Interim Sediment Quality Guidelines Research Articles

Little Akaki River sediment enrichment with heavy metals, pollution load and potential ecological risks in downstream, Central Ethiopia

Addis Ababa City’s river ecosystem is under extreme pressure as a result of inappropriate practices of dumping domestic and industrial wastes; thus, threatening its ability to maintain basic ecological, social and economic functions. Little Akaki River which drains through Addis Ababa City receives inorganic and organic pollutants from various anthropogenic sources. Most of inorganic pollutants such as toxic heavy metals released into the river are eventually adsorbed and settle in the sediment. The objective of this study was to evaluate the enrichment levels, pollution load and ecological risks of selected heavy metals (Zn, Cr, Cd and Pb) using various indices. The mean concentrations of heavy metals in Little Akaki River sediment were: Zn (78.96 ± 0.021–235.2 ± 0.001 mg/kg); Cr (2.19 ± 0.014–440.8 ± 0.003 mg/kg); Cd (2.09 ± 0.001–4.16 ± 0.0001 mg/kg) and Pb (30.92 ± 0.018–596.4 ± 0.066 mg/kg). Enrichment factor values indicated that sediments were moderate to significantly enriched with Zn and Cr; moderate to very highly enriched with Pb, and very highly enriched in all sampled sites with Cd. Geo-accumulation index and contamination factor values indicated that the sediments were moderate to very highly contaminated with toxic Cd and Pb. The decreasing order of pollution load index (PLI) in downstream was: (S9) > (S4) > (S8) > (S3) > (S6) > (S10) > (S5) > (S2) > (S7) > (S1). PLI and hierarchical cluster analysis revealed that the highest pollution load occurred in the lower course of the river (S9) which may be due to metals inputs from anthropogenic sources. The ecological risk (RI = 350.62) suggested that the contaminated Little Akaki River sediment can pose considerable ecological risks of pollution. The concentrations of Zn, Cr, Cd and Pb in Little Akaki River sediment surpassed eco-toxicological guideline limits of USEPA (threshold effect concentration) and CCME (Interim Sediment Quality Guidelines). Thus, the contaminated sediments can pose adverse biological effects on sediment dwelling organisms.

An assessment of heavy metal contamination in the surface sediments of Ha Long Bay, Vietnam

Ha Long Bay is an attractive landscape and a center of dynamic economic activity; however, it is subject to negative impacts from tourism, activity in its harbor, mining, industry, and urbanization, which is evidenced by the presence of pollutants, including heavy metals, in surface sediment at the bay. To ascertain the extent of the anthropogenic impact, 48 surface sediment samples were collected and analyzed for grain size and the presence of heavy metals (Cu, Pb, Zn, As, Cd). Thirteen sediment types were identified in Ha Long Bay: sand, muddy sand, silty sand, sandy mud, mud, silt, sandy gravel, muddy sandy gravel, gravelly mud, gravelly muddy sand, slightly gravelly sandy mud, slightly gravelly sand, and sandy silt; of these, sandy silt and silty sand are the most common, while the others are less so. Regarding the concentration of heavy metals in the sediment, Cu concentration ranges from 3.80 to 41.72 mg/kg, with an average of 14.53 mg/kg; Pb ranges from 10.17 to 69.90 mg/kg, with an average of 30.39 mg/kg; Zn ranges from 6.34 to 119.21 mg/kg, with an average of 50.87 mg/kg; Cd ranges from 0.03 to 0.20 mg/kg, with an average of 0.08 mg/kg; As ranges from 1.78 to 13.71 mg/kg, with an average of 6.06 mg/kg. The concentrations of Cu, Pb, and As are higher than the Interim Sediment Quality Guideline (ISQG) levels at stations near the shoreline, and lower than the ISQG levels distributed throughout offshore stations.

