Screening of organic and metal contaminants in Australian humpback dolphins (Sousa sahulensis) inhabiting an urbanised embayment

Concentrations of legacy persistent organic pollutants and naturally produced MeO-PBDEs in dugongs (Dugong dugon) from Moreton Bay, Australia

“…No specific pattern could be distinguished for the CHLs in the blubber samples, while cischlordane had the highest concentration in 9 out of 11 liver samples. This corresponds partly with the findings from the humpback dolphin study where cis-chlordane also had the highest concentration in liver, but the lowest concentration in blubber (Weijs et al, 2016b).…”

“…Within each class, profiles resembled the patterns commonly found in most marine mammal species worldwide and more specifically in the humpback dolphins from Moreton Bay (Weijs et al, 2016b). p,p'-DDE was the only DDT-related compound that was found in the dugongs suggesting that there has not been any recent input of DDXs in Moreton Bay, confirming the findings of Mueller et al (2011) This may mean that these compounds do not bioaccumulate readily as they were not detected in green turtles from the same region either (Weltmeyer et al, personal communication) but a capacity for metabolic biotransformation of some POPs in dugongs cannot be ruled out.…”

“…In the majority of the samples, contributions of p,p'-DDE to the total sum were higher than contributions of PCBs. This is unusual compared to humpback dolphins (Weijs et al, 2016b) and green turtles (Weltmeyer et al, personal communication) from Moreton Bay where proportions of PCBs were consistently higher than p,p'-DDE. Green turtles are omnivorous and inhabit open waters in the first years of their lives after which they adopt a coastal lifestyle and switch to an herbivorous diet for the rest of their lives.…”

“…Moreton Bay is a semi-enclosed and shallow embayment that receives inputs from several rivers and waterways, such as the Brisbane river, which flows through a highly urbanized city with a population over 2.4 million people (Brisbane, Queensland). In a previous study, concentrations of PCBs and DDT in blubber of some humpback dolphins (Sousa sahulensis) from Moreton Bay were found to be comparable to concentrations found in highly contaminated transient killer whales and to exceed several toxicity thresholds associated with immunotoxicity and reproductive effects (Weijs et al, 2016b). These results show that legacy POPs are present in the Moreton Bay ecosystem at considerable concentrations, which raises the question of how these chemicals bioaccumulate in this dugong population at large rather than only in adult females.…”

As, Cr, Hg, Pb, and Cd Concentrations and Bioaccumulation in the Dugong Dugong dugon and Manatee Trichechus manatus: A Review of Body Burdens and Distribution

“…Studies in aquatic mammals in general have focused on the importance of metals in their reproduction, decrease in their populations and increased mortality rates, as well as tolerance, which in some cases is higher than in other mammals [28,29,35,49,50,51,52,53,54,55,56]. The studies involve highly toxic metals, such as lead, cadmium or mercury, which generates a toxic response in aquatic mammals [50,57,58,59]. Due to different characteristics associated with longevity, low reproductive rate, sensitivity to anthropogenic activities and various pollutants, both inorganic (metals) and organic (hydrocarbons, pesticides, etc.…”