Sediment Contamination Levels Research Articles

The Preliminary Study of Organochlorine Pesticide Residues on Sediments of Bivalvia Fishing Ground at Eastern Part of Coastal Semarang

This paper presents the occurrence level of organochlorine contamination in marine sediments of Semarang coastal areas as a fishing ground of Bivalvia. Five compounds (Heptachlor, Aldrin, Endosulfan, Endrin and pp-DDT) of contaminant have been determined in the sediments surface of Semarang coastal waters. The samples were then analyzed by using gas chromatography and followed by using the method of Standard Method Examination. The result showed that the average concentration of organochlorine pesticides Heptachlor, Aldrin, Endosulfan, Endrin and pp-DDT were 25.5, bellow detected, 7.1, 37.2, 28.6 μ g/L, respectively. The high concentration of pesticide showed on Endrin (65,84 ppb), pp-DDT (29,53 μ g/L), and heptachlor (25,45 μ g/L). The low concentrations were detected on aldrin (bellow detected) and endosulfan (0,92 μ g/L). The concentration of organochlorine pesticides in these areas might contribute on four rivers which deposited the sediment in these coastal waters

The utility of solid-phase microextraction in evaluating polycyclic aromatic hydrocarbon bioavailability during habitat restoration with dredged material at moderately contaminated sites.

The over- or underprediction of risk in moderately contaminated sediments can have a large impact on the nature of applied management strategies given that concentrations border on being toxic or not toxic. Project managers should give significant consideration as to how moderate levels of contaminants in native sediments and dredged material used for restoration will impact recovery of habitat. Total solid-phase (Ctotal ) and porewater (Cfree ) polycyclic aromatic hydrocarbons (PAHs) were quantified in native sediments and dredged material to determine if the predictions of risk from Ctotal are consistent with those based on Cfree . The sediment matrix phase in which PAHs were quantified resulted in disparate conclusions regarding the predicted reduction in contamination following restoration. Total solid-phase PAH concentrations suggested a significant decrease following restoration, whereas little to no change was observed in measured Cfree . Risk metrics based on Ctotal gave inconclusive estimates for toxicity, whereas measured Cfree suggested toxicity is unlikely, a conclusion consistent with toxicity testing. The incorporation of black carbon (BC) into model estimates for Cfree gave predictions more consistent with measured Cfree , suggesting that geochemical conditions (especially BC) play an important part in predicting toxicity at moderately contaminated sites. In addition to the use of Cfree in toxicity evaluation, in-situ Cfree measurements provided a constraint on diffusive PAH loads from sediment relative to ongoing stream loads. If passive sampling had been employed during the sampling designs and site evaluations, the costs of toxicity testing would not have been incurred, given that Cfree suggested little to no toxicity. The results from the project highlight the benefits to be gained by moving beyond inconclusive, screening-level Ctotal metrics and implementing more sensitive and accurate Cfree metrics in assessments of risk in moderately contaminated sediments. Integr Environ Assess Manag 2018;14:212-223. © 2017 SETAC.

The use of bioassays to assess the toxicity of sediment in an acid mine drainage impacted river in Gauteng (South Africa)

Sediment contamination may occur from various anthropogenic activities, such as mining-, agricultural- and industrial practices. Many of the contaminants arising from these activities enter the aquatic system and precipitate from the surrounding water, becoming bound to sediment particles. These bound contaminants may reach concentrations higher than in the overlying water. Although water quality may be acceptable, an aquatic system may still be at risk if the contaminated sediment were to be disturbed through flooding, bioturbation or changes in the water chemistry. These contaminants may then desorb into the water column and prove detrimental to life forms in contact and dependent on that water source. Sediment quality monitoring has been a widespread international initiative and has led to the development of sediment toxicity assessment methods. This study focused on sediment bioassays, namely, Phytotoxkit, Ostracodtoxkit F and the Diptera bioassay, in assessing sediment quality of the Tweelopiespruit-Rietspruit-Bloubankspruit river system in Gauteng, South Africa. This river is known to have been impacted by acid mine drainage (AMD) since late August, 2002. Exposure of river sediment from 7 sampling sites to these bioassays provided an eco-toxicological estimation of the acute toxicity and chronic toxicity emanating from the contaminated sediments. Physico-chemical analyses revealed higher levels of sediment contamination closer to the mine. The bioassays displayed a similar trend with greater sensitivities to sediments closer to the mine and lower sensitivities to the less contaminated sites further downstream. AMD was therefore the main driver for sediment contamination. Whilst not all contaminants were bioavailable, statistical analysis showed that there were significant correlations between the elevated contaminant concentrations closer to the mine and bioassay responses. Keywords : acid mine drainage, sediment toxicity, bioassay, Ostracodtoxkit F, Phytotoxkit, Diptera bioassay

