Contaminants of emerging concern in tributaries to the Laurentian Great Lakes: II. Biological consequences of exposure

Abstract

The Laurentian Great Lakes contain one fifth of the world’s surface freshwater and have been impacted by human activity since the Industrial Revolution. In addition to legacy contaminants, nitrification and invasive species, this aquatic ecosystem is also the recipient of Contaminants of Emerging Concern (CECs) with poorly understood biological consequences. In the current study, we documented the presence, concentrations, and biological effects of CECs across 27 field sites in six Great Lakes tributaries by examining over 2250 resident and caged sunfish (Lepomis ssp.) for a variety of morphological and physiological endpoints and related these results to CEC occurrence. CEC were ubiquitous across studies sites and their presence and concentrations in water and sediment were highest in effluent dominated rivers and downstream of municipal wastewater treatment plant discharges. However, even putative upstream reference sites were not free of CEC presence and fish at these sites exhibited biological effects consistent with CEC exposure. Only the Fox River exhibited consistent adverse biological effects, including increased relative liver size, greater prominence of hepatocyte vacuoles and increased plasma glucose concentrations. Canonical Redundancy Analysis revealed consistent patterns of biological consequences of CEC exposure across all six tributaries. Increasing plasma glucose concentrations, likely as a result of pollutant-induced metabolic stress, were associated with increased relative liver size and greater prominence of hepatocyte vacuoles. These indicators of pollutant exposure were inversely correlated with indicators of reproductive potential including smaller gonad size and less mature gametes. The current study highlights the need for greater integration of chemical and biological studies and suggests that CECs in the Laurentian Great Lakes Basin may adversely affect the reproductive potential of exposed fish populations.

Divergent responsiveness of two isoforms of the estrogen receptor to mixtures of contaminants of emerging concern in four vertebrates

“…It is important to compare the receptor function utilizing a common promoter sequence such as a Gal4-luciferase system, which utilizes a Gal4 DBD-nuclear hormone receptor chimera with Gal4-binding site and is a wellestablished system to analyze the nuclear hormone receptors with the independence of hormone response elements (Hollenberg & Evans, 1988). The Gal4 system was utilized to identify efficiently the obesogenic endocrine disruptors (Grün et al, 2006), although alligator Esrs showed less sensitivity in the Gal4 system than in the estrogen response element system (Kohno et al, 2015). These estimates would likely not match our results due to differences in species and receptor isoforms, and estrogenic signals in all four species could be disrupted in both AG and UB habitats to a different degree and by divergent mechanisms.…”

“…The molecular mechanisms that may account for the observed difference among the species and isoforms also need to be investigated further. It is difficult to discuss the differences in efficacies among receptors and species due to most reports showing results as a percentage of maximum inductions instead of raw data (e.g., Kohno et al, 2015;Sun et al, 1999). One contributing factor may be the result of differences in LBD (Miyagawa et al, 2014).…”

Contaminants of emerging concern in tributaries to the Laurentian Great Lakes: I. Patterns of occurrence

“…A total EEQ was obtained for each site by summing the individual EEQs of each chemical measured at each site. The EEQ factors for individual chemicals are presented in the companion to this paper [ 21 ].…”

“…Data were also used to calculate estimates of estrogenicity and compared with benchmarks or known effects, when available, to highlight potential risks to aquatic biota. A companion paper [ 21 ] reports relationships between CEC occurrence and biological data to better understand the effects of CECs on aquatic biota.…”

Emerging Pollutants–Part I: Occurrence, Fate and Transport

“…Wilkinson et al (2017) reviewed the occurrence, fate and transformation of EPs in water, and reported that many types of Eps including pharmaceuticals and PPCPs have been detected in waters with the typically concentration of the ng/L. In Laurentian Great Lakes, a total of 32 chemicals were detected in water samples and their concentrations including flame retardants, alkylphenols and sterols, were ubiquitous across 27 field sites in six Great Lakes watersheds and the total concentration was as high as (Thomas et al 2017 According to the literature reports, several types of PPCPs found in 25 different nations were summarized in detail (Kwon and Lee 2017), and a variety of emerging chemicals of concern from PPCPs, It's worth noting that the concentration of ciprofloxacin, SMX, amoxicillin, norfloxacin, and ofloxacin in Indian wastewater treatment plant were up to 40 times higher than that in other countries in Europe, Australia, Asia and North America. In wastewater effluents from hospitals, antibiotics have been detected with concentrations ranging from meanwhile, 36 ARGs were also detected by cultureindependent approaches and the sulI and qac genes had the highest relative abundance with values ranging from 5.33×10 -2 to 1.94×10 -1 and from 1.94×10 -2 to 4.89×10 -2 copies/16 rRNA gene copies, respectively (Szekeres et al 2017).…”