Production of Hexagenia limbata nymphs in contaminated sediments in the Upper Great Lakes Connecting Channels

In April through October 1986, we sampled sediments and populations of nymphs of the burrowing mayfly, Hexagenia limbata (Serville), at 11 locations throughout the connecting channels of the upper Great Lakes, to determine if sediment contaminants adversely affected nymph production. Production over this period was high (980 to 9231 mg dry wt m^-2) at the five locations where measured sediment levels of oil, cyanide, and six metals were below the threshold criteria of the U.S. Environmental Protection Agency and the Ontario Ministry of Environment for contaminated or polluted sediments, and also where the criterion for visible oil given in the Water Quality Agreement between the U.S.A. and Canada for connecting waters of the Great Lakes was not exceeded. At the other six locations where sediments were polluted, production was markedly lower (359 to 872 mg dry wt m^-2). This finding is significant because it indicates that existing sediment quality criteria can be applied to protect H. limbata from oil, cyanide, and metals in the Great Lakes and connecting channels where the species fulfills a major role in secondary production and trophic transfer of energy.Contribution 733, of the National Fisheries Research Center-Great Lakes, U.S. Fish and Wildlife Service, 1451 Green Road, Ann Arbor, MI 48105.     

Distribution of Hexagenia nymphs and visible oil in sediments of the Upper Great Lakes Connecting Channels

As part of the study of the Upper Great Lakes Connecting Channels sponsored by the U.S. Environmental Protection Agency, the U.S. Fish and Wildlife Service examined the occurrence of Hexagenia nymphs and visible oil in sediments at 250 stations throughout the St. Marys River and the St. Clair-Detroit River system from May 14 to June 11, 1985. The mean density of Hexagenia nymphs per square meter averaged 194 for the total study area, 224 in the St. Marys River, 117 in the St. Clair River, 279 in Lake St. Clair, and 94 in the Detroit River. The maximum density of nymphs ranged from 1,081 to 1,164 m^-2 in the three rivers and was 3,099 m^-2 in Lake St. Clair. A comparison of nymph density at 46 stations where oil was observed in sediments physically suitable for nymphs showed that densities were lower in oiled sediments (61 m^-2) than in sediments without oil (224 m^-2). Densities of nymphs were relatively high at only four stations where oil was observed in sediments. In general, oiled sediments and low densities of nymphs occurred together downstream from industrial and municipal discharges.Contribution number 736 of the National Fisheries Research Center-Great Lakes, U.S. Fish and Wildlife Service, 1451 Green Road, Ann Arbor, MI 48105.     

A method for evaluating the impact of navigationally induced suspended sediments from the Upper Great Lakes Connecting Channels on the primary productivity

The impact of navigationally induced suspended sediments from the Upper Great Lakes Connecting Channels on the size-fractionated primary productivity was evaluated by the Carbon-14 technique. The method applied was on-site, rapid, sensitive, inexpensive, and provided dynamic-toxicological information essential for hazard assessment. Both enhancement and inhibition of the primary productivity was observed in various parts of the Upper Great Lakes Connecting Channels. These responses appear to depend on the type of natural plankton and their exposure to various contaminant/nutrient complexes generated by the disturbance of the bottom sediments during the passage of ships. Traditionally, only the inhibition of primary productivity has been monitored from a toxicity point of view, but it is important also to evaluate the implications of enhancement since it may result in increased eutrophication, propagation of nuisance blooms, and change of intricate food-web interactions. The procedure adopted in this study for the first time appears to possess considerable potential for a simple and rapid screening of environmental perturbations resulting from navigational activities.     

