Evaluation Of Human Health Risks Research Articles

Ecotoxicological and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Short-Neck Clam (Paphia undulata) and Contaminated Sediments in Malacca Strait, Malaysia.

The distribution, sources, and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediment and the edible tissue of short-neck clam (Paphia undulata) from mudflat ecosystem in the west coast of Malaysia were investigated. The concentrations of ∑16 PAHs varied from 347.05 to 6207.5 and 179.32 to 1657.5ngg-1 in sediment and short-neck clam samples, respectively. The calculations of mean PEL quotients (mean-PELQs) showed that the ecological risk of PAHs in the sediment samples was low to moderate-high level, whereas the total health risk through ingestion and dermal contact was considerably high. The PAHs biota sediment accumulation factors data for short-neck clam were obtained in this study, indicating a preferential accumulation of lower molecular weight PAHs. The source apportionment of PAHs in sediment using positive matrix factorization model indicated that the highest contribution to the PAHs was from diesel emissions (30.38%) followed by oil and oil derivate and incomplete coal combustion (23.06%), vehicular emissions (16.43%), wood combustion (15.93%), and natural gas combustion (14.2%). A preliminary evaluation of human health risk using chronic daily intake, hazard index, benzo[a]pyrene-equivalent (BaPeq) concentration, and the incremental lifetime cancer risk indicated that PAHs in short-neck clam would induce potential carcinogenic effects in the consumers.

Evaluation of Concentrations and Human Health Risk of Cu, Zn, Fe in Two Periwinkles Species from Three Local Government Areas, Bayelsa State, Nigeria.

This study has investigated the concentrations of Cu, Zn and Fe in P. aurita and T. fuscatus obtained from Bayelsa State, Nigeria and assessed the health risks associated with the consumption of these shellfishes. The concentrations of the metals in mg/kg dry wt basis mean + SD were Cu (57.0 + 4.0) Zn (63.8 + 9.6) and Fe (1260 + 159.2) in P. aurita, while T. fuscatus were, Cu (33.3 + 1.43), Zn (77.7 + 9.19) and Fe (1985 + 4.89). These values were higher than the guideline of WHO, and FEPA. The estimated daily intake of the metals in the periwinkles was all higher than their provisional tolerable daily and weekly intakes set by regulatory bodies. The non-carcinogenic risks (THQ and HI) of the individual and combined risk of the metals were within the limit of 1 set by USEPA, indicating no health risk at the moment. However, considering the bioaccumulative nature of heavy metals moderate intake of these periwinkles are recommended to avoid human health risk to consumers in future. Key words : Heavy metal, Pollution, Risk Assessment, Perewinkles.

Organochlorine pesticides in soil, air, and vegetation at and around a contaminated site in southwestern China: Concentration, transmission, and risk evaluation

Remediation and management of contaminated sites have become a prevalent problem under the current situation in China. The present study was conducted to investigate the concentration, transmission, and health risk of organochlorine pesticides (OCPs) in soil, air, and vegetation at and around a typical pesticide-contaminated site located in southwestern China. Exchange flux between soil and air was calculated to investigate the transmission of OCPs. Hexachlorocyclohexane (ΣHCHs, top soil: 19.1 mg/kg d.w., air: 52.3 ng/m3, vegetation: 0.17 mg/kg d.w.) and dichlorodiphenyltrichloroethane (ΣDDTs, top soil: 200 mg/kg d.w., air: 130 ng/m3, vegetation: 0.78 mg/kg d.w.) were the dominant pollutants at the contaminated site. Around the site, the soil, air, and vegetation samples had higher OCP concentrations than those in the normal areas, which were found to be dominated by ΣHCHs (top soil: 129 ng/g d.w., air: 5.09 ng/m3, vegetation: 81.8 ng/g d.w.) and ΣDDTs (top soil: 360 ng/g, air: 7.47 ng/m3, vegetation: 189 ng/g d.w.). The fugacity fractions of OCPs (>0.7) showed a net volatilization from soil into air, indicating that soil is an obvious pollution source for the atmosphere, especially at the site. Through human health risk evaluation, serious carcinogenic risk (CRn) and hazardous index (HIn) were found at the site (CRn: 7.4 × 10−6–1.04 × 10−4, HIn: 0.02 to 8.97) and the nearby areas (CRn: 3.37 × 10−6 for adults and 1.68 × 10−6 for children on average).

