlorophyll a concentration in the cultures were followed for 2 to 3 days. In two experiments, PCB-carrying natural particles were removed after desorption and prior to the introduction of algae. All incubations were carried out in the laboratory or in dialysis membrane bags suspended in the tidal channel of an estuarine marsh.Cultures containing 90 μg of illite-bound Aroclor 1254/L of water were severely damaged within 4 hours, by which time 72% of the PCBs had desorbed from particles and become available to the diatoms. Similarly, a natural phytoplankton community, incubated under natural conditions in the presence of 50 μg of Hudson River sediment-associated PCB/L of water, registered significant reductions of photosynthesis and chlorophyll a content for at least 3 days. When PCB-bearing New York Bight particles were removed from the medium prior to the introduction of algae, sufficient desorbed PCBs remained to reduce growth rates and chlorophyll a content of the culture. The latter experiment clearly demonstrates particle to water to cell transfer of desorbed PCBs.     

Contaminant-associated health effects in fishes from the Ottawa and Ashtabula Rivers,Ohio

The health of resident fishes serves as a biologically relevant barometer of aquatic ecosystem integrity. Here, the health of the Ottawa River and Ashtabula River (both within the Lake Erie Basin) were assessed using morphological and immunological biomarkers in brown bullheads (Ameiurus nebulosus) and largemouth bass (Micropterus salmoides). Biomarker metrics were compared to fish collected from a reference site (Conneaut Creek). Data utilized for analyses were collected between 2003 and 2011. Fish collected from all three river systems had markedly different contaminant profiles. Total PCBs were the dominant contaminant class by mass. In bullhead, PCBs were highest in fish from the Ashtabula River and there were no differences in fish collected pre- or post-remediation of Ashtabula Harbor (median = 4.6 and 5.5 mg/kg respectively). Excluding PCBs, the Ottawa River was dominated by organochlorine pesticides. Liver tumor prevalence exceeded the 5% trigger level at both the Ashtabula (7.7%) and Ottawa Rivers (10.2%), but was not statistically different than that at the reference site. There was no statistically significant association between microscopic lesions, gross pathology and contaminant body burdens. Collectively, contaminant body burdens were generally negatively correlated with functional immune responses including bactericidal, cytotoxic-cell and respiratory burst activity in both species. Exceptions were positive correlations of HCB and heptachlor epoxide with respiratory burst activity in largemouth bass, and HCB with respiratory burst activity in bullhead and ΣBHC for all three functional assays in bullhead. Data here provide additional support that organochlorine contamination is associated with immunomodulation, and that species differences exist within sites.     

表面活性剂对土壤中多氯联苯洗脱影响研究进展

多氯联苯(PCBs)作为典型的持久性有机污染物(POPs),在环境中广泛分布且具有生物毒性,土壤中的多氯联苯可通过食物链在生物体中富集,对生物体产生危害.多氯联苯易与土壤紧密结合,由于其难以降解,故去除土壤中多氯联苯非常困难.利用表面活性剂的亲水性和亲油性,可促进土壤中PCBs释放到水体中,水体中的多氯联苯便于进一步处...     

表面活性剂对土壤中多氯联苯洗脱影响研究进展

多氯联苯（PCBs）作为典型的持久性有机污染物（POPs）,在环境中广泛分布且具有生物毒性,土壤中的多氯联苯可通过食物链在生物体中富集,对生物体产生危害。多氯联苯易与土壤紧密结合,由于其难以降解,故去除土壤中多氯联苯非常困难。利用表面活性剂的亲水性和亲油性,可促进土壤中PCBs释放到水体中,水体中的多氯联苯便于进一步处理,以减轻对生态的危害。该文综述了近年来国内外对于表面活性剂促进多氯联苯从土壤向水体中释放的研究进展,在阐释了表面活性剂促进土壤中多氯联苯洗脱机理的基础上,具体分析了影响促进作用的各种因素。     

