Trends of brominated diphenyl ethers in fresh and archived Great Lakes fish (1979-2005)

While few environmental measurements of brominated diphenyl ethers (BDEs) were completed prior to the mid-1990s, analysis of appropriately archived samples might enable the determination of contaminant trends back to the introduction of these chemicals. In this paper, we first investigate the stability of BDEs in archived frozen and extracted fish samples, and then characterize trends of these chemicals in rainbow smelt (Osmerus mordax) and lake trout (Salvelinus namaycush) in each of the Great Lakes between 1979 and 2005. We focus on the four most common congeners (BDE-47, 100, 99 and 153) and use a change-point analysis to detect shifts in trends. Analyses of archived fish samples yielded precise BDE concentration measurements with only small losses (0.8% per year in frozen fish tissues, 2.2% per year in refrigerated extracts). Trends in fish from all Great Lakes showed large increases in BDE concentrations that started in the early to mid-1980s with fairly consistent doubling times (generally 2-4 years except in Lake Erie smelt where levels increased very slowly), though concentrations and trends show differences by congener, fish species and lake. The most recent data show that accumulation rates are slowing, and concentrations of penta- and hexa-congeners in trout from Lakes Ontario and Michigan and smelt from Lake Ontario started to decrease in the mid-1990s. Trends in smelt and trout are evolving somewhat differently, and trout concentrations in the five lakes are now ranked as Michigan>Superior=Ontario>Huron=Erie, and smelt concentrations as Michigan>Ontario>Huron>Superior>Erie. The analysis of properly archived samples permits the reconstruction of historical trends, congener distributions, biomagnification and other information that can aid the understanding and management of these contaminants.     

Polychlorinated biphenyls (PCB) and dichlorodiphenyltrichloroethane (DDE) air concentrations in the Lake Ontario region: Trends and potential sources

Airborne particle and gas samples were collected approx every 12 days from April 2002 to June 2006 at the Sterling Nature Center located near the southeast corner of Lake Ontario. These samples were analyzed for polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDE). Clausius-Clapeyron (C–C) regression analyses of PCBs and DDE yielded moderate correlations (r² = 0.54, p < 0.001; r² = 0.74, p < 0.001, respectively) indicating that much of the variations in concentrations can be explained by temperature. Back trajectory analysis indicated that the most important factors driving unusually high PCB partial pressures relative to those predicted by the C–C regression were slow wind speeds and winds generally from the southwest. This combination, which occurred frequently in 2004, increased contact of the air with contaminated upwind surfaces with minimum dilution. Hybrid receptor modeling (Potential Source Contribution Function (PSCF)) results for the total PCBs identified the midwestern US region that contains the urban areas of southern Indiana (IN), southwestern Ohio (OH), and northern Kentucky (KY) having the highest PSCF values. In general urban areas like Chicago (IL), Detroit (MI), Cleveland (OH), St. Louis (MO), and Nashville (TN) also had significant possibilities. In contrast, the PSCF modeling for DDE identified northern Alabama as the area with the highest probability where DDT was applied to cotton fields.     

Analysis of 2,3,7,8-Tetrachlorodibenzo-p-dioxin in Great Lakes fish

In fish samples from Lake Ontario and Lake Huron 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was found at concentrations from 2 to 162 pg/g (ppt) and from 2.5 to 29 ppt respectively. Fish from the other Great Lakes (Lake Superior, Lake Michigan and Lake Erie) generally had no detectable signals for TCDD although a few samples had < 3 ppt.     

Toxaphene congeners in the Canadian Great Lakes basin: temporal and spatial food web dynamics

