Concentrations Of Pb In Sediments Research Articles

Tracing the Pollution Source Using Pb Isotopes in Sediments of the Coastal Region Surrounding the National Industrial Complex, Korea

Jeong, H.; Ra, K.; Kim, K.-T.; Kim, E.-S.; Lee, S.-Y., and Choi, M.-S. 2018. Tracing the pollution source using Pb isotopes in sediments of the coastal region surrounding the national industrial complex, Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1456–1460. Coconut Creek (Florida), ISSN 0749-0208.166 sediment samples from Ulsan Bay and Shihwa Lake that is special management sea area were collected in 2014 not only to study the spatial distribution and pollution assessment of Pb but also to identify anthropogenic pollutions for Pb isotopes. The mean Pb concentrations of road-deposited sediments were higher than those of stream and coastal sediments in the study area. In all sediment samples, Ulsan showed an average concentration of 2 to 4 times higher than that of Shihwa. Pb concentrations in coastal sediments of more than 50 % were below the threshold effect level (TEL) of Korean marine sediment quality guidelines. The high exceedance of probable effect levels (PEL) showed in large harbors and near industrial facilities. Road-deposited sediments in Ulsan and Shihwa exceeded the class 2 (potentially toxic to benthic organisms) of Korean freshwater sediment quality guidelines. For both study areas, Pb isotope ratios tend to decrease with increasing Pb concentrations in sediments. In the case of Ulsan, high concentrations and low 206Pb/207Pb isotopic ratios were observed nearby the smelter and lead ore import harbor, indicating that Pb was released into the road surface during transportation using the vehicle and then moved to the marine area through the stream. However, Shihwa has a lot of small facilities (>19,000), it is difficult to clearly identify Pb pollution sources.

Sclerocollum saudii Al-Jahdali, 2010 (Acanthocephala: Cavisomidae) as a sentinel for heavy-metal pollution in the Red Sea.

Currently, fish helminth parasites, especially cestodes and acanthocephalans, are regarded as sentinel organisms to elucidate metal pollution in aquatic ecosystems. Here, 34 specimens of the fish Siganus rivulatus were collected in the Red Sea, from a seriously polluted, small lagoon named Sharm-Elmaya Bay, at Sharm El-Sheikh, South Sinai, Egypt; 22 (64.7%) were infected by Sclerocollum saudii (Acanthocephala: Cavisomidae). Thus, 22 natural infrapopulations (26-245 individuals) of this parasite were collected from infected fish. Samples of water and sediments from the bay, samples of muscle, intestine and liver from each fish, and samples from the parasite were taken for analysis of heavy metals (cadmium (Cd) and lead (Pb)). Both Cd and Pb concentrations in sediments were higher than those in water. The concentration of these metals were significantly higher in tissues (intestine, liver and muscle) of non-infected fish than those in infected fish, with Pb concentrations consistently higher than those of Cd, and both were drastically decreased in the order: liver > intestine > muscle. Metal concentrations in this acanthocephalan were much higher than those in its fish host. There were strong negative relationships between metal concentrations in tissues (intestine, liver and muscle) of infected fish and infrapopulation size, and between metal concentrations in the acanthocephalan and its infrapopulation size. These relationships strongly suggest competition for these metals between the fish host and its acanthocephalan parasite, and intraspecific competition among acanthocephalan individuals for available metals in the fish intestine. Bioconcentration factors were relatively high, since the mean Cd concentration in S. saudii was 239, 68 and 329 times higher than those in intestine, liver and muscle tissues, respectively, of its fish host. Also, mean Pb concentration was 55, 13 and 289 times higher than those in these tissues, respectively. The host-parasite system described here seems to be promising for biomonitoring of metal pollution in the Red Sea.