The potential impact of green agendas on historic river landscapes: Numerical modelling of multiple weir removal in the Derwent Valley Mills world heritage site, UK

The exploitation of river systems for power and navigation has commonly been achieved through the installation of a variety of in-channel obstacles of which weirs in Britain are amongst the most common. In the UK, the historic value of many of these features is recognised by planning designations and protection more commonly associated with historic buildings and other major monuments. Their construction, particularly in the north and west of Britain, has often been associated with industries such as textiles, chemicals, and mining, which have polluted waterways with heavy metals and other contaminants. The construction of weirs altered local channel gradients resulting in sedimentation upstream with the potential as well for elevated levels of contamination in sediments deposited there. For centuries these weirs have remained largely undisturbed, but as a result of the growth in hydropower and the drive to improve water quality under the European Union's Water Framework Directive, these structures are under increasing pressure to be modified or removed altogether. At present, weir modifications appear to be considered largely on an individual basis, with little focus on the wider impacts this might have on valley floor environments. Using a numerical modelling approach, this paper simulates the removal of major weirs along a 24-km stretch of the river Derwent, Derbyshire, UK, designated as a UNESCO World Heritage Site. The results suggest that although removal would not result in significant changes to the valley morphology, localised erosion would occur upstream of structures as the river readjusts its base level to new boundary conditions. Modelling indicates that sediment would also be evacuated away from the study area. In the context of the Derwent valley, this raises the potential for the remobilisation of contaminants (legacy sediments) within the wider floodplain system, which could have detrimental, long-term health and environmental implications for the river system. Worldwide, rivers have a common association with industry – being the focus of settlement and development since the earliest civilisations with channel engineering a common practice. Therefore, the conceptual issues raised by this study have global resonance and are particularly important where heritage protection is less robust and structures can be removed with little consideration of the environmental consequences.

Contamination of Detained Sediment in Sustainable Urban Drainage Systems

Adsorption is a key water pollution remediation measure used to achieve stormwater quality improvement in Sustainable urban Drainage Systems (SuDS). The level of contamination of detained sediment within SuDS assets is not well documented, with published investigations limited to specific contaminant occurrence in ponds, wetlands or infiltration devices (bioretention cells) and generally focused on solute or suspended sediment. Guidance on contamination threshold levels and potential deposited sediment contamination information is not included in current UK SuDS design or maintenance guidance, primarily due to a lack of evidence and understanding. There is a need to understand possible deposited sediment contamination levels in SuDS, specifically in relation to sediment removal maintenance activities and potential impact on receiving waterways of conveyed sediment. Thus, the objective of the research presented herein was to identify what major elements and trace metals were observable in (the investigated) SuDS assets detained sediment, the concentration of these major elements and trace metals and whether they met/surpassed ecotoxicity or contaminated land thresholds. The research presented here provides evidence of investigated SuDS sediment major element and trace metal levels to help inform guidance and maintenance needs, and presents a new methodology to identify the general cause (anthropocentric land use) and extent of detained SuDS fine urban sediment contamination through use of a contamination matrix.

