Ten global harbours were assessed for sediment quality by quantifying the magnitude of anthropogenic change and ecological risk. Anthropogenic change (enrichment) was high for Derwent River and ...Sydney estuary, moderate for Santander Harbour, Rio de Janeiro and Dublin Port, slight for Hong Kong, minimal for Darwin. All 10 enrichment indices used showed similar results. Derwent River sediment was rated at high ecological risk, followed by Sydney and Santander estuaries with moderate risk. Auckland and Darwin sediments exhibited minimal ecological risk and sediment in the remaining harbours (Dublin, Hong Kong, Ravenna, Ria de Vigo and Rio de Janeiro) were assessed at slight ecological risk.
The extraordinary variety of environments and types/quantities/qualities of data investigated resulted in as much a critique and development of methodology, as an assessment of human impact, including unique techniques for elemental normalisation and contaminant classification. Recommendations for an improved technical framework for sediment quality assessment are provided.
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•Ten global harbours were assessed for anthropogenic change (AC) and ecological risk (ER)•AC was high for Derwent River, Santander and Sydney estuaries•AC was moderate for Rio de Janeiro and Dublin Port, slight for Hong Kong, minimal for Darwin.•Derwent River sediment was rated at high ER, Sydney and Santander estuaries with moderate risk.•An improved technical framework for sediment quality assessment is provided.
The determination of age-dated metal sediment accumulation rates in a representative South American bay is able to portray the dimension of human impacts during the colonial occupation and industrial ...periods. Many studies have assessed metal distribution and chronology at Guanabara Bay, in Brazil. However, understanding natural variabilities associated to paleoclimatic changes and comparing these natural variabilities to anthropogenic processes are not well established to date. Accurate geochronological control integrating ages determined by 210Pb and 14C chronologies through an exponential spline fit model allowed for a precise definition of changes associated to the holocene marine transgression, as well as the colonial period, leading to intense land use changes, and the industrial period. The reference values of the system were defined based on their concentrations and the accumulation rates of ecotoxicologically important metals. Al, Ba, Fe, Cd, Cu, Cr, Li, Ni, Mn, Pb, Si, Ti, V, and Zn distributions were determined in a Guanabara Bay core (BG-28) by the EPA 3051 method. Elemental distribution profile assessment allowed for the identification of variabilities associated to weathering processes, predominantly of lithogenic origin, mainly for Al, Ba, Fe, Li, Si, and V. Weathering processes occurred simultaneously to land use changes in the drainage basin since the colonial period, at 400 cal yr BP, and during the industrial period, mainly after the 1960s, denoted by Cd, Cr, Cu, Mn, Pb and Zn increases. The highest average metal enrichment values metals associated to industrial processes reached 5.95, with 119.1-fold higher accumulation rates than the background accumulation values observed between 4200 and 500 cal yr BP.
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•Al, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn, V were determined by EPA method 3051 in a 5,500 year sediment record from Guanabara Bay.•The natural variability of weathering processes, transport and deposition were predominant for Al, Ba, Fe, Li, Si, and V.•Land-use change since the colonial period, at 400 cal yr BP, and industrial period, indicates Cd, Cr, Cu, Mn, Pb and Zn increase.•The highest normalized degree of contamination and average accumulation enrichment reached 5.95 and 119 respectively in 90’s.
A rhamnolipid extract from
Pseudomonas aeruginosa
was tested on soils from short- and long-term contamination sites. Mass spectrometry analysis revealed a predominance of di-rhamnolipid congeners ...(85%), of which hydroxydecanoyl-hydroxydecanoate was the most abundant. Artificial contamination of a sandy soil resulted in final concentrations of arsenic, cadmium and zinc of 182, 20 and 983 mg kg
−1
, respectively. The rhamnolipid showed a high extractive capacity for transition metals and metalloids, removing 53% of the arsenic, 90% of the cadmium and 80% of the zinc from the artificially contaminated soil. When tested against soil samples from a deactivated mining site, the rhamnolipid removed 59% of the arsenic, 57% of cadmium and 9% of zinc. The biosurfactant showed excellent biocompatibility with
Artemia salina
. Well diffusion tests demonstrated that the rhamnolipid was innocuous for commensally soil bacteria and yeast. A method for precipitation of As, Cd and Zn was tested to allow eco-friendly disposal of these metal(loid) contaminants. The precipitation method was able to remove all the arsenic and cadmium, while removing 84.5% of zinc in the biosurfactant solution. The possibility of applying this biosurfactant to soil remediation processes without purification steps and the development of new and rapid methods for metal precipitation are strategically important for the mining industry, to properly dispose or recycle metal contaminants and thus reduce the demand for new raw materials.
