Effect Range Median Research Articles

Quality Evaluation and Study of Ecological Toxicity of Heavy Metals in Shadegan Wetland

Wetlands hold a principal position in storing food for primary producers, so they are not able to bear the pressure. The slightest disturbance, hence, may harm wetlands and cause detrimental effects. The present study aims at monitoring heavy metals and evaluation of the sediment quality index of Shadegan wetland in Iran. Thus, a sampling of surface sediments of the wetland was performed at ten stations with three replications; after the preparation of samples with aqua regia, the concentrations of heavy metals were measured by atomic absorption spectroscopy. The quantification of sediment pollution using the contamination factor, contamination degree, pollution load index, ecological risk assessment index, and ecological toxicity of heavy metals in the region were all carried out. The results of Cf and Cd showed that the degree of zinc and copper contamination is low; however, the degree of lead contamination is moderate. Moreover, the obtained PLI was less than 1 indicating a lack of sediments contamination with heavy metals. The RI was less than 150 indicating a low risk of contamination. In addition, comparing the concentrations of elements with National Oceanic and Atmospheric Administration and Sediment Quality Guidelines showed slightly toxic and non-toxic sediments, respectively. Finally, based on a mixture of effect range median, all sediment samples are placed in the first category with less than 12% toxicity probability. Copyright © 2017 Journal of Contemporary Urban Affairs.

Polychlorinated biphenyls (PCBs) in recreational marina sediments of San Diego Bay, southern California

Polychlorinated biphenyl (PCB) concentrations were determined in surface sediments from three recreational marinas in San Diego Bay, California. Total PCB concentrations ranged from 23 to 153, 31–294, and 151–1387ngg−1 for Shelter Island Yacht Basin (SIYB), Harbor Island West (HW) and Harbor Island East (HE), respectively. PCB concentrations were significantly higher in HE and PCB group composition differed relative to HW and SIYB, which were not significantly different from each other in concentration or group composition. In marina sediments there was a predominance (82–85%) of heavier molecular weight PCBs with homologous groups (6CL-7CL) comprising 59% of the total. In HE 75% of the sites exceeded the effect range median (ERM), and toxicity equivalence (TEQ dioxin-like PCBs) values were higher relative to those of HW and SIYB, suggesting a potential ecotoxicological risk.

Single and combined metal contamination in coastal environments in China: current status and potential ecological risk evaluation.

With the development of industrialization and urbanization, metal and metalloid pollution is one of the most serious environmental problems in China. Current contamination status of metals and metalloid and their potential ecological risks along China's coasts were reviewed in the present paper by a comprehensive study on metal contents in marine waters and sediments in the past few decades. The priority metals/metalloid cadmium (Cd), mercury (Hg), chromium (Cr), lead (Pb), and arsenic (As), which were the target elements of the designated project "Comprehensive Prevention and Control of Heavy Metal Pollution" issued by the Chinese government in 2011, were selected considering their high toxicity, persistence, and prevalent existence in coastal environment. Commonly used environmental quality evaluation methods for single and combined metals were compared, and we accordingly suggest the comprehensive approach of joint utilization of the Enrichment Factor and Effect Range Median combined with Pollution Load Index and Mean Effect Range Median Quotient (EEPME); this battery of guidelines may provide consistent, internationally comparable, and accurate understanding of the environment pollution status of combined metals/metalloid and their potential ecological risk.

Assessment of Pollution, Sources, and Risks of Polycyclic Aromatic Hydrocarbons in Soil from Urban Parks in Xi'an City, China

