Effects Range Low Research Articles

Ecological and human health risk assessment of trace element pollution in sediments and five important commercial fishes of the Oman Sea

The distribution of trace elements in sediments and five commercially important fish species of the Oman Sea were assessed using an atomic absorption spectrometer to determine ecological and human health risk assessment. The ranges of trace elements concentration in sediments were: Cr: 5.42-68.94, Zn: 5.22-18.11, Cu: 1.44-4.87, As: 18.07-79.96, Cd: 0.10-1.27, Ni: 43.0-65.34 and Pb: 8.92-30.53 mg/kg dry weight. Cr, Zn, Cu, Cd and Pb were below the ERL (effects range low) and TEL (threshold effect level) values at all the sampling stations with rarely biological effects. Whereas, As and Ni were higher than ERL and TEL with occasionally biological effects. The patterns of trace elements bioaccumulation in the tissues of all species were: liver> skin> gill> muscle. A significant positive correlation suggests that trace elements accumulation in fish is determined by trace elements in sediments. Estimated Daily Intake (EDI) was significantly lower than the tolerable daily intake (TDI) value. Target Hazard quotient (THQ), total target hazard quotient (TTHQ) and target carcinogenic risk (TR) values indicated no hazard risk from fish consumption. Hence, the consumption of concerned species to people in the Oman Sea is safe.

Spatial distribution, source analysis, and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the sediments from rivers emptying into Jiaozhou Bay, China

Sediment samples had been collected from five major rivers into Jiaozhou Bay, China to study the spatial distribution, sources, and ecological risks of 16 priority polycyclic aromatic hydrocarbons (PAHs) in April 2018. Results showed that the contents of PAHs in the sediments from the five rivers were significantly different. The distribution trend was Dagu < Yang < Licun < Baisha < Moshui River. The contents of PAHs in the eastern rivers were higher than those in the western portions. The contribution rate of HMW-PAHs was higher than LMW-PAHs in the sediments, with the majority of PAHs being four rings. PAHs in sediments were mainly derived from combustion sources, including the incomplete combustion of petroleum, coal, and wood. The benzo[a]pyrene toxic equivalent method (TEQ) showed that Moshui River had a high risk of carcinogenesis. The evaluation results of Effects Range Low(ERL), Effects Range Median (ERM) and Mean- Effects Range Median-quotient (M-ERM-Q) showed that PAHs in the sediments of Moshui River would occasionally have adverse biological effects, as well as possible medium and low ecological risks. The ecological risks of PAHs in the sediments of the other four rivers were low. Hence, we should focus on and control the input of PAHs in the Moshui River.

Evaluation of Polycyclic Aromatic Hydrocarbon Pollution From the HMS Royal Oak Shipwreck and Effects on Sediment Microbial Community Structure

Despite many shipwrecks containing oil there is a paucity of studies investigating their impact on surrounding environments. This study evaluates any potential effect the World War II shipwreck HMS Royal Oak is having on surrounding benthic sediments in Scapa Flow, Scotland. HMS (Her Majesty’s Ship) Royal Oak sank in 1939, subsequently leaked oil in the 1960s and 1990s, and is estimated to still hold 697 tonnes of fuel oil. In this study, sediments were analysed, over a 17.5 cm depth profile, along a 50–950 m cruciform transect away from the shipwreck. Analysis of polycyclic aromatic hydrocarbons (PAHs) revealed low concentrations (205.91 ± 50.15 μg kg–1 of dry sediment), which did not significantly differ with either distance from the shipwreck or sediment depth. PAH concentrations were well below the effects-range low (ERL) for the OSPAR (Oslo/Paris convention for the Protection of the Marine Environment of the North-East Atlantic) maritime area. The average Pyrogenic Index, in sediments around HMS Royal Oak, was 1.06 (±0.34), indicating PAHs were pyrogenic rather than petrogenic. Moreover, analysis of sediment microbiomes revealed no significant differences in bacterial community structure with distance from the shipwreck, with extremely low levels of obligate hydrocarbonoclastic bacteria (OHCB; 0.21% ± 0.54%). Both lines of evidence suggest that sampled sediments are not currently being impacted by petrogenic hydrocarbons and show no long-term impact by previous oil-spills from HMS Royal Oak.

