Use of fractionation procedures and extensive chemical analysis for toxicity identification of a chemical plant effluent

Abstract

As a part of a National Pollutant Discharge Elimination System (NPDES) biomonitoring program a series of toxicity tests was conducted with process water from a chemical plant using Ceriodaphnia dubia and Pimephales promelas. There were marked differences among the two tested species. The acute (LC50) values from 96‐h static toxicity tests with Pimephales promelas were always lower (higher toxicity) than the values obtained from the invertebrate tests. The concentration of ammonia in the effluent, particularly its un‐ionized form (250 mg NH4‐N/L, which represents 0.7 mg NH3‐N/L), was above the threshold concentration for most freshwater species and therefore was the primary suspect of the toxicity present in the effluent. Prior to initiation of the toxicity identification evaluation (TIE) program, chemical analyses that included measurements of inorganic and organic parameters were conducted with the effluent. During the TIE fractionation, a portion of the sample was purged with nitrogen to remove volatile organics, and a second portion of the sample was pressure‐filtered through a 0.45‐μm filter. Because toxicity equal to the whole sample was found in these fractions, a portion of the inorganic fraction was subfractionated into zeolite, clinoptilolite, activated carbon, pH‐adjustment, aeration, and cation fractions. The results of these tests confirmed that ammonia played a role in the sample's toxicity. However, when ammonia was removed from the effluent sample, toxicity was still present. Next organic chemicals were fractionated as suspected sources of toxicity. At first, organics were removed from the effluent by passing the filtered sample over an XAD‐resin column. Because a portion of the reconstituted organic fraction was toxic, the organic fraction was subfractionated further by extracting with dichloromethane at pH > 11, pH < 2, and pH 7.1. The dichloromethane extracts were toxic, whereas the aqueous portions were not toxic. The neutral extract, which was more toxic than the basic and acidic extract, was further fractionated by using HPLC. Seventeen HPLC fractions were isolated and tested for toxicity to determine which constituent(s) were responsible for the observed whole effluent toxicity.

Assessment of toxicity and genotoxicity of hydrophobic organic compounds in wastewater

“…tify Phase II , and confirm Phase III compounds responsible for sample toxicity. These procedures have been widely used and have proven successful in most Ž instances Jop et al, 1991;Amato et al, 1992;Ankley and Burkhard, 1992;Doerger et al, 1992;Burkhard . and Jenson, 1993;Schubauer-Berigan et al, 1993 .…”

Effect-directed analysis: a promising tool for the identification of organic toxicants in complex mixtures?

“…For this reason and because of the relative ease of extraction and chemical analysis by gas chromatography, most EDA studies until about 1997 focused on lipophilic organics. While in early studies lipophilic compounds were extracted from aqueous environments by liquid/liquid extraction [13], the intended reduction of solvent consumption tended to replace this method within the last 15 years by solid-phase extraction (SPE) using C18 phases [14,15] or XAD resins [16] for lipophilic compounds. As an alternative, new passive samplers were developed for a time-integrated long-term sampling of lipophilic compounds in aqueous environments.…”

Wirkungsorientierte Analytik komplexer Mischungen Erfahrungen aus der Umwelt- und Ökotoxikologie für die Lebensmitteluntersuchung

“…Diese hat die früher übliche arbeits-und lösemittelintensive Flüssig/Flüssig-Extraktion (Holmborn et al, 1984) nahezu vollständig abgelöst. Häufig verwendete Sorbentien in der wirkungsorientierten Analytik sind C18-Phasen Amato et al, 1992) und XAD-Harze (Jop et al, 1991), die sich insbesondere für die Extraktion unpolarer Verbindungen eignen. In wässrigen Proben wie z.B.…”

“…Reichen Massenspektrum und Retentionsindex für eine Identifizierung nicht aus, können zusätzliche spektroskopische Verfahren herangezogen werden. Von Bedeutung sind dabei insbesondere 1 H und 13 C NMR, auch wenn der Bedarf an großen Substanzmengen in hoher Reinheit die Verwendung in der Identifizierung toxischer Spurenstoffe deutlich einschränkt (Jop et al, 1991;Shiozawa et al, 2000). Im Falle polyaromatischer Verbindungen liefern UV-Absorptionsspektren wichtige Informationen über das aromatische Grundgerüst (Holmborn et al, 1984;Brack und Schirmer, 2003).…”