Metal concentrations were evaluated in water, bottom sediments, and biota in four field campaigns from 2002 to 2004 in the Potiguar Basin, northeastern Brazil, where offshore oil exploration occurs. ...Analyses were performed by inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry. Total metal concentrations in water (dissolved + particulate) and sediments were in the range expected for coastal and oceanic areas. Abnormally high concentrations in waters were only found for Ba (80 μg l
−1
) and Mn (12 μg l
−1
) at the releasing point of one of the outfalls, and for the other metals, concentrations in water were found in stations closer to shore, suggesting continental inputs. In bottom sediments, only Fe and Mn showed abnormal concentrations closer to the effluent releasing point. Metal spatial distribution in shelf sediments showed the influence of the silt–clay fraction distribution, with deeper stations at the edge of the continental shelf, which are much richer in silt–clay fraction showing higher concentrations than shallower sediments typically dominated by carbonates. Metal concentrations in estuarine (mollusks and crustaceans) and marine (fish) organisms showed highest concentrations in oysters (
Crassostrea rhizophorae
). Fish tissues metal concentrations were similar between the continental shelf influenced by the oil exploration area and a control site. The results were within the range of concentrations reported for pristine environments without metals contamination. The global results suggest small, if any, alteration in metal concentrations due to the oil exploration activity in the Potiguar Basin. For monitoring purposes, the continental inputs and the distribution of the clay–silt fraction need to be taken into consideration for interpreting environmental monitoring results.
A three-step sequential extraction procedure, which was based on the BCR method, was used to analyse Guanabara Bay sediment samples to evaluate the potential mobility of some metals and metalloids. ...Zn and Cd were found to be the most labile metals because these were recovered in the first extraction stage and were associated with the non-residual fraction of the sediment. In contrast, Cr, Cu, Ni, and Hg were the least labile metals, and 62 to 84 % of the concentrations of these metals were found in the organic residual fraction of the sediment samples. The spatial distribution of the metal concentrations in Guanabara Bay led to the identification of various sources of contamination. The continental sources, which were related to Fe and Al, were distributed in the northern and central sectors, although lower concentrations were found in the mouths of the rivers that flow into the estuarine system of Guanabara Bay. The urban emission sources are related to the discharges of the São João de Merití River, which exhibit significant levels of Ba, Cd, Ni, Zn, and Hg. The São João de Merití River and harbour activities also show a predominance of Pb and Cu. The system formed by the Iguaçu River and the Sarapuí River is mainly characterised by V and Cr. The metals associated with biogeochemical processes, such as As and Mn, were found in the central sector of Guanabara Bay.
We present a geochemical record of a 113.6-cm sediment core (LPT V) from Lagoa da Pata, which is located in the forested upper Rio Negro basin. The record reveals significant changes in the ...environmental history of Amazonia during the late Quaternary. The results of biogeochemical analyses revealed three hydrological and climatic regimes from 50,000 to 10,000calyr BP. The first phase, between 50,000 and 26,300calyr BP, was characterized by a relatively wet climate as suggested by relatively high total organic carbon (TOC) and chlorophyll derivate concentrations, indicating high productivity linked to a high lake level. A decrease of the TOC and chlorophyll derivate accumulation rates between 43,100calyr BP and 26,300calyr BP marks a decrease in the productivity linked to a reduced lake level, indicating a decrease in moisture at the end of this phase. The second phase, between 26,300 and 15,300calyr BP, was characterized by a decrease in productivity, reaching a minimum at 21,950calyr BP, as indicated by a minima in sedimentary chlorophyll and TOC accumulation rates. Values of δ13C increased by 5‰ in relation to the preceding phase, indicating an influence of the C4 organic matter. High iron concentrations and accumulation rates, related to intense erosion of the lateritic crust in the watershed, were observed. All of the observations indicate a dry phase during this period. A third phase, from approximately 15,300 to 10,000calyr BP, was characterized by an increase in lacustrine productivity, as shown by an increased in TOC and chlorophyll derivate concentrations and accumulation rates. These increases likely correspond to a lake level rise due to a wetter climate.
