Canadian Sediment Quality Guidelines Research Articles

Assessment of hydrological, geological, and biological parameters of a river basin impacted by old Hg mining in NW Spain

Mercury (Hg) is a toxic metal that can cause adverse effects for the health of ecosystems. The Caudal River is one of the main rivers in the Asturias region (NW Spain), whose basin is highly anthropized, hosting several Hg mines, closed in the last century. Arsenic (As) is also found in the mineral paragenesis of the Hg deposits, posing a greater environmental risk. In the mining sites, remaining old facilities and tailings continue to release these elements into the environment. In this work, samples of fluvial sediments and water were taken, both in areas affected by anthropic activity and in pristine areas, in order to establish the background levels for the critical elements. The mineralogical study of the sediments, combined with EDS microanalysis, is useful to identify mineralogical traps such as Fe oxides or clays to retain the As. The As content in all sampled sediments is above the threshold effect levels (TEL), the possible effect range within which adverse effects occasionally occur, according to the Canadian Sediment Quality Guidelines for the Protection of Aquatic Life. This fact is related to a naturally high geochemical background in the basin, due to the existing mineral deposits. The PEL threshold (the probable effect range within which adverse effects frequently occur) is exceeded by more than an order of magnitude in the sediments downstream of the Hg mines. In these points, the As content in the water, exceeding 700 μg L−1 As, is also above the quality standard established in Spanish legislation. As a result, the Caudal River tributaries in the lower part of the basin do not reach a good ecological state, according to the Hydrological Planning Office, and in some cases their state is deficient, showing low richness and high dominance of macroinvertebrates. Although the concentrations decrease with distance from the source, these findings justify the low ecological quality of the affected watercourses.

ORGANOCHLORINE PESTICIDES POLLUTION OF THE BOTTOM SEDIMENTS OF NAKHODKA BAY AND PARTIZANSKAYA RIVER

Link for citation: Mazlova E.A., Blinovskaya Ya.Yu., Sokolova L.I., Tursunova G.Sh. Organochlorine pesticides pollution of the bottom sediments of Nakhodka bay and Partizanskaya river. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 25-35. In Rus. Relevance. The new data on the organochlorine pesticides pollution of the bottom sediments of Nakhodka bay and Partizanskaya river were obtained in 2020–2021. The objective of the article is to report the organochlorine pesticides pollution level of the bottom sediments and to define the possible sources of organochlorine pesticides in the marine environment. Techniques: sample collection of bottom sediments, Gas Chromatography Mass Spectrometry analysis of samples, Gas-liquid Chromatography method with electronic capture detector, statistical processing, assessment of the organochlorine pesticides contamination of sediments. Results. The new data were obtained on the organochlorine pesticides concentrations in Nakhodka bay in 2020–2021. The previous data on the studied area are described. The concentration of HCH pesticides (α- , β- and γ-HCH), DDT and its metabolites was analyzed. It was found that the concentration of α- , β- HCCH and DDT in bottom sediments increased in 2021.To determine the quality of bottom sediments, the average annual values of organochlorine pesticides concentrations in the bottom sediments gathered during the field works were compared with the quality guidelines. There are no approved quality guidelines for maximum permissible concentrations of pollutants in bottom sediments in the Russian Federation. For this reason, we used the quality guidelines applied in foreign countries («Dutch sheets» (Neue Niederlandische Liste. NNL) and Canadian quality standards for marine and estuarine bottom sediments (Canadian Sediment Quality Guidelines, CSQGs). Possible sources of organochlorine pesticides in the marine environment were analyzed. The results of this work showed that despite the ban on the use of these substances, these pesticides are included in the multiple compounds used in different industries and continue to enter and accumulate in the marine environment.

Concentrations and total mass storage of fine sediment, potentially toxic elements (PTEs) and phosphorus in the channel bed of an urban river: a multi-year study