Trend analysis of heavy metals, Ni, Pb, Cd and As in marine sediments – A case study of ONGC Block (KG OSN 2009/2) in Krishna-Godavari Basin, Bay of Bengal

Heavy metals can be termed as conservative pollutants, introduce into the aquatic systems as a result of the weathering of soils and rocks, from under water volcanic eruption and other anthropogenic activities. Thereby it changes the natural concentration of metals in seawater resulting in a ten or even hundred fold increase near the source of an effluent discharge. While some metals like manganese (Mn), copper (Cu), iron (Fe) and zinc (Zn) are biologically important for marine life, others like Nickel (Ni), Lead (Pb), Cadmium (Cd), and Arsenic (As) are non-essential and become toxic at higher concentrations. Associated to particulate matters, heavy metals tends to stay in solution for a very long time, but they will end up in the sediments, Therefore concentrations in the sediments are often higher than those in solution. In the sediments, these particles may form an important secondary source of contamination, even after the primary source has disappeared. Therefore, there is a need for timescale monitoring of the levels of these metals in all the marine resources, so as to establish the trends that could be linked to anthropogenic activities. In this paper, the effect of E&amp;P activities of ONGC Block (KG OSN 2009/2) in Krishna-Godavari Basin, Bay of Bengal is studied, by carrying out a trend analysis of heavy metal concentration (60Ni, 208Pb, 111Cd, and 75As) in the sediments from this block. Sediments samples were collected from the ONGC Block (KG OSN 2009/2) using OSPAR commission guidelines and the heavy metal concentration values averaged out. These average values are used to analyze the trend for a period extending from 2015 up to 2019. In the years 2016, the pollution level recorded was minimum. Overall, from 2015 to 2019, 208Pb shows a decreasing trend line, but 60Ni, 111Cd, and 75As shows an increasing trend line. Albeit the increasing trend of 60Ni, 111Cd, and 75As concentration are a matter of concern, but all the values are below the ERL (effects range low) set by the National Oceanographic and Atmospheric Administration (NOAA), USA. Hence, it can be concluded that the oil field activity of ONGC in the Eastern Offshore has not made any significant impact on the marine environment, in terms of heavy metal pollution. A statistical analysis in terms of Relative Contamination Factors and Pollution Load Index has also been done in the paper.

Distribution, sources, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Daya Bay, South China.

In this study, the concentrations of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Daya Bay were determined and analyzed. Results showed that 16 PAHs were detected in all the samples, and the total PAH concentration ranged from 70.18 to 128.04 ng g-1, with an average of 103.17 ng g-1. The cyclic number distribution of PAHs in the sediments was mainly 4 and 5 rings. Six classic PAH ratios named Ant/(Ant + Phe), Fla/(Fla + Pyr), [InP/(InP + BghiP)], [BaA/(BaA + Chr)], BaA/BghiP, and LMW/HMW, and principal component analyses showed that the main source of PAHs in this region was combustion (biomass, coal, and petroleum combustion), and the secondary source was petroleum. The ecological risk analysis of PAHs by using effect range low/median method and mean effects range-median quotient method showed that all of PAHs are lower than the effect range low (ERL) level and the effects range-median quotient (M-ERM-Q) value of all stations is 0.0027-0.0067, with an average value of 0.0046. Thus, it can be seen that PAHs are at a low-risk level in surface sediments of Daya Bay.

Distribution, sources, and ecological risk assessment of polycyclic aromatic hydrocarbons in the sediments of Daihai Lake in Inner Mongolia, China.