The use of portable X-ray spectrometer in monitoring anthropogenic toxic metals pollution in soils and sediments of urban environment of Dar es Salaam Tanzania

The levels of toxic metals in sediments and soils along high traffic Sam Nujoma highway and in the densely populated Sinza area in Dar es Salaam Tanzania were determined using portable X-ray fluorescence spectrometer (pXRF) and atomic absorption spectrometer (AAS) in order to assess the levels of the metals in the sediments and soil and evaluate the use of pXRF in monitoring anthropogenic toxic metal pollution in the urban environment.Sediments from different areas in Sinza, especially those occurring near metal workshops, contained high toxic metal contents (e.g. Co, Zn, Pb and Ti) above the maximum permissible allowable limit by the Tanzania Bureau of Standards (TBS) for soils or sediments in an urban environment. This toxic metal content decreases sharply (~5m) away from workshops, and so reflecting pollution of the metals by workshop activities. Along Sam Nujoma highway, toxic metal contents of sediments and soils were lower than those of samples from Sinza, but also decreases as one moves from the road to the surroundings of the highway. Chromium and Zn contents in parts of Sam Nujoma highway were found, in places, to be above the maximum permissible allowable limit by the TBS for soils or sediments. As the geology of Dar es Salaam is mainly unconsolidated sands and clay and coral limestones, which are not likely natural source of the metals, then results of this study reflect anthropogenic addition of the metals to the Dar es Salaam environment.Similarity in concentration of Pb in sediments determined from previous study in the year 2009 along Sam Nujoma highway and those presented for this study suggests that Pb and most likely other metals as well, are not accumulating along or near the highway over time, but dispersed by water during wet season, when water table is high and most of roads and street are covered by surface runoff. Part of these contaminated surface runoff ends up in water, sediments and soils in downstream in the Msimbazi River, in which most of vegetables are grown and food sources like fish thrive, which highlights a potential risk of exposure of toxic metals in human food chain. Moreover, high levels of toxic metals in soils and sediments near workshops in Sinza pose high exposure risk to children and people leaving around the workshops.Successful application of pXRF in monitoring of anthropogenic toxic metals pollution in urban environment of Dar es Salaam open up possibility for similar applications in fast growing cities or artisanal miners’ sites that are frequently affected by anthropogenic pollution in the country and abroad.

Lead accumulation in oyster shells, a potential tool for environmental monitoring

Pb/Ca profiles were measured on ten live collected Ostrea edulis from three sites characterized by different levels of lead content. Intra-shell and inter-shell reproducibility were tested comparing several Pb/Ca profiles measured by LA-ICP-MS within a specimen, and within specimens from the same site. Results indicate that signals recorded are reproducible and mean shell Pb/Ca values are site-dependent. Second order variability is explained either by smoothing effects, biological effects or micro-environmental heterogeneities in lead distribution. Mean Pb contents measured in marine bivalve shells are reviewed here. Ranging from 0 to 50ppm, they show a strong relationship with the environmental level of local lead contamination, and do not appear species-dependent. Our measurements show a linear relationship between mean shell Pb/Ca and surface sediment Pb concentrations, making marine bivalves and particularly O. edulis a potential accurate bio-monitoring tool able to monitor bioavailable lead along European coasts since Mesolithic, with an annual resolution.

Pollution-induced community tolerance in benthic macroinvertebrates of a mildly lead-contaminated lake