A River-wide Survey of Polychlorinated Biphenyls (PCBs), Polycylic Aromatic Hydrocarbons (PAHs), and Selected Organochlorine Pesticide Residues in Sediments of the Detroit River—1999

The spatial distribution of hydrophobic organic contaminants, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and octachlorostyrene (OCS) in sediments of the Detroit River was established using data from a 1999 river-wide survey. The survey employed a stratified random sampling design that divided the river into six geostatistical zones consisting of upper, middle, and lower U.S. and equivalent Canadian river reaches. Organic carbon normalized OCS sediment concentrations demonstrated no significant differences between U.S. or Canadian sediments or upstream/downstream gradients suggesting that OCS is derived primarily from sources upstream of the Detroit River. In contrast, sum PCBs and sum PAHs were significantly elevated at U.S. as compared to Canadian stations and demonstrated significant increasing upstream/downstream gradients in organic carbon normalized sediment contamination. The upper and middle U.S. river reaches contained a number of near-shore stations with high localized PCB and PAH sediment concentrations suggesting multiple inputs along the upper U.S. portion of the river. Consistent with past surveys, wide-spread sediment contamination of PCBs and PAHs continues to be observed in the highly industrialized Trenton Channel and downstream of Grosse Isle. Threshold effect level (TEL) sediment quality guidelines for PAHs and PCBs were exceeded in 92.6 and 77.8%, respectively, of stations in Trenton Channel and downstream of Grosse Isle. This large reservoir of degraded sediments in the lower U.S. river reach has the potential to enter Lake Erie during sediment disturbance events and likely contributes to gentoxic stress and increased bioaccumulation of PCBs in resident benthos, fish, and wildlife.     

Source identification of PCBs in sediments from the Milwaukee Harbor Estuary,USA

This work focuses on the determination of PCB source profiles and their contributions to sediments in the Milwaukee Harbor Estuary by a principal component analysis (PCA) model. The model was recently developed and, for the first time, applied to apportion pollutant sources in sediments. Factor loadings and scores were computed, rotated via nonnegative constraints, and matched with candidate Aroclor profiles. Contamination by Aroclors 1016, 1242, 1254, and 1260 were identified for cores VC 6, 9, and 12 based on a log Q² criterion. The majority of PCB contribution was from a combination of Aroclors 1016 and 1242. Similarity between Aroclors 1016 and 1242 obscured resolution between the two profiles. Results from a chemical mass balance (CMB) model with known Aroclor profiles were in good agreement with the prediction from the PCA model.     

Anomalous Concentrations and Chlorination of Polychlorinated Biphenyls in Sediment Downwind of Lake Ontario

Relatively high concentrations (up to 98.5 ng/g dry wt) of polychlorinated biphenyls (PCBs) have been found in two cores penetrating fluvial sands east of Lake Ontario. One core was taken from the upper Salmon River reservoir on the Tug Hill Plateau and the other from Rice Creek near the lake at Oswego. In both instances, portions of the cores containing PCBs and other organochlorines (OCs) lack excess radiogenic ²¹⁰Pb and ¹³⁷Cs, implying depositional ages predating widespread OC commercial production, use, and release. Within each core there is little vertical variation in PCB composition and highly chlorinated congeners dominate the pattern. In addition, the PCB signature is analytically indistinguishable between cores despite collection over 50 km apart. This argues against local sources, and implies deposition and accumulation by processes operating over a substantial area and time period. Transport and introduction of a residual fraction of colloidal-bound PCBs to the sands via tannin-rich riverine waters is proposed.The PCB congener-specific pattern of air samples collected during the spring and summer of 1999 downwind of the lake at two locations (Rice Creek and Sterling) are similar to the sediments and display anomalous concentrations and chlorination with respect to other air sampling localities in the Great Lakes. A link between the residual fraction of PCBs observed in the sediment and air patterns via volatilization from the terrestrial surface is proposed. Elevated PCB concentrations and chlorination in non radiogenic fluvial sands and air may reflect regional accumulation and weathering processes operating over many decades and/or enhancement of contaminant deposition and partitioning downwind of the lake related to lake-effect precipitation.     

