TY - JOUR
T1 - Nitrate-N-mediated toxicological responses of Scenedesmus acutus and Daphnia pulex to cadmium, arsenic and their binary mixture (Cd/Asmix) at environmentally relevant concentrations
AU - Awoyemi, Olushola M.
AU - Subbiah, Seenivasan
AU - Velazquez, Anahi
AU - Thompson, Kelsey N.
AU - Peace, Angela L.
AU - Mayer, Gregory D.
N1 - Funding Information:
This study was funded by the National Science Foundation, NSF DMS-1615697. We appreciate Dr. Kaz Surowiec at the Chemistry Department of Texas Tech University (TTU), for assisting with the CHNS/O elemental analysis. Also, we appreciate Dr. Nathaniel Miller at the University of Texas (UT Austin), Jackson School of Geosciences for assisting with the ICP-MS metal analysis.
Funding Information:
This study was funded by the National Science Foundation , NSF DMS-1615697 . We appreciate Dr. Kaz Surowiec at the Chemistry Department of Texas Tech University (TTU), for assisting with the CHNS/O elemental analysis. Also, we appreciate Dr. Nathaniel Miller at the University of Texas (UT Austin), Jackson School of Geosciences for assisting with the ICP-MS metal analysis.
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2020/12/5
Y1 - 2020/12/5
N2 - Several biomarkers used for ecological risk assessment have been established for single contaminant toxicity, many of which are less predictive of the influence of media and/or dietary nutrients on toxicity outcomes of contaminant mixtures. In this study, we investigate toxicological responses and life traits of Scenedesmus acutus and Daphnia pulex to heavy metals (cadmium-Cd, arsenic-As, binary mixture-Cd/Asmix) in media and diets with varied nutrient (nitrate-N) conditions (low-LN, median-MN, optimum−COMBO). Results showed that nitrate-N-mediated metal inhibitory effects on growth and productivity of primary producer (S. acutus) were significantly interactive (p < 0.05; effect size, ƞ2≤56 %). Cadmium toxicities (Cd-IC50s) in S. acutus were 1.2×, 5.3×, and 4.3× As-IC50s in LN, MN and COMBO media, respectively, while mixture (Cd/Asmix) toxicities were synergistic in MN medium and partial additivity in COMBO and LN media. Nitrate-N and metal exposure effects on S. acutus nutrient stoichiometry, metal uptake and bioaccumulation were significantly interactive (p < 0.05, ƞ2≤100 %). Moreover, survival of primary consumer (D. pulex) was significantly impaired by single and mixed dietary-metal exposures with greater effect under LN condition coupled with significant interactive effects on reproductive capacity (p < 0.05, ƞ2≤21.2 %) but not on swimming activity. We recommend that nitrate-N-mediated metal exposure effects/toxicity in bioindicator species should be considered during ecological risk assessments.
AB - Several biomarkers used for ecological risk assessment have been established for single contaminant toxicity, many of which are less predictive of the influence of media and/or dietary nutrients on toxicity outcomes of contaminant mixtures. In this study, we investigate toxicological responses and life traits of Scenedesmus acutus and Daphnia pulex to heavy metals (cadmium-Cd, arsenic-As, binary mixture-Cd/Asmix) in media and diets with varied nutrient (nitrate-N) conditions (low-LN, median-MN, optimum−COMBO). Results showed that nitrate-N-mediated metal inhibitory effects on growth and productivity of primary producer (S. acutus) were significantly interactive (p < 0.05; effect size, ƞ2≤56 %). Cadmium toxicities (Cd-IC50s) in S. acutus were 1.2×, 5.3×, and 4.3× As-IC50s in LN, MN and COMBO media, respectively, while mixture (Cd/Asmix) toxicities were synergistic in MN medium and partial additivity in COMBO and LN media. Nitrate-N and metal exposure effects on S. acutus nutrient stoichiometry, metal uptake and bioaccumulation were significantly interactive (p < 0.05, ƞ2≤100 %). Moreover, survival of primary consumer (D. pulex) was significantly impaired by single and mixed dietary-metal exposures with greater effect under LN condition coupled with significant interactive effects on reproductive capacity (p < 0.05, ƞ2≤21.2 %) but not on swimming activity. We recommend that nitrate-N-mediated metal exposure effects/toxicity in bioindicator species should be considered during ecological risk assessments.
KW - Contaminant mixtures
KW - Ecotoxicological risk assessment
KW - Heavy metals
KW - Interactive effects
KW - Nitrogen availability
UR - http://www.scopus.com/inward/record.url?scp=85087319103&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2020.123189
DO - 10.1016/j.jhazmat.2020.123189
M3 - Article
C2 - 32947745
AN - SCOPUS:85087319103
VL - 400
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
SN - 0304-3894
M1 - 123189
ER -