Samples of a top predator fish species, lake trout (Salvelinus namaycush) and predominant forage species including smelt (Osmerus mordax), alewife (Alosa pseudoharengus), slimy sculpin (Cottus cognatus), deepwater sculpin (Myoxocephalus quadricornis) and lake herring (Coregonus artedii) were, collected from throughout 4 of the 5 Great Lakes (Superior, Huron, Erie and Ontario) (Fig. 1). Lake trout were also collected from three isolated lake systems (Lakes Nipigon, Simcoe and Opeongo), all located within the basin. All the samples were analysed for body burdens of total toxaphene and 22 toxaphene congeners. In addition, from each of the Great Lakes sites samples of major invertebrate dietary items, which included Mysis relicta, Diporeia hoyi and plankton, were similarly analysed. Whole lake trout samples, archived at -80 degrees C, were reanalysed to determine historical trends of toxaphene congeners plus carbon and nitrogen stable isotope signatures. The Lake Superior food web consistently had the highest levels of total toxaphene of all the Great Lakes monitored. The primary source of toxaphene to Lake Superior has been identified as atmospheric transport and deposition from sites in the southern US, Mexico and Central America (Hoff, R.M., Strachan, W.M.J., Sweet, C.W., Chan, C.H., Shackelton, M., Bidleman, T.F., Brice, K.A., Burnison, D.A., Cussion, S., Gatz, D.F., Harlin, K., Schroeder, W.H., 1996. Atmospheric deposition of toxic chemicals to the Great Lakes: A review of data through 1994. Atmospheric Environ. 30, 3505-3527). Of the offsystem lakes surveyed. Lake Nipigon, situated due north of Lake Superior and with a Lake Basin area of about 6% of Lake Superior (Hendendorf, C.E., 1982. J. Great Lakes Res. 8(3), 379-412) had total toxaphene levels in lake trout equivalent to about 50% of those found in lake trout from Lake Superior. Temporal trend toxaphene congener analysis was conducted on archived whole fish samples collected over the period 1980 through to the 1990's. Initially a nonachlorobornane congener (Parlar #50) was predominant, with congeners #40, #62 and #21 being the next most prominent in the 1980 samples. Samples from the 1990's showed a significant decline in the presence of lower chlorinated congeners #40 and #21. Analysis of total toxaphene in food webs, indicated elevated levels in lower trophic level species such as Diporeia and Cottus sp. which have a benthic association. The stable isotope temporal trend 13C signature identified a significant shift in the lake trout diet over the period 1993 to 1996.     

Organochlorine compounds in soils and sediments of the mountain Andean Lakes

Semi-volatile organochlorine compounds (OC) were analyzed in remote Andean soils and lake sediments. The sampling sites covered a wide latitudinal gradient from 18 degrees S to 46 degrees S along Chile and an altitudinal gradient (10-4500 m). The concentrations were in the order of background levels, involving absence of major pollution sources in the high mountain areas. Significant correlations were found between log-transformed concentrations of hexachlorobenzene, alpha- and gamma-hexachlorocyclohexane in soils and total organic content (TOC). In addition, TOC-normalized concentrations of the most volatile OC showed a significant linear dependence with air temperature. This good agreement points to temperature as a significant factor for the retention of long range transported OC in remote ecosystems such as the Andean mountains, although other variables should not be totally excluded. The highest concentrations of OCs were achieved in the sites located at highest altitude and lowest temperature of the dataset.     

The dualistic approach of FCA: a further insight into Ontario Lake sediments

The investigation of object-by-attribute matrices is very common in statistics and data analysis with the aim of uncovering every possible relationship among objects and/or attributes. Formal Concept Analysis (FCA) is a method, which stems directly from partial order and lattice theory, which provides an efficient tool to symmetrically uncover linkages among objects and attributes whenever a relation stands among the two sets. It provides efficacious graphical representation and computes association rules between attributes, thus helping in the detection of possible synergism or antagonism of attributes. In this paper, FCA potentialities are discussed and described by means of a case study already investigated by other partial order techniques: the case of Lake Ontario sediment samples. Data derive from a ‘test battery’ for a simultaneous analysis of degradation of Lake Ontario samples, which are basically of two typologies: hygienic and toxicity tests. A multi-valued approach is adopted to cope with the ordinal feature of data. Results highlight interesting interaction among hygienic compounds and a synergism between the two toxicity tests.     

Assessment of environmental endocrine disruptors in bald eagles of the Great Lakes

Environmental endocrine disruption in wildlife has primarily focused on estrogenic/androgenic end points and their antagonists. We describe here the work that has occurred within the Great Lakes of North America that has used the bald eagle (Haliaeetus leucocephalus) as a sentinel species of the effects of environmental toxicants, including endocrine disruption. Our data suggests that population level effects of hormone disrupting chemicals, not necessarily estrogen/androgen mimics and their antagonists, have been associated with reproductive and teratogenic effects observed in the bald eagle population within the Great Lakes Basin. Additional laboratory and field studies are necessary to further clarify the role of environmental endocrine disruptors on reproduction in avian populations. The use of sea eagles (Haliaeetus spp.) as biosentinels of pollution in other regions of the world is also discussed.     

Immunoassay monitoring of polychlorinated biphenyls (PCBs) in the Great Lakes

Although polychlorinated biphenyls (PCBs) are no longer manufactured, they are still entering the environment. In some compartments of the environment, PCB concentrations are a serious concern. This is especially true in compartments which accumulate PCBs, and in food items consumed by humans and wildlife. Also, there are situations in which management decisions require rapid, sensitive, accurate measurements, which can be made in real time under field conditions. Methods to use an enzyme-linked immunosorbent assay (ELISA) for PCBs were developed and applied to sediments and fish muscle homogenates collected from the Great Lakes. The extraction methods developed can be applied in the field with non-hazardous solvents, in the absence of sophisticated laboratory equipment. The method detection limit for PCBs in dimethyl sulfoxide (DMSO) extracts of sediment was 0.9 mg/kg. For PCBs in isopropanol extracts of fish tissue, the method detection limit was 0.6 mg/kg. The resolution of the ELISA was 0.83 mg/kg at 1.1 mg/kg and 1.6 mg/kg at 1.7 mg/kg, for sediment and fish tissue, respectively.     