Heavy metals' contamination in sediments of Wadi Al-Aqiq water reservoir dam at Al-Baha region,KSA: Their identification and assessment

Sediments are the ultimate sump for heavy metal pollutants. The main purpose was to investigate the ecological and health risk assessment of heavy metals in the sediments of Wadi Al-Aqiq water reservoir. The metals detected were arranged in decreasing order Fe > Mn > Cr > Cu > Zn > Ni > Co > Pb. Pearson correlation analysis indicated strong positive association and significant linear relation between various pairs of metals. Different evaluation indices used indicated that source of contamination from lithogenic sources and sediments can be classified as low polluted quality. A comparison of the concentrations of metals with International Sediment Quality Guidelines criteria showed that only Cu and Ni concentrations above the ERL and below the ERM guideline values suggest possible adverse effects. On comparing with US Environmental Protection Agency prepared sediment quality criteria it indicated that Pb and Zn have concentrations below the non-polluted criteria, Fe, Mn, and Ni lies in the range of moderately polluted criteria, and Co and Cu are within the heavily polluted criteria. Non-carcinogenic risk quantification indicated health concern from ingestion route and no health effects for dermal exposure. On considering additive effect, the dermal exposure may cause health harm. The carcinogenic risk assessment for lead and chromium showed an acceptable risk to human health.     

Heavy metal surveys in sediments of five important Cuban bays

This paper presents data obtained between 1983 and 1989 on concentration of heavy metals in sediments of five Cuban bays having different physical and geographical characteristics and differing degrees of anthropogenic activities. Data are normalized with respect to Al, Fe, and organic content and processed through statistical techniques of multivariate analysis. The degree of heavy metal pollution among the harbors decreases in the following order: Havana, Santiago de Cuba, Cienfuegos Matanzas, Cárdenas     

Assessment of sediment contamination at Great Lakes Areas of Concern: the ARCS Program Toxicity-Chemistry Work Group strategy

In response to a mandate in Section 118(c)(3) of the Water Quality Act of 1987, a program called Assessment and Remediation of Contaminated Sediments (ARCS) was established. Four technical work groups were formed. This paper details the research strategy of the Toxicity-Chemistry Work Group.The Work Group's general objectives are to develop survey methods and to map the degree of contamination and toxicity in bottom sediments at three study areas, which will serve as guidance for future surveys at other locations. A related objective is to use the data base that will be generated to calculate sediment quality concentrations by several methods. The information needed to achieve these goals will be collected in a series of field surveys at three areas: Saginaw Bay (MI), Grand Calumet River (IN), and Buffalo River (NY). Assessments of the extent of contamination and potential adverse effects of contaminants in sediment at each of these locations will be conducted by collecting samples for physical characterization, toxicity testing, mutagenicity testing, chemical analyses, and fish bioaccumulation assays. Fish populations will be assessed for tumors and external abnormalities, and benthic community structure will be analyzed. A mapping approach will use low-cost indicator parameters at a large number of stations, and will extrapolate by correlation from traditional chemical and biological studies at a smaller number of locations. Sediment toxicity testing includes elutriate, pore water and whole sediment bioassays in a three-tiered framework. In addition to the regular series of toxicity tests at primary mater stations, some stations are selected for a more extensive suite of tests.     

Heavy Metal Distribution in Open Canals and Drains in the Upper Rio Grande Basin

The inclusion of reclaimed effluents for irrigated agriculture may allow communities along the U.S.-Mexico border to use water resources more efficiently and reduce urban costs of wastewater treatment. However, metal inflow from industry and urbanization may threaten food safety. This study examines metal concentrations in sediments from open canal systems charged with flow from the Rio Grande and from effluents discharged from border communities. At the surface of canal beds, sediments were collected from six canal segments that began at the fringe of the El Paso/Juarez metroplex to rural areas downstream, and ranged from 9 to 24?km in length. Sediments were analyzed for Cd, Co, Cr, Cu, Ni, Pb, and Zn. These metals rarely exceeded 20?mg kg^?1. Drainage and effluent conveyance increased the variability of metal concentrations in sediments. Geostatistical models did not significantly account for spatial variability of metals, except in Mexico. This may implicate multiple rather than single inflow sources of metals. Peaks in metal concentrations often coincided with growing rural communities. However, most metal concentrations were within conventional global ranges and were not at levels high enough to threaten food safety. Future sampling strategies will require reduced sampling intervals from 1 to <0.13?km.     