PurposeGiven the rapid growth of people living in urban and peri-urban areas, this study examined the downstream trends in concentrations and determined the total storage of potentially toxic elements (PTEs) and phosphorus (P) associated with fine-grained sediment (0.45 to 63 µm) stored in the channel bed of an urban river.Materials and methodsSamples were collected from seven sites along McMillan Creek (watershed area = 55 km2) in the city of Prince George, British Columbia, Canada, between 2010 and 2016 using a resuspension approach. Grabs samples were also collected from two key tributaries and a large culvert.Results and discussionSome elements (e.g., As, Mn and P) decreased in a downstream direction due to inputs from agricultural sources in the headwaters, while others (e.g., Cr, Cu, Pb and Zn) increased downstream reflecting inputs from urban sources in the lower part of the watershed. Several PTEs increased significantly due to a large culvert which supplied road-deposited sediment (RDS) and other urban materials. In some cases (e.g., As, Mn, Zn) PTE concentrations exceeded Canadian sediment quality guidelines (SQGs) for the protection of aquatic organisms. While concentrations were similar for most years, they were elevated in 2016 which may reflect higher rainfall prior to sample collection. The average total storage of fine-grained sediment in the channel bed of McMillan Creek was 155 t (4198 g m−2), while for PTEs this ranged from 0.01 kg (0.0002 g m−2) for Hg to 1130 kg (30.7 g m−2) for Mn.ConclusionsThe channel bed of an urban river stored large amounts of fine sediment, PTEs and P, with concentrations that exceeded SQGs for some elements. Given the expected increase of people living in urban and peri-urban areas, more studies are required to assess the impacts of this growth on the amount and quality of fine-grained sediment stored in urban rivers.

Sediment Spatial Distribution and Quality Assessment of Metals in Chinook Salmon and Resident Killer Whale Marine Habitat in British Columbia, Canada.

At-risk resident killer whale (Orcinus orca) populations of the northeastern Pacific, Canada, and their main prey, Chinook Salmon (Oncorhynchus tshawytscha), are exposed to a variety of contaminants including chemical elements from both natural and anthropogenic sources, which may be constraining their recovery. Concentrations of 36 chemical elements in subtidal surface sediments (1-435m depth) collected from 98 sites along the British Columbia coast were used to characterize coast-wide patterns, and a subset of metals (mercury (Hg), cadmium (Cd), arsenic (As), nickel (Ni), copper (Cu), and lead (Pb)) were selected to assess Chinook Salmon and resident killer whale marine habitat quality. Principal component analysis (PCA) showed a dominance of Hg, antimony (Sb), Pb, Cu, and zinc (Zn) for Prince Rupert Harbour, Victoria Harbour, and Burrard Inlet, suggesting local sources. Based on the PCA, geochemical properties such as total organic carbon (TOC), acid volatile sulfide (AVS), and pH explained the spatial distribution of all elements in sediment (p < 0.001). Mercury, Cd, As, Ni, Cu, and Pb hotspots were identified along the coast of Vancouver Island, the central and north coast, in the Strait of Georgia, and Haida Gwaii. Bischof Island of Haida Gwaii and Ardmillan Bay on the central coast were most contaminated and enriched by Cd, determined by geoaccumulation index (Igeo) and enrichment factor (EF), respectively. Marine habitat quality was assessed by comparing metal concentrations to Canadian Sediment Quality Guidelines (SQGs). Chinook Salmon populations may be indirectly affected by metal toxicity (As > Cd and Cu > Ni > Hg > Pb) to lower trophic level prey species. Toxicity related impacts to benthic organisms as a result of exposure to elevated Cd and As concentrations in Northern Resident Killer Whale critical habitat and to Hg, Cd, As, Ni, Cu, and Pb concentrations in Southern Resident Killer Whale critical habitat may indirectly pose a threat to resident killer whale populations, highlighting a need for management actions to reduce risks associated with these metals.

Geochemical evaluation and environmental risk assessment of heavy metals: A case study from Ireland using Tellus stream sediment data (2011–2017)