Polycyclic aromatic hydrocarbons (PAHs) are typical toxic organic pollutants that can accumulate in sediments and may be toxic to aquatic organisms. In the present study, the contamination level, composition pattern, and sources of sixteen PAHs listed by the United States Environmental Protection Agency were investigated in surface sediments and a sediment core from Daihai Lake, which is located in a typical semiarid area of Inner Mongolia, China, and the ecological risk of these PAHs was assessed. The results show that the total concentration of PAHs in the surface sediments ranged from 204.6 to 344.5ng/g with an average value of 287.2ng/g and that compared with other aquatic systems, the level of PAHs in the sediments from Daihai Lake was low. However, a general upward trend was observed for the concentrations of PAHs in the sediment core, which might be related to the increase in human activities in the area. Moreover, the PAH concentrations were significantly positively correlated with the total organic carbon (TOC) content in the sediments, and it is thus inferred that TOC regulates the distribution of PAHs in Daihai Lake. Three-ring and four-ring PAHs were found to be predominant in all the sediment samples, and phenanthrene (Phe) was the most abundant compound. According to the composition of PAHs and the anthracene (Ant)/(Ant+Phe) or fluoranthene (Flt)/(Flt+pyrene (Pyr)) ratios, the PAHs in Daihai Lake mainly originated from the combustion of domestic coal, grass, and wood, and petroleum cannot be ignored as a source considering the growth of industry. Risk assessment based on a comparison of PAH concentrations and the effect range low (ERL) and effect range median (ERM) values demonstrated that acenaphthene (Ace) at 11 sites and fluorene (Flu) at 7 sites had occasional adverse biological effects.

Distribusi Spasial dan Analisis Risiko Ekologi Senyawa Polisiklik Aromatik Hidrokarbon (PAH) di Perairan Cilincing – Teluk Jakarta

&lt;p&gt;&lt;strong&gt;Spatial distribution and ecological risk analysis of Polycyclic Aromatic Hydrocarbons in Cilincing waters – Jakarta Bay&lt;/strong&gt;. Within a few decades, Polycylic Aromatic Hydrocarbon (PAH) pollution increases in marine environment in seawater, sediment, and organism. Generally, this pollutant comes from industrial and household waste, agricultural runoff, shipping activities, and input from atmospheric deposition. This study aims to determine the concentration, spasial distribution, source, and ecological risks analysis in Cilincing waters, Jakarta Bay. Samples of seawater, total suspended solid (TSS), and sediment were collected on April 2019 at ten stations. Samples were stored at 4&lt;sup&gt;o&lt;/sup&gt;C afterward analyzed in the laboratory. All samples were then extracted with dichloromethane and n-hexane solvents. They were then fractionated with n-pentane: dichloromethane, and the results were injected into a Gas Chromatography-Mass Spectrometer (GCMS) instrument. The highest concentration of PAH compounds in seawater, TSS, and sediment samples are 208.74 ng.L&lt;sup&gt;1-&lt;/sup&gt;; 5.90 ng.L&lt;sup&gt;1-&lt;/sup&gt;; and 63.63 ng.g&lt;sup&gt;1-&lt;/sup&gt; dry weight (dw) respectively. The highest spatial distribution of PAHs in seawater and TSS samples were detected in station 1, 9, and 10, whilst in sediment sample was in station 5 and 6. The ratio of ∑Low Molecular Weight (LMW)/∑High Molecular Weight (HMW), Fluo/(Fluo + Pyr), and An/(An + Phe) revealed that the source of PAH pollution dominated from pyrogenic, especially petroleum combustion from vehicle engine. The total concentration of ∑PAH-9 in sediment was 31.21 ng.g&lt;sup&gt;1-&lt;/sup&gt;dw which was lower than Effects Range Low (ERL), Effects Range Median (ERM), Threshold Effect Levels (TEL), and Probably Effect Levels (PEL) values referred to sediment quality guideline. These results were indicated low potential of causing an adverse biological effect.&lt;/p&gt;

Human health and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in sediment of Woji creek in the Niger Delta region of Nigeria

Human health risk was determined by assessing risk due to dermal contact with the sediment and Benzo [a] pyrene -equivalent concentrations (BaP-TEQ- carcinogenic equivalents and BaP-MEQ- mutagenic equivalents). Ecological risk of PAHs in the sediment was determined by comparing PAHs concentrations to effect range low (ERL) and effect range median (ERM); to estimate the risk associated with the combined effects of PAHs, mean ERM quotient (mERMq) was calculated. Results revealed that hazard index (HI) due to dermal contact of the sediment for adults are 596 and 73.84 for children. Similarly, cancer risk for adults was all >10−1 and was within 10−3 ≤ 10−1 for children, for every compound; the sum of cancer risk for adults and children were 8.26 and 1.022 respectively.