A regional approach to the environmental risk assessment - Human health risk assessment case study in the Campania region

Environmental quality is fundamental for the wellbeing of human life. Environmental risk assessment and analysis have a crucial role in the evaluation of human health risk, especially in intensive urbanized and industrialized areas, such as the Campania region (Italy). In Italy, after the Legislative Decree 152/2006, the environmental risk assessment has become mandatory for contaminated lands such as brownfield sites.For the purposes of the present study 3535 topsoil samples were collected across the whole regional territory. The concentrations of 53 elements have been determined by aqua regia extraction followed by a combination of ICP-MS and ICP-AES methods.A new approach to assess/rank environmental risk was applied by using geospatial analysis in a GIS platform to adapt a European-wide accepted methodology for the preliminary assessment of human health risks at single contaminated sites to a regional scale.The methodology chosen for the risk assessment procedures is the PRA.MS (Preliminary Risk Assessment Model for the identification and assessment of probelm areas for Soil contamination in Europe). Following the PRA.MS guidelines, a conceptual model for the human health risk assessment in the Campania region has been based on four different exposure routes: 1) dispersion of contaminants in groundwater, 2) dispersion in surface water, 3) dispersion in air, and 4) direct contact with the contaminated media (soil). The source, pathway and receptor for each exposure route are scored fusing a quantitative or qualitative analysis of some characteristic features (parameters).A total of 14 representative parameters were chosen, based on the available regional data for Campania. Starting from the values of these parameters, the information is aggregated to higher levels in several steps, adopting a mixed additive and multiplicative algorithm, up to the overall risk score. The final risk map is classified into four risk classes. This map is useful for identifying high risk areas, where monitoring and more detailed analysis has to be carried out.

Real-time monitoring of respiratory absorption factors of volatile organic compounds in ambient air by proton transfer reaction time-of-flight mass spectrometry

Respiratory absorption factors (AFs) are essential parameters in the evaluation of human health risks from toxic volatile organic compounds (VOCs) in ambient air. A method for the real time monitoring of VOCs in inhaled and exhaled air by proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) has been developed to permit the calculation of respiratory AFs of VOCs. Isoprene was found to be a better breath tracer than O2, CO2, humidity, or acetone for distinguishing between the expiratory and inspiratory phases, and a homemade online breath sampling device with a buffer tube was used to optimize signal peak shapes. Preliminary tests with seven subjects exposed to aromatic hydrocarbons in an indoor environment revealed mean respiratory AFs of 55.0%, 55.9%, and 66.9% for benzene, toluene, and C8-aromatics (ethylbenzene and xylenes), respectively. These AFs were lower than the values of 90% or 100% used in previous studies when assessing the health risks of inhalation exposure to hazardous VOCs. The mean respiratory AFs of benzene, toluene and C8-aromatics were 66.5%, 70.2% and 82.3% for the three female subjects; they were noticeably much higher than that of 46.4%, 45.2% and 55.3%, respectively, for the four male subjects.

Spatial response surface modelling in the presence of data paucity for the evaluation of potential human health risk due to the contamination of potable water resources

Potential human health risk from waterborne diseases arising from unsatisfactory performance of on-site wastewater treatment systems is driven by landscape factors such as topography, soil characteristics, depth to water table, drainage characteristics and the presence of surface water bodies. These factors are present as random variables which are spatially distributed across a region. A methodological framework is presented that can be applied to model and evaluate the influence of various factors on waterborne disease potential. This framework is informed by spatial data and expert knowledge. For prediction at unsampled sites, interpolation methods were used to derive a spatially smoothed surface of disease potential which takes into account the uncertainty due to spatial variation at any pre-determined level of significance. This surface was constructed by accounting for the influence of multiple variables which appear to contribute to disease potential. The framework developed in this work strengthens the understanding of the characteristics of disease potential and provides predictions of this potential across a region. The study outcomes presented constitutes an innovative approach to environmental monitoring and management in the face of data paucity.

Metals Contents in Black Tea and Evaluation of Potential Human Health Risks to Consumers

Tea is one of the most common beverages in all over the world. Next to water, it is the most consumed beverage. During the last decades, there has been an extensive increase in the level of heavy metals in tea and other foods. The contamination of tea by heavy metals may pose a serious threat to human due to their toxicity, wide sources, non-biodegradable properties and accumulative behaviors. The aim of this study was to investigate the copper, iron and lead content of several commercially available brands of tea (Camellia sinensis) in Egypt. Ten of the most widely consumed brands of black tea were purchased from local markets. Copper, Iron and Lead contents in the tea were determined by atomic absorption spectrophotometer after acid digestion. Among the investigated metals Fe was the highest (193.82 μg/g). Copper was the second highest (16.18 μg/g) metal found in black tea samples, whereas Pb showed minimum levels (1.41 μg/g). The data obtained in the present work compared well with the counterpart data reported internationally. Based upon the present safety standards, the tea versions selected in the present study were found to be safe for human consumption. On the other hand, routine check and frequent analysis of foodstuff is also required with intention to avoid the risk of exceeding the intake beyond the tolerance limits standards.

