Identification of Ammonia as an Important Sediment-Associated Toxicant in the Lower Fox River and Green Bay, Wisconsin

Abstract

Toxicity of sediment pore water from 13 sites in the lower Fox River/Green Bay watershed was assessed using a number of test species. Sediment pore water from the 10 lower Fox River sites exhibited acute toxicity to fathead minnows (Pimephales promelas) and Ceriodaphnia dubia, and pore water samples from all 13 sites were chronically toxic to C. dubia. Sediment pore water from seven of the sampling sites was toxic to Selenastrum capricornutum, but none of the samples were toxic to Photobacterium phosphoreum. Toxicity characterization, identification and confirmation procedures indicated that a significant amount of the acute toxicity of the pore water to fathead minnows and C. dubia was due to ammonia. The identification of ammonia, a naturally occurring compound in sediments, as a potentially important sediment‐associated toxicant has implications for sediment toxicity assessment and control, not only in the Fox River and Green Bay, but in other freshwater and marine systems as well.

Background and overview of current sediment toxicity identification evaluation procedures

“…If there are two (or more) species that exhibit markedly different sensitivities to a specific suspect toxicant in single chemical toxicity tests, and the same patterns in sensitivity are seen with the test sample, this provides evidence for the validity of the suspect being the true toxicant (Ankley et al, 1990a;Burkhard & Jenson, 1993). This approach can be particularly powerful, for example, when testing the suite of epibenthic/benthic species commonly utilized for freshwater sediment TIEs (see Section 3.3) because their relative sensitivity tends to be quite compound-specific, i.e., no one species is the most or least sensitive to a variety of different contaminants (Phipps et al, 1995).…”

“…For the correlation approach to succeed, variations in toxicity among samples must be wide enough to provide arange of values adequate for meaningful analyses. In the case of effluents, this variation generally is achieved by collecting samples over time (e.g., Amato et al, 1992;Ankley & Burkhard, 1992;Burkhard & Jenson, 1993); however for sediments, among-sample variation in concentrations of toxicants may have to be maximized by collecting samples from a number of locations (e.g., Ankley et al, 1990a). By utilizing the toxicity correlation technique,, the analyst has a statistical basis for reliably attributing sample toxicity to a specific compound (or compounds).…”

“…Sediments can contain toxic concentrations of ammonia and/or hydrogen sulfide (Ankley et al, 1990a;1992;Schubauer-Berigan et al, 1990;SchubauerBerigan & Ankley, 1991;Burgess et al, 1993). Although these contaminants can to a large extent be derived from natural microbial processes, in many cases the accumulation of these compounds may be exacerbated by the presence of other, anthropogenically-derived materials (e.g., high levels of nutrients).…”

“…These toxicity identification evaluation (TIE) procedures utilize toxicity-based fractionation schemes to characterize (Phase I), identify (Phase II) and confirm (Phase III) compounds responsible for sample toxicity. A number of studies have focused on the use of these, and similar, TIE procedures for identifying toxicants in effluents (e.g., Doi & Grothe, 1987;Jop et al, 1991;Ankley & Burkhard, 1992;Amato et al, 1992;DiGiano et al, 1992;Doerger et al, 1992;Burkhard & Jenson, 1993;Schubauer-Berigan et al, 1993a); in addition, it has been demonstrated that TIE methods can be used to successfully identify acutely toxic compounds in ambient waters (Norberg-King et al, 1991), hazardous waste leachates (Kuehl et al, 1990), and aqueous fractions of sediments (Ankley et al, 1990a;1991a;1992;Schubauer-Berigan et al, 1990;Schubauer-Berigan & Ankley, 1991;Dave, 1992;Burgess et al, 1993;Maltby et al, 1995). A summary of several of these studies, including sample type and toxicants identified is shown in Table 1.…”

Toxicity analysis of freshwater and marine sediments with meio- and macrobenthic organisms: a review

“…Overall, a test with benthic species involving direct exposure to a sediment sample is more adequate and ecologically relevant for an assessment of sediment toxicity than tests in isolated liquid phases ; see Ankley et al ., 1990) . Static bioassays, in which benthic organisms are exposed to whole sediment and overlying water in a beaker, have been used to test experimentally spiked sediments and field contaminated samples (Wentsel et al .…”