Assessment of element concentrations in surface sediment samples from Sığacık Bay (eastern Aegean)

Concentrations of Al, Fe, As, Co, Cr, Cu, Mn, Ni, Pb, Zn, Hg, and organic carbon, and grain size distribution were investigated in the surface sediments of 7 sampling stations in the Sığacık Bay (western Anatolia) in December 2016. At all of the sampling stations, the concentrations of Pb, Ni, Cr, and As were higher than the average shale values. The highest concentrations of Pb, Cu, Zn, As, and Hg were found at stations near Doğanbey Cape. The possible sources of pollution were evaluated using several parameters: the enrichment factor (Ef), contamination factor (Cf), and contamination degree (Cd). The Ef values ranged between 0.12 and 7.61 in the bay. The high Ef (&gt;1.5) values of Pb, Cu, Ni, Co, and As were assessed to explain the influence of anthropogenic sources. Additionally, the Cf values ranged from 0.46 to 5.61, while the Cd values ranged from 11.69 to 20.45 in the study area. The Cd of the Cr and As ranged between moderate and considerable, and the highest Cd was measured at stations near Doğanbey Cape. Additionally, the pollution degrees were assessed using sediment quality guidelines (SQGs), the threshold effect level (TEL), the probable effect level (PEL), the effects range low (ERL), and the effects range median (ERM). It was demonstrated that the sediments were generally heavily polluted with Cr and Ni, and moderately with Pb and Cu, according to the numerical SQGs. The concentrations of Pb, Cr, Cu, Zn, and Ni were above the TEL, while Cr and Ni were also higher than the PEL levels for all of the samples.

Residue in the Mangrove Surface Sediment with the Feasibility of Phytoremediation Application

The present study investigated heavy metal contaminations in the mangrove surface sediment of Rayong coast, Thailand. Sediment samples were collected from 5 locations with each 3 sampling sites and analyzed for heavy metal (Cu, Pb, Cr, Zn and Mn) contents using microwave digestion and MP-AES. The results revealed that concentrations of the heavy metals ranged from 10.54-66.53 mg/kg for Cu, 21.71-116.40 mg/kg for Pb, 21.21-66.66 mg/kg for Cr, 17.67-397.01 mg/kg for Zn and 46.55-1609.53 mg/kg for Mn. Although, the concentrations of Cu, Pb and Zn in surface sediments exceed the effects range low (ERL), did not exceed the effects range median (ERM) of the guidelines. Meanwhile, the feasibility of treating a heavy metal-contaminated soil via mangrove phytoremediation showed the removal efficiency of heavy metals contaminated in sediment occurred in descending order of Mn>Pb>Cr>Cu>Zn (93.11, 80.42, 70.03, 67.09 and 52.50 %, respectively). After spiked more concentration of heavy metals, decreasing removal efficiency was occurred in all treatments that might be caused of the higher heavy metal intake. Beside of these contaminated conditions, the mangrove plants can still survived after 30 days. Which indicated the tolerated to the high level of heavy metals.