Pollution-induced community tolerance (PICT) has been used to demonstrate effects of sediment contamination on microbes and meiofauna. Our study explored the potential to detect PICT in benthic macroinvertebrates of a lake with long-term mild lead (Pb) contamination. We collected macrobenthos from two areas in Caddo Lake, Texas, a control area (CO) with a mean sediment Pb level of 11μg/g and Goose Prairie (GP) where sediment Pb levels averaged 74μg/g. Upon return to the laboratory, we exposed macroinvertebrates to a lethal lead concentration and assessed 48-h mortality. Mortality of CO macrobenthos was significantly higher than that of GP macrobenthos, providing evidence that these communities differed in their tolerance to lead. A comparison of macrobenthos community composition between the areas showed that the GP macrobenthos lacked metal-sensitive taxa such as gastropods and amphipods (which were present at CO). Similarly, a higher proportion of the GP benthos belonged to metal-tolerant taxa such as isopods and chironomids. Thus, changes in community composition appeared to be at least partly responsible for differences in community tolerance. Our results showed that a sediment Pb concentration below effect-based sediment quality guidelines had a measurable impact on macrobenthos, thus demonstrating that results from single-species toxicity tests may underestimate impacts on communities. This study also confirms that the PICT approach with macroinvertebrates is a feasible and potentially powerful approach for detecting contaminant impacts.

APLIKASI SELULOSA BAKTERIAL-DIETILENTRIAMINA SEBAGAI LAPISAN PENGIKAT LOGAM Pb DAN Cd PADA METODE DIFFUSIVE GRADIENT IN THIN FILMS (DGT)

This research aimed to synthesis and apply of bacterial cellulose-diethylenetriamine as a binding layer on the diffusive gradients in thin films method for preconcentration of labile metal Pb and Cd in aquatic systems and sediment of Palu Bay. The results are expected to be used for the analysis of environmental contaminants aquatic pollutant/sediment replace conventional methods. DGT method easily carried into the field and sensitive to identify certain metal ions. The results showed concentration of heavy metals dissolved in seawater for Pb between 0.024 to 0.048 mg / L, while for Cd between 0.006 to 0.015 mg / L. The concentration of Pb in sediments from 7.426 to 16.043 mg / L and Cd 0.387 to 0.950 mg / L. Partial regression analysis between Pb and Cd concentrations in water with a concentration of cadmium metals Pb and Cd in the sediments showed that the concentration of heavy metals in water has a positive correlation with the concentration of Pb and Cd in the sediment.Keyword: Pb, Cd, DGT, bacterial cellulose-diethylenetriamine, Palu Bay

CONCENTRATION HEAVY METALS (Cu AND Pb) IN MUSI RIVER ESTUARY

<p><em>The Musi River is one of the biggest river of twelve big rivers in South Sumatra Province. Water quality of this river affects the water quality in the estuary and biological health in its surrounding so that it is important to determine the Cu and Pb concentrations. The purposes of this study were to analize distribution of heavy metals (Cu and Pb) and to determine the water quality status in March and September 2014. The water and sediment samples were collected from eight stations along the Musi River from downstream to the estuary. Heavy metal concentration was analized by employing USEPA 30050B method using AAS Spektra plus variant with air mixure flame – acetylene. Dissolved Cu and Pb concentrations in March were 0,002 - 0,006 mg/l and 0,002-0,003 mg/l, respectively, while in September were 0,001-0,010 mg/lfor Cu and 0,001-0,005 mg/lfor Pb. Cu and Pb concentrations in sediment detected in March were 6,92-16,4 mg/l and 1,9-11,4 mg/l, respectively, while in September were 2,3-13,9 mg/l for Cu and 4,29-9,95 mg/l for Pb. Student test analysis showed that was no significant differences between Pb and Cu concentrations (dissolved and sediment) between March and September. Generally, the concentration of heavy metals Cu and Pb in Musi River estuary were still below specified quality standards.</em></p><p><em></em><br /><strong><em>Keywords:</em></strong><strong> </strong><em>h</em><em>eavy metal, Cu, Pb, </em><em>the </em><em>Musi River</em><em>,</em><em> estuary</em></p><p><em><br /></em></p>

