Title : Metal contamination and oxidative system in Brazilian restinga fruits
Abstract:
The Restinga ecosystem consist of a mosaic of plant communities that cover the Brazilian sandy coastal plains, that can be strongly impacted by anthropic action, such as the Fundão Dam Failure, in 2015, which released nearly 50 million m3 of mining that were transported for over 600 km until reaching the Doce River mouth and the coastal zone. Plants growing in contaminated environment as this can present a decrease in growth and development, and thereby, the assessment of their reproductive resources is important, given the potential impacts on trophic chains and health of the human surrounding communities. We investigated the responses of Restinga species in the coastal zone affected by mining tailings contamination aiming to evaluate the metal(oide)s contamination levels and oxidative system response in fruits of six species with potential for biological activity: Chrysobalanus icaco L. (CHRY), Garcinia brasiliensis Mart. (GAR), Guapira pernambucensis (Casar.) Lundell. (GUA), Ouratea cuspidata (A.St.-Hil.) Engl. (OUR), Scaevola plumieri (L.) Vahl (SCA) and Tocoyena bulata (Vell.) Mart. (TOY). The study was carried in areas to the north and south of the Doce River mouth, northern coastal region of Espírito Santo state, southeastern Brazil in march 2020 and 2022. Samples of fruits and sediments were analyzed by inductively coupled plasma mass spectrophotometer (ICP-MS - NexION™ 300, Perkin Elmer, United States) and inductively coupled plasma optical emission spectrometry (ICP-OES - Optima 7000DV, Perkin Elmer) with which the element levels (As, Cd, Cr, Cu, Fe, Pb, Zn, Co, Mn, Sn, V and Ni) were determined in triplicate. For antioxidant system, metabolites and antioxidant capacity (by Ferric Reducing Antioxidant Power method) were estimated in fruits samples according to the plant species. The extent of cellular damage was also determined by quantification of malondialdehyde (MDA) via thiobarbituric acid reactive substances. Higher levels of metal(loids) in fruits of Restinga species were related to increases in metal concentration (Mn, Ni, Al, Cr, Cu and Zn) in the sediment. Accumulations of Mn, Zn and Ni in fruits were associated with increased oxidative responses, especially in OUR, GUA and CHRY. Such accumulations in plant tissues resulted in increases in the production of phenolic compounds and antioxidants pigments, as well as their antioxidant capacity. However, in some species, as GUA and CHRY, a lower capacity for adjustment of the antioxidant system resulted in cell damage, as observed by the increase in MDA levels. These results show that the responses of the six Restinga species to metal contamination were species-dependent and directly related to the biota's ability to absorb mineral elements, highlighting the importance of understanding the pattern of accumulation of mineral elements in reproductive structures and its influence on quality of natural resources.
Audience Take Away Notes:
- Knowledge of Restinga species with potential for natural antioxidants and new ecosystem services to a susceptible ecosystem
- Metal tolerance can be accompanied by an increase in antioxidant activity in a great number of Restinga species
- The capacity of response of Restinga species to metal contamination can be the basis for understanding the pattern of accumulation of mineral elements in reproductive structures and the quality of natural resources
