RESUMO
Remobilization and deformation of surficial subaqueous slope sediments create turbidites and soft sediment deformation structures, which are common features in many depositional records. Palaeoseismic studies have used seismically-induced turbidites and soft sediment deformation structures preserved in sedimentary sequences to reconstruct recurrence patterns and - in some cases - allow quantifying rupture location and magnitude of past earthquakes. However, current understanding of earthquake-triggered remobilization and deformation lacks studies targeting where these processes take place, the subaqueous slope and involving direct comparison of sedimentary fingerprint with well-documented historical earthquakes. This study investigates the sedimentary imprint of six megathrust earthquakes with varying rupture characteristics in 17 slope sediment cores from two Chilean lakes, Riñihue and Calafquén, and evaluates how it links to seismic intensity, peak ground acceleration, bracketed duration and slope angle. Centimetre-scale stratigraphic gaps ranging from ca 1 to 20 cm - caused by remobilization of surficial slope sediment - were identified using high-resolution multi-proxy core correlation of slope to basin cores, and six types of soft sediment deformation structures ranging from ca 1 to 25 cm thickness using high-resolution three-dimensional X-ray computed tomography data. Stratigraphic gaps occur on slope angles of ≥2.3°, whereas deformation already occurs from slope angle 0.2°. The thickness of both stratigraphic gaps and soft sediment deformation structures increases with slope angle, suggesting that increased gravitational shear stress promotes both surficial remobilization and deformation. Seismic shaking is the dominant trigger for surficial remobilization and deformation at the studied lakes. Total remobilization depth correlates best with bracketed duration and is highest in both lakes for the strongest earthquakes (M w ca 9.5). In lake Riñihue, soft sediment deformation structure thickness and type correlate best with peak ground acceleration providing the first field-based evidence of progressive soft sediment deformation structure development with increasing peak ground acceleration for soft sediment deformation structures caused by Kelvin-Helmholtz instability. The authors propose that long duration and low frequency content of seismic shaking favours surficial remobilization, whereas ground motion amplitude controls Kelvin-Helmholtz instability-related soft sediment deformation structure development.
RESUMO
This study examines the mercury content in the marine matrices water column, surface sediment and benthic invertebrates of Coronel and Coliumo bays, central Chile, under winter and summer conditions. Coronel Bay has been subject to intense industrialization in the last three decades, while Coliumo Bay remains as a fisherman's cove and a popular summer tourism destination. Our results reveal significantly higher mercury concentrations in the three environmental matrices analyzed for Coronel Bay, while Coliumo Bay exhibits levels within the range considered natural. Moreover, the mercury levels in Coronel Bay exceed the optimal criteria for aquatic life, indicating a deterioration in environmental quality of this locality. Industrial development is identified as main factor explaining the differences observed between these two coastal water bodies. This study presents the most updated record of mercury levels in the Southeast Pacific and represents the first comprehensive evaluation of marine environmental matrices in two bays with divergent activities.
Assuntos
Mercúrio , Poluentes Químicos da Água , Mercúrio/análise , Chile , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , Água do Mar , Água , Biota , Baías , Sedimentos GeológicosRESUMO
Freshwater fishes are among the most threatened taxa worldwide owing to changes in land use, species introductions, and climate change. Although more than half of the freshwater fishes in the Chilean Mediterranean ecoregion are considered vulnerable or endangered, still little is known about their biogeography. Fishes of the family Perciliidae are endemic of this region and ideal cases to study potential implications of global warming given their endangered conservation status, small size, restricted range, and limited dispersal capacity in fragmented habitats. Here, we model the spatial distribution of habitats for Percilia irwini and P. gillissi under current (1970-2000) and future (2050-2080) climatic scenarios (SSP245, SSP585). We implement maximum entropy (MaxEnt) models adapted for stream networks using high-resolution datasets of selected geophysical and climatic variables. At present, both species inhabit relatively low-quality habitats. In the future (SSP585), suitable habitats for P. irwini are predicted to be reduced drastically (99%) with potential local extirpations in its northern range. Similarly, up to 62% of suitable habitats for P. gillissi would also be reduced in the future. Our study provides insights about assessing future threats and vulnerability of endemic, endangered, range-restricted, and small-bodied freshwater species in this region and elsewhere.
