Global Pollution Monitoring of PCBs and Organochlorine Pesticides Using Skipjack Tuna as a Bioindicator

Abstract

Concentrations of organochlorines (OCs) representing persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), hexachlorocyclohexane isomers (HCHs), and hexachlorobenzene (HCB), were determined in the liver of skipjack tuna (Katsuwonus pelamis) collected from the offshore waters of various regions in the world (offshore waters around Japan, Taiwan, Philippines, Indonesia, Seychelles, and Brazil, and the Japan Sea, the East China Sea, the South China Sea, the Bay of Bengal, and the North Pacific Ocean). OCs were detected in livers of all of the skipjack tuna collected from the locations surveyed, supporting the thesis that there is widespread contamination of persistent OCs in the marine environment. Within a location, no significant relationship between growth-stage (body length and weight) and OC concentrations (lipid weight basis) was observed, and the OC residue levels were rather uniform among the individuals. Interestingly, the distribution of OC concentrations in skipjack tuna was similar to those in surface seawaters from which they were taken. These results suggest that OC concentrations in skipjack tuna could reflect the pollution levels in seawater from which they are collected and that this species is a suitable bioindicator for monitoring the global distribution of OCs in offshore waters and the open ocean. Concentrations of PCBs and CHLs in skipjack tuna were higher in offshore waters around Japan (up to 1100 and 250 ng/g lipid wt, respectively), suggesting the presence of sources of PCBs and CHLs in Japan. High concentrations of DDTs and HCHs were observed in samples from the Japan Sea, the East China Sea, the South China Sea, and the Bay of Bengal (up to 1300 and 22 ng/g lipid wt, respectively). This result suggests recent use of technical DDT and HCH for agricultural and/or public health purposes in Russia, China, India, and some other developing Asian countries. Relatively high concentrations of PCBs, CHLs, HCHs, and HCB were also observed in samples collected from some locations in the middle of the Pacific Ocean, indicating the expansion of OC contamination on a global scale. Considering these facts, continuous studies monitoring these compounds in offshore waters and the open seas, using skipjack tuna as a bioindicator, are needed to further understand the future trend of contamination.

Deep-ocean foraging northern elephant seals bioaccumulate persistent organic pollutants

“…In previous research on epipelagic foraging marine predators from the North Pacific Ocean, intraspecific variability in POP concentrations was observed in shearwaters (Calonectris leucomelas) (Ito et al, 2013), skipjack tuna (Katsuwonus pelamis) (Ueno et al, 2003), humpback whales (Elfes et al, 2010), and Hawaiian monk seals (Lopez et al, 2012), and attributed to differences in geographic location. However, the influence of foraging behavior on POP concentrations may depend on foraging characteristics beyond geography.…”

Organochlorine pesticides in seawater and the surrounding atmosphere of the marginal seas of China: Spatial distribution, sources and air–water exchange

“…Chlordane was one type of the OCPs that occurred most frequently in the environment all over the world, however, only limited literatures reported the concentration levels of chlordane in the open ocean water (Iwata et al, 1993). Recently, some researchers suggested that skipjack tuna is a suitable bioindicator for monitoring the global distribution of organochlorines in offshore waters and the open ocean (Ueno et al, 2003). Chlordane levels were found to be the second highest OCPs in skipjack tuna liver, which may imply that significant amounts of chlordane exist in seawater.…”

“…In recent years, the production of OCPs was either eliminated or their release into the environment reduced under the Stockholm Convention on OCPs, which was adopted by many countries. However, in Southeast Asian countries, the late production ban as well as the current legal and illegal application for agricultural practices and for the control of certain diseases, such as malaria, typhus and cholera, have contributed to higher concentrations of OCPs in the environment (i.e., the atmosphere, water and sediment) (Hung and Thiemann, 2002;Iwata et al, 1994;Zhang et al, 2002), aquatic wildlife (e.g., mussels) (Ueno et al, 2003) and the human population (e.g., human breast milk) (UNEP, 2002;Wong et al, 2002). Oceanic waters are a receptor of land based pollutant sources, and coastal waters are particularly affected by inputs of OCPs via discharges of sewage, industrial effluents and significant rivers that drain into the marginal seas of China.…”

Understanding the accumulation features of POPs in squid from the offshore waters of southeast Korea

“…These levels are lower than those around most parts of Japan. A huge amount of PCB was manufactured in Japan [28], so relatively high PCB levels were observed in Japanese coastal samples compared with other Asian countries [3,[10][11][12]. The mean concentrations of CHLs and HCHs were also lower in offshore Korean waters than in other Asian locations.…”

“…Globally, research on the distribution and accumulation characteristics of POPs in the open ocean has utilized various marine organisms, including cephalopods, fish and mammals as monitoring species [7][8][9][10][11][12][13][14]. In particular, cephalopods are easy to collect and reflect the concentrations of compounds in ambient seawater promptly because they breathe through gills [15].…”