Heavy metal content of sediments in the Calcasieu River/Lake Complex,Louisiana

The heavy metals Cd, Cr, Cu, Pb, Hg, Ag, and Zn, and the metalloid As were measured in surface sediments at permanent stations located in the Calcasieu River/Lake Complex. The relationships among metal concentrations in different areas of the system were investigated to determine sources, source strength, and transport. The point-source inputs of heavy metals were assumed to be industrial outfalls (Bayou d'Inde) and sewage outfalls (Bayou d'Inde and Contraband Bayou). Although these inputs have not seriously affected the entire river/lake system, stressed regions exist within each bayou.The background levels of arsenic and heavy metals were: 0.60 (As), 0.3 to 1.4 (Cd), 25 (Cr), 10 (Cu), 15 (Pb), < 0.05 (Hg), 0.07 (Ag), and 40 mg kg^–1 (Zn). Stations near sewage outfalls and industrial outfalls had increased metal concentrations above these background levels, but the increases were restricted to the regions near the outfalls. The metals discharged into the bayous were not being transported to the remainder of the river/lake complex.     

Trace metal distribution in the sediments of the whole lake basin for Lochnagar,Scotland: a palaeolimnological assessment

Analyses of trace metals on multiple sediment cores from the whole-lake basin of Lochnagar, Scotland, show that the depth of departure from stable values towards a rapid increase of the Pb/Ti and Hg concentration profiles provides a good dating feature for the 1860s. In relatively shallow areas of the lake, inferred sediment accumulation rates and the trace metal inventories change with water depth, but in the deep water area, sediment accumulation rates are lower than in most other areas of the lake. Mercury, Pb, Cu and Zn inventories in the sediments accumulated since 1860 in the deepest area are 61%, 64%, 73% and 56% of the corresponding average inventories for the whole sediment area of the lake, respectively. This is mainly due to low sediment accumulation in the deep basin. This finding differs from the expected sediment focusing pattern and makes quantitative interpretations of palaeolimnological features using sediments from the deep area of this lake difficult. The influence of sediment focusing from the north-eastern side, the largest portion of the sediment area of the lake basin, on the deepest area of the lake may be limited, so the sediments in the north-east could be difficult to be transported to the deepest area through sediment focusing. Therefore, the sediments in the deepest area of the lake may not represent the whole-lake basin well for the relative abundances of different types of fossils.     

Distribution and contamination pattern of heavy metals from surface sediments in the southern part of Caspian Sea,Iran

This study concentrates on the speciation and distribution patterns of some heavy metals (Pb, Ni, Cd, Zn, and Cu) in surface sediments in the southern part of the Caspian Sea, the biggest lake in the world, to obtain an overall classification for the origins of metals in the area using a sequential extraction technique. At all sampling stations, Pb, Ni, Zn, and Cu were mostly (>50%) accumulated in the resistant fraction, which indicated that there were no significant anthropogenic inputs of Pb, Ni, Zn, and Cu into the surface sediments of the south Caspian Sea. Guilan province on the west coast of Caspian Sea accumulated higher percentages of non-resistant fractions of Pb and Zn, while Mazandaran and Golestan provinces in the middle and western parts of the Caspian Sea, in the Iranian zone, accumulated higher percentages of non-resistant fractions of Ni and Cu. The present study revealed that the coastal area of the south Caspian Sea is still not seriously contaminated. Cadmium in Guilan and Golestan provinces were dominated by non-resistant fractions (55–69%), which indicated more anthropogenic inputs of Cd on the south coast of the Caspian Sea in comparison with other metals.     