Polycyclic aromatic hydrocarbons (PAHs) in surface sediments near a mining site in Okobo-Enjema, Nigeria: concentrations, source apportionment and risk assessment

PAHs are pollutants of serious environmental and human health concerns. PAH studies in environmental compartments may assist in designing PAH control measures. The levels of selected PAHs in surface sediment samples of a stream near a mining site at Okobo-Enjema, Nigeria, were investigated. The data were used to determine the possible sources of the PAHs and to assess the potential health risk of the PAHs to humans which was evaluated based on the sediment quality, contamination level and cancer risk guidelines. Sediment samples were collected in replicates at various locations in the stream. A mixture of acetone, dichloromethane and n-hexane was used to extract the PAH compounds by sonication. The extracts were cleaned-up, concentrated and quantitatively analyzed using gas chromatography-mass spectrometry. The results indicated 14, 10 and 4 out of the 16 target PAHs were detected at various sampling stations. The total concentrations of the PAHs ranged from 0.09 to 1.2mg/kg dry weight. High molecular weight PAHs dominated over the low molecular weight compounds at distances nearer to the coal mine. The PAH contamination came from pyrogenic and petrogenic sources. The results suggested that there was no eco-toxicological risk for organisms in the sediments beyond 400m from the coal mine. The sediments were highly contaminated at ≤400m from the coal mine; moderately contaminated at between 400 and 500m from the mine; and lowly contaminated at beyond 500m from the mine. The cancer risk is low on ingestion and skin contact with the sediments.

Geoenvironmental Impact of Effluents Generated from Al Subiya Power Plant on the Northern Kuwait Bay, State of Kuwait

The present study proposed to assess the geo-environmental impacts of Al Subiya desalination plant discharges in the Arabian Gulf, Kuwait. Most of the power and freshwater needs in the Middle East are met by the desalination of seawater. With approximately 11 million m³ of freshwater being produced each day, the salinity of the seawater along the Gulf coast is increasing. Due to brine discharge into outlet, salinity combined with higher sea surface temperatures was increased is a big environmental challenge. Therefore, in the current study the evaluation of Salinity and conductivity was higher in outlet samples than the inlet. Understanding chemical quality of sediment is important since many pollutants bind strongly to sediment particles and are persistent in the aquatic environment. The chemical and physical make-up of sediment is largely a reflection of upstream and local geology, land use, surface run off and many other complex phenomena. Many persistent compounds have high molecular weight and therefore settle out quickly and are incorporated with other settled organic materials. Since the sediment-water layer is the most reactive layer of the sea bed, changes in the sediment distribution and its physio-chemical characteristics will certainly occur in relation to time and space. In view of this, a distribution map of the sediment is important to understand the changes in composition and nature of contamination in the aquatic environment. This study set out to survey Al Subiya desalination plant inlet and outlet of marine area in Kuwait's Arabian Gulf water and to generate an updated map of the sediments of Kuwait's marine environment, in terms of pollutant factors and the corresponding map of water quality parameters during the survey of one year. The specific objectives were: 1) total organic carbon (TOC), and total petroleum hydrocarbons(TPH) in the sediment collected from selected station, 2) analyze the water quality parameters (pH, Dissolved Oxygen, temperature, salinity, turbidity, conductivity potential) in Al Subiya desalination plant inlet and outlet region, and 3) examine the level of contamination in sediments in terms of size, composition and concentration of different metals and correlate this data with the available physical water quality parameters.

Vertical Distribution and Pollution Risk Assessment of Nitrogen, Phosphorus, and Organic Matter in Sediment of Inflowing Rivers of Erhai Lake Estuarine Wetland in Wet and Dry Seasons