A total of seventeen surface soil samples were collected from urban parks in Xi'an city. The concentration of sixteen priority polycyclic aromatic hydrocarbons (PAHs) were analyzed by high performance liquid chromatography (HPLC). In addition, the composition, source, pollution level and a risk assessment of PAHs in surface soil of park were evaluated. The results showed that the total concentrations of sixteen PAHs ranged from 0.362 to 1.336 μg·g-1, with a mean value of 0.591 μg·g-1. The concentration of seven carcinogenic PAHs (Σ7CPAHs) ranged from 0.051 to 0.528 μg·g-1, with a mean value of 0.181 μg·g-1. Compared to the ΣPAHs levels of other cities of China, the ΣPAHs in park surface soils in Xi'an are relatively low. PAHs in the soil samples were dominated by low molecular weight PAHs with 2 and 3 rings. The results of source analysis showed that the PAHs in park surface soil mainly originated from the combustion of fossil fuels, however, the source of PAHs in some samples is complex and from mixed sources, such as oil spills, oil burning, and incomplete combustion of coal and biomass. The ecological risks of PAHs in the surface soil were evaluated according to the soil quality guidelines to be ERL (effects range low) and ERM (effects range median), and these results showed that all samples, in general, were polluted. However, the potential ecological risks of PAHs were at a low level. The incremental life cancer risk (ILCR) assessment indicated that health risks for children and adults were both in a permissible range, however, the risks for children exposed to the soil were considerably higher than for adults. Dermal contact was the main exposure pathway that resulted in the relatively higher risk, followed by ingestion.

Heavy metal fractionation and ecological risk implications in the intertidal surface sediments of Zhelin Bay, South China

Intertidal surface sediments collected from Zhelin Bay, the largest mariculture base of eastern Guangdong Province of China, were analyzed for total metal concentrations and chemical speciation. Average total metal concentrations (mg/kg) were 0.063 (Cd), 35.69 (Pb), 23.07 (Cr), 7.50 (Ni), 7.95 (Cu), 74.95 (Zn), and 751.32 (Mn). Concentrations of Cd, Cu, Zn, and Mn were significantly higher than the corresponding background values of Zhelin Bay. All studied metals were dominated by residual fractions, whereas the second relatively higher average portions of Cd (24.10%) and Mn (15.17%) were strongly associated with the acid-soluble fraction. Overall, the intertidal surface sediments of Zhelin Bay were only slightly polluted based on the pollution load index (PLI), with a 21% probability of toxicity based on the mean effects range–median quotient. The metals Cd and Mn posed medium to high risk levels based on the method of risk assessment code (RAC).

Distribution characteristics, sources, and ecological risk assessment of polycyclic aromatic hydrocarbons in sediments from the Qinhuangdao coastal wetland, China

Sixteen USEPA priority polycyclic aromatic hydrocarbons (PAHs) were analyzed by gas chromatography–mass spectrometry. Twenty-three samples were collected from the surface sediments of Qinhuangdao coastal wetlands in this survey. This research aimed to identify the PAHs contamination level, composition pattern, pollution sources, and assess the ecological risk of PAHs. The results showed that the sum of PAH concentrations ranged from 341.61ng/g to 4703.80ng/g (mean: 1367.80ng/g), which is higher than the reported values for different wetlands worldwide. Five- and four-ring PAHs (34.08% and 32.97% of Ʃ16PAHs, severally) were predominant in the wetland sediment. The PAH source distribution in the surface sediments was determined using diagnostic ratio and PCA/MLR. Consequently, multiple PAH sources were found. Of the total PAHs, 70.01% was derived from vehicular emission, 25.73% from coke oven, and 4.26% from petroleum-based product spills. The effect range low/effect range median (ERL/ERM) values indicated a low toxicity risk level. However, the DBahA concentrations exceeded the ERL level, and even the ERM level, in some stations. The mean effects range–median quotient (M-ERM-Q) suggests a low ecological risk for the PAHs, but a medium risk for some stations in the coastal wetland sediments.

Spatial distribution and potential biological risk of some metals in relation to granulometric content in core sediments from Chilika Lake, India.