Concentrations of Polychlorinated Biphenyls in the Water Column of the Laurentian Great Lakes: Spring 1993

PCB concentrations were measured in the Laurentian Great Lakes of North America in the Spring of 1993. Quality control criteria were met for 97% of the dissolved phase samples and 90% of the particulate phase samples. Data are reported as total PCBs and as homolog groups for both of the operationally-defined phases at a 0.7 μM cutoff. Detection limit estimates were 21 pg/L for dissolved phase and 23 pg/L for particulate phase total PCBs, based on a sample volume of 190 L. Total PCB concentrations ranged from 100 pg/L in Lake Superior to 1.6 ng/L in the western basin of Lake Erie. Lakes Michigan and Ontario had the highest lakewide average total PCB concentrations, followed by Lake Huron, and then Lake Superior. Lakewide averaging across the three basins of Lake Erie was too variable to be useful.     

Analysis of Polychlorinated Biphenyl (PCB) Loading Trends in Lake Michigan

PCB concentrations in coregonid fishes (bloater chubs) collected from Lake Michigan between 1972 and 1980 are used to infer an historical loading trend for polychlorinated biphenyls (PCBs). A mass balance model was developed to describe the dynamics of PCBs by assuming that historical fish concentrations are proportional to concurrent water column concentrations of PCB. The validity of this assumption is strengthened, since the data represent a single species of fish (a pelagic feeder), a specific age class of that species, and a single laboratory performing the collections and analysis of the data. The results of model analysis indicate that PCB loading to Lake Michigan during the period of observation can be described by a linearly decreasing trend. The calibrated model also forecasts the response of selected fish species to various loading scenarios. Forecast results indicate that a continuously decreasing load will result in compliance with U.S. and Canadian guideline value for human consumption by 1987. However, should PCB loadings not continue to decrease, compliance with the proposed U.S. and extant Canadian guideline of 2.0 mg/kg is doubtful. Forecast accuracy may be improved by the availability of precise measurements of water:fish distribution coefficients.     

Modeling PCB Bioaccumulation by the Zebra Mussel (Dreissena polymorpha) in Saginaw Bay,Lake Huron

Zebra mussels were collected from navigation buoys in Saginaw Bay and the lower Saginaw River and analyzed for PCBs. Total PCB concentrations ranged from 0.076 to 1.2 μg/g, with the highest values for zebra mussels collected near the mouth of the Saginaw River. These data were combined with PCB concentration measurements in water and suspended solids to calculate congener-specific partition coefficients and bioaccumulation factors. Lipid-normalized bioaccumulation factors for PCB congeners ranged from 10^5.6 to 10^7.0. A model based on three-phase equilibrium partitioning and a bioaccumulation mass balance were applied to simulate the concentration ratios. Model results provided an unbiased best fit of the observed partition coefficients and bioaccumulation factors, as well as optimum parameter estimates. PCB fluxes mediated by zebra mussels were calculated from the model. Transfer across the gut was found to be the predominant route of PCB uptake for zebra mussels. Egestion and fecal excretion were estimated to generate a PCB flux of 1 to 30 μg/m²/d at zebra mussel densities reported for the Great Lakes. This flux exceeds the gross settling flux of PCBs to inner Saginaw Bay, demonstrating the potential of zebra mussels to alter particle and contaminant fluxes in the Great Lakes ecosystem. Zebra mussels may contain as much PCBs as the surficial sediments in Saginaw Bay.     