The estuarine wetland of Luoshijiang River, which flows into Erhai Lake in Yunnan province, was regarded as the typical research object. Sediment samples in the estuarine wetland of Luoshijiang River were collected by the cylindrical sediment sampler and the samples were from surface layer (0-10cm), middle layer (10-30 cm), and bottom layer (30-60 cm). The vertical distribution of total nitrogen, total phosphorus, and total organic material in dry and rainy season was analyzed and contamination risk assessment of sediment was accomplished. The results showed that: ① In dry season, average concentrations of total nitrogen in sediment on surface, middle and bottom layer at estuarine wetland of Luoshijiang River were respectively 1.734, 1.453 and 1.255 g·kg-1, the average concentrations of total phosphorus were respectively 1.085, 1.034 and 0.992 g·kg-1, the average concentrations of organic material were respectively 59.051, 47.730 and 42.133 g·kg-1. In rainy season, average concentrations of total nitrogen in sediment on surface, middle and bottom layer at estuarine wetland of Luoshijiang River were respectively 1.147, 0.948 and 0.895 g·kg-1, the average concentrations of total phosphorus were respectively 0.599, 0.523 and 0.519 g·kg-1, the average concentrations of organic material were respectively 53.098, 46.897 and 43.395 g·kg-1. ② Single factor pollution index, organic nitrogen and organic index assessment were used to evaluate the contamination level of sediment, the assessment results showed that: In dry season, the contamination level of nitrogen and phosphorus in sediment was on severe level, organic material contamination was on medium level. In rainy season, the contamination levels of ON and OI were medium, and that of PI was mild. Generally, the contamination levels of nitrogen, phosphorus and organic material in sediment tendency were as follows: dry season>rainy season, and the pollution index of each layer followed the sequence of surface layer > middle layer > bottom layer, and the most extraordinary contamination of them on surface layer was uncovered whatever the season was. ③ Pollution origin of estuarine wetland of Luoshijiang River in dry and wet season had great differences, it was mainly the exogenous source in dry season, but it was the internal source in wet season; The potential risk of release of nutrient salt of sediment in dry season was higher than the wet, and the risk in the surface layer was the highest.

Microbiome Dynamics of a Polychlorobiphenyl (PCB) Historically Contaminated Marine Sediment under Conditions Promoting Reductive Dechlorination.

The toxicity of polychlorinated biphenyls (PCB) can be efficiently reduced in contaminated marine sediments through the reductive dechlorination (RD) process lead by anaerobic organohalide bacteria. Although the process has been extensively investigated on PCB-spiked sediments, the knowledge on the identity and metabolic potential of PCB-dechlorinating microorganisms in real contaminated matrix is still limited. Aim of this study was to explore the composition and the dynamics of the microbial communities of the marine sediment collected from one of the largest Sites of National Interest (SIN) in Italy (Mar Piccolo, Taranto) under conditions promoting the PCBs RD. A long-term microcosm study revealed that autochthonous bacteria were able to sustain the PCB dechlorination at a high extent and the successive addition of an external fermentable organic substrate (lactate) caused the further depletion of the high-chlorinated PCBs (up to 70%). Next Generation Sequencing was used to describe the core microbiome of the marine sediment and to follow the changes caused by the treatments. OTUs affiliated to sulfur-oxidizing ε-proteobacteria, Sulfurovum, and Sulfurimonas, were predominant in the original sediment and increased up to 60% of total OTUs after lactate addition. Other OTUs detected in the sediment were affiliated to sulfate reducing (δ-proteobacteria) and to organohalide respiring bacteria within Chloroflexi phylum mainly belonging to Dehalococcoidia class. Among others, Dehalococcoides mccartyi was enriched during the treatments even though the screening of the specific reductive dehalogenase genes revealed the occurrence of undescribed strains, which deserve further investigations. Overall, this study highlighted the potential of members of Dehalococcoidia class in reducing the contamination level of the marine sediment from Mar Piccolo with relevant implications on the selection of sustainable bioremediation strategies to clean-up the site.

Occurrence and Distribution Pattern of Alkylphenol Ethoxylates and Brominated Flame Retardants in Sediment Samples from Vaal River, South Africa.

High environmental concentrations for alkylphenol ethoxylates (APEs) and brominated flame retardants (BFRs) have been observed near cities than in rural environment. This is due, in part, to sewage systems receiving effluents from many industrial processes along with domestic wastewater. While these classes of compounds are being phased out in most developed countries, there is still widespread use in low to middle income countries. To better understand the extent of APEs and BFRs contamination in the environment, this study reports on the concentration and distribution of APEs and BFRs in sediments samples collected from Vaal River, South Africa. Measurable concentrations of these contaminants were obtained using GC-MS after heptafluorobutyric derivatization. The concentrations range (ngg(-1)) for these pollutants were as follows: nd-46, 20-127, 24-38, 3-5, 14-28, 16-54 for octylphenol penta ethoxylates, nonylphenol ethoxylates (mono- di), nonylphenol penta ethoxylates, PBB101, PBDEs, and HBCD; respectively. The distribution observed in this study indicated higher levels of sediment contamination by APEs relative to BFRs. These results underline the need to further investigate the burden and risks associated with chemical contamination in developing countries.

