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- Analysis of the use of microcystin-contaminated water in the growth and nutritional quality of the root-vegetable, Daucus carotaPublication . Machado, J.; Azevedo, J.; Freitas, Marisa; Pinto, Edgar; Almeida, A.; Vasconcelos, V.; Campos, A.Toxic cyanobacterial blooms are often observed in freshwaters and may reflect the increased eutrophication of these environments and alterations in climate. Cyanotoxins, such as microcystins (MCs), are an effective threat to many life forms, ranging from plants to humans. Despite the research conducted to date on cyanotoxins, the risks associated to the use of contaminated water in agriculture require further elucidation. To tackle this aim, a research was conducted with the root-vegetable Daucus carota. The specific aims of this work were the following: (i) to evaluate the effects of MC-LR on the plant growth and photosynthesis; (ii) to evaluate the nutritional quality of carrot roots; and (iii) to measure bioaccumulation. To this purpose, young carrots were grown in soil during 1 month in natural conditions and exposed to Mycrocystis aeruginosa aqueous extracts containing environmentally realistic concentrations of MC-LR (10 and 50 MC-LR μg/L). The results showed that MC-LR may decrease root growth after 28 days of exposure to 50 μg/L and increase photosynthetic efficiency. We also observed changes in mineral and vitamin content in carrots as a result of the exposure to contaminated water. Moreover, MC-LR was detected in carrot roots by ELISA at very low concentration 5.23 ± 0.47 ng MC eq./g FW. The soil retained 52.7 % of the toxin potentially available for plants. This result could be attributed to MC-LR adsorption by soil particles or due to microbial degradation of the toxin. We conclude that the prolonged use of MC-LR-contaminated water may affect crop growth, alter the nutritional value of vegetable products, and potentiate contamination.
- Assessment of Constructed Wetlands’ Potential for the Removal of Cyanobacteria and Microcystins (MC-LR)Publication . Bavithra, Guna; Azevedo, Joana; Oliveira, Flávio; Morais, João; Pinto, Edgar; Ferreira, Isabel M. P. L.V. O.; Vasconcelos, Vítor; Campos, Alexandre; Almeida, C. Marisa R.Microcystis blooms and the subsequent release of hepatotoxic microcystins (MCs) pose a serious threat to the safety of water for human and livestock consumption, agriculture irrigation, and aquaculture worldwide. Microcystin-LR (MC-LR), the most toxic variant of MCs, has been widely detected in a variety of environments such as water, sediments, plants, and many aquatic organisms.
- Analysis of the Use of Cylindrospermopsin and/or Microcystin-Contaminated Water in the Growth, Mineral Content, and Contamination of Spinacia oleracea and Lactuca sativaPublication . Llana-Ruiz-Cabello, Maria; Jos, Angeles; Cameán, Ana; Oliveira, Flavio; Barreiro, Aldo; Machado, Joana; Azevedo, Joana; Pinto, Edgar; Almeida, Agostinho; Campos, Alexandre; Vasconcelos, Vitor; Freitas, MarisaCyanobacteria and cyanotoxins constitute a serious environmental and human health problem. Moreover, concerns are raised with the use of contaminated water in agriculture and vegetable production as this can lead to food contamination and human exposure to toxins as well as impairment in crop development and productivity. The objective of this work was to assess the susceptibility of two green vegetables, spinach and lettuce, to the cyanotoxins microcystin (MC) and cylindrospermopsin (CYN), individually and in mixture. The study consisted of growing both vegetables in hydroponics, under controlled conditions, for 21 days in nutrient medium doped with MC or CYN at 10 μg/L and 50 μg/L, or CYN/MC mixture at 5 + 5 μg/L and 25 + 25 μg/L. Extracts from M. aeruginosa and C. ovalisporum were used as sources of toxins. The study revealed growth inhibition of the aerial part (Leaves) in both species when treated with 50µg/L of MC, CYN and CYN/MC mixture. MC showed to be more harmful to plant growth than CYN. Moreover spinach leaves growth was inhibited by both 5 + 5 and 25 + 25 µg/L CYN/MC mixtures, whereas lettuce leaves growth was inhibited only by 25 + 25 µg/L CYN/MC mixture. Overall, growth data evidence increased sensitivity of spinach to cyanotoxins in comparison to lettuce. On the other hand, plants exposed to CYN/MC mixture showed differential accumulation of CYN and MC. In addition, CYN, but not MC, was translocated from the roots to the leaves. CYN and MC affected the levels of minerals particularly in plant roots. The elements most affected were Ca, K and Mg. However, in leaves K was the mineral that was affected by exposure to cyanotoxins.
- Impact of microcystin contaminated water on quality of carrots (Daucuscarota)Publication . Machado, J.; Azevedo, J.; Freitas, Marisa; Pinto, Edgar; Vasconcelos, Vitor; Campos, AlexandreCyanobacteria blooms are often found in freshwaters and may reflect the increased eutrophication of these environments and because of this many water resources worldwide may have a limited utilization. The presence of these microorganisms may pose a serious threat to water quality because many of them produce a large diversity of toxins that can be harmful to human health (Figueiredo et a l., 2004). On the other hand contaminated waters used to agricultural purposes may pose additional concerns to food safety. The absorption of toxins by plants may induce morphological and physiological changes that can lead to a loss of productivity as well as toxin bioaccumulation in edible tissues. However, the impact of cyanotoxins on plants and its ability to enter the food chain via this pathway is not fully understood (Kitleret al ., 2012). Microcystin (MC) is the cyanotoxin most frequently present in eutrophic freshwaters causing serious problems to human health, being the liver the main target. These toxins are potent and specific inhibitors of protein phosphatases PP1 and PP2Ain both animals and higher plants (Figueiredo et al., 2004). It is known that MC affect a number of physiological processes in plants (Corbel et al ., 2013). The plant root system is usually more exposed, via soil irrigation, and therefore root-vegetables more prone to contamination. Carrots (Daucuscarota) are root-vegetables with great importance for human nourishment and economy, with extensive use all over the world (Singh et al ., 2012).