The article presents first systematic report on the concentration of selected major elements [iron (Fe) and manganese (Mn)] and minor elements [zinc (Zn), copper (Cu), chromium (Cr), lead (Pb), nickel (Ni), and cobalt (Co)] from the core sediment of Chilika Lake, India. The analyzed samples revealed higher content of Pb than the background levels in the entire study area. The extent of contamination from minor and major elements is expressed by assessing (i) the metal enrichments in the sediment through the calculations of anthropogenic factor (AF), pollution load index (PLI), Enrichment factor (EF), and geoaccumulation index (Igeo) and (ii) potential biological risks by the use of sediment quality guidelines like effect range median (ERM) and effect range low (ERL) benchmarks. The estimated indices indicated that sediment is enriched with Pb, Ni, Cr, Cu and Co. The enrichment of these elements seems to be due to the fine granulometric characteristics of the sediment with Fe and Mn oxyhydroxides being the main metal carriers and fishing boats using low grade paints, fuel, and fishing technology using lead beads fixed to fishing nets. Trace element input to the Chilika lake needs to be monitored with due emphasis on Cr and Pb contaminations since the ERM and ERL benchmarks indicated potential biological risk with these metals.

Ecological risk assessment of the Assaluyeh and Bassatin estuaries (northern Persian Gulf) using sediment quality indices

The Assaluyeh and Bassatin estuaries are located in Nayband Bay in the northern Persian Gulf, which faces long-term contamination and ecological risks. The research objectives of this study were designed to assess the ecological risks for human health and aquatic life and to evaluate impacts on environmental changes. Accordingly, an index analysis approach (using the contamination factor Cf, contamination degree Cd, potential ecological risk factor for individual metals Er, and potential ecological risk index for the basin, RI) in conjunction with the enrichment factor (Ef) and sediment quality levels (comprised of the threshold effect level, TEL, the probable effect level, PEL, and the effects range medium, ERM) were employed. In total, 147 sediment samples were tested to determine the content of organic matter and sulfur, as well as the concentrations of terrestrial and rare earth elements (REEs) and toxic metals, namely As, Cd, Cr, Cu, Ni and Hg, using inductively coupled plasma optical emission spectroscopy (ICP-OES). Gulf War oil spills in addition to oil and gas industries of the Pars South Especial Economic Zone (PSEEZ) were identified as the primary source of pollution in the study area. Gulf War contamination in the study area is highlighted by increased levels of Cd and RI at key horizons at 29 cm, 35 cm and 49 cm depth in the sedimentary columns of the Assaluyeh and Bassatin estuaries and Gavbandi River, respectively. Adverse effects of PSEEZ were revealed by increasing concentrations of toxic metals, P and S in the top 25–30 cm of the sedimentary columns. As a result, superficial sediments have been severely polluted by As, Ni, Cd, Cu and Cr, while the entire sedimentary column of the Assaluyeh estuary has been polluted by Hg. Based on the locations of the key horizons, the sedimentation rates of the previous decade at the Assaluyeh and Bassatin estuaries and the Gavbandi River were calculated to be 1.26 cm, 1.52 cm, and 2.13 cm, respectively. The capability of the index analysis approach, as well as of certain lanthanides, for highlighting environmental evolutionary trends in catchments in which extensive land use changes have occurred was demonstrated by the present investigation. The present research concluded that aquatic life and human health in the study area have been subjected to different ranges of hazards by toxic metals due to regional and local anthropogenic activities.

Source and Toxicological Assessment of Polycyclic Aromatic Hydrocarbons in Sediments from Imo River, Southeastern Nigeria

ABSTRACTPolycyclic aromatic hydrocarbons (PAHs) in sediments from the Imo River were analyzed to characterize their sources and assess their toxicity potential. The total PAH concentrations ranged from 409.43 to 41,198 ng/g dw with standard deviation of 4,796 ± 1,941. This wide variation reflects a localized contamination in the study area. The inadequacy in the use of traditional isomeric ratios for PAHs source characterization in sediment from tropical environments with shallow water depth of < 10 m was highlighted. A more robust principal component analysis coupled with n-alkanes unresolved complex mixture profiles approach to apportioned specific chemical signatures to samples was proposed. This approach differentiated stations that were heavily—from those that were mildly—impacted by oil and discriminated among stations that were influenced by pyrogenic sources. Effect range low (ERL) and effect range median (ERM) as well as risk quotients (RQwcs) revealed that only naphthalene, flourene, dibenzo(a,h)anthracene and low molecular weight PAHs were implicated with ERL and ERM exceeding the US National Oceanic and Atmospheric Administration's limit of concern and RQwcs > 1, as compounds of concern. The maximum toxicity equivalency value of 179.81 ng/g TEQscarc measured for the illegal petroleum refinery site indicated that this site requires some control measure and remedial action.