Evaluation of potential human health risk and investigation of drinking water quality in Isparta city center (Turkey).

Isparta city center is selected as a work area in this study because the public believes that the tap water is dirty and harmful. In this study, the city's drinking water in the distribution system and other spring waters which are used as drinking water in this region were investigated from the point of water quality and health risk assessment. Water samples were collected from major drinking water springs, tap waters, treatment plants and dam pond in the Isparta province center. Ca-Mg-HCO3, Mg-Ca-HCO3, Ca-Na-HCO3, Ca-HCO3, Ca-HCO3-SO4 and Ca-Mg-HCO3-SO4 are dominant water types. When compared to drinking water guidelines established by World Health Organization and Turkey, much greater attention should be paid to As, Br, Fe, F, NH4, PO4 through varied chemicals above the critical values. The increases of As, Fe, F, NH4 and PO4 are related to water-rock interaction. In tap waters, the increases of As and Fe are due to corrosion of pipes in drinking water distribution systems. The major toxic and carcinogenic chemicals within drinking water are As and Br for both tap water and spring water. Also, F is the non-carcinogenic chemical for only spring waters in the study area.

Evaluation of human health risk for a population from Cali, Colombia, by exposure to lead, cadmium, mercury, 2,4-dichloro-phenoxyacetic acid and diuron associated with water and food consumption

Exposure to pollutants such as pesticides and heavy metals has been linked to health problems. Several studies have revealed the presence of these contaminants in Cali; however, there is no information available about the main routes of exposure and risk of these contaminants. To estimate the risk associated with the intake of cadmium, lead and mercury, and pesticides 2,4-D and diuron through the consumption of water and food in a population in Cali. Population and environmental data were obtained, and a risk assessment was performed using United States Environmental Protection Agency guidelines. The concentrations of the evaluated pollutants were below permissible levels as established by the Colombian Ministerio de Ambiente, Vivienda y Desarrollo Territorial (3 µg/L -1 of cadmium; 10 µg/L -1 of lead; 1 µg/L -1 of mercury; 1 µg/L -1 of 2,4 D; 1 µg/L -1 of diuron). Salema butterfish ( Peprilus snyderi ) samples contained levels of cadmium between 20 and 80 µg/kg -1 , which are below the permissible limit set by the World Health Organization (100 µg/kg -1 ). The results of the risk assessment indicated that the carcinogenic and non-carcinogenic attributable risk to population health from the intake of food contaminants was below the maximum level permitted by the United States Environmental Protection Agency. It is believed that the findings in previous studies on pollutants may have been due to specific contamination events; therefore, monitoring and early warning about water intake is recommended. Furthermore, the report of cadmium being found in fish consumed as food suggests the need for quality control by regulators.

Adsorption of uranium composites onto saltrock oxides – experimental and theoretical study

The study encompassed experimental mass spectrometric and theoretical quantum chemical studies on adsorption of uranium species in different oxidation states of the metal ion, and oxides of UxOyn+ type, where x = 1 or 3, y = 2 or 8, and n = 0, 1 or 2 onto nanosize-particles of saltrock oxides MO (M = MgII, CaII, NiII, CoII, SrII or BaII), M2Oy (M = AuIII or AgI, y = 3 or 1) silicates 3Al2O3.2SiO2, natural kaolinite (Al2O2·2SiO2·2H2O), illite (K0.78Ca0.02Na0.02(Mg0.34Al1.69FeIII0.02)[Si3.35Al0.65]O10(OH)2·nH2O), CaSiO3, 3MgO·4SiO2,H2O, and M1M2(SiO4)X2 (M1 = M2 = Al or M1 = K, M2 = Al, X = F or Cl), respectively. The UV-MALDI-Orbitrap mass spectrometry was utilized in solid-state and semi-liquid colloidal state, involving the laser ablation at λex = 337.2 nm. The theoretical modeling and experimental design was based on chemical-, physico-chemical, physical and biological processes involving uranium species under environmental conditions. Therefore, the results reported are crucial for quality control and monitoring programs for assessment of radionuclide migration. They impact significantly the methodology for evaluation of human health risk from radioactive contamination. The study has importance for understanding the coordination and red-ox chemistry of uranium compounds as well. Due to the double nature of uranium between rare element and superconductivity like materials as well as variety of oxidation states ∈ (+1)–(+6), the there remain challenging areas for theoretical and experimental research, which are of significant importance for management of nuclear fuel cycles and waste storage.