Etiology of chick edema disease in Herring Gulls in the lower Great Lakes

Severe reproductive failure among fish-feeding birds on the lower Great Lakes was investigated in the early 1970s. Examination of Lake Ontario and Lake Erie Herring Gull chicks at hatching showed signs consistent with chick edema disease and thus with the presence of a chick edema factor. Subsequent microcontaminant analysis of stored eggs revealed the presence of 2,3,7,8-TCDD at concentrations that could account for the poor reproductive success and the signs of chick edema disease.     

Spatial and temporal trends in surface water and sediment contamination in the Laurentian Great Lakes

Data from recent sediment and surface water surveys have been collated and mapped to illustrate the spatial distribution of contaminants across the entire Great Lakes basin. Information from historical surveys, together with data from surface water monitoring programs in three major connecting channels, has also been collated in order to evaluate temporal trends. In general, Lakes Superior and Michigan exhibited the lowest levels of sediment contamination while Lake Ontario had the highest. Contaminants such as gamma-HCH (lindane) and dieldrin were ubiquitous in surface waters across the entire basin, which was indicative of atmospheric sources. The distribution of other compounds including hexachlorobenzene, octachlorostyrene and mirex indicated the presence of local sources within the watersheds of the connecting channels. Surficial sediment contamination was found to have decreased markedly since the late 1960s and 1970s. Similarly, surface water contamination decreased over the period 1986-1997 with concentrations of dieldrin, hexachlorobenzene, octachlorostyrene and mirex reduced by over 50%. However, the spatial distributions of both sediment and surface water contamination indicate that further effort is warranted in reducing local sources of contaminants, particularly in Lake Ontario.     

Wet and dry deposition of sulfur and nitrogen compounds in Ontario

Measurements have been made of sulfur and nitrogen compounds in precipitation since 1980 and in air since 1981 in Ontario. This paper presents results of the atmospheric deposition measurement program to the end of 1985. As is to be expected from the distribution of emission sources, annual concentrations of SO₄²⁻ andNO₃⁻ in precipitation, and of SO₂,SO₄²⁻ andNO₃⁻ in air are higher in southern Ontario than in northern Ontario. The corresponding distribution pattern for deposition is similar to that of concentration. A wet SO₄²⁻ deposition rate of 20 kg ha¹⁻ y¹⁻, a value considered critical for the acidification of sensitive water bodies, is exceeded in all of central and southern Ontario. On a province-wide basis, sulfur wet deposition is about four times higher than sulfur dry deposition. For nitrogen, wet and dry deposition are more comparable, though the former is still higher. The S- and N-species display different seasonal trends in concentration and deposition reflecting a dependence on meteorological factors, and on the associated chemical transformation rates. On the other hand, year to year variations are small.     

Trends and gaps in biodiversity and ecosystem services research: A text mining approach

Understanding the relationship between biodiversity conservation and ecosystem services concepts is essential for evidence-based policy development. We used text mining augmented by topic modelling to analyse abstracts of 15 310 peer-reviewed papers (from 2000 to 2020). We identified nine major topics; “Research & Policy”, “Urban and Spatial Planning”, “Economics & Conservation”, “Diversity & Plants”, “Species & Climate change”, “Agriculture”, “Conservation and Distribution”, “Carbon & Soil & Forestry”, “Hydro-& Microbiology”. The topic “Research & Policy” performed highly, considering number of publications and citation rate, while in the case of other topics, the “best” performances varied, depending on the indicator applied. Topics with human, policy or economic dimensions had higher performances than the ones with ‘pure’ biodiversity and science. Agriculture dominated over forestry and fishery sectors, while some elements of biodiversity and ecosystem services were under-represented. Text mining is a powerful tool to identify relations between research supply and policy demand.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-022-01776-2.     