Seasonal variations of metal pollution and distribution, sources, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in sediment of the Al Hawizah wetland, Iran

ABSTRACTThe pollution of surface sediments of Al Hawizah wetland by metals and polycyclic aromatic hydrocarbons (PAHs) has been fully investigated. For determination of PAHs and metals concentration in sediments, eight sampling stations were selected in the study area. The results showed that the concentration of Mn is the highest, while the content of Cr is the lowest in both the seasons. The concentration of Cr and V is lower than mean crust content, while Cu concentration is more than mean crust content. The results obtained from Muller's geochemical index are indicative of range from uncontaminated to moderately contaminated. Based on potential ecological risk (RI), the Al Hawizah wetland had low ecological risk. The total PAHs concentrations ranged from 1071 to 15540 ng/g dry weight, with a mean of 9417.50 ng/g in the summer, while total amounts of PAHs in the winter ranged from 1542 to 17283 with a mean 10321.25 ng/g dry weight. The area of study was affected by pyrogenic and petrogenic sources (51.74 and 48.26%, respectively), in the winter. The concentrations of polycyclic aromatic hydrocarbons (PAHs) compounds were lower than effects range median (ERM) standard while were higher than effects range low (ERL) standard, except station 1, in both seasons.

Compositions, sources, and ecological risk assessment of poly-aromatic hydrocarbons in surface sediments along the Suez Gulf, Egypt

ABSTRACTPoly-aromatic hydrocarbons (PAHs) were analyzed in sediments collected from the Suez Gulf to evaluate the composition, sources, and ecological risk assessment. The highest concentration of total PAHs is recorded in sediments collected from Inlet of Suez Oil Petroleum Company (SOPC), followed by east of the Outlet of SOPC and Outlet of SOPC. While lower concentrations of total PAHs are detected in Suez Beach west of the Outlet of SOPC, from Inlet of Al-Nasr Petroleum Company (NPC). The ratio of ∑LPAHs/∑HPAHs was <1, revealing their pyrogenic sources. The concentration levels of PAHs in the current study were compared to the effect range low (ERL) and the effect range medium (ERM) values for all investigated stations was below the ERL except for Inlet of SOPC. This finding indicated that PAHs in the surface sediments of the studied area have adverse biological effects, which may cause severe adverse biological and acute effects. The high levels of BaP equivalent (BaPE) values east of the Outlet of SOPC indicate that PAHs have relatively high toxicity among all sites. The toxic equivalent (TEQcarc) values of the sediment samples varied from 0.1883 to 1449.286 ng/g TEQ, with the mean value of 144.295 ng/g TEQ; the higher total TEQcarc values were found at 50 m east of the Outlet of SOPC: 1449.286 ng/g TEQ.

Assessment and source identification of pollution risk for touristic ports: Heavy metals and polycyclic aromatic hydrocarbons in sediments of 4 marinas of the Apulia region (Italy)

The Apulia region in Italy has the longest Adriatic coastline; thus, maritime tourism is the driving force for its economic development. Pollution risk for four representative touristic ports of the region was assessed by determining the concentrations of 10 metals, 16 polycyclic aromatic hydrocarbons (PAHs) congeners, and the main nutrients. The cumulative mean Effects Range–Median quotient (mERMq) was used to assess the hazard degree, while the distribution patterns and content ratios of different PAH sediment concentrations were investigated to identify the pollution sources. Principal component analyses indicated an anomalous pollution trend for one of the small touristic ports assessed; this trend emerged from contamination by heavy metals and PAHs to a larger extent than expected, considering the main activity in this port, especially in its inner basin. The reason of this anomaly is thought to be the hydrodynamic and/or other stress factors.