A comprehensive assessment of the distribution, spatial mapping and ecological risk of heavy metals in stream sediments of 17 counties of Ireland based on the Tellus geochemical survey programme in Ireland was carried out. Average trace metal concentrations of chromium (Cr), nickel (Ni), copper (Cu), lead (Pb), zinc (Zn), vanadium (V), cobalt (Co), arsenic (As), and major and minor oxides iron oxide (Fe2O3), manganese oxide (MnO) in the stream sediments were above the background values, but lower than Irish sediment quality guidelines for livestock and Canadian sediment quality guidelines (ISQG); threshold effect level (TEL) and probable effect level (PEL). 69.65% of Ni, 22.13% of Zn, and 96.7% of Pb samples exceeded the low-effect-range (ERL) values, whereas only 21%, 1.80% and 0.69% of the same elements exceeded the median effect range (ERM) values. Hotspots of Zn (>12000 mg kg−1), Pb (>10,000 mg kg−1), Fe2O3 (61.38%), MnO (26%), Cr (>2300 mg kg−1) and Ni (874.2 mg kg−1) were observed at Wicklow, Dublin, Mayo, Galway and Cavan counties. Catchment geochemistry was identified for the presence of heavy metals in the stream sediments. The geo-accumulation index (Igeo) indicated Kildare to be the least contaminated county with Igeo < 0 for Cr, Ni, Cu, Zn, Pb and As for 50% of the samples. The enrichment factor (EF) indicated that some sites located in Mayo and Donegal were highly contaminated. PInemerow followed the trend, Tipperary > Dublin > Waterford > Monaghan > Donegal > Wexford > Galway > Wicklow > Cavan > Meath > Kilkenny > Leitrim > Mayo > Louth > Sligo > Kildare > Carlow. Based on potential ecological risk index (PERI), 83.1% of the sites posed low ecological risk (PERI <150), 11.9% sites posed moderate risk (150 < RI < 300) and high ecological risk was posed by 0.3% (PERI >1200) of the sites. Lithology, topography and anthropogenic factors influenced the distribution and ecological risks of heavy metals. Non-carcinogenic and carcinogenic risk for adults and children were above the recommended value.

Ecological indicators and source diagnostic ratios of aliphatic and polyaromatic hydrocarbons in marine sediments of Qatar

The marine ecosystems surrounding oil and gas production sites are particularly vulnerable to ecological harm that may be affected by its operations. In this study, we examined the composition, contaminant sources, and the potential ecological risk of aliphatic hydrocarbons (AH) and polyaromatic hydrocarbons (PAH) in the marine sediments along the western coast of Qatar. The ΣAHs concentration ranged from <0.10 to 246 ng⋅g−1 (site SD2) while the ΣPAH concentration ranged from <0.10 to 44 ng⋅g−1 (site SD10). Pollution concentration profile was site specific where AH and PAH concentrations were relatively higher within close proximity to the oil and gas production. TOC appeared to be positively correlated with PAH and therefore a good indicator for PAH but not for AH. Low molecular weight even-carbon numbered alkanes (n-C10-18) were more abundant than the higher molecular weight (n-C20-34) AHs. The Σ16PAHs compositional analysis mean concentrations were composed of 2-ring (6%), 3-ring (18%), 4-ring (48%), 5-ring (28%), and 6-ring (0.14%), respectively. Fluoranthene obtained the highest concentration of 11 ng⋅g−1 (site SD10). Diagnostic ratios and hydrocarbon parameters suggested mixed sources of petrogenic, pyrolytic, and biomass except for vehicular traffic. The overall results for AH and PAH indicated low pollution based on pollution criteria and were below the threshold limit set by the National Oceanic and Atmospheric Administration (NOAA) and the Canadian Sediment Quality Guidelines (CSQG). This suggests low probability of a negative toxic effect caused by these contaminants however, continuous long term-monitoring is needed to ensure these pollutants do not exceed the current levels.

Mercury content in mining waste and its effect on the surrounding environment (Case study: Small-scale gold mining locations-West Sumbawa)

This study was conducted to determine the content of mercury in the flowing river around small-scale gold mines. Mining wastes from the run of mining are dumped into the watersheds and potentially contaminate the water and sediment in the watershed near the gold mining area. We analyzed the characteristics of the waste and the result was compared with the water quality standards (Environment Minister Decision No.202 of 2004 and Government Regulation No.82 of 2001) and sediment quality standard (the Canadian sediment quality guidelines for the threshold effect level (TEL) and probable effect level (PEL)). We found that wastewater from the gold mining areas was categorized in class IV. The mercury content in the sediment samples did not meet the standards of Canadian sediment quality guidelines for TEL. The content of mercury in the sediment samples from the gold mine site was very high. The sediment mercury samples had been settled for a long time around the watershed. The content of mercury in the mining location indicated that mercury had been contaminating the area around the small-scale gold mining.

