First assessment of trace metal concentration in mangrove crab eggs and other tissues, SE Brazil

Abstract

The mangrove crab Ucides cordatus is widespread in the Brazilian coast, which has an important role in nutrient cycling. This species reproduces in summer and females carry eggs about a month, when they maintain contact with water and sediments. It remains unclear if trace metals can be absorbed or adsorbed by the eggs during development. The present study aims to investigate, for the first time, trace metal concentrations in ovigerous female tissues and eggs of U. cordatus in two areas with different metal pollution levels in the Southeastern Brazil. Samples were collected in two different mangroves, Guanabara Bay (GB) highly polluted environment and Paraíba do Sul River (PSR). In both populations, we observed significant increase of V, Cr, and Mn concentrations along eggs maturation. The higher metals averages were found in PSR population. This trend was reported since the 1990s and lower concentrations in GB marine organisms were attributed to reducing conditions, high organic load, and the presence of sulfide ions. These conditions restrict the bioavailability of metals in the bay, with exception of Mn. No significant differences were observed in gills and muscles. In both populations of the present study, V, Zn, As, and Pb were higher in eggs of initial stage, whereas Mn, Ni, Cu, and Cd were higher in hepatopancreas. Beside this, V, Cr, Mn, As, and Pb showed an increase concerning egg development. Thus, V, As, and Pb in eggs come from two sources previous discussed: females and environment. Zinc came mainly from females due to essential function. Those new information should be considered as one of the mechanisms of trace metal transfer to the trophic chain, between benthonic and pelagic environment.

Contamination in newly hatched larvae of the mangrove crab Ucides cordatus and a new perspective about trace elements transport

“…The Ucides cordatus females sampling was made in the same locations and with the same methods seen in Almeida et al (2016). The two study sites were the Caceribu River mangrove (Guanabara Bay -GB) and the Gargaú mangrove (Paraíba do Sul River, secondary estuary -PSR), which are in SE Brazil (Fig.…”

“…Gargaú mangrove -Paraíba do Sul River (PSR), both on Southeastern Brazilian Coast, State of Rio de Janeiro. Modified from Almeida et al (2016).…”

“…Contamination analysis in crab eggs is still rare, and we can mention studies with N. granulata (BELTRAME et al, 2010, SIMONETTI et al, 2012, Callinectes sp. (LAVRADAS et al, 2014), and Ucides cordatus (ALMEIDA et al, 2016). Regarding crab larvae, there is a predominance of ecotoxicological studies (LÓPEZ-GRECO et al, 2002;FERRER et al, 2006;AMIN;COMOGLIO 2010;LYLA;KHAN, 2010).…”

“…During embryonic development, the U. cordatus egg mass remains in contact with water and sediments, being susceptible to contamination (ALMEIDA et al, 2016). The maternal transference during vitellogenesis and the absorption of mangrove pore water and minerals during embryonic development would be the main sources of trace element contamination.…”

Chapter 10. The Crab Ucides cordatus (Malacostraca, Decapoda, Brachyura) and Other Related Taxa as Environmental Sentinels for Assessment and Monitoring of Tropical Mangroves from South America

“…In the case of decapod crustaceans, such as U. cordatus, some contaminants such as toxic metals can accumulate in the muscles (meat), gills, midgut gland (hepatopancreas), 30,[89][90][91] including the carapace (e.g., Pb), and even in eggs carried in the female abdomen. 92 On the São Paulo state coast, Brazil (see Figure 10.4), there are highly contaminated mangrove areas, contrasting with pristine areas inside conservation areas managed by governmental institutions (e.g., Juréia-Itatins Ecologic Station, supervised by the Florestal Foundation, an environmetal agency). In general, the north coast of São Paulo has a few mangrove fragments, with greater abundance occurring on the central and south coasts of this state.…”