Distribution, sources and potential toxicological significance of polycyclic aromatic hydrocarbons (PAHs) in the south west coast of Kerala, India

To assess the potential eco-risk of PAHs along the study sites (Site1 – characterized by tourist influx and a religious pilgrimage centre resulting in domestic and organic pollution and massive foot traffic. Site 2 – Neendakara characterized by oil pollution since it is a fishing harbour and port with large scale motor boat / trawler traffic. Site 3 –characterized by inorganic pollution of heavy metals, trace metals, polycyclic aromatic hydrocarbons and organochlorins due to discharge of effluents from KMML Titanium dioxide industrial factory. Site 4 –control site since it is presumed to be near pristine being post tsunami and lacking any industrial / agricultural enterprise in the vicinity. The concentrations of N, B (a) A, Fl, ACN, and Ph cases were higher than effects range low (ERL) values, lower than the effects range median (ERM) values, except for Naphthalene and Acenaphthene. At site 2, the sampling areas are found to be stagnant with limited water circulation. Woefully, without attaining any pre-treatment on the issue, the regional industries and shipping harbor are still discharging their wastes into the area, resulting in high ∑ PAH concentration. An alarming fallout of the study is that site 4 also recorded appreciable concentrations of PAHs in the sediment, though it was found negligible in the water column. These results indicated that pessimistic eco-risks are likely to occur, although with a likelihood of 50% effects in this area. However, the remaining compounds were recorded below ERL values, which revealed the low risk of biological impairments. The study has disclosed various concentrations of PAH pollutants of low, moderate, and very high levels from the study sites signaling, effective sustainable management measures, and as a first step for long-term goals, the evaluation of water and sediments along the Kerala coastal ecosystem is recommended.

Spatial distribution, fractionation and ecological risk assessment of potentially toxic metals in bottom sediments of the Zarivar freshwater Lake (Northwestern Iran)

Freshwater lakes are one of the most vulnerable ecosystems to environmental contamination. This study was initiated to assess the spatial distribution, fractionation, ecological risk of selected potentially toxic metals (Pb, Zn, Cu, Cr, and Ni) in bottom sediments of the Zarivar lake, the second largest freshwater lake in Iran. The results revealed that Pb, Zn and Cu had the high spatial variability (coefficient of variation >50) across the sampling sites and their maximum concentrations (197.5 for Pb, 198.7 for Zn and 185.6 mg/kg for Cu) were observed in sampling sites from the northern, western and eastern margins of the lake. Cr and Ni with average concentrations of 28.3 and 31.38 mg/kg respectively, exhibited low spatial variability (coefficient of variation <20) and their concentrations did not vary significantly among the sampling sites. Based on the redundancy analysis (RDA), sediment organic matter was strongly correlated with Pb, Zn and Cu while Fe2O3 and Al2O3 showed a positive correlation with Ni and Cr. The calculated average enrichment factor (EF) and geoaccumulation index (Igeo) showed that the contamination level of metals can be arranged in the following order of Pb> Cu > Zn > Cr > Ni. Results from the modified five-step sequential extraction analysis indicated that 40 % of total Pb and Zn were associated with the reducible fraction, 45 % of Cu with the oxidizable fraction and more than 80 % of total Ni and Cr were retrieved from the residual fraction. It was also noticed that Pb, Zn and Cu were more incorporated into the non-residual fractions in the sites with a higher total concentration of these metals, suggesting that both total concentration and fractionation behavior of metals were influenced by their potential sources in the study area. Ecological risk assessment using the potential ecological risk index (PERI) and the modified potential ecological risk index (MPERI) showed that sediments from the eight sampling sites pose a moderate to considerable risk whereas the other sites had low ecological risk level. In comparison to sediment quality guidelines (SQGs), the effects range low (ERL) and probable effect level (PEL) values for Pb, Cu and Zn were exceeded at some sampling sites while Ni and Cr concentrations were found to be below or close to their SQGs values at all the sampling sites. Pb was generally identified as the contaminant of most concern in the study area. Taking into account the results obtained from the fractionation study and the source contribution estimate, it can be inferred that the Pb, Zn and Cu with the average contribution of 79, 54 and 64 % respectively, were mainly derived from anthropogenic sources whereas Ni and Cr with the estimated contribution of 80 and 89 % were predominately from the lithogenic source.