Assuntos
Mudança Climática , Ecossistema , Peixes , Animais , Peixes/fisiologia , América do Sul , Rios , Espécies em Perigo de Extinção , Conservação dos Recursos Naturais/métodos , Chile , Água DoceRESUMO
In recent years, Chile has experienced an extraordinary drought that has had significant impacts on both the livelihoods of people and the environment, including the Andean glaciers. This study focuses on analyzing the surface processes of Universidad Glacier, a benchmark glacier for the Dry Andes. Multiple remote sensing datasets are used alongside a novel spectral index designed for mapping of rock material located on the glacier's surface. Our findings highlight the precarious state of the glacier, which serves as a crucial water source for the region. The glacier exhibits locally varied debris accumulation and margin retreat. The most significant impacts are observed on the tongue and secondary accumulation cirques, with the latter at risk of disappearing. The debris cover on the tongue is expanding, reaching higher elevations, and is accompanied by glacier retreat, especially at higher altitudes. The equilibrium line is rapidly shifting upglacier, although the mid-season snow cover still frequently reaches the 2013 equilibrium line, even in 2020. Changes in stream density on the glacier tongue indicate an increased water supply in this area, likely due to enhanced melting of glacial ice. These observed processes align well with meteorological data obtained from reanalysis products. The behavior of dust and debris is influenced by precipitation amount, while the rate of retreat is linked to air temperature.
RESUMO
Cyanobacterial blooms have serious adverse effects on human and environmental health. In Latin America, one of the main world's freshwater reserves, information on this phenomenon remains sparse. To assess the current situation, we gathered reports of cyanobacterial blooms and associated cyanotoxins in freshwater bodies from South America and the Caribbean (Latitude 22° N to 45° S) and compiled the regulation and monitoring procedures implemented in each country. As the operational definition of what is a cyanobacterial bloom remains controversial, we also analyzed the criteria used to determine the phenomena in the region. From 2000 to 2019, blooms were reported in 295 water bodies distributed in 14 countries, including shallow and deep lakes, reservoirs, and rivers. Cyanotoxins were found in nine countries and high concentrations of microcystins were reported in all types of water bodies. Blooms were defined according to different, and sometimes arbitrary criteria including qualitative (changes in water color, scum presence), quantitative (abundance), or both. We found 13 different cell abundance thresholds defining bloom events, from 2 × 103 to 1 × 107 cells mL-1. The use of different criteria hampers the estimation of bloom occurrence, and consequently the associated risks and economic impacts. The large differences between countries in terms of number of studies, monitoring efforts, public access to the data and regulations regarding cyanobacteria and cyanotoxins highlights the need to rethink cyanobacterial bloom monitoring, seeking common criteria. General policies leading to solid frameworks based on defined criteria are needed to improve the assessment of cyanobacterial blooms in Latin America. This review represents a starting point toward common approaches for cyanobacterial monitoring and risk assessment, needed to improve regional environmental policies.
Assuntos
Cianobactérias , Humanos , América Latina , Toxinas de Cianobactérias , Lagos , ÁguaRESUMO
Responses at low levels of biological organization to evaluate environmental changes and water quality have been used for many years. South America is no different, and recently biochemical endpoints in fish have been used to assess the impacts of industrial and sewage effluents on wild fish populations. For Chilean native freshwater fish, basic biological data is scarce and data on 7-ethoxyresorufin-O-deethylase (EROD) and Acetylcholinesterase (AChE) activity is practically absent. Moreover, extensive variation in these two biochemical endpoints exists among species and seasons. In this article we evaluate seasonal variation in liver EROD and brain AChE activities in Trichomycterus areolatus and Percilia gillissi, two widely distributed native freshwater fish species in central Chile. We observed a marked seasonality in hepatic EROD activity in both species, with maximums for P. gillissi during winter months and sex differences in February, July, August and December. T. areolatus showed no sex differences, and peaks in EROD activity in the middle of summer, winter and late spring. Species differences in EROD activity were observed with activity being 1-2 orders of magnitude higher in P. gillissi compared to T. areolatus. Scarce seasonal variation and no sex related differences in brain AChE for both species were observed. Multivariate analysis (PCA) indicated that physical water quality parameters had some degree of responsibility for the seasonal responses found. The seasonal variability data of these biochemical endpoints were used to optimize study design for future monitoring programs, planning timing of sampling, increasing statistical power by collecting specific sample sizes required.