Microbial community structures in anoxic freshwater lake sediment along a metal contamination gradient

Contamination, such as by heavy metals, has frequently been implicated in altering microbial community structure. However, this association has not been extensively studied for anaerobic communities, or in freshwater lake sediments. We investigated microbial community structure in the metal-contaminated anoxic sediments of a eutrophic lake that were impacted over the course of 80 years by nearby zinc-smelting activities. Microbial community structure was inferred for bacterial, archaeal and eukaryotic populations by evaluating terminal restriction fragment length polymorphism (TRFLP) patterns in near-surface sediments collected in triplicate from five areas of the lake that had differing levels of metal contamination. The majority of the fragments in the bacterial and eukaryotic profiles showed no evidence of variation in association with metal contamination levels, and diversity revealed by these profiles remained consistent even as metal concentrations varied from 3000 to 27 000 mg kg⁻¹ total Zn, 0.125 to 11.2 μ pore water Zn and 0.023 to 5.40 μ pore water As. Although most archaeal fragments also showed no evidence of variation, the prevalence of a fragment associated with mesophilic Crenarchaeota showed significant positive correlation with total Zn concentrations. This Crenarchaeota fragment dominated the archaeal TRFLP profiles, representing between 35% and 79% of the total measured peak areas. Lake DePue 16S rRNA gene sequences corresponding to this TRFLP fragment clustered with anaerobic and soil mesophilic Crenarchaeota sequences. Although Crenarchaeota have been associated with metal-contaminated groundwater and soils, this is a first report (to our knowledge) documenting potential increased prevalence of Crenarchaeota associated with elevated levels of metal contamination.     

A comparative study of chemical contamination in sediments of East River (Dongjiang) and selected reservoirs in Hong Kong

Abstract

The levels of TKN, orthophosphate, heavy metals and trace organics including total PCBs and PAHs in the sediments of the East River (Dongjiang) and various reservoirs in Hong Kong were chemically analyzed. It was found that the sediments of various sections of Dongjing and the Shenzhen Reservoir were contaminated by heavy metals at slight to medium levels. Generally speaking, the highest levels of Cd, Cu, Ni, Pb and Zn were recorded in the middle and lower tributaries of Dongjaing, particularly those near Tangxia and Guanlan. Slight amount of PCBs, PAHs were also detected in the lower sections of Dongjiang, indicating industrial contamination due to economic growth in the 1980–90s. Comparatively, only slight amounts of heavy metals were detected in the sediments of some Hong Kong reservoirs that store imported Dongjiang water. Moreover, trace organics including PCBs and PAHs were rarely detected in the reservoirs of Hong Kong. Nevertheless, the high acidity in the sediments of Hong Kong reservoirs is noteworthy. Results revealed that the Dongjiang waters were purified to a certain extent before being imported to and stored at the Hong Kong reservoirs. At present, health risks from the drinking water of Hong Kong are not apparent. However, the long-term trend of organic and inorganic contamination in Dongjiang should not be overlooked and remedial actions should be taken as early as possible. Collaboration between the governments of Hong Kong and Mainland China in tackling chemical pollution in drinking water is an example of cross-border cooperation and control measures should be stepped up as soon as possible.     

Survey of atmospheric heavy metal deposition in Suqian using moss contamination

Abstract

Heavy metal pollution in the atmosphere is a major environmental problem, which has important impacts on ecosystems and human health. In this study, the atmospheric deposition of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn) in Suqian, China, was investigated by using the moss Haplocladium microphyllum as a bioindicator. The survey was carried out during the summer of 2017 at 40 homogenously distributed sampling sites. Cr, Cu, Ni, Pb, V, and Zn were analyzed by inductively coupled plasma atomic emission spectrometry, and Cd was analyzed by inductively coupled plasma mass spectrometry. Wide variations in heavy metals (Cd, Pb, and Zn) indicated that the concentrations of elements are influenced by local emission sources. Spatial distribution maps of the elements were constructed using geographic information system technology. The pollution load index showed that the study area was moderately polluted to unpolluted. Significant positive correlations (p?<?.01) and weak positive correlations (p?<?.05) were identified among some of the elements, indicating that they originated from common sources. A principal component analysis classified the heavy metals into natural and anthropogenic sources, and identified four primary sources: nature soil dust, industry activities, traffic emission, and agricultural activities.     