A Multi-Index Analysis Approach to Heavy Metal Pollution Assessment in River Sediments in the Ponce Enríquez Area, Ecuador

The area of Ponce Enríquez, Southern Ecuador, is one of the most important artisanal and small scale gold mining (ASGM) areas in the country, where informal mining operations can be found using amalgamation technique, even though it has been prohibited since 2010. Considering the potential impact of these mining operations, the present research focused on heavy metal pollutants in subsurface sediments at 214 sampling locations from several detailed sampling campaigns in the rivers Fermín, Fermín Norte, Guanache, Villa, and Siete. Four parameters were calculated to evaluate the geochemical composition of the river sediment and heavy metal concentrations: The enrichment factor (EF), the geo-accumulation index (Igeo), the contamination factor (Cf) and the pollution load index (PLI). The analyzed elements were Cu, Pb, Zn, Ni, As, Cd, Sb, Sr, and Hg. Due to the lack of standards for pollution levels in sediments in Ecuador, Canadian guidelines were used as interim sediment quality guidelines (ISQG) in this research for comparison with the obtained results in subsurface sediments. The multi-index geochemical analysis indicated elevated heavy metal concentrations in all subsurface sediments in the studied river ecosystems.

Assessment of environmentally contaminated sediment using a contact assay with early life stage zebrafish (Danio rerio)

Lake Saint-Louis, a shallow fluvial lake near the western tip of the island of Montreal, QC, Canada is an important spawning ground for many species of fish. Sediments in certain areas of the lake are known to be contaminated with high levels of metals and legacy organic chemicals. To improve our understanding of risk to native fish populations, we conducted a study evaluating levels of sediment contamination and potential effects on early life stage fish. Concentrations of PAHs, PCBs, PCDDs and PCDFs were several orders of magnitude higher at two industrial sites (B1 and B2) than at a nearby reference site (IP). Concentrations of 32 metals and metalloids were at least 5-fold higher at B1 and B2 than at IP. Moreover, all available interim sediment quality guidelines (ISQGs) were exceeded at the two contaminated sites, while none were exceeded at the reference site. Biological effects were evaluated using a sediment contact assay. Zebrafish (Danio rerio) embryos were exposed to clean water (control), or to sediment from IP, B1, and B2 until 120 h post fertilization (hpf). Mortality was significantly elevated in fish exposed to the B1, but not the B2 sediment. The frequency of deformities increased with increasing contamination, but this trend was not statistically significant (p > 0.05). Genes that are implicated in the response to PAHs, PCBs, dioxins and furans (cyp1a, cyp1b1, ahr2) were significantly elevated in the 120 hpf larvae exposed to the B1 and B2 sediments. Global DNA methylation, and mRNA expression of genes related to oxidative stress (maft, cat, hmox1, sod2), embryonic development (bmp2b, baf60c), metal exposure (mt2), and DNA repair (gadd45b) were unaffected. Our results suggest that the Beauharnois sector of Lake Saint-Louis is poor quality spawning habitat due to high levels of contamination, and the potential for harmful effects on early life stage fish.

Metal concentrations in waters, sediments and biota of the far south-east coast of New South Wales, Australia, with an emphasis on Sn, Cu and Zn used as marine antifoulant agents.

Tin, Cu, Zn, Cd, Pb, Ag and Hg concentrations were measured in waters, sediments and three ubiquitous sedentary molluscs: the oyster, Saccostrea glomerata, a rocky intertidal gastropod, Austrocochlea porcata, and a sediment-dwelling gastropod, Batillaria australis, at 12 locations along the far south coast of NSW, Australia, from Batemans Bay to Twofold Bay during 2009. Metal concentrations in water for Sn, Cd, Ag and Hg were below detection limits (< 0.005 μg/L). Measurable water metal concentrations were Cu: 0.01-0.08 μg/L, Zn: 0.005-0.11 μg/L and Pb: 0.005-0.06 μg/L. Mean metal concentration in sediments were Sn < 0.01-2 μg/g, Cu < 0.01-605 μg/g, Zn 23-765 μg/g, Cd < 0.01-0.5 μg/g, Pb < 0.01-0.3 μg/g, Ag < 0.01-0.9 μg/g and Hg < 0.01-2.3 μg/g. Several locations exceeded the Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand (Australian and New Zealand guidelines for fresh and marine water quality 2000) low and high interim sediment quality guidelines' levels for Cu, Zn, Cd and Hg. Some sites had measurable Sn concentrations, but these were all well below the levels of tributyltin known to cause harm to marine animals. Elevated metal concentrations are likely to be from the use of antifoulants on boats, historical mining activities and agriculture in the catchments of estuaries. All molluscs had no measurable concentrations of Sn (< 0.01 μg/g) and low mean Ag (< 0.01-1.5 μg/g) and Hg (< 0.01-0.5 μg/g) concentrations. Mean Cu (24-1516 μg/g), Zn (45-4644 μg/g), Cd (0.05-5μg/g) and Pb (0.05-1.1 μg/g) in oysters were close to background concentrations. Oysters have Cd and Pb concentrations well below the Australian Food Standards Code (2002).] There were no significant correlations between metal concentrations in sediments and in organisms within locations, and no relationship with levels of boating activity and suspected antifouling contamination. Although not pristine, the low levels of metal contamination in sediments and molluscs in comparison with known metal-contaminated areas indicate that this region is not grossly contaminated with metals and suitable for the development of mariculture.].