The environmental quality of a Ramsar wetland site located at the Cananéia-Iguape-Peruíbe Protected Area (CIP-PA), in São Paulo, Brazil, was assessed by geochemical analyses and biomarker assessments ...(GPx, GST, GSH, GST, MT, LPO, DNA damage) performed in swimming crab
Callinectes danae
Smith, 1869 organs (posterior and anterior gills and hepatopancreas) to estimate sediment contaminant bioavailability. The results indicated that two sampling stations, PT and PM, exhibited the worst environmental conditions, as sediments collected at both points contained metal contamination, while crabs exhibited significant responses for GPx, GST, and LPO (mostly during winter). Sediment contamination tended to be associated to fine sediments (both seasons) and organic matter (winter). During the summer survey, Pb concentrations in sediments of station PT exceeded the Brazilian Sediment Quality Guidelines (SQGs) and the Canadian Interim Marine Sediment Quality Guidelines. Metal concentrations in sediments sampled in winter were higher compared with summer, with Co, Ni, and Pb exceeding SQGs levels at PT, whereas Co, Ni, Hg, Zn, and Pb exceeded SQGs at PM. Biomarker induction during summer appeared to be caused by natural variables (water salinity and temperature, and molting cycle), whereas oxidative stress and tissue damage during winter appeared to be more clearly linked to metal contamination. Anterior gills presented the clearest signs of seasonal variability, being more responsive to sediment contamination. The results suggest that metals originated from the upper Ribeira de Iguape River are transported toward the estuarine system, causing effects on
C. danae
individuals. Additionally, seasonality is a strong factor concerning CIP-PA toxicity, since the rainfall regime significantly modifies the freshwater flow and, consequently, estuarine water salinity, suspended particle and metal inputs, as well as the location of depositional areas. Thus, efforts to mitigate CIP-PA contamination should be based on the control of upstream pollution sources.
The potential association of acid-volatile sulfides (AVS) and reactive (HCl soluble) Fe with the distribution of reactive trace metals (Cu, Cd, Ni, Pb and Zn) was investigated in sediment cores ...collected in the Iguaçu river estuarine system (Guanabara bay, Brazil), within the river (core R) and the bay (core B) areas. Moderate to extremely high AVS concentrations (33–314 μmol
g
−1) were found in the rapidly-accumulated sediments of this eutrophicated estuary. AVS showed significant correlations with Fe, Ni and Pb in core B, whereas no correlation between AVS and metals was observed in core R. Results suggest that the AVS:Fe molar ratio may often reflect the diagenetic conditions controlling the distribution of Cd and Cu in core B better than AVS and Fe levels themselves. A shift in the biogeochemical controls of metal distribution from the river to the open bay sediments is suggested, with a greater association of most metals with AVS and Fe in bay sediments.
Guanabara Bay is an estuarine environment of great socio-economic importance, where around 12 million people live in its drainage basin. We aim to characterize the sedimentary matter of Guanabara ...Bay, two mangrove systems therein (Suruí and Piedade mangroves), and the rivers, São João do Merití, Iguaçu, Sarapui, Suruí, and Guapimirim, by performing sedimentological, mineralogical, elemental/isotopic organic matter composition (total organic carbon and total nitrogen,
13
C and
15
N) and organic matter petrography. Samples from the entrance of the bay present high values of quartz, low values of C/N ratio, and high percentages of diffuse amorphous organic matter indicating marine influence, whereas samples from rivers mouths present high percentages of translucent lignocellulosic, opaque lignocellulosic, gelified organic matter, and high C/N ratio probably due to the influence of terrestrial organic matter that comes from the drainage basin and the mangroves areas. Stations of the central sector of the bay were characterized by high percentages of TOC, intermediated values of δ
13
C, low C/N ratio, and also high diffuse amorphous organic matter indicating a predominant influence of organic matter from algae origin. High values of δ
15
N indicate large assimilation of nitrate or a high denitrification process in the highest productivity areas. In the river mouth regions, it is mainly influenced by terrestrial organic matter; however, in the northwestern and western sectors, organic matter is influenced both by terrestrial and domestic sewage influences which promote anaerobic decomposition of organic matter.
The preferential arsenic (As) accumulation in the central sector of the Guanabara Bay (a heavily impacted coastal system located in SE Brazil) is different from most metal contaminants, which present ...higher concentrations at harbour areas and the rivers mouths that drain large areas with highly deficient pollution control. The estuary is characterised by organic contents and minerals gradients, which induce different redox conditions and different biogeochemical process. Elemental and isotopic analyses on bulk organic matter, mineralogical and textural analyses of sediments were conjugated with a three-step sequential extraction procedure, based on the BCR method (Community Bureau of Reference). This approach was used to evaluate the potential of arsenic mobility. The distribution of the sum of arsenic in the three fractions presented a significant positive correlation with manganese mainly in the oxidised fraction (F2), which corresponded to the most representative fraction conditioned by physicochemical processes. In the exchangeable fraction (F1), which represents the most reactive arsenic phase, this element seems to be associated with the labile organic matter. The high productivity in the central sector might result in a greater deposition of arsenic in the sediment through co-precipitation with manganese deposition in an oxidising environment. Organic matter and sulphide in reducing environments were also found to be important factors controlling the distribution and speciation of arsenic, as indicated by the oxidizable fraction (F3) data.
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