Food of Young-of-the-Year Lake Trout (Salvelinus Namaycush) in Presque Isle Harbor,Lake Superior

The food habits of young lake trout (Salvelinus namaycush) were studied by examining the digestive tracts of 293 young-of-the-year collected in Presque Isle Harbor, Lake Superior. Lake trout in the 25 to 27-mm length range started to eat food organisms before all of their yolk material was absorbed. Organisms consumed by the 25 to 27-mm young-of-the-year included Chironomidae, Copepoda (Harpacticoida, Calanoida, Cyclopoida), and Cladocerea (Daphnia spp., Bosmina sp., Chydorus sp.). Chironomid pupae and chironomid larvae accounted for 74% and 5%, respectively, of the total volume of food eaten by the young lake trout in Presque Isle Harbor. Although copepods, cladocerans, and mysids were present in many stomachs, their contribution to the total volume of food was only 15%. Some lake trout in the 32 to 54-mm length range had consumed fry of sculpin (Cottus spp.) or rainbow smelt (Osmerus mordax), but the overall contribution of fish fry to the total volume of food was only 4% (frequency of occurrence, 10%). The lake trout in Presque Isle Harbor fed heavily on planktonic organisms, sparingly on benthic organisms, and were opportunistic feeders that appeared to prey on whatever forage organisms were available in the shallow nearshore waters.     

Characterization of Surface-Associated Protozoan Communities in a Lake Erie Coastal Wetland (Old Woman Creek,Ohio)

Examination of surface-associated protozoa in Great Lakes coastal marshes has been minimal, although they play crucial roles in nutrient and energy transfer in similar systems. Spatio-temporal patterns of artificial substrate-associated protist and bacterial abundances are related to physico-chemical conditions at this “freshwater estuary.” Assemblages were sampled monthly (May-October) at upstream, downstream, and at two mid-estuarine sites. A total of 278 protistan taxa were observed, and greatest richness occurred in late June. Richness at the estuary mouth was consistently higher than upstream, possibly due to the influence of Lake Erie assemblages and variability in hydrology-driven habitat characteristics. PCA yielded two components accounting for 90% of total variance in species by sites data. Species abundances at the two mid-estuarine sites were most highly correlated, and taxa seasonally abundant at any one site tended to be abundant at others. Presence/absence data were used to calculate community similarity indices, and a permutation-computed test statistic compared the mean similarity of triplicate substrates in one month (at a given site) to the between-month similarity. Significant differences (α = 0.05) between some months (site by site) were observed, with a unique assemblage noted in October. Following classification into six functional feeding groups, bactivores (mainly heterotrophic microflagellates) and primary producers (mainly cryptomonads and chlamydomonads) dominated assemblages. Organisms in other functional groups comprised only 10–15% of observed taxa. A preponderance of bactivorous taxa is consistent with observations of a dense and metabolically active bacterial community associated with abundant paniculate organic matter in easily -resuspended surficial sediments.     

Horizontal and Vertical Distribution of PCBs in Southern Lake Michigan Sediments and the Effect of Waukegan Harbor as a Point Source

The spatial distribution of PCBs in southern Lake Michigan sediments was obtained from the analysis of 66 box cores and 8 grab samples. PCB concentrations in surficial sediments were closely related to sedimentation zone and to the oxidizable organic matter content of the sediments. Average surficial sediment concentrations ranged from 81 ng/g in depositional zones to 7.2 ng/g in non-depositional zones. The vertical distribution of PCBs was determined at several sites and was used to estimate the areal burden and flux of PCBs in each of the southern sedimentation zones. The total sediment PCB burden in the southern portion of the lake was estimated to be 5,900 kg. Southern Lake Michigan has received PCBs since approximately 1930 at an average flux of 7.1 μg/m² yr.The effect of Waukegan Harbor as a point source of PCBs to Lake Michigan was evaluated by comparing the PCB distribution and Aroclor composition of harbor sediments to those of sediments of decreasing distances from the harbor. Significant differences in total PCB concentration between non-depositional zones near the harbor and those in other areas of the basin indicate that Waukegan Harbor has influenced the PCB burden of Lake Michigan.     

