Local and interannual variations in mercury and cadmium in eggs of eight seabird species of the Sinaloa coast, México

Abstract

Mercury (Hg) and cadmium (Cd) concentrations in eggs of 8 seabird species inhabiting 5 coastal ecosystems in Sinaloa, México were determined during 2 breeding seasons (2012 and 2013): blue-footed booby (Sula nebouxii), brown booby (Sula leucogaster), double-crested cormorant (Phalacrocorax auritus), magnificent frigatebird (Fregata magnificens), brown pelican (Pelecanus occidentalis), royal tern (Thalasseus maximus), laughing gull (Leucophaeus atricilla), and Heermann's gull (Larus heermanni). The interspecific differences found in the concentrations of both metals were attributed to the diet and foraging ecology of the species. The highest Hg concentrations were detected in piscivorous species (brown pelican, 0.42 µg/g; brown booby, 0.31 µg/g; blue-footed booby, 0.26 µg/g; and double-crested cormorant, 0.23 µg/g); whereas species with more varied diets presented the highest Cd concentrations (Heermann's gull, 0.31 µg/g; laughing gull, 0.27 µg/g; and magnificent frigatebird, 0.27 µg/g). Cadmium concentrations were significantly greater in 2013 than 2012 for most species, and brown pelican and laughing gull also had higher Hg concentrations in 2013 in Santa María Bay, suggesting a relationship as a result of the changes either in oceanographic conditions or in continental runoff. Mercury concentrations in brown pelican and Cd concentrations in Heermann's gull and laughing gull were above threshold levels for adverse effects on reproduction and survival. Environ Toxicol Chem 2016;35:2330-2338. © 2016 SETAC.

Review of the biomonitoring of persistent, bioaccumulative, and toxic substances in aquatic ecosystems of Mexico: 2001-2016

“…García-Hernández et al (2006) evaluated the concentration of Cd and Pb in eggs and embryos (in different stages) of aquatic birds living in the Colorado River Delta (Sonora) and found concentrations of 0.13-0.78 and 0.06-0.20 µg g -1 dw for Cd and Pb respectively. Similarly, Ceyca et al (2016) reported values of 1-1.6 µg g -1 dw for Cd in seabird eggs in the coastal zone of Sinaloa, similar values to those found in the muscle tissue of several seabirds collected in the Altata-Ensenada de Pabellón Lagoon (Sinaloa), with concentrations of 0.2-1.6 µg g -1 dw, which suggests that a high percentage of this contaminant is transferred via the mother.…”

“…All cases of Hg in fish muscle reviewed here were below this concentration. In birds, Ceyca et al (2016) indicated that Hg concentrations of 0.5-1 µg g -1 ww in sea bird eggs could cause mortality, malformations, and neurological damage. Ceyca et al (2016) also reported maximum Hg values of 0.55-187 µg g -1 ww in eight species of seabirds collected on the coast of Sinaloa.…”

“…In birds, Ceyca et al (2016) indicated that Hg concentrations of 0.5-1 µg g -1 ww in sea bird eggs could cause mortality, malformations, and neurological damage. Ceyca et al (2016) also reported maximum Hg values of 0.55-187 µg g -1 ww in eight species of seabirds collected on the coast of Sinaloa. Zhang et al (2013) reported that the lowest probable adverse effect (LOAEL) of Hg on aquatic birds' blood occurred at 0.73 µg g -1 ww.…”

Trace element concentrations in feathers from three seabird species breeding in the Timor Sea

“…Trace elements are typically differentiated into two categories: essential elements required for important processes within organisms, and non-essential elements that are not required for any biological purpose and are therefore particularly toxic when they accumulate within organisms (Burger, 1993;Ceyca et al, 2016;Moura et al, 2018). Several trace elements are of particular concern due to the concentrations released into the environment, as well as the documented toxicological effects at relatively low concentrations.…”

“…In the marine environment, three elements (Hg, Pb, and Cd) have been extensively studied because they bioaccumulate and biomagnify in aquatic food webs (Burger, 1993). Exposure can harm species in a variety of ways, including impaired biological function of proteins, enzymes, and cell damage (Burger, 1993;Ceyca et al, 2016). These impacts are often demonstrated using marine birds as sentinels, or bioindicators, as apex predators can also provide information on broader ecosystem health (Borghesi et al, 2016;Durant et al, 2009).…”