Distribution of polycyclic aromatic hydrocarbon (PAH) residues in several tissues of edible fishes from the largest freshwater lake in China, Poyang Lake, and associated human health risk assessment

The residual levels, tissue distribution and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in edible fishes, bighead carp (Aristichthys nobilis) and silver carp (Hypophthalmichthys molitrix), from the largest freshwater lake in China, Poyang Lake, were studied. PAH concentrations ranged from 105 to 513ngg−1ww and from 53.9 to 401ngg−1ww in different tissues of bighead carp and silver carp, respectively. Low molecular weight (LMW) PAHs were the predominant compounds, suggesting the gill-water transfer might be the major exposure route for PAHs in the studied fish species. Tissue distribution indicated that the hepatobiliary system accumulated higher concentrations of PAHs than the extrahepatic tissues with bile being the most predominant tissue for both species. Composition analysis demonstrated that PAHs were from the combined petrogenic and pyrogenic origin, and the gasoline combustion might be the main source. A preliminary evaluation of human health risk using benzo[a]pyrene (BaP) potency equivalent concentration (PEC) as well as the incremental lifetime cancer risk (ILCR) indicated that PAHs in fish would induce potential carcinogenic effects.

Evaluation of human health risks posed by carcinogenic and non-carcinogenic multiple contaminants associated with consumption of fish from Taihu Lake, China

The present study estimated the human daily intake and uptake of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and toxic trace elements [mercury (Hg), chromium (Cr), cadmium (Cd), and arsenic (As)] due to consumption of fish from Taihu Lake, China, and the associated potential health risks posed by these contaminants. The health risks posed by the contaminants were assessed using a risk quotient of the fish consumption rate to the maximum allowable fish consumption rate considering the contaminants for carcinogenic and non-carcinogenic effect endpoints. The results showed that fish consumption would not pose non-cancer risks. However, some species would cause a cancer risk. Relative risks of the contaminants were calculated to investigate the contaminant which posed the highest risk to humans. As a result, in view of the contaminants for carcinogenic effects, As was the contaminant which posed the highest risk to humans. However, when non-carcinogenic effects of the contaminants were considered, Hg posed the highest risk. The risk caused by PBDEs was negligible. The results demonstrated that traditional contaminants, such as As, Hg, DDTs (dichlorodiphenyltrichloroethane and its metabolites), and PCBs, require more attention in Taihu Lake than the other target contaminants.

Human health risk evaluation of selected VOC, SVOC and particulate emissions from scented candles

Airborne compounds in the indoor environment arise from a wide variety of sources such as environmental tobacco smoke, heating and cooking, construction materials as well as outdoor sources. To understand the contribution of scented candles to the indoor load of airborne substances and particulate matter, candle emission testing was undertaken in environmentally controlled small and large emission chambers. Candle emission rates, calculated on the basis of measured chamber concentrations of volatile and semi-volatile organic compounds (VOC, SVOC) and particulate matter (PM), were used to predict their respective indoor air concentrations in a standard EU-based dwelling using 2 models: the widely accepted ConsExpo 1-box inhalation model and the recently developed RIFM 2-box indoor air dispersion model. The output from both models has been used to estimate more realistic consumer exposure concentrations of specific chemicals and PM in candle emissions. Potential consumer health risks associated with the candle emissions were characterized by comparing the exposure concentrations with existing indoor or ambient air quality guidelines or, where not existent, to established toxicity thresholds. On the basis of this investigation it was concluded that under normal conditions of use scented candles do not pose known health risks to the consumer.