Assuntos
Acetilcolinesterase/metabolismo , Citocromo P-450 CYP1A1/metabolismo , Monitoramento Ambiental/normas , Peixes/metabolismo , Água Doce , Estações do Ano , Acetilcolinesterase/análise , Animais , Encéfalo/metabolismo , Chile , Citocromo P-450 CYP1A1/análise , Feminino , Fígado/metabolismo , Masculino , Fatores SexuaisRESUMO
The Patagonian Lakes have particular environmental conditions with or without intermittent disturbances. The study of the microorganisms present in aquatic ecosystems has increased notably because they can be used as micro-scale bioindicators of, among others, anthropogenic pollution and climatic change. The aim of the work was to compare the composition of the bacterial communities associated with sediments of three Patagonian Lakes with different geomorphologic patterns and disturbances. The lake sediments were characterized by molecular techniques, physiology profiles and physico-chemical analyses. The metabolic and physiological profiles of the microbial community demonstrated that non-impacted Tranquilo Lake is statistically different to impacted Bertrand and Plomo Lakes. Similar results were detected by DGGE profiles. FISH results demonstrated that betaproteobacteria showed the highest count in the Tranquilo Lake while gammaproteobacteria showed the highest counts in the Bertrand and Plomo Lakes, indicating that their sediments are highly dystrophic. The results demonstrate differences in the metabolic activity and structural and functional composition of bacterial communities of the studied lakes, which have different geomorphological patterns due to disturbances such as volcanic activity and the climatic change.
Assuntos
Bactérias/classificação , Bactérias/metabolismo , Biota , Lagos/microbiologia , Bactérias/genética , Chile , Eletroforese em Gel de Gradiente Desnaturante , Sedimentos Geológicos/microbiologia , Hibridização in Situ FluorescenteRESUMO
Among the main sources of atmospheric mercury emissions are thermoelectric plants that use coal to generate electricity. This heavy metal is transported by air from its origin to neighboring coastal areas, where it is deposited in the sediment record. This research evaluated the content and temporal distribution of Hg in the coastal sediments of Central Chile, Coronel Bay, industrialized zone with two operative thermoelectric plants, and Coliumo Bay, reference zone free of industry. To this end, sediment cores from the centers of the two bays were obtained. Laboratory results show that the greatest Hg contents were found in the surface strata of the Coronel Bay core, with concentrations up to an order of magnitude greater than those obtained in the same strata in Coliumo Bay. This increase in Hg concentration coincides with the beginning of industrial activity in Coronel, with greater concentrations observed from 2012 on, the year in which the industrial operation of two coal-fired thermoelectric plants on the bay began. Based on 210Pb activity and the relationships between Hg content and organic matter, it was established that the main pathway of Hg to sediment is atmospheric deposition, while Coliumo presented inputs that reflect local non anthropogenic sources.
Assuntos
Mercúrio , Poluentes Químicos da Água , Baías , Chile , Carvão Mineral , Monitoramento Ambiental/métodos , Sedimentos Geológicos , Mercúrio/análise , Poluentes Químicos da Água/análiseRESUMO
Polyurethane foam (PUF) disks in passive air samplers (PAS) and passive dry deposition (Pas-DD) collectors were used to assess the presence of persistent organic pollutants (POPs) and current-use pesticides (CUPs) in a rural area of central Chile (Peumo, VI Region). The samplers were exposed from September 2015 (spring) to March 2016 (summer), with the PUFs collected at intervals of 30, 60, and 90â¯days. Both samplers (PUF-PAS and Pas-DD) captured more than one pesticide per sampling period. Chlorpyrifos-ethyl and pyrimethanil presented the highest air concentration with PUF-PAS (3470.2â¯ngâ¯m-3 for chlorpyrifos-ethyl and 52.8â¯ngâ¯m-3 for pyrimethanil). The deposited amount of chlorpyrifos-ethyl, pyrimethanil, penconazole, diazinon and malathion in some Pas-DD, was superior to amount of pesticides captured by PUF-PAS. Differences between the amount deposited and captured by each sampler should be studied in greater detail, because wind speed, atmospheric particulate matter size and sampler design are some fundamental variables in this process. These results provide preliminary information on the presence of current-use pesticides in the atmosphere of Peumo, VI Region, serving as a foundation for future environmental monitoring programs.