CONCENTRATION HEAVY METALS (Cu AND Pb) IN MUSI RIVER ESTUARY

The Musi River is one of the biggest river of twelve big rivers in South Sumatra Province. Water quality of this river affects the water quality in the estuary and biological health in its surrounding so that it is important to determine the Cu and Pb concentrations. The purposes of this study were to analize distribution of heavy metals (Cu and Pb) and to determine the water quality status in March and September 2014. The water and sediment samples were collected from eight stations along the Musi River from downstream to the estuary. Heavy metal concentration was analized by employing USEPA 30050B method using AAS Spektra plus variant with air mixure flame – acetylene. Dissolved Cu and Pb concentrations in March were 0,002 - 0,006 mg/l and 0,002-0,003 mg/l, respectively, while in September were 0,001-0,010 mg/lfor Cu and 0,001-0,005 mg/lfor Pb. Cu and Pb concentrations in sediment detected in March were 6,92-16,4 mg/l and 1,9-11,4 mg/l, respectively, while in September were 2,3-13,9 mg/l for Cu and 4,29-9,95 mg/l for Pb. Student test analysis showed that was no significant differences between Pb and Cu concentrations (dissolved and sediment) between March and September. Generally, the concentration of heavy metals Cu and Pb in Musi River estuary were still below specified quality standards.Keywords: heavy metal, Cu, Pb, the Musi River, estuary

Evidence for mild sediment Pb contamination affecting leaf-litter decomposition in a lake.

Much work has focused on the effects of metal-contaminated sediment on benthic community structure, but effects on ecosystem functions have received far less attention. Decomposition has been widely used as an integrating metric of ecosystem function in lotic systems, but not for lentic ones. We assessed the relationship between low-level sediment lead (Pb) contamination and leaf-litter decomposition in a lentic system. We measured 30-day weight loss in 30 litter-bags that were deployed along a Pb-contamination gradient in a cypress-forested lake. At each deployment site we also quantified macrobenthos abundance, dissolved oxygen, water depth, sediment organic content, sediment silt/clay content, and both total sediment and porewater concentrations of Cd, Cu, Ni, Pb and Zn. Principal components (PC) analysis revealed a negative relationship between Pb concentration and benthic macroinvertebrate abundance, and this covariation dominated the first PC axis (PC1). Subsequent correlation analyses revealed a negative relationship between PC1 and percent leaf-litter loss. Our results indicate that leaf-litter decomposition was related to sediment Pb and benthic macroinvertebrate abundance. They also showed that ecosystem function may be affected even where sediment Pb concentrations are mostly below threshold-effects sediment quality guidelines--a finding with potential implications for sediment risk assessment. Additionally, the litter-bag technique used in this study showed promise as a tool in risk assessments of metal-contaminated sediments in lentic systems.

Influence of exogenous lead pollution on enzyme activities and organic matter degradation in the surface of river sediment.

As lead is one of the most hazardous heavy metals in river ecosystem, the influence of exogenous lead pollution on enzyme activities and organic matter degradation in the surface of river sediment with high moisture content were studied at laboratory scale. The dynamic changes of urease, catalase, protease activities, organic matter content, and exchangeable or ethylenediaminetetraacetic acid (EDTA)-extractable Pb concentration in sediment were monitored during different levels of exogenous lead infiltrating into sediment. At the early stage of incubation, the activities of catalase and protease were inhibited, whereas the urease activities were enhanced with different levels of exogenous lead. Organic matter content in polluted sediment with exogenous lead was lower than control and correlated with enzyme activities. In addition, the effects of lead on the three enzyme activities were strongly time-dependent and catalase activities showed lower significant difference (P < 0.05) than urease and protease. Correlations between catalase activities and EDTA-extractable Pb in the experiment were significantly negative. The present findings will improve the understandings about the ecotoxicological mechanisms in sediment.