Use of a commercial enzyme-linked immunosorbent assay for rapid detection of Giardia duodenalis in dog stools in the environment

Giardia duodenalis is considered a potentially zoonotic protozoan. Some animal species, including infected dogs, may play an important role in the spread of Giardia cysts through environmental contamination with their feces. In the present study, a commercial enzyme-linked immunosorbent assay (ELISA) was used to examine 143 samples of dog feces collected in urban areas as an indicator of the risk of field contamination. Using a Bayesian statistical approach, the ELISA showed a sensitivity of 88.9% and a specificity of 95.8% with positive and negative predictive values of 89.6% and 95.4%, respectively. The test affords the advantage of rapid processing of fecal samples without a complex technical structure and extensive costly labor. Moreover, the present results show that the assay provides public health veterinarians with a practical tool that can be used in screening programs, as a valid alternative or as an adjunct to other tests, in order to assess the biological risk of exposure to G. duodenalis cysts from dogs in human settlements. However, the test may not be completely accurate for human health risk evaluation, as it does not discriminate between zoonotic and non-zoonotic isolates.

Introducing a land-use-based spatial analysis method for human health risk evaluation of soil heavy metals

A land-use-based method for potential human health risk analysis was introduced by employing soil sampling data in Zhuzhou City, China. It was found that distribution and sources of heavy metals (As, Cd, Pb, Zn and Cr) in soil had a large variation among different land-use types. A total of 8.3 % of the study area recorded a hazard index (HI) above the threshold of 1.0. High HIs were located mainly in the industrial area. The largest contribution to HI was the arsenic (over 87 %) and the pathway of soil ingestion (about 76 %). The mean standardized error and root mean square standardized error indicated that the land-use-based simulation method provided more accurate estimates than the method that applied geostatistical methods to the whole study area and did not consider land-use information. The areas of greater concern for human health can be spatially identified and health risks can be better quantified by evaluation of different land-use types.

The Volatilization of Pollutants from Soil and Groundwater: Its Importance in Assessing Risk for Human Health for a Real Contaminated Site

Pollution of different elements (air, water, soil and subsoil) resulting both from accidental events and from ordinary industrial and civil activities causes negative effects on the human health and on the environment. The present paper examines the analysis of a contaminated site, focusing the attention on the negative effects for receptors exposed to soil and groundwater contamination caused by industrial activities. The case study investigated is a contaminated area located in the industrial district of Trento North once occupied by the Italian Carbochimica plant. Pollution in that area is mainly due to contamination of soil and groundwater with polycyclic aromatic hydrocarbons. The methodology applied is the risk evaluation for human health, in terms of individual cancer risk and hazard index. In particular the attention has been focused on a specific migration way: if pollutants in the soil or in the groundwater undergo a phase change, they spread and get to the soil surface, causing a dispersion of vapors in the atmosphere. In this case risk assessment calls for the evaluation of volatilization factor. Among the different models dealing with the estimation of volatilization factor, those mostly known and used in the national and international field of Human Health Risk Assessment were chosen: Jury’s and Farmer’s models. A sensitivity analysis of models was performed, in order to identify the most significant parameters to estimate the volatilization factors among the wide range of input parameters for the application of models. Performing an accurate selection and data processing of the contaminated site, models for the volatilization factors calculation are applied, thus evaluating air concentrations and Human Health Risk. The analysis of the resulting estimates is an excellent aid to draw interesting conclusions and to verify if the soil and groundwater pollutants volatilization affects the human health considerably.

Trace elements concentrations (Zn, Cu, Pb, Cd, As and Hg) in the Mediterranean mussel (Mytilus galloprovincialis) and evaluation of mussel quality and possible human health risk from cultivated and wild sites of the southeastern Adriatic Sea, Montenegro

The Mediterranean mussel Mytilus galloprovincialis (L) was collected from the fall 2005 to the winter 2009 from the six sites on the Montenegrin coastline. Two wild samples were collected from the open sea coastline, and two cultivated and two wild were from the Boka Kotorska Bay. The mussels soft tissue was analyzed for zinc (Zn), copper (Cu), lead (Pb), cadmium (Cd), arsenic (As) and total mercury (Hg). Concentrations of these metals ranged from 135.5-210 for Zn, 6.2-14.5 for Cu, 4.0-11.5 for Pb, 1.7-2.1 for Cd, 5.8-12.4 for As and 0.11-0.51 for Hg, in mg kg-1 dry weight. The metals were found to be present in the samples at different levels, but not in concentrations higher than maximum residual levels prescribed by the European Union (EU) and US Food and Drug Administration (USFDA) regulations for seafood. This indicates that the consumption of wild or cultivated mussels from the studied area is safe in moderate quantities.