Application of enrichment factor, geoaccumulation index, and ecological risk index in assessing the elemental pollution status of surface sediments.

Sediment can accumulate trace elements in the environment. This study profiled the magnitude of As, Ba, Cd, Co, Cu, Cr, Ni, Pb, Se, and Zn pollution in surface sediments of the west coast of Peninsular Malaysia. Trace elements were digested using aqua regia and were analyzed using the inductively coupled plasma-mass spectrometry. The extent of elemental pollution was evaluated using with the enrichment factor (EF) and geoaccumulation index (Igeo). This study found that the elemental distribution in the sediment in descending order was Zn > Ba > Cr > Pb > Cu > As > Ni > Co > Se > Cd. Zn concentrations in all samples were below the interim sediment quality guideline (ISQG) (124mg/kg). In contrast, Cd concentrations (2.34 ± 0.01mg/kg) at Station 31 (Merlimau) exceeded the ISQG (0.70mg/kg), and the concentrations of As in the samples from Station 9 (Tanjung Dawai) exceeded the probable effect level (41.60mg/kg). The Igeo and EF revealed that Station 9 and Station 31 were extremely enriched with Se and Cd, respectively. All stations posed low ecological risk, except Station 31, which had moderate ecological risk. The outputs from this study are expected to provide the background levels of pollutants and help develop regional sediment quality guideline values. This study is also important in aiding relevant authorities to set priorities for resources management and policy implementation.

PAHs as quality markers of the sediments in the Lower Taquari subbasin during the period of intervention in a contaminated site

The region studied on the Taquari River, is close to a site with soil contaminated by wood preservatives, where a route of contaminants into the river was identified. This site was submitted to the first stage of the intervention process excavating the soil to remove the main active sources. To assess sediment quality the PAHs concentrations were analyzed: before, during and after the process. The PAHs concentration was compared to the guide values adopted by CONAMA resolution 344/04, aiming to protect aquatic life. Four points on Taquari River were tested, upper (TA032), in front (TA010) and lower (TA006, TA004) the contaminated site. Besides these, the Stream that is considered a source of contamination for TA010 was evaluated in the last step. The results indicated values between ISQG (Interim Sediment Quality Guidelines and PEL (Probable Effect Level) observed for eight PAHs. The PAHs values, probably carcinogenic to humans, were between ISQG and PEL in different samplings at TA010, more expressives during and after intervention. These values were also found at TA006 and TA004 during the same periods. The persistent contamination of the critical point TA010, even after intervention, is a warning regarding the environmental quality and aquatic life of this region.

Optimization and application of a low cost, colorimetric screening method for mercury in marine sediment.

A rapid, inexpensive, colorimetric screening method for mercury (Hg) has been optimized to provide a semi-quantitative measurement of Hg concentration in marine sediment within the range 0.038 to 1.5mgkg-1 encompassing the interim sediment quality guideline (ISQG) value of 0.13mgkg-1 (CCME 1999) and the probable effects level (PEL) of 0.7mgkg-1 for Hg in marine sediment (CCME 1999). Neither salinity (up to 41 practical salinity units (psu)) nor sediment organic matter (ΟΜ) content (up to 10%) affected the performance of the method. Accurate results were obtained for spike recovery experiments and analysis of certified reference material (CRM) BCR 580 Estuarine Sediment. The method was applied to sediment samples from Elefsina Bay, Greece. Screening results indicated Hg contamination in the bay, with concentrations exceeding the PEL value. Findings were confirmed by quantitative analysis of the samples by cold vapor atomic absorption spectrometry (CV-AAS), where results in the range 1.4-2.96mgkg-1 were determined.