Heavy Metals in Surface Sediments of the Coastal Area Around Daerah Istimewa Yogyakarta, Indonesia: Their Relations to Land-Use Types

The province of Daerah Istimewa Yogyakarta (DIY) has experienced significant changes in urbanization, industry, and tourism, making it one of Indonesia's fastest-growing areas. Increased anthropogenic activity in the coastal region may cause heavy metal contamination in that zone to grow. Based on different land-use types, this study examined the distribution of heavy metals, namely cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn), in surface sediment. It assessed the feasibility of sediment quality standards based on the Canadian Sediment Quality Guidelines (CSQG). Nine stations made up the sampling site, each representing a different land-use type, including mangrove ecosystem, tourist attraction, airport, harbor, mining area, bare land, shrimp pond, agricultural land, and settlement. The concentrations of Cd in bare land, shrimp pond, agricultural land, and settlement (with values of 2.707, 2.955, 2.983, and 2.873, respectively), and Cu in the mangrove ecosystem (with values of 42.893) slightly exceeded the corresponding Threshold Effect Level (TEL) value of CSQG. Meanwhile, the content of other heavy metals in all land use types tends to be low, even below the Limit of Detection (LOD). The data on the level of heavy metal pollution in the study area shows no connection between heavy metal contamination and different land-use types. It is brought on by a variety of circumstances, such as the fact that human activity in the study area did not significantly contribute to heavy metal contamination or that heavy metals were contaminated and then spread to other forms of land-use types, in this case, the mangrove ecosystem, by runoff and wind. This is because variations in salinity, estuary flushing, physical mixing and dilution, and chemical processes, including sorption, complexation, cation exchange, and redox reactions, all affect how heavy metals are transported by water. The government should create environmental regulations, laws, quality norms and standards, more funding for cutting-edge scientific research, and technical tools to prevent heavy metal pollution in coastal areas.

Geochemical changes in Eastern Canadian lake sediment cores spanning the last ∼150 years highlight a relative shift towards increased metals and erosive materials

Since the start of the Industrial Revolution, the chemical cycling of numerous elements has been fundamentally altered. Using 210Pb-dated sediment cores from 37 Eastern Canadian lakes situated in 4 ecozones, we quantified the geochemical change experienced across this region since ca. 1850 CE using high-resolution computed X-ray Tomography and micro-X-ray fluorescence (µ-XRF) ITRAX scanners. Independent calibrations of µ-XRF ITRAX intensities using ICP-MS and -AES found strong correlations for numerous elements. Using relative abundance measures and absolute concentration estimates, we observed that most of our study lakes recorded temporal enrichments of metals, with several sites exceeding Canadian sediment quality guidelines. Using principal component analysis, we identified that parameters commonly associated with erosion (strontium and titanium), organic matter (molybdenum incoherence to coherence scattering ratio), and metals (zinc and lead) were key variables structuring within and among-lake variation since ca. 1850 CE. Calcium was identified as an additional variable, particularly for lakes in the Mixedwood Plains (MWP) ecozone, which may be linked to catchment activities including land-use changes. Temporally, many lakes shifted towards greater accumulation of inorganic sediment, coeval with higher Pb and Zn concentrations, reaching maxima ca. 1970 CE before decreasing rapidly. These results suggest that most lakes in the region were subjected to environmental pollution but that controls on key atmospheric pollutants in North America were effective across a large part of the country.

Geochemical and environmental assessment of potential effects of trace elements in soils, water, and sediments around abandoned mining sites in the northern Iberian Peninsula (NW Spain)

The mineral deposits and traces in the Iberian Peninsula are very numerous and of varied mineralogy. This study aimed to analyze the geochemical and environmental changes detected in soil, water, and sediments around the La Sierre mine, and to determine if contamination persists over time. The concentrations of ten trace elements (As, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn) were measured in 20 soil samples, 10 water samples, and 6 sediment samples, sampling at the most affected points. Soil and sediment samples were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and water samples by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). From the Principal Component Analysis (PCA), soil samples SOI-6, 7, and 20 presented high amounts ranging from 14489.86a±7 to 3031.72b ± 1 mg/kg of Co, Cu, Ni, and As, respectively. Water samples WAT-6, 8, and 10 presented high contents of As, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn, being sample WAT-8 with high values of As, Co, Cu, Fe, and Ni with 48.1 ± 0.82, 368 ± 4, 68.3 ± 0.1, 97.5 ± 1.2, and 152 ± 2 μg/L, respectively, exceeding the regulation given by R.D 314/2016 (Water for human consumption). The sediment samples were compared with the IInterim Sediment Quality Guideline (ISQG) and Probable Effect Level (PEL) values given by the Canadian Sediment Quality Guidelines for the Protection of Aquatic Life. When presenting a high ISQG value, but low PEL, they partially comply with the regulations, which happens with samples SED-1, 2, and 8 for As and SED-5, 6, and 7 for Pb. On the contrary, Cr and Cu do not comply with what is established in samples SED-8 and SED-1 and 8, respectively, whereas, in samples SED-2 and 5, Cu partially complies with the established regulations. The values found for the trace elements present in the abandoned traditional mining area with abundant epithermal deposits prevail over time in soil, water, and sediments.

