Novel contaminants identified in fish kills in the Red River watershed, 2011–2013

Abstract

Provisional molecular weights and chemical formulas were assigned to 4 significant previously unidentified contaminants present during active fish kills in the Red River region of Oklahoma. The provisional identifications of these contaminants were determined using high-resolution liquid chromatography-time-of-flight mass spectrometry (LC-TOFMS), LC-Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICRMS), and LC-ion trap mass spectrometry (LC-ITMS). Environmental water samples were extracted using a solid-phase extraction (SPE) method, and sediment samples were extracted using a modified sonication liquid extraction method. During screening of the samples, 2 major unknown chromatographic peaks were detected at m/z 624.3 and m/z 639.3. The peak at m/z 639.3 was firmly identified, through the use of an authentic standard, as a porphyrin, specifically chlorin-e6-trimethyl ester, with m/z 639.31735 (M + H) and molecular formula C H N O . The other major peak, at m/z 624.3 (M + H) , was identified as an amide-containing porphyrin. It was discovered that the amide compound was an artifact created during the SPE process by reaction of ammonium hydroxide at 1 of 3 potential reaction sites on chlorin-e6-trimethyl ester. Other unique nontargeted chemicals were also detected and the importance of their identification is discussed. Environ Toxicol Chem 2018;37:336-344. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Investigating the 2017 Erratic Fishkill Episode in the Jhelum River, Kashmir Himalaya

“…There is a plethora of literature that suggests both human-induced [1][2][3] and natural causes [4][5][6] for the fishkill. While the human-induced kills include known or accidental additions of harmful chemicals, sewage ingress, and fertilizers from agricultural fields into natural waters [7][8][9][10], the natural causes on the contrary are attributed to temperature fluctuations [11,12], anoxic conditions [13,14], cyanobacterial blooms [15,16], and disease outbreak [17,18]. These episodes sometimes tend to impact the entire lake or river stretch [19] or at times are extremely localized [20].…”

Application of Nontarget High Resolution Mass Spectrometry Data to Quantitative Source Apportionment

“…While such detections represent only small molecule (<1000 Da) synthetic chemicals and natural products amenable to chromatographic separation and MS detection, they do reflect a substantial fraction of the analyzable chemical composition of a sample . Many research efforts have exploited the richness of HRMS data to annotate and identify novel chemical contaminants without prior knowledge of their presence. − Such outcomes are exciting and insightful, especially the discovery of novel and toxicologically relevant contaminants and transformation products. − However, identification typically requires substantial curation and individual effort to translate accurate mass detections to chemical formulas and subsequently confirmed identity, especially for true nontarget data. Indeed, significant resources are dedicated to developing improved tools for prioritizing HRMS detections and expediting identifications …”