Assessment of heavy metal pollution and ecological risk in marine sediments (A case study: Persian Gulf)

ABSTRACTThis study was made to determine the pollution status and potential ecological risk of heavy metals in sediment of Persian Gulf. Surface sediments were collected seasonally by Peterson grab, and the concentrations of heavy metals were measured by using inductively coupled plasma–optical emission spectrometry (ICP–OES). The range concentrations obtained in mg/kg were 10,800–22,400 for Fe, 5.32–10.12 for Pb, 24.63–42.38 for Ni, 22.52–39.46 for Cu, and 31.64–47.20 for Cr. The concentrations of Pb, Ni, Cu, and Cr have been found lower than the Interim Sediment Quality Guidelines and probable effect level values suggesting that heavy metal contents in sediments from area of study would not be expected to cause adverse biological effects on the biota. The obtained enrichment factor values for various metals were between minimal enrichment (Pb = 0.5) and extremely enrichment (Cu = 3.11). The values of Igeo for Pb, Ni, Cu, and Cr were characterized under no pollution (0). The highest value of potential ecological risk index (RI) (8.36) was observed at St. 4 while the lowest value (5.25) was detected at station 6. Based on potential ecological RI, the Persian Gulf had low ecological risk.

ENVIRONMENTAL AND ECOLOGICAL RISK ASSESSMENT OF HEAVY METAL IN DREDGED SEDIMENTS IN LAGOS, NIGERIA: AN INDEX APPROACH ANALYSES

The present study investigate the distribution of Heavy metals (Cadmium, Copper, Zinc, lead and Nickel) and potential ecological risk associated in surface sediments samples from six coastal communities (Ajah, Imore, Ilado, Ajindo, Ojo and Gbelejo) in Lagos, Nigeria. Composite samples were collected from ten (10) different locations in each of the communities and analysed of heavy metals using employing Atomic Absorption Spectrophotometer (AAS). The interim Sediment Quality Guidelines (ISQG) was applied to characterize the dredged sediments and assess the potential ecological risk on the environment through multivariate quality indices such as pollution index (Pi), pollution classification (Pc), geo accumulation index(I geo) and potential ecological risk index (RI). The concentration of zinc was observed higher in the sediments from commercially dredge areas (Ajah and Imore). The result obtained classified entire study area as polluted with respect of Pb and Ni, and as contaminated with (Cd, Cu, and Zn) respect of other metals investigated. The overall ecological risk for the six study areas revealed moderate potential risk (110 ? RI &lt; 200), except Imore and Gbelejo which showed low potential risk (RI &lt; 110). The need for regular monitoring by the relevant agencies cannot be overemphasized to ensure sustainable environment.

Impact of copper sulfate application at an urban Brazilian reservoir: A geostatistical and ecotoxicological approach

A landscape ecotoxicology approach was used to assess the spatial distribution of copper in the recent bottom sediment (surficial sediment) of a Brazilian subtropical reservoir (the Guarapiranga reservoir) and its potential ecotoxicological impacts on the reservoir ecosystem and the local society. We discuss the policies and procedures that have been employed for the management of this reservoir over the past four decades. Spatial heterogeneity in the reservoir was evaluated by means of sampling design and statistical analysis based on kriging spatial interpolation. The sediment copper concentrations have been converted into qualitative categories in order to interpret the reservoir quality and the impacts of management policies. This conversion followed the Canadian Water Framework Directive (WFD) ecotoxicological concentration levels approach, employing sediment quality guidelines (SQGs). The SQG values were applied as the copper concentration thresholds for quantitative-qualitative conversion of data for the surficial sediment of the Guarapiranga. The SQGs used were as follows: a) interim sediment quality guideline (ISQG), b) probable effect level (PEL), and c) regional reference value (RRV). The quantitative results showed that the spatial distribution of copper in the recent bottom sediment reflected the reservoir's management policy and the copper application protocol, and that the copper concentrations varied considerably, ranging from virtually-zero to in excess of 3gcopper/kgds. The qualitative results demonstrated that the recent bottom sediment was predominantly in a bad or very bad condition, and could therefore have impacts on the local society and the ecosystem. It could be concluded that the management policy for this reservoir was mainly determined by the desire to minimize short-term costs, disregarding long-term socioeconomic and environmental consequences.

