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- Stepwise strategy for monitoring toxic cyanobacterial blooms in lentic water bodiesPublication . Macário, Inês P E; Castro, Bruno B; Nunes, Isabel M S; Pizarro, Cristina; Coelho, Carla; Gonçalves, Fernando; de Figueiredo, Daniela RClimate change has been causing the increase in frequency, severity, and duration of harmful algal blooms, which makes the establishment of water management strategies indispensable. For cyanobacteria, several methods are currently used in monitoring programs. However, these methods are time-consuming and require specialists, and results are usually not provided within an adequate timeframe for taking timely mitigation actions. This work proposes a strategy for a faster, easier, and more cost-effective monitoring of cyanobacterial blooms, using a stepwise approach based on fluorometric determination of phycocyanin at an early stage. Complementary parameters (chlorophyll a, enumeration of dominant cyanobacterial species and cyanotoxin potential and quantification) are determined when necessary, thus progressively allocating human and financial resources within the monitoring program. This strategy was applied and validated using nine lentic eutrophic freshwater bodies prone to the occurrence of cyanobacterial blooms. Samples were sequentially evaluated, and the study ended up with two samples that showed high health risks. However, according to WHO guidelines, eight of the nine samples would be classified as having "moderate risk of adverse health effects" and could lead to preventive measures that would have an important regional economic impact. Therefore, the present approach proved to be a promising alternative to increase the effectiveness and accuracy of the risk assessment process in water bodies where cyanobacterial blooms occur.
- Toxicity of environmental pollutants: from the bench research to human biomonitoring studiesPublication . Pinto, Miguel; Sacadura, Joana; Louro, Henriqueta; Costa, Pedro Manuel; Lavinha, João; Costa, Maria Helena; Caeiro, Sandra; Silva, Maria JoãoBeing subjected to diverse anthropogenic pressures, from industrial to agricultural activities, estuaries have long been regarded as ecosystems particularly sensitive to contamination. A recent study addressed the potential adverse effects of the Portuguese Sado river sediment contaminants on human and ecosystem health. Several complementary approaches were used to assess the effects on human health, including: (i) an epidemiological one to characterize the exposure pathway to the estuary environment; (ii) an in vitro characterization of the genotoxic potential of sediments’ contaminants in a human cell line; (iii) an in vivo study of gene and chromosome alterations induction in LacZ plasmid-based transgenic mice. The epidemiological survey confirmed the occurrence of direct and indirect (through food chain) exposure of the local population to estuarine contaminants. On the other hand, the complex mixture of contaminants extracted from sediments, which contain metals and polycyclic aromatic hydrocarbons, was toxic to human liver cells exposed in vitro, causing cell death, oxidative stress and genetic damage [3, 4]. Furthermore, the results of an in vivo study showed a time-dependent increase in chromosome damage in blood immature erythrocytes but did not show induction of mutations in liver cells or DNA damage in blood, spleen, kidney or liver cells of exposed comparatively to control mice. Although the histopathological analysis of liver tissues did not reveal specific alterations associated with exposure, changes observed in hepatocytes structures indicated that liver function related to carbohydrate metabolism and storage was compromised, therefore revealing an important chronic effect. Overall, the complementary approaches used in this study suggested that the exposure of local populations to the Sado river estuary contaminants may have a negative impact on their health. Nevertheless, there is still a need to perform a biomonitoring study, i.e., obtain and integrate data from exposure and from cellular and molecular biomarkers of early biological effects and susceptibility in the exposed comparatively to a control population, in order to try to derive an indicator of risk of estuary-associated chronic diseases.