Burdens of mercury in residents of Temirtau, Kazakhstan: II: Verification of methodologies for estimating human exposure to high levels of Hg pollution in the environment

A considerable amount of work has been conducted developing exposure estimate models for quantitative evaluation of mercury (Hg) intake and human health risks, but few have assessed the applicability and the validity for evaluating the risks posed by Hg in the environment and have achieved very mixed results. The present study focused on verifying estimated daily Hg intake using exposure equations with either the deterministic or probabilistic (the Monte Carlo) approaches. The simulated daily Hg intake doses were compared with those established from measured Hg concentrations in the hair of 289 participants. The results showed that the single-value deterministic method for simulating Hg exposure levels overestimated the level of risk by a factor of 1.5 when compared with the highest concentration of Hg observed in the hair of the study population. Contrarily, the average daily Hg intake doses simulated using the probabilistic simulation were similar in distribution to the biomarker data. When the reference dose (RfD) of 0.1 μg/kg body weight/day was adopted as the acceptable dose for daily intake rate, there were approximately 19% estimated to have potential Hg exposure risks based on the Monte Carlo simulation. This percentage was favourably similar to the 17% determined from Hg concentrations in the hair samples. The difference between the probabilistic simulation and the data derived from hair Hg levels was considered mainly due to the uncertainties in unconfirmed questionnaire-based survey data, small sampling sizes and the surrogates used in the exposure models. The findings implied that the existing exposure models together with the probabilistic approach were appropriate for research of human exposure to Hg.

Evaluation of Efficacy and Human Health Risk of Aerial Ultra-Low Volume Applications of Pyrethrins and Piperonyl Butoxide for Adult Mosquito Management in Response to West Nile Virus Activity in Sacramento County, California

The Sacramento and Yolo Mosquito and Vector Control District (SYMVCD, also referred to as "the District") conducts surveillance and management of mosquitoes in Sacramento and Yolo counties in California. Following an increase in numbers and West Nile virus (WNV) infection rates of Culex tarsalis and Culex pipiens, the District decided on July 26, 2007, to conduct aerial applications of Evergreen EC 60-6 (60% pyrethrins: 6% piperonyl butoxide) over approximately 215 km2 in the north area of Sacramento County on the nights of July 30, July 31, and August 1, 2007. At the same time, the District received notification of the first human WNV case in the area. To evaluate the efficacy of the applications in decreasing mosquito abundance and infection rates, we conducted pre- and post-trapping inside and outside the spray zone and assessed human health risks from exposure to the insecticide applications. Results showed a significant decrease in abundance of both Cx. tarsalis and Cx. pipiens, and in the minimum infection rate of Cx. tarsalis. Human-health risks from exposure to the insecticide were below thresholds set by the US Environmental Protection Agency.

Microcystin–LR, –RR, –YR and –LA in water samples and fishes from a shallow lake in Argentina

We evaluated the presence of four common microcystins (MC–LR, –RR, –YR and –LA) in water samples and tissues (liver and muscle) of Odontesthes bonariensis collected in Los Padres Lake (Argentina). MCs were quantified by HPLC–ESI-MS/MS. The total content of MCs in water samples (2.8 ± 5.6 μg L −1) and in O. bonariensis muscle (3.9 ± 2.2 μg kg −1) never surpassed guidelines values recommended by WHO for either recreational use of water or fish consumption. The total content of MCs in O. bonariensis liver was 33.6 ± 37.2 μg kg −1. However, we observed both spatial and temporal changes in MC profile, suggesting the need of an intensive monitoring program at such lake to ensure the health of people living in its surrounding. We observed a significant correlation between the content of total and dissolved MC in water and the concentration of these toxins in liver, showing the probable uptake of dissolved MC by O. bonariensis. MC–RR was the dominant variant in water samples, followed by MC–LA and MC–LR. MC–YR was always present in water samples, but in the lowest concentrations of the congeners measured. MC content in liver in O. bonariensis was ten-fold higher than the corresponding content in fish muscle. However, MCs were present in muscle of O. bonariensis during both wet and dry season, while we could not detect MCs in liver during the dry season. These results demonstrate that MC accumulation in liver and muscle of O. bonariensis occurred with different profiles. Moreover, different uptake, tissue distribution and excretion pathways may occur between diverse MC variants. For instance, during the dry season, an increase in the relative percentage of MC–LR in water samples was accompanied with an augmentation in the relative percentage of this toxin in muscle of O. bonariensis. Conversely, a rise in the relative percentage of MC–LA in water samples during the dry season did not impact on the distribution of this toxin in fish muscle. These results suggest the need of further studies on dynamics of different variants of MC to pursuit a complete evaluation of human health risk associated to MC occurrence.