Lead Concentrations in Sediments and Blue-Winged Teals (Anas discors) From El Palmar State Reserve, Yucatan, Mexico

Reserve regulations at El Palmar State Reserve, Yucatan, Mexico, prohibit the use of lead (Pb) shot, but hunters continue to use it, and no enforcement is implemented. Pb was quantified in sediments and in blue-winged teal Anas discors. No shot pellets were found in the sediment samples, nor were differences in sediment Pb concentrations observed within the reserve between popular hunting sites and those no longer used for hunting. However, there were differences between the hunting sites and sediments from an adjacent area where hunting is prohibited. Average Pb concentrations were highest at hunting entrances (15.69 ± 18.69 mg/kg) and lowest at decoy locations (5.24 ± 4.84 mg/kg). These averages are lower than the lowest effects level (31 mg/kg), although 10 samples exceeded this level. Pb-shot prevalence in gizzards was 4.88% (n = 41). Pb levels exceeded 5.0 mg/kg dry weight in one or more of the tested tissues (liver, gizzard, and bone) in 14 (34.14%; 7 female, 7 male; 11 adult, 3 juvenile) of the total birds. Bird weight, sex, and age had no effect on Pb concentration. Hunting using Pb shot in the reserve clearly affects Pb levels in sediments and in A. discors that winter there.

Lead isotopes as a tracer of Pb origin in the sediments from Beijiang River, South China

Concentrations and enrichment of heavy metals were determined in sediments collected from Beijiang River, South China. The Pb isotopic compositions in these sediment samples were also employed to effectively identify metal pollution sources. According to the measured Pb concentrations, the total Pb concentrations in sediments varied from 62.1 to 1,152.5 μg/g, with an average concentration of 249.6 μg/g. The assessment by Geoaccumulation Index indicates that Pb is at the 'strongly contaminated' level, indicating that the Pb pollution was mainly due to anthropogenic inputs. The observed isotopic ratios varied from 1.174 to 1.204 for ²⁰⁶Pb/²⁰⁷Pb, 2.452 to 2.478 for ²⁰⁸Pb/²⁰⁷Pb, 18.404 to 18.937 for ²⁰⁶Pb/²⁰⁴Pb, 15.631 to 15.790 for ²⁰⁷Pb/²⁰⁴Pb, 38.455 to 39.121 for ²⁰⁸Pb/²⁰⁴Pb. The majority of these ratios are lower than those reported for natural geological sources, especially for sediments collected from a smelter. Significant correlation between Pb concentration and isotopic ratios suggested possible binary mixing of Pb. Combined with Pb concentration and enrichment levels, our results show that Pb pollution in the sediments of Beijiang River was mainly derived from anthropogenic sources. The mining activities and metal smelting processing was the main source of Pb pollution in this region.

Determination of Distributions of Cd, Cu, and Pb Concentrations in Sediments of a Mexican Reservoir to Infer Their Environmental Risk

The José Antonio Alzate Dam in the State of Mexico, Mexico, receives wastewaters from domestic, industrial, and agricultural activities through the Lerma River. Chemical and physicochemical characteristics of the water were determined. Sediment has been studied in order to define the importance of its influence on the reservoir's state as a whole. The quantification of the metals, Cd, Cu, and Pb in total forms and the geochemical distribution and the chemical mobility of these metals in sediment have been established using a chemical sequential extraction scheme. The three metals showed a common characteristic, being more abundant in fraction F6 (residual), but the other fractions of the geochemical distribution were variable depending on the metal. First, the contamination level was evaluated with the results of the total metals, using the criteria of EPA, Thomas and Murdoch, and the Ontario Ministry of Environment for sediment in water bodies. Subsequently, the risk was assessed using the same criteria but considering the results of sequential extractions, where the geochemical distribution of each metal allowed a better understanding of metal portions with more influence on the risk, in which Cu and Pb presented low risk, but not Cd.