Contamination patterns and molluscan and polychaete assemblages in two Persian (Arabian) Gulf oilfields

AbstractThis study examined two shallow‐water, offshore oil facilities and their surroundings in the Umm Al Dalkh and Zakum oilfields [United Arab Emirates, Persian (Arabian) Gulf]. The focus was on sediment contamination levels and the detection of disturbance based on two representative invertebrate components of the benthos: molluscs and polychaetes. We tested the hypothesis that significant disturbance to the community has occurred, by examining whether distance from the platform or variation in contaminants explains among‐site variation in the composition of benthic communities. Moreover, we also tested the hypothesis that organic enrichment because of oil input has modified the feeding guild structure by examining whether the relative abundances of filter‐feeders, deposit‐feeders and omnivores are correlated with distance from the platform or with contamination by hydrocarbons. The contamination levels and their spatial distribution in the sediments differed significantly between the two fields, as did their mollusc and polychaete communities. The within‐field variability, however, was much lower: no clear structuring of contamination values and species composition and abundance was detectable in relation to distance from the oil platform. Contamination levels were low, often below detection levels or international guideline values. Variation in contaminant concentrations did not explain variation in taxonomic composition and abundance. The relative abundance of the above‐mentioned feeding guilds did not correlate with either distance from the platform or with contaminant concentrations. These patterns may reflect the long time that has elapsed since drilling (15–20 years), which appears to have allowed contaminants to disperse and degrade and assemblages to recover from the impact, if indeed such a disturbance ever occurred. In contrast to low values of barium and total petroleum hydrocarbons, associated with well drilling, some metals were at their highest concentrations beneath the central platforms. This suggests that production‐related activities (including platform cleaning and maintenance) are currently a more relevant contamination source.

Effects of Lumbriculus variegatus (Annelida, Oligochaete) bioturbation on zinc sediment chemistry and toxicity to the epi-benthic invertebrate Chironomus tepperi (Diptera: Chironomidae)

Classical laboratory-based single-species sediment bioassays do not account for modifications to toxicity from bioturbation by benthic organisms which may impact predictions of contaminated sediment risk to biota in the field. This study aims to determine the effects of bioturbation on the toxicity of zinc measured in a standard laboratory bioassay conducted with chironomid larvae (Chironomus tepperi). The epi-benthic chironomid larvae were exposed to two different levels of sediment contamination (1600 and 1980 mg/kg of dry weight zinc) in the presence or absence of annelid worms (Lumbriculus variegatus) which are known to be tolerant to metal and to have a large impact on sediment properties through bioturbation.Chironomids had 5–6x higher survival in the presence of L. variegatus which shows that bioturbation had a beneficial effect on the chironomid larvae. Chemical analyses showed that bioturbation induced a flux of zinc from the pore water into the water column, thereby reducing the bioavailability of zinc in pore water to the chironomid larvae. This also suggested that pore water was the major exposure path for the chironomids to metals in sediment. During the study, annelid worms (Oligochaetes) produced a thin layer of faecal pellets at the sediment surface, a process known to: (i) create additional adsorption sites for zinc, thus reducing its availability, (ii) increase the microbial abundance that in turn could represent an additional food source for opportunistic C. tepperi larvae, and (iii) modify the microbial community’s structure and alter the biogeochemical processes it governs thus indirectly impact zinc toxicity.This study represents a contribution in recognising bioturbating organisms as “ecological engineers” as they directly and indirectly influence metal bioavailability and impact other sediment-inhabiting species. This is significant and should be considered in risk assessment of zinc levels (and other metals) in contaminated sediment when extrapolating from laboratory studies to the field.