The use of two microbiotests to evaluate the toxicity of sediment from Mpumalanga, South Africa

Rapid urbanisation throughout the world has resulted in numerous ecological and environmental problems. The release of contaminants into the aquatic environment and the subsequent accumulation in sediment is a specific area of concern due to the potential re-release of the contaminants into solution. The responses of two microbiotests designed to evaluate sediment toxicity (the Ostracodtoxkit F and Phytotoxkit test) were compared once exposed to three samples collected in the vicinity of a power station in Mpumalanga, South Africa. Sediment characterisation and chemical analyses were conducted in order to determine possible correlations with the expressed results. Where possible, the concentration of chemicals in the sediment was compared to available sediment guidelines. The study showed that whilst the Phytotoxkit test results did not indicate any acute toxicity (< 50% inhibition), the Ostracodtoxkit F test indicated 100% mortality at the upstream site, with increased growth inhibition at the remaining two sites. The concentration of chrome at all three sites exceeded the interim sediment quality guidelines (37 mg/kg), with the sample collected at the upstream site exceeding the probable effect level (90 mg/kg). The findings from this study indicated that the Phytotoxkit and Ostracodtoxkit F test kits are sensitive enough to evaluate sediment toxicity. Keywords: Ostracodtoxkit F, Phytotoxkit, sediment contamination

Enrichment, contamination and geo-accumulation factors for assessing arsenic contamination in sediment of a Tropical Open Lagoon, Southwest Nigeria

The presence of toxic heavy metals and metalloids in aquatic environments constitutes a major risk and there is an urgent need for continuous monitoring of such pollutants. This study assesses the concentrations of arsenic (As) in surface sediments from 15 locations on the Lagos Lagoon, Nigeria during the wet and dry seasons to determine the degree of contamination. The results showed that the mean total As concentration in sediment (2.44 mg kg−1 dry weight) did not exceed the Canadian Interim Sediment Quality Guideline (CISQG) value of 7.24 mg kg−1 dry weight during the wet and dry seasons. Based on the Sediment Quality Guidelines (SQGs) of the United States Environmental Protection Agency (USEPA) and ecological risk assessment using the enrichment factor (EF), contamination factor (CF) and geo-accumulation index (Igeo), the study’s results indicate two things: firstly, low to moderate and significant levels of enrichment from As; and secondly, low to moderate degree of contamination in Lagos Lagoon during the study period.

Serpentine geology links to water quality and heavy metals in sediments of a stream system in central Queensland, Australia

Serpentinite soils, common throughout the world, are characterized by low calcium-to-magnesium ratios, low nutrient levels and elevated levels of heavy metals. Yet the water quality and heavy metal concentrations in sediments of streams draining serpentine geology have been little studied. The aim of this work was to collect baseline data on the water quality (for both wet and dry seasons) and metals in sediments at 11 sites on the Marlborough Creek system, which drains serpentine soils in coastal central Queensland, Australia. Water quality of the system was characterized by extremely hard waters (555–698 mg/L as CaCO3), high dissolved salts (684–1285 mg/L), pH (8.3–9.1) and dissolved oxygen (often >110% saturation). Cationic dominance was Mg > Na > Ca > K and for anions HCO3 > Cl > SO4. Al, Cu and Zn in stream waters were naturally high and exceeded Australian and New Zealand Environment and Conservation Council guidelines. Conductivity displayed the highest seasonal variability, decreasing significantly after wet season flows. There was little seasonal variation in pH, which often exceeded regional guidelines. Stream sediments were enriched with concentrations of Ni, Cr, Co and Zn up to 35, 21, 10 and 2 times the world average for shallow sediments, respectively. Concentrations for Ni and Cr were up to 60 and 16 times those of the relevant Interim Sediment Quality Guidelines Low Trigger Values, respectively. The distinctive nature of the water and sediment data suggests that it would be appropriate to establish more localized water quality and sediment guidelines for the creek system for the water quality parameters conductivity, Cu and Zn (and possibly Cr and Cd also), and for sediment concentrations of Cd, Cr and Ni.