Heavy Metals Accumulation and its Environmental Risk in Sediments of Xihe River, Shenyang City

Heavy metal accumulation in Xihe River sediments was studied, and also its potential environmental risk was evaluated using geoaccumulation index (Igeo). The results showed that mean concentrations of Hg, Cd, Zn, Pb, Ba, Bi, Sn and Sb were 2.73, 18.42, 1066.1, 128.8, 366.9, 7.76, 24.70 and 8.53 mg/kg, respectively. The values of examined heavy metals, except for Ba, were higher than the reference of deep soil. There were different accumulation characteristics for heavy metals at different river sections. Cadmium and Pb concentrations in sediment dropped from upper to lower reaches along river, but Ba was quite the reverse. The potential environmental risk of heavy metals in sediments was in order: Cd &gt; Hg &gt; Bi &gt; Zn &gt; Sb &gt; Sn &gt; Pb &gt; Ba. The river was subjected to a higher potential risk by Hg, Cd, Zn and Bi, a medium-high risk by Sn and Sb, and a lower risk by Pb and Ba.

Lead in the environment of Lake Wigry (NE Poland)

Lead in the environment of Lake Wigry (NE Poland)Analysis was performed for lead content in the sediments of Lake Wigry (NE Poland), taking into account lithology, basic chemical component content and physical characteristics of sediment, Several hundred sediment samples from different parts of the lake and peatland around the lake, were collected. Their locations were determined by GPS and the depth of sediment by echosounder. The surface layer (0-10 cm) of sediment and sediment cores were taken to determine the spatial and vertical distribution of Pb. Concentrations of lead in the surface sediment range from 2.52 to 469 mg kg-1. One of the most important factors influencing spatial distribution of Pb is sediment type. The highest content of Pb was found in samples of organic gyttja and the lowest in clastic sediment samples. Strong positive linear correlation (r = 0.7) between organic matter content and Pb concentration in sediment was observed. It may be the result of simple bio-accumulation of lead. A large influence of sediment location on Pb distribution was found. The largest concentration of this element was found in sediment of the Wigry Basin. The major part of Pb accumulates in the surface layer of sediment.

Bioaccumulation of trace metals in farmed fish from South China and potential risk assessment

Concentrations of trace metals were determined in water, sediment, fish feed and two species of farmed fish, pompano and snapper, collected from Daya Bay and Hailing Bay of South China in July 2007 and January 2008. Total average concentrations of Cu, Pb, Zn, Cd, Cr, Hg and As were 1.6, 2.7, 27.3, 0.025, 0.62, 0.18 and 0.59μg/gdrywt in pompano and 1.5, 2.6, 23.6, 0.020, 0.55, 0.22 and 0.53μg/gdrywt in snapper. In general, the concentrations of all target metals except Hg were positively correlated with lipid contents whereas negative correlations were observed between the metal concentrations and fish body weights. Model calculation indicated that dietary uptake of Zn and Cd predominate their accumulation in snapper, accounting for 99.9% and 98.2% of the total inputs. Risk assessments suggested that potential ecological and human health risk may be present due to elevated Pb concentrations in sediment and farmed fish.

Source and distribution of lead in the surface sediments from the South China Sea as derived from Pb isotopes

Rapid economic development in East Asian countries has inevitably resulted in environmental degradation in the surrounding seas, and concern for the environment and its protection against pollutants is increasing. Identification of sources of contaminants and evaluation of current environmental status are essential to environmental pollution management, but relatively little has been done in the South China Sea (SCS). In order to investigate the abundance, distribution, and sources of Pb within the SCS, stable Pb isotopes and their ratios were employed to assess the contamination status and to differentiate between natural and anthropogenic origins of Pb in the surface sediments. The total Pb concentrations in sediments varied from 4.18 to 58.7mgkg−1, with an average concentration of 23.6±8.9mgkg−1. The observed Pb isotope ratios varied from 18.039 to 19.211 for 206Pb/204Pb, 15.228 to 16.080 for 207Pb/204Pb, 37.786 to 39.951 for 208Pb/204Pb, 1.176 to 1.235 for 206Pb/207Pb, and 2.468 to 2.521 for 208Pb/207Pb. The majority of these ratios are similar to those reported for natural detrital materials. Combined with Pb enrichment factor values, our results show that Pb found within most of the SCS sediments was mainly derived from natural sources, and that there was not significant Pb pollution from anthropogenic sources before 1998. Further studies are needed to reconstruct deposition history and for trend analysis.