Annual pulses of copper-enriched sediment in a North American river downstream of a large lake following the catastrophic failure of a mine tailings storage facility

Failures of mine tailings storage facilities (TSF) can have profound and long-lasting effects on the downstream receiving environment. Virtually all spills to date have been into river systems without large lakes that may buffer downstream impacts. In August 2014, the failure of the Mount Polley copper (Cu)-gold mine TSF in British Columbia, Canada, released ~25 × 106 m3 of water and solids; globally, this is the second largest TSF spill in history. Over 18 × 106 m3 was delivered to Quesnel Lake, which is ~9 km from the TSF and is the third deepest lake in North America, and a crucial habitat for Pacific salmon and trout populations. We determined the sediment-associated Cu concentrations and fluxes in Quesnel River, downstream of the lake, from August 2014 to February 2021 based on the analysis of >400 samples of sediment, mainly collected using a continuous-flow centrifuge. During each winter since the spill, Cu concentrations in the fluvial sediment in the upper reaches of the river (~35 km from the TSF) were elevated relative to regional background concentrations and samples collected before the spill. Maximum Cu concentrations were ~410 mg kg−1 which exceeds Canadian sediment quality guidelines for the protection of aquatic organisms (197 mg kg−1). Monitoring of Quesnel Lake since the spill shows that these annual pulses in the winter are due to resuspension of unconsolidated tailings and sediments at the bottom of Quesnel Lake, during autumnal lake turnover, which become mixed throughout the water column and subsequently flow into Quesnel River. Results show that while large lakes may buffer downstream aquatic systems from contaminated sediment, they may prolong the environmental impact. These findings are crucial in understanding how lake processes may modify the effects of TSF spills on downstream aquatic systems.

Heavy Metals Contamination and Water Quality Parameter Conditions in Jatiluhur Reservoir, West Java, Indonesia

Waste pollution into the Citarum River (main water source of Jatiluhur Reservoir) was dominated by the manufacturing industry sector (textile, chemical, metal, pharmaceutical). Industrial was the most common contributor to heavy metal waste. Heavy metal contamination into waters will cause any problems, one of which was the emergence of various diseases both short and long term. Based on the issues, the study of heavy metal contamination and also water quality parameter conditions in the Jatiluhur Reservoir was necessary. The heavy metals (Cu, Zn, Hg, Pb, Cd) contents were determined using the X-Ray Fluorescence (XRF) Spectrometry method (for sediment) and Atomic Absorption Spectrometry (AAS) method (for water). The other water quality parameters were analyzed using the methods from the Indonesian National Standard (SNI). Furthermore, the data were compared to the Canadian Sediment Quality Guidelines (for heavy metal in sediment) and water quality standards from Government Regulation of the Republic of Indonesia Number 82 of 2001 (Class 3) (for water quality parameters). Concerning the discussion, Jatiluhur Reservoir was divided into three zones i.e. the inlet area, main inundation area, and outlet area. Conditions in the sedimentary layer, mercury (Hg) have accumulated throughout the Jatiluhur Reservoir area with conditions exceeding the maximum limit, while Cu metal tends to accumulate in the inlet area with conditions exceeding the minimum limit. For other heavy metals, exceed the minimum limit at some locations, but more results were below that. Although all heavy metals have not been detected in water, this was a warning that the presence of heavy metals in sediments can potentially dissolve into the water, the most extreme thing that can happen was upwelling. If this happens, the heavy metals can be contained excessively in water, harmful to and possibly consumed by aquatic biota and human. Considering these conditions, the biota that was most likely to be exposed was benthic organisms. In general, the water quality parameters in Jatiluhur Reservoir meet the quality standards. Only ammonia that does not meet the quality standards for sensitive fish life, regarding the massively of aquaculture activity in this reservoir.