RESUMO
In the last twenty years, pesticide use in Chile has increased more than 160%, generating a greater risk of water resources pollution. The objective of this study was to assess the presence of 22 pesticides and 12 degradation products in surface water samples from the Cachapoal River basin, Central Chile, an area characterized by intense agricultural activity. Pesticide concentrations in the dissolved phase (DP) and particulate phase (PP) in samples collected in the dry season and after precipitation events was assessed. The solid-phase extraction technique was used to preconcentrate the samples and GC/MS and LC/MS were used to detect pesticides. The results present spatio-temporal variations in the proportion and concentration of pesticides and their degradation products in both the DP and PP for each site and sampling period. The most ubiquitous compounds in the dissolved phase were atrazine, atrazine-2-hydroxy (HA), cyprodinil, pyrimethanil, and tebuconazole, while in the particulate phase HA, imidacloprid, diazinon and pyrimidinol were detected. The results presented in this study make up the first record of pesticides in the dissolved and particulate phases in surface water in Chile. They show that the problem of pesticide contamination undoubtedly affects the quality of bodies of water in agricultural areas in Chile and support the need for a proper assessment of the water quality of the Cachapoal River in the future.
Assuntos
Monitoramento Ambiental , Praguicidas/análise , Poluentes Químicos da Água/análise , Agricultura , Atrazina , Chile , Cromatografia Gasosa-Espectrometria de Massas , Neonicotinoides , Nitrocompostos , Rios/química , Estações do Ano , Extração em Fase Sólida , Água/químicaRESUMO
Mercury concentrations in the environment tend to decrease in recent years due to environmental restrictions. Lakes store mercury in their sediments, making them potential secondary contamination sources. In South America, the occurrence of mercury in lake systems has been associated mainly with volcanic emissions and only few records anthropogenic contamination in the pre-Hispanic period. The objective of this research was to study historical anthropogenic mercury concentration in two lakes in Central Chile (La Señoraza and Pillo), in order to establish background mercury levels and their variations from preindustrial to modern periods. Different background levels and mercury concentrations were found in each lake, with significantly higher concentrations in Lake La Señoraza during the last 150 years. Mining-related activities during the nineteenth century could have a negligible influence on mercury concentrations. Later on, the use of coal railroads and subsequent employment of mercury in the cellulose industry were associated with three- and fourfold increases in mercury concentration over the nineteenth century background levels, which decrease once these activities ceased. However, in the case of Lake Pillo, an important increase in mercury concentration can be observed between 1990 and the early twenty-first century, which could be related to a higher watershed/lake area ratio, extensive agriculture, and volcanic emission, being the latter that could have contributed with mercury to both systems. Nevertheless, sedimentological characteristics in Lake Pillo can be favorable to retain mercury in this aquatic system up to the present day.
Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Lagos/química , Mercúrio/análise , Poluentes Químicos da Água/análise , Chile , Monitoramento Ambiental/história , História do Século XIX , História do Século XX , História do Século XXI , Indústrias/história , Mineração/história , UrbanizaçãoRESUMO
Sediment cores from four Chilean lakes along the Andes Chain (Chungará, Laja, Castor and Venus) were analysed in order to investigate PCB concentrations and distributions in sediment samples. Sediment cores were analysed for PCBs using gas chromatography (GC-ECD/MS) and radioisotopically dated using 210Pb. Organic carbon content (OC) and 210Pb fluxes were also measured. Results showed that sediment PCB concentrations (ngg(-1) d.w.) at Lake Chungará (1.2 +/- 1) in northern Chile, Laja (5 +/- 4) in central, and in Lake Castor (3.5 +/- 4) in southern Chile (the eastern side of the Andes Mountain) were lower than sediments collected from Lake Venus (64 +/- 30) located in southern Chile (the western side) which contained 15-fold higher concentrations of PCBs. The percentage (%) of organic carbon was variable and showed a high range of values in the sediment fluctuating from 2% (Lake Laja) to 22% (Lake Chungará). Analysis of 210Pb fluxes, presented a decrease trend following Lake Laja>Castor>Chungará with a positive correlation with rainfall at each site. Sedimentation rates in Lake Castor (1846 gm(-2)yr(-1)) were higher than at Chungará (748 gm(-2)yr(-1)) and Lake Laja (508 gm(-2)yr(-1)). Focusing factor (FF) is used as a tool to elucidate PCB input in the aquatic ecosystem. FF were lower (<1) for the shallower lakes (Lakes Chungará and Castor). This study provides background levels of PCBs at remote lakes in Chile. Differences in geographical characteristics (orographic effect) might play an important role in the arrival of PCBs, particularly into the southern lakes. PCB fluxes indicated deposition of PCBs in recent sediments is higher than in previous years with peaks of PCB between 1991 and 1998. The continuing increase of PCB inputs in remote Chilean lakes, could be associated with long range atmospheric transport (LRAT).
Assuntos
Água Doce/análise , Sedimentos Geológicos/análise , Bifenilos Policlorados/análise , Poluentes Químicos da Água/análise , Carbono/análise , Chile , Cromatografia Gasosa-Espectrometria de Massas , Geografia , Radioisótopos de Chumbo/análiseRESUMO
Oxidation and removal of organic micropollutants (OMPs) on ultrapure (UPW) and natural water (NW) by ozone (O3) and ozone/powdered activated carbon (O3/PAC) have been studied. The OMPs atrazine (ATZ, herbicide), carbamazepine (CBZ, anticonvulsant), diclofenac (DCL, anti-inflammatory) and triclosan (TCS, antimicrobial) are incorporated continuously and uncontrolled on water treatment systems (e.g., drinking water treatment plants, wastewater treatment plants). Batch experiments on ultrapure and natural water showed that ATZ treated with O3 and O3/PAC has the slowest transformation rate (>90% at 30min reaction) while CBZ, DCL and TCS were oxidized very fast (>90% at ~5min). The radical scavenger tert-Butyl alcohol (TBA) was used to evaluate the contribution of HO on the OMPs oxidation. TBA, a hydrophilic compound with low adsorbability, was used as a strong HO scavenger to assess the role of the OH radical in the oxidation of the OMPs studied. ATZ oxidation was mainly driven by OH radicals. On the contrary, CBZ, DCL and TCS were removed by direct reaction with ozone. Infrared analysis (FTIR) showed changes in the PAC surface functional groups of the carbon exposed to ozone, decreasing its basic properties. The acute toxicity assays of the OMPs mixture dissolved in UPW performed with D. magna was significantly reduced by ozonation. The addition of PAC to the ozonation process, strongly improved the acute toxicity removal. Short chain mono- and di-carboxylic acids were identified as some of the oxidation intermediates formed during ozone treatment.
RESUMO
GOAL, SCOPE AND BACKGROUND: Chile signed the Stockholm Convention, which establishes measures to reduce or eliminate Persistent Organic Pollutants (POPs) release into the environment, including the prohibition of their use and reduction of secondary products release, as well as management related with waste treatment. Among POPs, PCBs are a family of 209 compounds that differ in chlorine level and position. These substances present a wide variability in their physicochemical properties such as vapor pressure, water solubility and partition coefficients that determine their behavior and mobility within the different environmental compartments. In Chile, as in other countries, the use of these compounds were and continue to occur in diverse industrial applications such as dielectric fluid in transformers and condensers, with a use in Chile of approximately 550,000 L. A sampling of bivalves was performed during the years 2000-2002 in order to obtain information on the spatial distribution of the PCB levels for the length of the long Chilean coast (18 degrees-54 degrees South latitude, 4,200 km), contributing in this way to a better understanding of the PCB trend and eventual fractionation along latitudinal gradients in Chile, using as the bivalve Perumytilus purpuratus ('Chorito Maico') bioindicator. METHODS: The marine bivalves Perumytilus purpuratus were collected in 16 localities in northern and southern Chile. All samples were lyophilized, and PCBs (51 congeners) were extracted in a Soxhlet system (24 h) with n-hexane. Samples were cleaned in florisil and analyzed by GC-ECD. Blanks, certified reference materials and standards were processed along with the samples. RESULTS AND DISCUSSION: The results obtained for P. purpuratus indicate a congeneric distribution profile associated to a latitudinal gradient, and the statistical analysis of the congeneric composition of the PCBs indicated five groups in relation to the molecular weight (number of chlorines), where the lighter congeners were observed in areas corresponding to high latitudes with total PCB values of 298 ng/g dry weight. CONCLUSION: P. purpuratus turns out to be a good bioindicator of PCB levels in the coastal areas of Chile due to its wide distribution. The highest concentrations and the more volatile congeners were found in southern Chile, which could be the result of processes of long-range transport or illegal discharge occurring in such remote areas. These results confirm previous data from the International Mussel Watch project ten years ago. RECOMMENDATION AND OUTLOOK: Future studies are needed to confirm our findings utilizing another environmental matrix such as soil/sediments and air samples.