Ecological risk assessment of trace metal accumulation in sediments of Veraval Harbor, Gujarat, Arabian Sea

In this study, different types of indices were used to assess the ecological risk of trace metal contamination in sediments on the basis of sediment quality guidelines at Veraval Fishery Harbor. Sediment samples were collected from three sectors in pre-, post-, and monsoon seasons in 2006. Trace metal concentrations were higher in the inner sector during post-monsoon, and it showed the highest statistical significance (p<0.01) among the stations. Pollution load index was higher than unity, indicating alternation by effluent discharge from industries. Enrichment factor and geo-accumulation index showed that Cd, Pb, and Zn were enriched in the northern part of the harbor and Pb had accumulated in the harbor sediment. The ecological risk assessment index revealed that Ni, Zn, and Pb were higher than the effect range median values, indicating their potential toxicity to the aquatic environment in the Veraval Harbor. Hence, the harbor is dominated by anthropogenic activities rather than natural process.

Radionuclides (210Po and 210Pb) and Some Heavy Metals in Fish and Sediments in Lake Bafa, Turkey, and the Contribution of 210Po to the Radiation Dose.

The pollution level of Lake Bafa was investigated by collecting fish samples {Dicentrarchus labrax (sea bass), Liza ramada (mullet) and Anguilla anguilla (eel)}, surface sediment, and core samples. In all these samples, 210Po and 210Pb concentrations were estimated, and total annual dose rates were obtained for each species. Some heavy metal (Cr, Ni, Pb, Cd, Mn, Fe, and Zn) concentration levels were obtained for the fish and a core sample. The sediment mass accumulation rate was found to be 3.27 g·m−2·day−1 (0.119 g·cm−2·y−1) from a core sample. The heavy metal concentrations in the vertical profile of samples from the core were also observed. The measured concentration of Zn, Pb, Cd, and Cr were between the ERL (effects range low) and ERM (effects range median) limits, while Ni concentrations were higher than the ERM limit. The observed concentrations of Cd, Pb, and Zn in fish samples did not exceed the limits in accordance with Turkish Food Regulations. Further, the maximum effective dose equivalent of 210Po in the area was found to be 1.169 µSv·y−1.

Spatial distribution of trace elements in the surface sediments of a major European estuary (Loire Estuary, France): Source identification and evaluation of anthropogenic contribution

Assessing the extent of metal contamination in estuarine surface sediments is hampered by the high heterogeneity of sediment characteristics, the spatial variability of trace element sources, sedimentary dynamics and geochemical processes in addition to the need of accurate reference values for deciphering natural to anthropogenic contribution. Based on 285 surface sediment samples from the Loire Estuary, the first high-resolution spatial distributions are presented for grain-size, particulate organic carbon (POC) and the eight metals/metalloids identified as priority contaminants (Cd, Zn, Pb, Cu, As, Cr, Ni, Hg) plus Ag (an urban tracer). Grain-size and/or POC are major factors controlling the spatial distribution of trace element concentrations. The V-normalized trace metal concentrations divided by the V-normalized concentrations in the basin geochemical background showed the highest Enrichment Factors for Ag and Hg (EF; up to 34 and 140, respectively). These results suggest a severe contamination in the Loire Estuary for both elements. Intra-estuarine Ag and Hg anomalies were identified by comparison between respective normalized concentrations in the Loire Estuary surface sediments and those measured in the surface sediments at the outlet of the Loire River System (watershed-derived). Anthropogenic intra-estuarine Ag and Hg stocks in the uppermost centimetre of the sediment compared with rough annual fluvial flux estimates suggest that the overall strong Enrichment Factors for Ag (EFAg) and and Hg (EFHg) in the Loire Estuary sediments are mainly due to watershed-derived inputs, highlighting the need of high temporal hydro-geochemical monitoring to establish reliable incoming fluxes. Significant correlations obtained between EFCd and EFAg, EFCu and POC and EFHg and POC revealed common behavior and/or sources. Comparison of trace element concentrations with ecotoxicological indices (Sediment Quality Guidelines) provides first standardized information on the sediment quality in the Loire Estuary. The overall mean Effect Range Median quotients (m-ERM-q) results suggested that the Loire Estuary is mainly characterized by slightly toxic sediments even if ecotoxicological impacts have been previously reported on biota.