Disturbance‐mediated Cyanobacterial Harmful Algal Bloom (CHAB) formation in a small Ohio reservoir

Cyanobacterial Harmful Algal Blooms (CHABs) in lentic waterbodies are becoming increasingly common because of climate change, changes in water usage and eutrophication. This study provides observational evidence that CHAB formation in a small Ohio reservoir (Lake Hope) is associated with metalimnetic disturbance during the summer months. Disturbance via lotic interflow may result in the appearance of CHABs in lentic habitats, with cyanobacterial maxima in the metalimnion.     

Blueback Herring (Alosa aestivalis) in Lake Ontario: First Record,Entry Route,and Colonization Potential

Two juvenile blueback herring (Alosa aestivalis) were caught in Lake Ontario in October 1995, the first record of this anadromous marine clupeid in the Great Lakes. Blueback herring most likely gained entry to Lake Ontario via the Erie Barge Canal, a navigation canal that links the Mohawk-Hudson rivers, which drain to the Atlantic Ocean, to Oneida Lake, which drains to Lake Ontario through the Oneida-Oswego rivers. Blueback herring ascend the Hudson River to spawn and were first reported from the upper Mohawk River in 1978. They currently spawn in several of the upper Mohawk's tributaries, including one about 430 km from the ocean but only 25 km from Oneida Lake. They were first found in Oneida Lake in 1982 and, in fall 1994, large numbers of juvenile blueback herring were found moving down the Oswego River. In the southern United States, blueback herring established self-reproducing populations in several reservoirs, and thus they have the potential to colonize Lake Ontario. If blueback herring become established in Lake Ontario, they could spread to other Great Lakes and impede recovery of depressed populations of indigenous fishes, like lake herring (Coregonus artedi) and lake trout (Salvelinus namaycush), through competition with, or predation on, their larvae.     

Assessing habitat for lake sturgeon (Acipenser fulvescens) reintroduction to the Maumee River,Ohio using habitat suitability index models

Lake sturgeon (Acipenser fulvescens) were a candidate for reintroduction in the Maumee River, Ohio, where they were historically abundant, but are now functionally extirpated. Our objective was to determine if current habitat quality and quantity could support reintroduction efforts. We developed a spatially explicit habitat suitability index model for two lake sturgeon life stages: spawning adult and age-0 fish. To estimate habitat quality, substrate, water depth, and water velocity were assessed and integrated into suitability index values to delineate good, moderate, and poor areas for each life stage. Each habitat characteristic was mapped and combined to provide an overall assessment of habitat suitability, quantity, and location. Model results indicated 208 ha (10.2% of all habitat) of good adult spawning habitat (e.g., coarse substrates, depths between 0.3 and 8 m, and velocity between 0.5 and 1 m/s) and 529 ha (28.2% of all habitat) of good age-0 habitat (e.g., fine substrates, depths between 0.2 and 6 m, and velocity between 0.1 and 0.7 m/s). Good age-0 habitat was located mostly downstream of good spawning habitat, which will provide nursery areas for age-0 fish after hatch. Our models suggested habitat is not limiting for lake sturgeon and efforts to reintroduce this species into the Maumee River, and for the first time in the Lake Erie basin, were supported. The results of this work supported reintroduction efforts that began in 2018.     