Assuntos
Mytilidae , Bifenilos Policlorados/análise , Poluentes Químicos da Água/análise , Animais , Chile , Monitoramento Ambiental , Análise de Componente Principal , Água do MarRESUMO
This paper reports the occurrence of polyaromatic hydrocarbons (PAHs) deposition inferred from a sediment core of an Andean lake in south central Chile. Sediments were carefully collected from one of the deepest section of the lake and sliced every 1 cm. The samples were analyzed for PAHs, (137)Cs, (210)Pb, organic carbon and grain-size. The stratigraphic chronology and the sedimentation rates were estimated using the sedimentary signature left by the (137)Cs and (210)Pb fallout as temporal markers. PAHs were quantified by HPLC-fluorescence detection (HPLC-Fluorescence). 15 priority EPA PAHs were analyzed in this study. Based on these results, PAH deposition over the last 50 years was estimated (a period characterized by an important intervention in the area). PAH concentration ranged from 226 to 620 ng g(-1) d.w. The highest concentrations of PAHs were found in the core's bottom. The PAH profile is dominated by the presence of perylene indicating a natural source of PAH. In addition, two clear PAH deposition periods could be determined: the most recent with two-four rings PAHs, the older one with five-seven rings predomination. Determined fluxes where 71 to 972 microg m(-2) year(-1), dominated by perylene deposition. PAH levels and fluxes are lower compared to the levels found in sediments from remote lakes in Europe and North America. It is concluded that the main source of PAHs into the Laja Lake sediments are of natural origin.
Assuntos
Sedimentos Geológicos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Carbono/análise , Chile , Monitoramento Ambiental , Água Doce , Radioisótopos de Chumbo , Nitrogênio/análise , Tamanho da PartículaRESUMO
Superficial sediments from Lenga estuary in the VIII region of central Chile were analysed for Polychlorinated Biphenyls (PCBs) and Hexachlorobenzene (HCB). Organic carbon (OC) analysis was also performed and the statistical correlations (Pearson correlations) between compounds were also tested. Results showed the total PCB concentrations (ng g(-)(1)d.w.) fluctuated from â¼ 20 to 10,000. These levels are higher than those reported in other coastal sediments of the world. The PCB profile was dominated by middle to highly chlorinated congeners (6-Cl=40% and 7-Cl=30%). HCB concentrations (ng g(-)(1)d.w.), were lower than the PCBs and, fluctuated between 1 (at L1) and 870 (at L4). OC values ranged from 1% (L1) to 7% (L4) showing a significant positive correlations between OC% and PCBs (r=0.86; p<0.05) and for HCB (r=0.71). These results are an important contribution to knowledge of levels of POPs levels in coastal Chilean environments.