Tracking historical sources of polycyclic aromatic compounds (PACs) in dated lake sediment cores near in-situ bitumen operations of Cold Lake, Alberta

Most bitumen in the Alberta oil sands (Canada) is extracted by thermal in-situ recovery. Despite the widespread use of in-situ bitumen extraction, little information is available on the release of petroleum hydrocarbons by this method to adjacent land and water. Here we analyzed the composition and abundance of parent and alkylated polycyclic aromatic compounds (PACs) in 11 radiometrically-dated lake sediment cores collected near in-situ operations at Cold Lake Alberta to assess potential petroleum contamination sources to surrounding lakes over the past century. Like open-pit mining areas, alkylated PACs in Cold Lake sediments were elevated compared to unsubstituted parent PACs and increased coeval with the onset of bitumen extraction in the area. Diagnostic ratios and pyrogenic indices showed that PAC sources to these lake sediments were dominantly pyrogenic, likely from historic forest fires, however they shifted to more petrogenic sources coeval with expanding oil sands extraction at Cold Lake. PACs in sediment from regional lakes are weakly correlated to their proximity to in-situ oil wells, once corrected for lake area. These results suggest that in-situ operations, via diesel-fueled vehicular emissions and the combustion of natural gas for steam generation, are a source of PACs to nearby lakes, but PACs did not exceed Canadian sediment quality guidelines for the protection of aquatic life.

Contamination and ecological risk assessment of trace metals in surface sediments from coastal areas (El Jadida, Safi and Essaouira) along the Atlantic coast of Morocco

Concentrations of four trace metals (Cd, Cr, Cu and Zn) in surface sediments were quantified seasonally to evaluate the metal contamination and to determine the possible environmental risks at three coastal areas in northwest Morocco (El Jadida, Safi and Essaouira). Sampling was conducted quarterly at six intertidal stations with two stations per area (north to south: El Jadida: S1 vs. S2; Safi: S3 vs. S4 and Essaouira: S5 vs. S6). The trace metal concentrations were generally found to be greater in wet seasons for all sampling stations, and their mean values were arranged in the following decreasing order: Zn (28.35–136.10 μg g−1 dry weight) > Cr (6.50–130.90 μg g−1) > Cu (5.00–83.40 μg g−1) > Cd (0.02–5.95 μg g−1). As expected, the highest metal concentrations were recorded at stations exposed to the polluting point-source discharges from important industrial phosphate plants near El Jadida (S2-Jorf Lasfar) and Safi (S4-Jorf Lihoudi), which greatly exceeded the geochemical background values (Cd: 0.3 μg g−1 dry weight, Cr: 90 μg g−1, Cu: 45 μg g−1 and Zn: 95 μg g−1). All of the four trace metals were significantly correlated with each other, implying the same source of contamination and a similar pollution history. This was mainly derived from industrial waste generated by these huge phosphate industry plants. Meanwhile, results from hierarchical cluster analysis confirmed the findings from the correlations. This ecotoxicological evidence was primarily associated with untreated industrial discharge. The contamination Factor, degree of Contamination, and modified Degree of Contamination indices confirmed that these two stations were the metal contamination hotspots, and the most affected in this region, especially for Cd. Moreover, Pollution Load Index and Geo-accumulation Index reflected a spatial distribution of pollution following the decreasing sequence S4 > S2 > S1 > S6 > S3 > S5. Based on the Potential Ecological Risk Index, Cd concentrations indicated a moderate to very high potential ecological risk at all sampling stations, except at one pristine station S5 (Bhibeh). The spatial distribution of Mean-Effect Range Median-Quotient (M-ERM-Q) showed a negligible ecological risk at Cap Beddouza (S3) and Bhibeh. The mean values of Toxic Units (Σ TU) were found in the following decreasing order Cd > Cu > Cr > Zn, with a major contribution to the Σ TU coming from Cd (35.42%) and Cu (24.99%). Comparison of the current results with those found in other areas around the world revealed that the metal levels obtained here are in general low, except for Cd, which appeared to be in higher concentrations. Concentrations of Cd, Cr and Cu in sediments at S2 and S4 exceeded either the Threshold Effect Level of the Canadian sediment quality guidelines and Effect Range Low of the US National Oceanic and Atmospheric Administration, which demonstrated that these trace elements posed environmental risks while Zn appeared to present no environmental threat at all of the studied areas.

