Trophic transfer and effects of DDT in male hornyhead turbot (Pleuronichthys verticalis) from Palos Verdes Superfund site, CA (USA) and comparisons to field monitoring

Abstract

High concentrations of DDT and metabolites (ΣDDT) have been detected in sediment and the demersal flatfish hornyhead turbot (Pleuronichtys verticalis) collected from Palos Verdes (PV), California, USA, a site contaminated with over 100 metric tons of DDT throughout 1960s to 70s. This study was elaborated to assess the transfer of ΣDDT from PV-sediment into polychaete (Neanthes arenaceodentata) and hornyhead turbot, and to investigate if the genomic responses in turbots from two different laboratory exposures mimic those in turbots caught in PV (PV-turbot). Turbot fed PV-sediment-contaminated polychaete for 7 days had liver concentrations of ΣDDT similar to PV-turbot. After 28 days, ΣDDT also accumulated by livers of turbot gavaged with ΣDDT mixture. In vitro cell bioassays indicated significant increases of 17β-estradiol equivalents (EEQ) in turbots as compared to the control in the 7-day study. These responses corresponded to those measured in PV-fish. Glucocorticoid receptor (GR), anti-androgen receptor (anti-AR), estrogen receptor (ER) or aryl hydrocarbon receptor (AhR) activities were also observed in PV-sediment, and PV-sediment-exposed worm. Anti-AR, AhR and GR activities were significantly higher in PV-sediment than reference sediment (San Diego, SD). Higher transcripts of hepatic VTG, ERα and ERβ were found in PV-turbot than SD-turbot, but unaltered in fish exposed to sediment-contaminated worms for the 7-day study. In contrast, liver extracts from the 28-day treatment of ΣDDT showed lower EEQ but similar hepatic VTG and ERβ transcripts relative to those of PV-turbot. These data indicated that trophic transfer of sediment-associated DDT in 7-day exposures corresponded to field measurements of DDT residues and in vitro ER bioactivities, but failed to mimic in vivo biological effects observed in field fish. In contrast, treatment with ΣDDT alone for 28 days mimicked in vivo biological effects of DDTs in PV fish, but did not correspond to liver concentrations or in vitro bioactivities.

Comparisons of field and laboratory estimates of risk of DDTs from contaminated sediments to humans that consume fish in Palos Verdes, California, USA

“…The calculated BMF value from the laboratory trophic transfer study (Crago et al 2016) (1.49 ± 0.47; N=5) is consistent with a previous field-based BMF study (Zeng and Tran, 2002) (1.49 ± 1.2; N=2).…”

“…The BSAF calculated from values obtained from the laboratory-based IDM (0.0105 ± 0.0026; N=9) (mean ± one standard error of the mean; N= number of replicates) (Jia et Al. 2014) was about 3-fold greater than the value based on the laboratory exposure of 8C PVS sediment to polychaetes ( Neanthes arenaceodentata) (0.0031 ± 0.0001; N=5) (Crago et al 2016). IDM BSAF was less than a field-collected tissue-based study (1.1 ± 1.3; N=2) (Zeng and Tran 2002).…”

“…2014) and compared with values measured from a field study (Zeng and Tran 2002) as well as a laboratory-based biological method which used Hornyhead turbot (Crago et al 2016). In the case of Zeng and Tran (2002) a BSAF value was not directly reported by the authors, in which case it was calculated using data reported in their publications (see Supporting Information; Table S2, Equation S1).…”

“…To estimate trophic transfer from benthic infauna to fish, Biomagnification Factor (BMF) for Hornyhead turbot was calculated from a field-based study (Zeng and Tran 2002) and was compared to a laboratory-based trophic transfer study (Crago et al 2016) (Equation S2). Since BMF values were not reported directly from the field studies, the appropriate data was used from these publications to calculate a BMF value for Hornyhead Turbot/polychaete (see Supporting Information; Table S1).…”

“…(2014) assessed bioavailable ΣDDT in PVS sediment (site 8C; [33° 41.91' N; 118° 20.14' W]) and validated these results with laboratory uptake studies in a marine polychaete ( Neanthes arenaceodentata) . Subsequent studies also using a laboratory trophic system exposing N. arenaceodentata and then feeding the worms to Hornyhead turbot ( Pleuronichthys verticalis ) calculated estimates of biota-sediment accumulation factors (BSAF) and biomagnification factors (BMF) (Crago et al 2016). The estimates were comparable to ΣDDT concentrations measured by the Los Angeles County Sanitation Districts (LACSD) in Hornyhead turbot ( Pleuronichthys verticalis ) collected from the locations where sediments were sampled (LACSD 2014).…”