Assuntos
Monitoramento Ambiental , Estuários , Sedimentos Geológicos/química , Hexaclorobenzeno/análise , Bifenilos Policlorados/análise , Poluentes Químicos da Água/análise , ChileRESUMO
Few data exist on the possible effects of pulp and paper effluent discharge on native fish populations in the Southern Hemisphere, relative to the research done in the Northern Hemisphere. The present research examined two native fish species (Trichomycterus areolatus and Percilia gillissi) for effects at both the molecular and individual level due to the discharge of effluent from a tertiary treated elemental chlorine-free pulp mill into a fluvial system in Central Chile over three seasons (February 2007, October 2007, January 2008). Different responses were observed between species and between sexes. There was an increase in the production of gonadal 17ß-estradiol in the females of both species but a drop in 11-ketotestosterone production in P. gillissi males. Female gonadal size was increased, especially during the summer period, with corresponding increases the frequency of advanced oocyte development, and in the oocyte diameter in both species. Hepatic ethoxyresorufin-O-deethylase (EROD) activity was elevated for both species downstream of the discharge point, although overall it was higher in P. gillissi than T. areolatus. Decreases in the frequency of smaller-sized fish for both species, as well as a drop in the size of the adults downstream of the discharge point, were observed. The present study is the first evidence of endocrine disruption in native freshwater fish associated with modern pulp mills in South America. This study establishes possible links in the reproductive alterations observed at the subindividual and individual levels that could explain the changes observed at the population level.
Assuntos
Peixes-Gato/fisiologia , Disruptores Endócrinos/toxicidade , Resíduos Industriais/efeitos adversos , Perciformes/fisiologia , Poluentes Químicos da Água/toxicidade , Antagonistas de Receptores de Andrógenos/toxicidade , Animais , Chile , Citocromo P-450 CYP1A1/metabolismo , Monitoramento Ambiental , Estradiol/metabolismo , Feminino , Água Doce/química , Gônadas/efeitos dos fármacos , Gônadas/metabolismo , Fígado/efeitos dos fármacos , Masculino , Papel , Densidade Demográfica , Testosterona/análogos & derivados , Testosterona/metabolismoRESUMO
The Lenga Estuary is a small brackish wetland located southwest of San Vicente Bay, Region VIII, Chile. Surface sediment from nine sites in the estuary were analysed for PAHs and compared to Sediment Quality Guidelines (SQG). Sediment samples were freeze dried and soxhlet extracted for 16 h using DCM. Identification and quantification was carried out by HPLC. Organic carbon was also determined. Results showed total PAH concentrations ranged from 290 to 6118 (2025 ± 1975)ng g(-1) d.w. (2025 ± 1975). Results for organic carbon percentages ranged from 1% to 7%. Statistical analysis showed a significant positive correlation (Pearson test) between organic carbon percentage PAHs. Comparison of contaminant levels and international Sediment Quality Guidelines (SQG) (ERL and ER) suggested that sediment of the Lenga estuary did not show any ecotoxicological risk for benthic organisms where high levels of PAHs were detected. Monitoring of this and other contaminants is recommended in Chile.
Assuntos
Sedimentos Geológicos/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Chile , Monitoramento Ambiental/métodos , Água Doce/química , Água do Mar/química , Poluição Química da Água/estatística & dados numéricosRESUMO
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment; they are of concern due to their toxic properties. Anthropogenic activities could contribute in a significant way to the total burden of PAHs in remote mountain areas. In this work, we document the analysis of PAHs deposition through sedimentary records obtained in three remote Andean lakes located in south central Chile. Sediment cores were taken in one of the deepest sections of each lake, ranging from 45 to 135 m depth. Sediments were carefully extruded in 1-cm layers for PAHs and dating analysis (210Pb and 137Cs). Sixteen Environmental Protection Agency prioritary PAHs were analyzed using high-performance liquid chromatography with fluorescence detection. Dating of sediments was possible for only two lakes (Laja and Galletue). The superficial composition of PAHs in each lake is rather similar with a characteristic dominance of perylene; levels ranged 355 to 3050 ng g(-1) d.w. Depositional fluxes averaged 118 microg m2 year(-1) in Laja Lake in contrast to that in Galletue Lake, where average fluxes reach 434 microg m2 year(-1). Dating back to 50 years, PAH profiles did not experience drastic changes despite the rapid development of industrialization over the past 30 years in the surrounding region, indicating that levels and composition remains fairly similar to those of the present. Finally, determined fluxes were in the lower range of depositional fluxes calculated for lakes located in the industrialized northern hemisphere.