Spatial and Temporal Variations of Heavy Metals in Surface Sediments in Bohai Bay, North China

Characteristics of the spatial and temporal distributions of selected heavy metals (Cu, Zn, Cd, Pb and Hg) in Bohai Bay, north China was examined. Surface sediment samples from 15 sites were collected and analyzed for the selected metals with atomic absorption spectrometry (AAS) from the year of 1997-2007. Mean concentrations of metals in the 11-year period showed that Hg and Zn concentrations slightly fluctuated, while Cu, Cd and Pb concentrations in sediments varied with time. High levels of heavy metals occurred not only along the shoreline but also at some site in the inner part of the bay, suggesting the contamination sources of heavy metals from both terrestrial inputs and the atmospheric deposition. Compared with the environmental background values of selected heavy metals it indicated that anthropogenic activities influenced the sediment quality. The contamination factor C(fi), which is used to evaluate the pollution of the environment, showed that the contamination by selected heavy metals was moderate. Cd, Zn and Pb were the main polluting elements in this area.

The preliminary assessment of the pollution status of streams and artificial lakes created by mining in the mining district of Enyigba, south eastern Nigeria, and their consequences

The distribution of Pb, Zn, Cu, Cd, Ni and As in waters and sediments in streams and entrapped water bodies around the mining district of Enyigba was evaluated. The result of analyses show that the concentration of Cu varies from 0.006 to 0.100 mg/l in waters in streams and mine pits (surface water), with a mean of 0.02 mg/l; Zn from 0.008 to 0.023 mg/l with a mean of 0.01 mg/l. The concentration of Pb, Ni, Cd and As in all samples of surface water is lower than 0.001 mg/l. The concentration of Pb in sediments vary from 54 mg/kg to 63356 mg/kg with a mean of 4245 mg/kg; Zn from 72mg/kg to 1386.5 mg/kg with a mean of 349.68 mg/kg; Cu from 11.5 mg/kg to 808.5 mg/kg with a mean of 84.48 mg/kg; Cd from 0.5 mg/kg to 5.5 mg/kg with a mean of 3.35 mg/kg; Ni from 0.5 mg/kg to 1197 mg/kg with a mean of 282.66 mg/kg and As from 0.05 mg/kg to 1.5 mg/kg. It is established that there is no significant pollution of surface water by heavy metals analysed, based on WHO Standard of 1993. There is however significant pollution of sediments by Pb, Zn and Ni and to a smaller extent Cu. The consequences of the observed pollution include the introduction of pollutants in the downstream reaches of the streams and the Ebonyi River during the periods of high flow, the accumulation of the pollutants in the tissues of organisms that live in the sediments which may get passed to higher organisms that prey on these organisms and the eventual effect on humans, through the food chain.

Mobilisation of sediment-associated metals from historical Pb working sites on the River Sheaf, Sheffield, UK

Spatial and temporal patterns of metal mobilisation from former water-powered, Pb working sites in a suburban area of Sheffield (UK) were investigated. Twelve time-integrated mass flux samplers were strategically deployed over two contrasting campaign periods (summer and winter). Suspended sediment samples were characterised magnetically and subjected to metal analysis. Metal levels in the upper River Sheaf showed a marked spatial and temporal variability. Pb concentrations in particular were relatively high (maximum 2132 mg kg(-1)). Their distribution tended to reflect the historical contamination of the valley by 17th to 19th century industry, especially during summer high discharge conditions. The mean suspended sediment Pb concentration (803 mg kg(-1)) exceeds contamination guidelines. It is unclear whether ground remediation of one of the seven floodplain sites in the catchment has been successful. The river is still affected by the legacy of at least two other Pb working sites.