Health risk assessment and source apportionment of PAHs in industrial and bitumen contaminated soils of Kermanshah province; NW Iran

A comprehensive study conducted for investigating the presence of polycyclic aromatic hydrocarbons (PAHs) in bitumen contaminated (BC) and industrial contaminated (IC) soils of Kermanshah province to evaluate their sources and health risk assessment. Forty-two surface soil (0-30 cm) samples were collected and analyzed for 16 PAHs. The total PAHs concentrations, show a mean value of 31.33 mg/kg and 56.31 mg/kg, ranging from 7.35 to 291.38 mg/kg and 6.59 to 662.83 mg/kg in BC and IC soil samples respectively. Positive matrix factorization model (PMF) was used to investigate the source apportionment of PAHs. PMF analysis identified four sources of PAHs as; fossil fuel combustion and unburned petroleum (28.76%), biomass/coal burning (23.55%), vehicular emissions (23.67%) and creosotes (24.01 %) in BC soils and biomass combustion (44.11%), unburned petroleum and coal combustion (17.54%), fossil fuel combustion (19.02%) and creosotes (19.32 %) in IC soils. Ecological risk assessment of PAHs showed that all of the PAHs levels are higher than the effects range low (ERL) values, except for benzo( a)anthracene. Three rings and fluoranthene of the PAHs in IC soils and Nap, Acy, Ace, Phe, Ant, Flt and DBA in BC soil samples reveal higher concentrations than the effects range median (ERM) values. Benzo( a)pyrene equation (BaPeq) values indicate that the carcinogenic potency of PAHs should be given more awareness due to impending environmental risk in the study area. The total incremental life time cancer risk (ILCR) of exposure to PAHs is 9.21×10-3 for adult and 9.54×10-3 for children in BC soil samples and 1.13×10-2 for adult and 1.17×10-2 for children in IC soil samples. Estimated results of ILCR indicate that soil samples are potentially exposed to high cancer risk via both ingestion and dermal contact.

Ecological and health risk-based characterization of agricultural soils contaminated with polycyclic aromatic hydrocarbons in the vicinity of a chemical plant in China

Polycyclic aromatic hydrocarbons (PAHs) from chemical plants can cause serious pollution of surrounding agricultural soils. A comprehensive study of agricultural soils was conducted in the vicinity of a chemical plant in China to characterize the soil PAH concentration, as well as their composition and sources. Human health and a screening–level ecological risk assessment were conducted for PAH contamination in agricultural soils. The results showed that the total concentrations of 16 priority PAHs ranged from 250.49 to 9387.26 ng g−1, with an average of 2780.42 ng g−1. High molecular weight PAHs (four to six rings) were the dominant component, accounting for more than 60% of all PAHs. Principal component analysis (PCA) and positive matrix factorization model (PMF) suggested that diesel emissions, coal combustion, coke ovens, and fuel combustion and gasoline emissions were the main sources of PAHs in agricultural soils. The ecological risk assessment results based on the effects range–low (ERL), the effects range–median (ERM), and the ecological screening levels (ESL) indicated that the exposure to ∑PAH16 was >ERL, >ERM, and ≥ERL and <ERM at 21.9, 0, and 21.9% of the soil sampling stations, the exposure to ∑PAH16 was >ESL at 78.1% of the soil sampling stations, and could induce biological effects in mammals. The Bapeq concentrations posed a potential carcinogenic risk to humans. Further risk management and control of soil PAHs in these agricultural soils is required to ensure the safety of the biocoenosis and human health.