Heavy metal and PCB contamination of Bryozoan colonies in the River Meuse (Belgium)

In the Meuse River (Liège area, Belgium), large amounts of three species of Bryozoans, Fredericella sultana (BLUM.), Plumatella emarginata ALL. and Plumatella fungosa (PALL.) occur. They cover 3 to 40% of the bank walls and their biomass ranges from 12 to 293 g m^–2 (dry weight). In the heated waters of a nuclear power plant (Tihange) and of industries lined up along the river, colony development occurs 3 to 4 weeks earlier than at an upstream station. The heavy metal content of living colonies ranges from 4 to 21 mg kg^–1 Cd, 45 to 182 mg kg^–1 Cu, 803 to 2232 mg kg^–1 Zn, 150 to 483 mg kg^–1 Pb and 21 to 138 mg kg^–1 Cr (DW). The mean concentration of PCBs was 925 µg kg^–1 (DW). Heavy metal and PCB concentrations in the sediments were close to those of colonies, suggesting that most of the pollutants found in the Bryozoans is in fact in the sediment trapped by the colonies.     

Heavy metal contamination of water and fish in peri-urban dams around Bulawayo,Zimbabwe

Urban effluents are significant sources of heavy metal pollution in fresh water. Metal contamination in dams around the city of Bulawayo, Zimbabwe, were monitored during October 2014 to assess ecological and public health risks. Heavy metals were measured in water, sediment and fish in dams located downstream of effluent discharge zones in Bulawayo and were compared to those in a pristine upstream dam. Water conductivity indicated pollution of downstream dams. Levels of lead (0.13–0.28 ppm) and cadmium (0.02–0.06 ppm) in water from downstream dams exceeded WHO safe limits for drinking water. Cadmium levels in polluted dams also exceeded the safe limit for agricultural use. Sediments of effluent-polluted dams had metal contamination factors ranging from 8.8 to 31.2 relative to the control, and fish from the dams had higher metal content and were unfit for human consumption. Metal levels were also measured along an urban stream to establish the sources of metals. The city’s industrial zone had the highest levels of metals, suggesting that industrial effluents were major sources of contamination. The environmental consequences and human health risks of the pollution of peri-urban water bodies from urban effluents are discussed.     

Heavy Metals in Sediments of the Gold Mining Impacted Pra River Basin,Ghana, West Africa

Total concentrations of Hg, Al, Fe, As, Pb, Cu, Cr, Ni, Mn, Co, V, and Zn were determined in surface sediments collected from 21 locations within the gold mining impacted Pra River basin in southwestern Ghana. Samples were collected during both the rainy and dry seasons. We hypothesized that in the rural southwestern portion of Ghana, the lack of industrial activities makes artisanal gold mining (AGM) by Hg amalgamation the main source of water resource contamination with heavy metals. Therefore, metals showing concentration trends similar to that of Hg in the studied system are likely impacted by AGM. We found that total-Hg (THg) concentrations in riverine sediments are rather low as compared to other aquatic systems that are impacted by similar mining activities. Measured THg concentrations ranged from 0.018 to 2.917 mg/kg in samples collected in the rainy season and from about 0.01 to 0.043 mg/kg in those collected during the dry season. However, the determination of the enrichment factor (EF) calculated using shale data as reference background values showed signs of severe contamination in most of the sampled sites. In the dry season, THg concentrations correlated positively and significantly to the concentrations of As (r = 0.864, p < 0.01), Cu (r = 0.691, p < 0.05), and Ni (r = 0.579, p < 0.05). Based on our previously stated hypothesis, this could then be an indication of the impact of AGM on ambient levels of these 3 elements. However, the determined concentrations of Cu, and Ni co-varied significantly with Al, suggesting that natural sources do account for the observed levels. Accordingly, both AGM and metal inputs from weathered natural deposits are likely co-responsible for the observed levels of Cu and Ni. In contrast, the lack of correlation between As and Al tends to suggest an impact of AGM on As levels. Overall, our data suggest that besides Hg and to some extent As, the impact of AGM on ambient levels of investigated metals in the gold mining impacted Pra River remains negligible. Finally, the increase in metal concentrations from the dry to the rainy season underlines the impact of changes in hydrologic conditions on levels and fate of metals in this tropical aquatic system.     