Development of a spatially resolved linked hydrodynamic and exposure model (LOTOX2) for PCBs in Lake Ontario

A linked hydrodynamic–hydrophobic organic chemical mass balance and food chain bioaccumulation model, LOTOX2, was developed to support the Lake Ontario Lakewide Management Plan (LaMP) for establishing contaminant load reduction strategies. This paper describes the development of LOTOX2, including the linkage with a relatively finer-scale hydrodynamic model (the Princeton Ocean Model, POM). An important component of this development was the reconstruction of PCB loading history (1930–2005), which was used to understand historic trends and to conduct model calibration/confirmation for total PCBs (tPCBs) in the lake water, sediments, and adult lake trout using data for the last 25 years. A separate mass balance was conducted for the radioisotope cesium-137 (¹³⁷Cs) in order to develop a sorbent mass balance model for the system. Following calibration and confirmation, a diagnostic application of the model showed that the lake is not yet at steady-state with current loads. It will take more than 50 years for tPCB concentration in lake trout to decrease to a steady-state value of about 0.4 ppm if year 2005 loads remain constant. If all external loads were instantaneously eliminated in 2005, it would take approximately 40 years for the adult lake trout tPCB concentration to reach 0.05 ppm (the uniform Great Lakes protocol value for unrestricted consumption) from its current level of 0.74 ppm.     

Temporal and Age-Related Trends in Levels of Polychlorinated Biphenyl Congeners and Organochlorine Contaminants in Lake Ontario Lake Trout (Salvelinus namaycush)

Concentrations of 21 organochlorine contaminants (OCs) and 61 polychlorinated biphenyl (PCB) congeners were determined in archived samples of whole lake trout (Salvelinus namaycush), age 4 years, collected yearly from eastern Lake Ontario between 1977 and 1993. Temporal trend data show decreases in all parameters analyzed in samples collected from 1977 to 1993. OC levels declined between 60 and 90% from 1977 to 1993. Trends of total PCB and PCB congeners concentrations were variable, but overall levels declined 80% between 1977 and 1993, from 9,060 ng/g in 1,977 to 1,720 ng/g in 1993. Reanalyzed total PCB levels vary randomly from the historical total PCB levels, but overall exhibit a much smoother trend. The means of the two sample sets were not significantly different at a probability of 0.05. Lake trout aged from 3 to 9 years old, collected in 1988, were analyzed to determine changes in contaminant concentrations with age. OC levels on average increased three-fold from 3-year-old lake trout up to 9-year-old lake trout. Total PCB levels increased from 2,760 ng/g in 3-year-old lake trout to 8,000 ng/g in 9-year-old lake trout, and PCB congener concentrations showed similar increases over the same age range. Lipid content declined 30% between 1977 and 1993, but lipid normalizing the data did not change the observed trends.     

Development of the Hydropower Potential of the Grande De Santiago River (Mexico)

Organization of the construction of three hydroelectric power plants on the Grande de Santiago River is described, namely the Aguamilpa, El Cajòn, and     

Mercury Distribution in the Biota of a Great Lakes Estuary: Old Woman Creek,Ohio

A study of mercury contamination in a wetland ecosystem was undertaken to assess degree of contamination in various compartments of the food web, and determine the most important routes for mercury to enter fish species. Old Woman Creek is a freshwater estuary on the southern shore of Lake Erie and has been recognized as an important nursery area for fish. Although there is no point source of mercury to the wetland, there is evidence of biomagnification of mercury in the food web. Mercury concentrations in water were not detectable (< 20 ng/L) by methods used in this study. The sediments had a mean concentration of 0.04 /μg total Hg/g wet weight. Zooplankton, benthos, and macro-phytes had less than 0.05 μg total Hg/g wet weight, but mean concentrations in fish tissue ranged from 0.001 to 0.636 μg total Hg/g wet weight. There was a positive correlation between mercury concentration and both length and weight in channel catfish Ictalurus punctatus and common carp Cyprinus carpio. In general, channel catfish accumulated higher levels of mercury than common carp, suggesting that the pelagic food web may be more efficient in delivery of mercury (to channel catfish) than the benthic pathway (to common carp). The highest value for fish occurred in a bowfin Amia calva. Tissue from one great blue heron Ardea herodias had the highest concentration at 1.62 μg total Hg/g wet weight. In this system, as in others, top predators tended to accumulate the highest mercury levels and were therefore most susceptible to mercury poisoning, even at sublethal levels.