English

This study was undertaken to re-evaluate the heavy contamination level of Bagega community which recorded acute lead poisoning in 2010 and was reclaimed between 2010 and 2012. The levels of the following heavy metals (Zn, Pb, Hg, As and Cd) was measured in sixteen sampling sites around Bagega and its environs using Varian AA240 Atomic Absorption Spectrophotometer. The assessment of pollution was achieved using the Effect Range Low (ERL) and Effect Range Median (ERM), pollution index (PI) and geoaccumulation index (Igeo). The result revealed that the soil samples within Bagega community recorded concentration below the geochemical background for analyzed heavy metals. Soils around abandoned gold mine fields show high concentration of Pb, Cd, Hg and As. Based on the ERL and ERM values, Bagega and Topeki communities recorded low to high contamination of heavy metals, while abandoned mine fields and within farmland recorded moderate to very high contamination. Pollution index analysis show insignificant contamination within Bagega and Topeki communities while farmland and abandoned mining axis recorded significant contamination of Pb, Hg and As. The Igeo indicates that relatively higher levels of Pb, Cd and Hg was recorded; suggesting heavy metalcontamination. Generally, soils around Bagega community were found to range from uncontaminated to moderately contaminated. Though land reclamation within Bagega community may have reduced heavy metal levels, the study reveals high risk of heavy metals toxicity to inhabitants due to farming of arable land around mining areas. Keywords: Lead poisoning, risk, toxicology, effect range low, effect range median, pollution index, geoaccumulation.

Coking wastewater treatment plant as a sources of polycyclic aromatic hydrocarbons (PAHs) in sediments and ecological risk assessment

The spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was investigated in sediments of Maba River, a major tributary of Beijiang River (South China). A total of 13 samples from Maba River and its tributary, Meihua River, were analyzed for 16 PAHs. The total concentration of 16 PAHs (ΣPAH) in high and low water period ranged between 47.61 to 25480.98 ng g−1, with a mean concentration of 4382.98 ng g−1, and 60.30 to 15956.62 ng g−1 with a mean concentration of 3664.32 ng g−1, respectively. Three-ring and four-ring PAHs were the dominant species. It was concluded that a pattern of pyrolytic input as a major source of PAHs in sediments through the molecular ratio method for the source identification, such as HMW/LMW PAHs, Flu/(Flu+Pyr), IcdP/(IcdP+BghiP) and BaA/(BaA+Chr). It is suggested that the pollution emission from the iron and steel plant might be the most important sources of PAHs into Maba River water system. The threat of PAHs contamination to biota of the river was assessed using effect range low (ERL) and effect range median (ERM) values, which suggested that PAHs in Maba River and its tributary had already caused ecological risks.

The impact of seasonal waterlogging on the depth-wise distribution of major and trace metals in the soils of the eastern Ganges basin

In the Ganges River basin, studies related to the depth-wise distribution of major and trace metals in these floodplain soils (seasonally waterlogged and non-water logged) have been limited thus far. This research attempts to address this gap in the current literature by geochemical and geostatistical analyses and assessment of soil pollution. Significant concentrations of major and trace metals in these soils could greatly impact the health of local communities. Soil samples were collected in the eastern Ganges basin from a shallow seasonally waterlogged (SWL) site and a shallow non-waterlogged (SNWL) site up to 3 m below ground level (mbgl) and a deep seasonally waterlogged (DWL, up to 14 mbgl) site. The soils were analysed to determine soil texture and the concentration of major oxides and trace metals with increasing depth. The average concentration of trace metals (Ba, Rb, V, Cr, Ni, As, Pb, Ga, Co, Cs, Nb, W) and major oxides (Al2O3, Fe2O3, K2O, MgO) are higher in the SWL soil than the SNWL soil. A higher concentration of metals generally occurred in the upper soil layers due to the adsorption of elements by the silt and clay fractions. Soil pollution assessment indicated that W, As, Sb and Cu are enriched in both the waterlogged and non-waterlogged soils, while Sn is enriched in the SNWL soil profile only. The values obtained for the geochemical indices, which were geoaccumulation index (Igeo), enrichment factor (EF), contamination factor (CF) and pollution load index (PLI), were relatively higher in the top layers for the SWL and DWL sites. Based on effects range-low (ERL) and effects range-median (ERM) values, the possibility of adverse biological effects caused by the metals is highest for Ni in the DWL site, Cr and Ni in the SWL site and Cu in the SNWL site. Pearson’s correlation and principal component analysis (PCA) justify the role of soil texture, phyllosilicates, Fe-Mn oxyhydroxides and carbonates in the occurrence and distribution of metals in these soils. Seasonal waterlogging facilitates the dissolution and precipitation of oxides, hydroxides, carbonates and adsorption/desorption processes, leading to the accumulation and retention of more trace metals in the soil. This study implies that the silt and clay present in the vadose zone may act as a filter to protect local groundwater aquifers from metal contamination. This work provides insights on the behaviour of major and trace metals in the soil depth profile of seasonally waterlogged floodplain soil that is used for local agriculture.