Pharmaceuticals and personal care products found in the Great Lakes above concentrations of environmental concern

The monitoring of pharmaceuticals and personal care products (PPCPs) has focused on the distribution in rivers and small lakes, but data regarding their occurrence and effects in large lake systems, such as the Great Lakes, are sparse. Wastewater treatment processes have not been optimized to remove influent PPCPs and are a major source of PPCPs in the environment. Furthermore, PPCPs are not currently regulated in wastewater effluent. In this experiment we evaluated the concentration, and corresponding risk, of PPCPs from a wastewater effluent source at varying distances in Lake Michigan. Fifty-four PPCPs and hormones were assessed on six different dates over a two-year period from surface water and sediment samples up to 3.2 km from a wastewater treatment plant and at two sites within a harbor. Thirty-two PPCPs were detected in Lake Michigan and 30 were detected in the sediment, with numerous PPCPs being detected up to 3.2 km away from the shoreline. The most frequently detected PPCPs in Lake Michigan were metformin, caffeine, sulfamethoxazole, and triclosan. To determine the ecological risk, the maximum measured environmental concentrations were compared to the predicted no-effect concentration and 14 PPCPs were found to be of medium or high ecological risk. The environmental risk of PPCPs in large lake systems, such as the Great Lakes, has been questioned due to high dilution; however, the concentrations found in this study, and their corresponding risk quotient, indicate a significant threat by PPCPs to the health of the Great Lakes, particularly near shore organisms.     

Response of phytoplankton communities to acidification and recovery in Killarney Park and the Experimental Lakes Area,Ontario

It has been widely speculated that controls of SO2 emissions would stimulate recovery of acidified freshwater lakes in Canada, the United States and Europe. Phytoplankton communities from 22 lakes near Killarney Park Ontario, covering a pH range from 4.5-7.7, were studied from 1998-2000 and compared to data from experimentally acidified (pH decreased 6.7 to 4.5) and recovered (pH increased to 6.0) Lake 302 South at the Experimental Lakes Area (ELA), northwestern Ontario to assess recovery from acidification. Based on historical data, pH levels have rebounded to above 6.0 in several lakes in the Killarney area that were previously acidified to pH 5.0-5.5. Phytoplankton biomass was not correlated to pH, but there was a highly significant relationship between species richness and pH. Recovery trajectories were observed in a subset of 6 lakes, combining species diversity data from the present study with historical data. Correspondence analysis indicated that several of the lakes that experienced increased pH have shifted towards phytoplankton assemblages typical of circumneutral environments.     

Patterns and sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in surficial sediments of Lakes Erie and Ontario

This study determines spatial trends and congener patterns of 2378-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in surficial sediments of Lakes Erie and Ontario. Sediments are enriched in 2378-PCDFs in Lake Ontario, and the PCDD/F concentrations increased from shallow near-shore sediments towards deep-water depositional zone sediments. In Lake Erie, sediments were dominated by octachlorodibenzo-p-dioxin, and the highest PCDD/F concentrations were observed in the western basin and the southern shoreline of the central basin with a decrease towards the eastern basin and the northern shoreline of the central basin. Principal components analysis revealed that chemical manufacture and disposal of chemical waste along the Niagara River has been a major PCDD/F source to Lake Ontario; while PCDD/Fs in Lake Erie are from multiple sources including industrial sources along the Detroit River, major tributaries along the southern shoreline of the lake, and atmospherically-derived material from the upper lakes and connecting channels.     

Determination of mutagenic potential and organic contaminants of Great Lakes drinking water

Extracts of organic compounds were obtained, using XAD-2 macroreticular resin, from drinking water supplies in 12 Great Lakes municipalities. The extracts were tested for mutagenic potential using the Salmonella/mammalian-microsome assay and analysed for organochlorine pesticides, polyaromatic hydrocarbons, organophosphorous pesticides and trialkyl-arylphosphates. Grab samples of drinking water were also analysed for volatile organic compounds. Dose-related increases in mutagenicity were found in extracts from 11 of the drinking water supplies.     

Organochlorine contaminants in eggs of Common Terns from the Canadian Great Lakes, 1981

To determine if contaminant levels in Common Terns had changed over the last decade, we collected and analyzed eggs from four nesting colonies on the three lower Great Lakes during 1981. DDE and PCBs were detected in every egg from the four colonies. Dieldrin, mirex and trans-nonachlor were detected in more than 45% of the eggs. Seven other organochlorine contaminants (DDD, DDT, hexachlorobenzene, oxychlordane, cis-chlordane, cis-nonachlor and toxaphene) were detected in less than 25% of the eggs. Eggs from the Lake Ontario colony were generally the most heavily contaminated. Comparisons of DDE and PCB data with earlier studies of Common Terns indicated that contaminant levels in eggs from the four sampled colonies, or nearby sites, have decreased by up to 80-90% from 1969-1973 to 1981. Interspecies comparisons showed that Common Tern eggs have lower organochlorine residue levels than eggs of Caspian Terns or Herring Gulls. Dietary variation and migratory status are possible explanations for the differences in residue levels among species. Eggshell thickness, log-PCBs, and log-DDE were not significantly intercorrelated. Elevated contaminant levels in the early 1970s might be at least partly responsible for the decline of the Great Lakes Common Tern population over the past decade. Stabilization of population numbers during the early 1980s suggests that organochlorine pollution levels have been reduced to a point where they are no longer an important factor in the population dynamics of this species on the Great Lakes.