Baseline PAHs, N-PAHs and 210Pb in Segment Samples from Bodo Creek: Comparison with Bonny Estuary, Niger Delta

Polycyclic aromatic hydrocarbons (PAHs), the nitrogen-containing analogues (N-PAHs) and lead 210 (210Pb) were measured in 2-cm interval core segments from Bodo Creek to evaluate impact of oil pollution in the waterbody. PAHs and N-PAHs were measured by gas chromatography analysis with mass spectrometry detection, and 210Pb activity concentration was determined by alpha spectrometry measurement. Data shows that ƩPAHs and ƩN-PAHs ranged from 12,774.3–18,470.2 µg/kg and 524.0–672.2 µg/kg, respectively. Concentrations were found to increase with increase in depth (cm). Petrogenic PAHs predominated the surface sediment (with elevated levels of 2,3,6-trimethyl-naphthalene, phenanthrene and 1-methyl-phenanthrene), while pyrogenic-PAHs dominated the deeper segments (with high levels of pyrene, benzo[a]anthracene, chrysene and benzo[k]fluoranthene). For N-PAHs, benzo[h]quinoline, 4,7-phenanthroline and benzo[a]acridine recorded high values. Chemicals comparison with values measured from Bonny Estuary revealed greater PAHs contamination in the estuary, while N-PAHs recorded elevated values in the creek. 210Pb activity concentration in the creek showed relatively low activity compared to the estuary, and similar distribution with the aromatic hydrocarbons. The measured hydrocarbons were high and exceeded the Canadian sediment quality guidelines. However, there are concerns over toxic ratios > 70% and radioactivity (EPR-D-values) > 3 – 4.E ± 01 Bq measured in the polluted creek. This gives insight on the level of radioactivity, PAHs, N-PAHs and PAHs toxic ratios in Bodo creek which would be useful in future remediation studies and/or monitoring the ability of sediments to recover under natural conditions.

Occurrence of polychlorinated biphenyl congeners in marine sediment of Makran region, Chabahr bay, Iran

In this study, selected PCB congeners (IUPAC numbers 28, 52, 101, 138, 153, and 180) were quantified in 34 stations of Chabahr bay and around it in the Makran region of Iran. The sum of total PCB concentrations varied from below the detection limit to 485 ng kg−1 dry weight of sediment. Based on the Canadian Sediment Quality Guidelines, the effect of detected PCBs was negligible for aquatic organisms. According to the dominance of PCB 28 and 52 with average range of 62 to 100% of total PCBs, maritime transportation and atmospheric deposition appear to be the important source of PCBs in this region. Further, the presence of components of commercial products such as ClophenA50 appears to be one of the probable sources.

Assessment of the ecological and human health risks from metals in shrimp aquaculture environments in Central Java, Indonesia.

The occurrence and contamination level of seven important toxic metals (Cd, Cu, Co, Cr, Hg, Pb, and Zn) and three additional metals (Al, Fe, and Mn) in the water, sediment, and shrimp muscle in aquaculture areas located in Central Java, Indonesia, were investigated. The results suggest that the majority of metals have higher concentrations in the inlet followed by the outlet and ponds. Cd dissolved in the waters exhibited the highest level in Pekalongan (3.15 ± 0.33μgL-1). Although Pb was not detected in the water, it was detected in the sediment, and the concentration ranged from 7.6 to 15.40mgkg-1 dw. In general, the heavy metal concentrations in the sediments were found to decrease in the sequence Al > Fe > Mn > Zn > Cr > Cu > Co > Pb. Concentrations below the effects range low level based on the Canadian sediment quality guidelines were found for Cr, Cu, Pb, and Zn, whereas moderate sediment pollution (25-75mgkg-1 dw) was observed for Cr (all regions), Cu (except in the Pekalongan region), and Zn (Brebes and Tegal regions) according to the US EPA standard. The status of the waters was evaluated by calculating a pollution index derived mostly from Mn and Zn. The ecological risk (geoaccumulation index (Igeo), contamination factor (CF), pollution load index (PLI), and potential ecological risk index (ERI)) determined in the sediments indicated that all studied areas had low to moderate contamination. The concentrations of all metals in shrimp were generally below the maximum limits for seafood, except for Zn (in all stations), Pb, and Cr (Tegal and Pekalongan). The hazard index values for metals indicated that consuming shrimp would not have adverse effects on human health.