Heavy metal (Pb) accumulation in metallophytes as influenced by the variations in rhizospheric and non-rhizospheric soils physico-chemical characteristics

Activities at root-soil interface determine the solubility and uptake of metals by plants. Metal accumulation in plant species (Imperata cylindrical, Cynodon dactylon, Eleucine indica, Gomphrena celosoides, Sporobolus pyramidalis, Chromolaena odorata and Rhynchospora corymbosa) growing on Pb contaminated site as influenced by variations in physico-chemical characteristics, dissolved organic matter (DOM), Pb fractionation and different functional groups (using Fourier Transmittance Infra-red) of rhizospheric and non-rhizospheric soils was assessed. The electrical conductivity (2660–5520 µs) and Pb concentrations (51390.0–64080.0 mg/kg) were more in non-rhizospheric than rhizospheric soils having 276 µs to 3160 µs EC and 3289.0 to 44850.0 mg/kg Pb. More nutrients, DOM and carbohydrates functional groups (C-O; 1100 -1000 and O-H; 3700–3600) were found in rhizospheric compared to non-rhizospheric soils. The pH was slightly acidic (5.0–5.54) and E. indica with the lowest pH (5.0) accumulated highest Pb concentrations in shoot (8030 mg/kg) and root (16380 mg/kg) while C. odorata with highest values of pH, P, Ca and Mg in rhizospheric soil accumulated the least (root; 331.6 and shoot: 209.0 mg/kg). Pb was more in organic and residual fractions of rhizospheric and non-rhizospheric soils respectively. Reduction in pH, EC coupled with nutrients and DOM availability increased Pb uptake by plants.     

Elemental composition of the sub-aquatic liverwort Pellia endiviifolia (Dicks.) Dum. in relation to heavy metal contamination

The concentrations of fifteen elements (B, Na, Mg, Al, P, K, Ca, Ti, Mn, Fe, Cu, Zn, Sr, Cd, Pb) in thalli of the sub-aquatic liverwort Pellia endiviifolia (Dicks.) Dum. collected from seven sites in Japan, were analyzed by inductively coupled plasma atomic emission spectrometer (ICP). The average concentration of major essential elements in the thalli was: 49 600 µg g^–1 K, 9 140 µg g^–1 Na, 6740 µg g^–1 Ca, 3 840 µg g^–1 P, and 3 060 µg g^–1 Mg. Thalli of P. endiviifolia from sites polluted by heavy metals (Cu, Zn, Pb) contained high concentrations of these elements (maxima 0.88% Cu, 0.55% Zn and 0.36% Pb in the older thallus), thus demonstrating the potentiality of this liverwort as an indicator for heavy metal contamination.     

Habitat Capacity for Cougar Recolonization in the Upper Great Lakes Region

Background

Recent findings indicate that cougars (Puma concolor) are expanding their range into the midwestern United States. Confirmed reports of cougar in Michigan, Minnesota, and Wisconsin have increased dramatically in frequency during the last five years, leading to speculation that cougars may re-establish in the Upper Great Lakes (UGL) region, USA. Recent work showed favorable cougar habitat in northeastern Minnesota, suggesting that the northern forested regions of Michigan and Wisconsin may have similar potential. Recolonization of cougars in the UGL states would have important ecological, social, and political impacts that will require effective management.

Methodology/Principal Findings

Using Geographic Information Systems (GIS), we extended a cougar habitat model to Michigan and Wisconsin and incorporated primary prey densities to estimate the capacity of the region to support cougars. Results suggest that approximately 39% (>58,000 km²) of the study area could support cougars, and that there is potential for a population of approximately 500 or more animals. An exploratory validation of this habitat model revealed strong association with 58 verified cougar locations occurring in the study area between 2008 and 2013.

Conclusions/Significance

Spatially explicit information derived from this study could potentially lead to estimation of a viable population, delineation of possible cougar-human conflict areas, and the targeting of site locations for current monitoring. Understanding predator-prey interactions, interspecific competition, and human-wildlife relationships is becoming increasingly critical as top carnivores continue to recolonize the UGL region.