Occurrence and distribution of anthropogenic persistent organic pollutants in coastal sediments and mud shrimps from the wetland of central Taiwan.

Sediment profile and mud shrimp (Austinogebia edulis) from the coastal wetland of central Taiwan in 2017 and 2018 were analyzed for concentration, source, and composition of persistent organic pollutants (POPs) including polycyclic aromatic hydrocarbon (PAHs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides (OCPs; DDT and HCB), and polychlorinated biphenyls (PCBs). Sediment profiling indicated PAH concentrations reaching 254.38 ng/g dw in areas near industrial areas and PAH concentrations of 41.8 and 58.42 ng/g dw in sampling areas further from industrial areas, suggesting that the determining factor for spatial distribution of POPs might be proximity to contaminant sources in industrial zones. Based on molecular indices, PAHs were substantially of both pyrolytic and petrogenic origins. The main sources for PCBs were Aroclor 1016 and 1260 and the congener BDE-209 was the dominant component among PBDE congeners. While we were unable to obtain live mud shrimp samples from the heavily contaminated areas, in samples from less contaminated areas, the risk assessment on mud shrimp still illustrated a borderline threat, with DDT concentrations almost reaching standardized values of Effects Range-Low (ERL). Bioaccumulation factors for DDTs and PCBs (17.33 and 54.59, respectively) were higher than other POPs in this study. Further study is essential to assess and understand the impact of these chemicals on the wetland ecosystem near this heavily industrialized area.

Evaluation of Total Mercury in Sediments of the Descoberto River Environmental Protection Area-Brazil.

To evaluate the total mercury accumulation (THg) in the Descoberto river basin environmental protection area (DREPA), nine sediment and water samples were collected from the Descoberto reservoir (lentic environment), and 23 in its tributaries (lotic environment), which are located in a densely urbanized area within the Descoberto river watershed, Brazil. The following physicochemical parameters of water were determined: dissolved oxygen (DO); hydrogen potential (pH); total dissolved solids (TDS); nitrate (NO3−); chloride (Cl−); temperature (T); sulfate (SO42−), and in sediment, the concentration of total mercury (THg) and volatile material (VM) was determined. THg concentrations in sediments showed a significant difference (p = 0.002) between tributaries (0.03 µg g−1 ± 0.02) and reservoir (0.08 µg g−1 ± 0.04), indicating accumulation in the lentic environment. Most of the results evaluated for ecotoxicological risks presented values below the concentration, at which adverse effects would rarely be observed, ERL (effects range low). However, in relation to the enrichment factor (EF), applied to identify the anthropogenic contribution, the results indicate that most of the samples are moderately polluted through atmospheric deposition due to vehicular traffic and agriculture. These results show that the likelihood of methylation in the lentic environment is higher than in the lotic environment.