Assessment of heavy metals and arsenic contamination in the sediments of the Moulouya River and the Hassan II Dam downstream of the abandoned mine Zeïda (High Moulouya, Morocco)

To evaluate the sediment contamination level near the abandoned (PbZn) mine Zeïda, heavy metal concentrations were determined in sediment samples from the Moulouya River, the Ansegmir tributary and the Hassan II Dam located downstream of the abandoned mine. These samples were analysed for their geochemical properties: mineralogy by XRD, carbonate content, pH, particle size and the total concentrations of Pb, Zn, As and Cu elements by ICP-AES. The assessment of the sediment pollution extent was performed by using the multiple pollution indices: contamination factor (CF), pollution load index (PLI) and the geoaccumulation index (Igeo). The Highest CF values (>6) of Pb that have been observed downstream of the tailings promote a high Pb contamination in that specific area. The PLIs results showed that all stations, except for those upstream of the tailings and on the Hassan II Dam, have been found moderately to highly contaminated. The Igeo results confirmed the Pb high contamination but also the extreme As contamination. The potential ecological risk factor results and the comparison with the sediment quality guidelines revealed that the Pb and As levels are potentially toxic to the sediment-dwelling organisms. Based on the multivariate statistical analysis results and the spatial distribution of the sediment contamination level, the pollution of Pb and As have different sources. Pb contamination is located exclusively near and downstream of the tailings. These latter's may be considered as an important point source of Pb into the Moulouya River. The As contamination is derived from a larger scale input sources which can be related to anthropogenic and/or lithogenic effects.

Heavy metals bioaccumulation in selected tissues of red swamp crayfish: An easy tool for monitoring environmental contamination levels

In this paper we explored the heavy metal bioaccumulation (Cd, Cu, Pb and Zn) in Procambarus clarkii, a crayfish recently suggested as a potential bioindicator for metals pollution in freshwater systems. The present study is focused on crayfishes populations caught in a heavily polluted industrial and in a reference sites (Central Italy), though the results are generalized with a thorough analysis of literature metadata. In agreement with the literature, the hepatopancreas (Hep, detoxification tissues) of the red swamp crayfish showed a higher concentration of heavy metals in comparison to the abdominal muscle (AbM, not detoxification tissues) in the sites under scrutiny. Hep/AbM concentration ratio was dependent on the specific metal investigated and on its sediment contamination level. Specifically we found that Hep/AbM ratio decreases as follows: Cd (11.7)>Cu (5.5)>Pb (3.6)>Zn (1.0) and Pb (4.34)>Cd (3.66)>Zn (1.69)>Cu (0.87) for the industrial and reference sites, respectively. The analysis of our bioaccumulation data as well as of literature metadata allowed to elaborate a specific contamination index (Toxic Contamination Index, TCI), dependent only on the bioaccumulation data of hepatopancreas and abdominal muscle. In the industrial site, TCI expressed values much higher than the unit for Cd and Cu, confirming that these metals were the main contaminants; in contrast for lower levels of heavy metals, as those observed in the reference site for Cu, Zn and Pb, the index provided values below unit. TCI is proposed as a useful and easy tool to assess the toxicity level of contaminated sites by heavy metals in the environmental management.

Bioanalytical and instrumental screening of the uptake of sediment-borne, dioxin-like compounds in roach (Rutilus rutilus).

To examine the uptake of dioxin-like compounds (DLCs), common roaches (Rutilus rutilus) were exposed for 28days to differently contaminated sediments from two major European rivers in a purpose-built facility. Dietary transfer of DLCs was investigated by exposing fish to sediments inoculated or non-inoculated with black worms (Lumbriculus variegatus). Dioxin-like polychlorinated biphenyls (DL-PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), measured via high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) in sediments and whole fish, were used to calculate toxicity equivalent quotients (TEQs). TEQs were compared with biological toxicity equivalent quotients (BEQs) determined via the 7-ethoxyresorufin-O-deethylase (EROD) assay, performed with mammalian (H4IIE) and fish (RTL-W1) liver cell lines. TEQs and BEQs indicated an uptake of sediment-borne DLCs by roach, which was independent of sediment contamination levels, but rather reflected sediment-specific characteristics. For most sediment treatments, DLC uptake did not increase with time. Highest congener-specific uptake (DL-PCB 123) was 10-fold compared to control. Exposure to worm-inoculated sediment of highest overall DLC contamination caused a 2-fold (TEQ and H4IIE BEQ) greater uptake of DLCs by fish compared to the respective non-inoculated treatment. H4IIE cells showed the greatest sensitivity (0.37 ± 0.25pM TCDD) and the strongest correlation with TEQs (r (2) = 0.79), hence, they seem to be best suited for DLC screening of sediments and biota, amended by compound-specific instrumental analysis if required.