Assessment of heavy metal contamination status in sediments and identification of pollution source in Ichkeul Lake and rivers ecosystem, northern Tunisia

The aim of this study was to determine the concentration of Pb, Zn, Cu, Cd, Cr, and Fe in sediments of the Ichkeul Lake and rivers ecosystem in northern Tunisia; their comparison with international sediment quality criteria was also proposed to assess the extent of metal pollution and their origin using various pollution indicators. For this purpose, sediment samples were collected in thirteen locations and characterized for metal content (Pb, Cr, Zn, Cu, Cd, and Fe) using the total digestion technique. Pollution level was assessed via the geoaccumulation index (Igeo), enrichment factor (EF), contamination factor (C ), potential ecological risk (PER), and pollution load index (PLI). Our results showed that all metals were lower than the threshold effect levels (TEL), the effect range low (ERL), the probable effect level (PEL), the effect range median (ERM), and the probable effect concentration (PEC) value, except Pb and Cr (higher than TEL), the threshold effect concentration (TEC), and the toxicity reference value (TRV). The geoaccumulation index (Igeo) indicated no pollution for Cr, Cu, Zn, and Fe, but moderate pollution for Pb. The enrichment factor showed no enrichment for most of the studied metals. This was further confirmed by the contamination factor that indicated low contamination levels, with the exception of Pb. The pollution load index (PLI) showed moderate pollution status in all the studied stations in the Ichkeul Lake and rivers ecosystem. The statistical results presented similar trends of Zn and Pb probably due to their similar pollution sources. It was found that the Ichkeul Lake and river ecosystems are characterized by moderate pollution status in all the studied sites except for that of a feeder river drained from an old lead mine which had relatively high metallic concentrations of Pb and Cd. It can be argued that effective remediation strategies and environmental management plans are required to control and reduce the input of environmentally hazardous toxic pollutants (Cd and Pb). This study may serve as a useful reference tool pertinent to approaches to the remediation of the old lead mine area surrounding the Ichkeul Lake as well as other areas under similar ecological conditions..

Polycyclic aromatic hydrocarbons (PAHs) in coastal sediments from urban and industrial areas of Asaluyeh Harbor, Iran: distribution, potential source and ecological risk assessment.

The distribution and toxicity levels of 16 EPA priority pollutant polycyclic aromatic hydrocarbons (PAHs) in the sediments of Asaluyeh shore, Iran were investigated. The total concentrations of the PAHs in surface sediments ranged from 1,054 to 17,448 ng/g dry weights with a mean concentration of 8,067 ng/g. The spatial distribution of PAHs showed that PAH levels are much higher in the industrial areas in comparison with urban areas. Based on diagnostic ratios, pyrogenic activities were dominant sources of PAHs pollution in sediments comparing petroleum sources. The toxic equivalent concentrations (TEQ Carc) of PAHs ranged from 172 to 2,235 ng TEQ/g with mean value of 997.9. Toxicity levels were evaluated using sediment quality guidelines (SQGs) and toxic equivalent factors. Samples were collected from industrial and urban stations in Asaluyeh shores. According to SQGs, ΣPAHs concentrations in sediments of urban areas were below the ERL (effects range low), but the industrial samples had ΣPAHs concentrations between ERL and ERM (effects range median). Furthermore, ΣHPAHs (heavy PAHs) and some individual PAHs in some industrial stations exceeded ERM, indicating adverse ecological risk effects frequently occur. Findings demonstrate that the surface sediment from Asaluyeh shore is highly to very highly contaminated with PAHs.

Polycyclic aromatic hydrocarbons (PAHs) in sediments of Zhelin Bay, the largest mariculture base on the eastern Guangdong coast, South China: Characterization and risk implications

We investigated distribution, sources, and potential risks of polycyclic aromatic hydrocarbons (PAHs) in the surface sediments from the largest mariculture base in the eastern part of the province of Guangdong in southern China. Total concentrations of ∑PAHs were 29.38–815.46ng/g (dry weight), with a mean of 421.48ng/g. The composition of PAHs was characterized by an abundance of low molecular weight PAHs (2–3 benzenoid ring), and Phenanthrene (PHE), Anthracene (AN) and Fluoranthene (FA) were the predominant constituents. PAHs in this area appear to have mainly originated from petroleum sources and the combustion of grass, wood, and coal. PAHs in surface sediments of Zhelin Bay had a 9% incidence of causing adverse biological effects on aquatic organisms, according to the mean effects range–median quotient.