Spatial distribution, environmental risk and sources of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in surface sediments-northwest of Persian Gulf

In the current study, environmental risk, potential sources and spatial distribution of heavy metals and polycyclic aromatic hydrocarbons (PAHs) were investigated in the sediments of Musa Estuary, the largest Estuary in the Persian Gulf. A total of 68 surface sediment samples were collected and analyzed for heavy metals and PAH concentration using inductively coupled plasma mass spectrometry (ICP-MS) and High-Performance Liquid Chromatography (HPLC). Enrichment factor (EF) and ecological risk (E) calculation revealed the highest contamination and risk for Hg, mostly due to the activity of a petrochemical complex in the area. Also, most samples showed a mean probable effect level (PEL) quotient of 0.51–1.50, and a probable 49% toxicity. Pearson's correlation coefficient and principal component analysis (PCA) indicated the same (anthropogenic) origin for Cu, Hg, Pb and Zn. Five-six ring PAHs are dominant in sediments, and most studied compounds showed higher concentrations than their effect range low (ERL) and effect range median (ERM). Moreover, the highest toxic equivalent (TEQ) and ecological risk were observed in the main treatment lagoon. PAH diagnostic ratios and PCA revealed both petrogenic and pyrogenic sources for these compounds, and calculated mass inventory (I) values indicated a relatively high potential of the sediments (0.2–12.28 tons) for contaminating the marine environment. The results indicated that the wastewater treatment has good efficiency in reducing contaminant levels, as Mann-Whitney U test results showed a significant difference in Ni, Cr, Hg and ∑PAH concentration between treatment lagoons and estuarine sediments.

Prevalence and Ecotoxicological significance of heavy metals in sediments of lower stretches of the Hooghly estuary, India

The concentration and distribution of selected eight heavy metals in five stations from lower stretches of the Hooghly estuary were studied to ascertain the level of anthropogenic contaminant loading resulting from the development of the region. Atomic absorption spectroscopy showed that the mean concentration of Fe, Zn, Cu, Ni, Pb, Cr, Cd and As (mg kg-1, dry weight,) ranged from 29950.70 – 39567.94, 61.45 – 98.83, 40.65 – 54.46, 25.44 – 42.78, 36.93 – 48.56, 29.07 – 46.35, BDL – 3.48 and 1.18 – 6.44 respectively. Pollution load index (PLI) and Index of geoaccumulation (Igeo) revealed overall low values but the enrichment factors (EFs) for Cd was typically high for three of the stations. Calculations based on Effect Range Low (ERL) and Threshold Effect Level (TEL) showed that the mean concentration of Cu, Ni and Cd and to some extent Pb exceeded these levels, indicating that there is chance of ecotoxicological effects on benthic organisms dwelling in this region. Inter-elemental relationship and cluster analysis revealed identical behavior of the elements during transport and distribution. The study will help to further the cause of environmental protection of this sensitive biorealm in conjunction with the need for development of the region.

Distribution, Geochemical Speciation, and Bioavailable Potencies of Cadmium, Copper, Lead, and Zinc in Sediments from Urban Coastal Environment in Osaka Bay, Japan

Due to proximity to the urban and industrial areas, coastal environments of the Osaka Bay have been continuously polluted with the human activities. Coastal sediments are known as large pool of contaminants including heavy metals. The Osaka Bay is no exception. However, recent information regarding the distributions, geochemical speciations, and risk evaluations of metals is limited for coastal sediments in the Bay. Therefore, we investigated the distributions, geochemical speciations, bioavailabilities, and conducted risk evaluations of the heavy metals, such as cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) in sediments collected from 25 sites of the urban coastal environment of Osaka Bay, Japan. We observed high concentrations of Zn (76–967 mg/kg dry weight; DW) followed by Cu (not detected; ND-399 mg/kg DW), Pb (ND-73 mg/kg DW), and Cd (0.2–2.9 mg/kg DW). A considerable fraction of Cd was exchangeable (ND-0.4 mg/kg DW) and carbonate-bound (0.03–0.4 mg/kg DW). Cu occurred predominantly in the organic material-bound fraction (ND-348 mg/kg DW). Both Pb and Zn occurred predominantly in the Fe-Mn oxide fraction, with concentration ranges of ND-41 mg/kg DW and 24–277 mg/kg DW, respectively. Comparison with the effect range low (ERL) and effect range median (ERM) revealed that Cd, Cu, and Zn contribute potential biological toxicities to the sediments of Osaka Bay. High bioavailable concentrations of Cd and Zn may have ecotoxicological significance, because these metals are potentially highly available, especially to the benthic organisms.