Comparative Investigation of Total, Recoverable and Bioavailable Fractions of Sediment Metals and Metalloids in the Lagos Harbour and Lagoon System

This study investigated and characterised concentration of some selected metals and metalloids (As, Cd, Cr, Cu, Co, Fe, Mn, Ni, Pb, Sn, V and Zn) present in surface sediments of the Lagos Harbour (LH) and associated Lagos Lagoon (LG) system using a combination of metal extraction and analytical methods within 26 sampling sites including a control (Apese Lagoon, APL). Sampling was carried out using a Van-veen grab sampler on three occasions (dry seasons 2013, 2014; wet season 2013). The total, recoverable and bioavailable fractions were measured separately by X-ray fluorescence (XRF), Aqua regia (AR) extraction with inductively coupled plasma optical emission spectrometry (ICP-OES) and 1 M hydrochloric acid (1 M HCl) extraction with inductively coupled plasma mass spectrometry (ICP-MS) analysis, respectively. Results were compared with National Oceanic and Atmospheric Administration (NOAA)/Canadian Sediment Quality Guidelines (CSQG) and geochemical spatial distribution maps. Threshold effect level (TEL) were exceeded by total concentration of Cu, Zn and recoverable As across the lagoons. Bioavailable As was below TEL while Ni was associated with the ports in the LH.

Receptor-mediated potencies of polycyclic aromatic hydrocarbons in urban sediments: comparisons of toxic equivalency risk assessment

The Klip River, flowing through South Africa’s most populated urban area—Soweto and Lenasia—is subject to various pollution and anthropogenic influences, including great concentrations of polycyclic aromatic hydrocarbons. The aims were to determine the aryl-hydrocarbon receptor-mediated potencies of the 16 priority polycyclic aromatic hydrocarbons in sediments of the Klip River, using chemical- and bio-analytical assessments of hazard, and to compare these results with international sediment quality guidelines. Sediment samples were collected from nine sites during the dry seasons of 2013 and 2014. Two sets of toxic equivalents were calculated from analytically obtained polycyclic aromatic hydrocarbon concentrations using: (1) 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalency factors and (2) relative potency factors for fish. The fraction of the sediment extracts containing polycyclic aromatic hydrocarbons was assayed with the H4IIE-luc reporter gene bio-assay, and the aryl-hydrocarbon receptor potency expressed as bio-assay equivalents. The bio-assay equivalents and tetrachlorodibenzo-p-dioxin equivalency factors were compared to Canadian sediment quality guidelines and of the three approaches, the bio-assay equivalents and the relative potency factors for fish proved the most protective. Results of this study are proof of the utility of combining biological analysis with instrumental analysis when predicting hazard. Even though there were instances where the bio-assay equivalents were orders of magnitude greater than the tetrachlorodibenzo-p-dioxin equivalency factors, the results still showed similar trends. It was concluded that hazard from aryl-hydrocarbon receptor-mediated potency to adversely affect aquatic organisms in the Klip River was relatively great, which indicated the need for further investigation into possible mitigations.

Identification of the highest potential human health and environmental hazard in contaminated sediment near the point sources in the northwest Persian Gulf

The overall goal of this work was to determine the concentration levels and the potential ecological risks of 30 polycyclic aromatic hydrocarbons in the Persian Gulf sediments, Iran. The study also predicted the bioaccumulation of PAHs using the Monte Carlo simulation. For these goals, 68 surface sediment samples were collected from the Persian Gulf in January 2017. Then, the experiments were performed with Soxhlet system, chromatographic column and GC-MS instrument. According to the Canadian Sediment Quality Guidelines, 35.29% of sampling sites exhibited high potential adverse biological effects and 79.41% of samples have a low probability of toxicity. The mean bioaccumulated concentrations of carcinogenic PAHs in the Persian Gulf were predicted as 207.78 ± 262.23, 116.06 ± 146.47 and 69.26 ± 87.41 ng g–1 for mollusks, shrimps and crabs, respectively. The mean Toxic Equivalency and Mutagenic Equivalent Quotient for sediments was 702.06 ± 1012.37 and 500.37 ± 665.71 ng g−1, respectively. The 95th percentile carcinogenic and non-carcinogenic risks calculated for children and adults were lower than the threshold values of 10−6 and 1.0, respectively, revealing no potential health risk. The highest potential risks for toxicity were observed at sampling sites close to the Nowruz oil field and Mahshahr petrochemical economic zone based on the highest TEQcarc and MEQcarc values in this area.