Endocrine-disruptor molecular responses, occurrence of intersex and gonado-histopathological changes in tilapia species from a tropical freshwater dam (Awba Dam) in Ibadan, Nigeria

In the present study, the occurrence of endocrine disruptive responses in Tilapia species from Awba Dam has been investigated, and compared to a reference site (Modete Dam). The Awba Dam is a recipient of effluents from University of Ibadan (Nigeria) and several other anthropogenic sources. A total of 132 Tilapia species (Sarotherodon malenotheron (n=57 and 32, males and females, respectively) and Tilapia guineensis (n=23 and 20, males and females, respectively)) were collected from June to September 2014. At the reference site, samples of adult male and female S. melanotheron (48 males and 47 females) and T. guineensis (84 males and 27 females) were collected. Gonads were morphologically and histologically examined and gonadosomatic index (GSI) was calculated. Hepatic mRNA transcriptions of vitellogenin (Vtg) and zona radiata protein (Zrp) genes were analyzed using validated RT-qPCR. Significant increase in Vtg and Zrp transcripts were observed in male tilapias from Awba Dam, compared to males from the reference site. In addition, male tilapias from Awba Dam produced significantly higher Vtg and Zrp mRNA, compared to females in June and July. However, at the natural peak spawning period in August and September, females produced, significantly higher Vtg and Zrp mRNA, compared to males. Fish gonads revealed varying incidence of intersex with a striking presence of two (2) pairs of testes and a pair of ovary in S. melanotheron from Awba Dam. The entire fish population examined at Awba Dam showed a high prevalence of intersex (34.8%), involving phenotypic males and females of both species. Analysis of sediment contaminant levels revealed that As, Cd, Pb, Hg and Ni (heavy metals), monobutyltin cation, 4-iso-nonyphenol and PCB congeners (138, 153 and 180) were significantly higher in Awba Dam, compared to the reference site. Principal component analysis (PCA) showed that fish variables were positively correlated with sediment contaminant burden at Awba Dam, indicating that the observed endocrine disruptive responses are associated with contaminant concentrations. Overall, the occurrence of intersex and elevated expressions of Vtg and Zrp in male fish, suggest that the measured contaminants were eliciting severe endocrine disruptive effects in Awba Dam biota, which is an important source of domestic water supply and fisheries for the University of Ibadan community.

Baseline Information on the Metallic Pollution of Sediments of the Lakes of the Ossa Complex, Dizangue, Cameroon

The aim of this study was to evaluate the state of metallic pollution of the sediments of the three main Lakes (Mevia, Ossa and Mwembe) of the Ossa lake complex by the analysis of some heavy metals from May to July 2011. Copper, Nickel, Lead, Zinc, Cadmium and Iron were measured using atomic absorption spectrophotometry method. According to the standard values of GESAMP (group of Experts on the Scientific Aspects of Marine Pollution), lead concentrations were low in Lake Mwembe (4.985±0.060 mg.kg, dry weight), closer to standard values in Lake Mevia (12.935±0.815 mg.kg, dry weight) and very high in Lake Ossa (39.935±2.480 mg.kg, dry weight). Original Research Article Guy et al.; BJAST, 14(6): 1-14, 2016; Article no.BJAST.24001 2 As for Zinc and Cadmium, the contents were superior to standard values in the three lakes. The level of sediment contamination was evaluated using the Pollution Index (PI) and Enrichment Factor (EF). Only cadmium had a PI value greater than 3 and the highest EF (491.456 in Lake Mevia, 480.310 in Lake Ossa and 1761.099 in Lake Mwembe). All heavy metals presented EF values superior to 50 exception being observed for lead in Lake Mwembe (EF value less than 30). Generally, gross values of the different heavy metals measured, associated with EF values, indicated an anthropogenic pollution of these waters. This pollution could be linked to the use of chemical fertilizers and biocides around the neighborhood of Ossa lake complex by the African Forestry and Agriculture Company of Cameroon (SAFACam).