Assessment of urban stream sediment pollutants entering estuaries using chemical analysis and multiple bioassays to characterise biological activities

Stormwater contaminants are a major source of often neglected environmental stressors because of the emphasis placed on the management of municipal and industrial wastewaters. Stormwater-derived pollutants in sediments from two New Zealand estuaries was characterised by analytical chemistry and bioassays. Contaminants were extracted from sediment using accelerated solvent extraction (ASE), recovered and concentrated by solid phase extraction (SPE), and analysed for polycyclic aromatic hydrocarbons (PAHs), selected metals, and musk fragrances. The concentrations of PAHs were below the ANZECC Interim Sediment Quality Guideline values while those of lead and zinc exceeded them in some samples. The sediment extracts containing organic contaminants exhibited acute toxicity in the zebrafish fish embryo toxicity (FET) and teratogenicity, induction of biotransformation (EROD activity), and genotoxicity (comet assay) in zebrafish. The potential of the extracts to interact with endocrine signalling processes was assessed by GeneBLAzer reporter gene bioassays and they exhibited estrogenic, androgenic, and anti-progestagenic activities.

Assessment of heavy metal pollution in surface sediments of the Bayan Lepas area, Penang, Malaysia

This study aimed to evaluate the spatial and temporal distribution of heavy metals (Cd, Cr, Cu, Co, Fe, Pb, Ni, V, and Zn) in the sediments of Bayan Lepas Free Industrial Zone of Penang, Malaysia. Ten sampling stations were selected and sediment samples were collected during low tide (2012−2013). Metals were analyzed and the spatial distribution of metals were evaluated based on GIS mapping. According to interim sediment quality guidelines (ISQG), metal contents ranged from below low level to above high level at different stations. Based on the geoaccumulation index (Igeo) of sediment, sampling stations were categorized from unpolluted to strongly polluted. The enrichment factor (EF) of metals in the sediment varied between no enrichment to extremely high enrichment. The potential ecological risk index (RI) indicated Bayan Lepas FIZ was at low risk.

Mercury and methylmercury distribution in the intertidal surface sediment of a heavily anthrophogenically impacted saltwater-mangrove-sediment interplay zone

Total mercury (THg) and methylmercury (MeHg) concentrations were determined from sediment samples collected from thirty sampling stations in Port Klang, Malaysia. Three stations had THg concentrations exceeding the threshold effect level of the Florida Department of Environmental Protection and the Canadian interim sediment quality guidelines. THg and MeHg concentrations were found to be concentrated in the Lumut Strait where inputs from the two most urbanized rivers in the state converged (i.e. Klang River and Langat River). This suggests that Hg in the study area likely originated from the catchments of these rivers. MeHg made up 0.06–94.96% of the sediment's THg. There is significant positive correlation (p < 0.01) between THg and MeHg concentrations. Significant positive correlation (p < 0.05) was also observed between fine sediment particles (i.e. clay and silt) with MeHg concentrations. Sediment particle size, however, was not found to have any influence on THg concentrations in the sediment in the study area.

Distribution, enrichment, and source identification of selected heavy metals in surface sediments of the Siran River, Mansehra, Pakistan.

To assess the trace metal pollution in the Siran River, sediments were collected from 12 sites, from the left and right banks of the river in 2013. The concentrations, accumulation, distribution pattern, and pollution status of heavy metals in sediments were investigated using geoaccumulation index (I geo) and enrichment factor (EF). The toxic risk of heavy metals was assessed using interim sediment quality guidelines (ISQGs), portable effect level (PEL), threshold effect level (TEL), and toxic effect threshold (TET). I geo and EF values showed that sediments were loaded with Ni, Cd, Pb, and Co and no obvious variations were found among the left and right banks of the river. The EF and I geo values were found in order of Co>Pb>Ni>As>Cd>Cu>Zn>Fe and Cd>Co>Pb>Ni>As>Fe>Zn>Cu>Mn, respectively. Furthermore, multivariate statistical analysis like inter-metal correlation, cluster analysis (CA), and principal component analysis (PCA) results revealed that geogenic and anthropogenic activities were major sources of sediment contamination in the study area. These results indicated that more attention should be paid to the inner loads of sediment in order to achieve improvements in reservoir water quality after the control of external pollution.