Classification efficiency of the B-IBI comparing water body size classes in Chesapeake Bay

The Benthic Index of Biotic Integrity (B-IBI) was developed and is currently employed for environmental assessment in Chesapeake Bay. The index consists of a variety of benthic community metrics (e.g. abundance, biomass, diversity, stress tolerance groups, etc.) scored by thresholds applied to seven benthic community habitats (tidal freshwater, oligohaline, low mesohaline, high mesohaline mud, high mesohaline sand, polyhaline mud, and polyhaline sand) This index was verified as being a sensitive and robust tool for summarizing the status of benthic communities. In our study we tested the classification efficiency of the index using new benthic data by characterizing each sample a priori as degraded or undegraded using criteria of sediment contaminant levels, bioassays and bottom dissolved oxygen levels. A primary objective of our study was to test the classification efficiency of the B-IBI in small water bodies connected to larger water bodies of the mainstems of the large rivers of Chesapeake Bay, as well as the efficiency of the index over time (1990 through 2009). The B-IBI was affected by the size of the water body, e.g., index accuracy was higher for water bodies in small watersheds in lower salinity habitats, whereas large water bodies of the mainstem of rivers were better classified by the B-IBI in habitats with higher salinities. Across the seven benthic habitat types overall correct classification was moderate to low and lower for correctly classifying undegraded sites. In general the index metrics showed some deficiencies that suggest improvements could be made by recalibrating existing metric thresholds or selecting new suitable metrics.

Multi-organ histopathology in gobies for estuarine environmental risk assessment: A case study in the Ibaizabal estuary (SE Bay of Biscay)

Multi-organ (liver, gills, kidney and spleen) histopathology in gobies (Pomatoschistus spp.) together with metal bioaccumulation and sediment contamination levels were studied during 2011–2013 for estuarine environmental risk assessment in the Ibaizabal estuary (SE Bay of Biscay). Results indicate that sediments were moderately-strongly impacted by metals and organic compounds, suggesting that adverse biological effects could be likely. Similar metal bioaccumulation levels and multi-organ histopathological indices were detected in gobies collected along the estuary, indicating a similar affection degree. Accordingly, both metal bioaccumulation levels and histopathological indices decreased in gobies collected in 2013 reflecting a lower impact on fish health status. Liver, gills and kidney presented higher histopathological damage than spleen. Fat vacuolation of hepatocytes, lamellar fusion and melanomacrophage centers were the most prevalent hepatic, branchial and renal alterations, respectively. These histopathological changes may indicate exposure to non-specific toxicants. Nevertheless, the influence of other environmental variables should not be excluded as causative factors. No severe pathological traits were registered in gonads, suggesting undisturbed reproductive status. In conclusion, the use of multi-organ histopathology in gobies in combination with metal bioaccumulation and sediment contamination levels, contribute to a better understanding of sub-lethal effects and a more accurate environmental risk assessment in the Ibaizabal estuary.

Ecotoxicological effects of sediments from Mar Piccolo, South Italy: toxicity testing with organisms from different trophic levels

The Mar Piccolo of Taranto (Ionian Sea, Southern Italy) is a semi-enclosed and strongly polluted basin. For decades, it has been subjected to different anthropogenic impacts. These stressors caused severe sediments contamination with high concentration of different pollutants (PAHs, PCB, heavy metals). In order to assess the current status of sediments contamination, an ecotoxicological investigation combined with chemical analysis (heavy metals, PAH, and PCB) has been performed. In order to derive ecologically relevant conclusions, a multiorganisms and multiend-points approach has been applied, exposing organisms from different trophic levels to elutriate and whole sediment. The battery of bioassays consists of a microalgal growth inhibition test (Dunaliella tertiolecta), acute and sublethal assays (end-points: mortality, immobilization and swimming speed alteration) on crustaceans larvae and juveniles, and rotifers (Amphibalanus amphitrite, Artemia salina, Corophium insidiosum and Brachionus plicatilis), and embryotoxicity test on echinoderms (Paracentrotus lividus). Considering the high levels of sediment contamination highlighted from chemical analysis, an unexpected very low toxic effect was observed, even considering the sublethal end-point (larval swimming speed alteration). The results of this study suggest a very complex contaminants dynamic in the Mar Piccolo sediments that, despite a strong level of contamination, seems to not affect in a proportional manner the biological compartment.