PAH distributions in sediments in the oil sands monitoring area and western Lake Athabasca: Concentration, composition and diagnostic ratios

Oil sands activities north of Fort McMurray, Alberta, have intensified in recent years with a concomitant debate as to their environmental impacts. The Regional Aquatics Monitoring Program and its successor, the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring (JOSM), are the primary aquatic programs monitoring this industry. Here we examine sediment data (collected by Ekman grabs) to investigate trends and sources of polycyclic aromatic hydrocarbons (PAHs), supplementing these data with sediment core studies. Total PAH (ΣPAH) concentrations were highest at Shipyard Lake (6038 ± 2679 ng/g) in the development center and lower at Isadore's Lake (1660 ± 777 ng/g) to the north; both lakes are in the Athabasca River Valley and lie below the developments. ΣPAH concentrations were lower (622–930 ng/g) in upland lakes (Kearl, McClelland) located further away from the developments. ΣPAH concentrations increased at Shipyard Lake (2001–2014) and the Ells River mouth (1998–2014) but decreased in nearshore areas at Kearl Lake (2001–2014) and a Muskeg River (2000–2014) site. Over the longer term, ΣPAH concentrations increased in Kearl (1934–2012) and Sharkbite (1928–2010) Lakes. Further (200 km) downstream in the Athabasca River delta, ΣPAH concentrations (1029 ± 671 ng/g) increased (1999–2014) when %sands were included in the regression model; however, 50 km to the east, concentrations declined (1926–2009) in Lake Athabasca. Ten diagnostic ratios based on anthracene, phenanthrene, fluoranthene, pyrene, benz[a]anthracene, chrysene, indeno[123-cd]pyrene, dibenz[a,h]anthracene, dibenzothiophene and retene were examined to infer spatial and temporal trends in PAH sources (e.g., combustion versus petrogenic) and weathering. There was some evidence of increasing contributions of unprocessed oil sands and bitumen dust to Shipyard, Sharkbite, and Isadore's Lakes and increased combustion sources in the Athabasca River delta. Some CCME interim sediment quality guidelines were exceeded, primarily in Shipyard Lake and near presumed natural bitumen sources.

Use of a multi-proxy method to support the restoration of estuaries receiving inputs from industry

In New South Wales (NSW), Australia, the availability of water from estuarine lakes combined with the use of coal as an energy source has resulted in coal-fired power stations on the margins of coastal lakes. The purpose of this study was to use a multi-proxy method to evaluate the extent and trends of historical metal inputs from a coal-fired power station to sediments in Lake Budgewoi. Metal concentrations in 15-cm sediment cores showed a uniform depth profile. The highest concentrations of zinc and copper were found close to the Munmorah Power Station outlet, while arsenic and lead were found in the deposition basin of sediments. Background values for metal concentrations of Zn<80mg/kg, As<15mg/kg, Se<1mg/kg, Cu<16mg/kg, Cd<0.8mg/kg and Pb<20mg/kg were used as the baseline for future studies in this lake. The history of sediment metal concentrations is consistent with power station activities in the lake. Maximum metal concentrations found in sediments of Lake Budgewoi were Zn 122mg/kg, Cu 45mg/kg, As 10mg/kg, Se 1.8mg/kg, Cd 0.2mg/kg and Pb 41mg/kg. The ratio of these values to the national interim sediment quality guidelines are Pb 0.8, Cu 0.7, Zn 0.6, As 0.5 and Cd 0.1. Although concentrations were below guideline values, the multi-proxy method applied in this study was sensitive enough to detect metal concentration changes over the 45 years of power station operation. The results of this study provide environmental regulators with a baseline of the past and current situation of power station metal contamination, and in the future will provide insights into how long it takes the environment to revert to background metal concentrations.