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Ecotoxicological information

Toxicity to other aquatic organisms

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Administrative data

Endpoint:
toxicity to other aquatic vertebrates
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2002

Materials and methods

Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
An integrated model stream ecosystem.
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Sampling was done two to three times weekly at both the head and tail of each stream. Sampling was done in triplicate.

Test organisms

Test organisms (species):
other:
Details on test organisms:
other: Baetis sp. (mayfly), Isonychia sp. (mayfly), Stenonema sp. (mayfly), Thienemannimyla sp. (chironomid), Tanytarsus sp. (chironomid), Cricotopus sp. (chironomid), Polypedilum sp. (chironomid), Reotanytarsus sp. (chironomid), Naididae (aquatic worm)

Study design

Test type:
other: out-door experimental streams
Water media type:
freshwater
Limit test:
no
Total exposure duration:
56 d
Remarks on exposure duration:
Exposures ranged from 126 to 2978 ¿g/L

Test conditions

Nominal and measured concentrations:
Exposures ranged from 126 to 2978 ¿g/L
Details on test conditions:
An integrated model stream ecosystem fate and effects study of a C12LAS homologue, with a high content (35.7%) of its most hydrophobic and toxic 2-phenyl isomer, was performed in the summer and fall of 1996 in Procter and Gamble¿s Experimental Stream facility. The study addressed responses of periphytic microbes, immature benthic fauna including abundance and drift, and emergence of adult insects in a 56-day exposure.

Results and discussion

Effect concentrations
Duration:
56 d
Dose descriptor:
NOEC
Effect conc.:
268 µg/L
Basis for effect:
other: bioavailailability model
Details on results:
Microbial heterotrophs acclimated to C12LAS exposure quickly (14 days) and biodegraded C12LAS at all concentrations. Blue-green algae responded by increasing in abundance with increasing C12LAS concentration. Invertebrates responded by increased drift and reduced benthic abundances at concentrations exceeding 293 ug/L. Emergence at 927 ¿g/L also declined relative to the control. Adverse responses for mayflies and chironomids were indicated using univariant statistical techniques. Multivariant techniques indicated these taxa plus molluscs, aquatic worms, caddisflies, and stoneflies were impaired at some concentrations. Bioavailability of C12LAS was investigated in streams as a function of the total suspended solids load in the water column driven by local weather and watershed patterns. A continuous bioavailability model indicated exposure was reduced by an average of 8.5 ± 8.9%. A model ecosystem NOEC (no-observed-effect-concentration) was concluded to be 293 ug/L based on measured water column exposure and adjusted to 268 ug/L by the bioavailability model. A summary of selected population and community responses at 8 weeks from the current study is shown in the table below.

Any other information on results incl. tables

Community/Measure

Dose Response

Temporal

NOEC (µg/L)

Heterotrophic microbial

Biomass (total lipid phosphate/mm2)

Amino acid uptake (3H dpm/mm2/min)

Phospholipid fatty acid (PLFA) distr.

Surfactant mineralization (% CO2)

NS

NS

Shift at >293 µg/L

Acclimation at all conc.

Autotrophic microbial

Bicarbonate uptake (14C dpm/mm2/min)

Algal density (cells/mm2)

Algal biovolume (µm3/mm2)

Blue-green algal density (cells/mm2)

Green algal density (cells/mm2)

Diatom algal density (cells/mm2)

Algal richness

Dominant taxa (cells/mm2)

  Cocconeis placentula

  Melosira varians

  Chrococcus sp.

  Nitzschia dissipata

  Navicula salinarum v. intermedia

  Pleurosira (= Biddulphia) laevis

  Nitzschia inconspicua

  Nitzschia palea

  Diatoma vulgare

  Gyrosigma acuminatum

+

NS

NS

++

NS

NS

-

-

NS

+

NS

NS

NS

++

+

--

-

+

++

-

-

+

++

+

--

-

927

927

927

927

Invertebrates

Richness

Diversity (Shannon-Weaver)

Total abundance (No./m2)

Insect abundance (No./m2)

EPT abundance (No./m2)

Mayfly abundance (No./m2)

Caddisfly abundance (No./m2)

True fly abundance (No./m2)

Chironomid abundance (No./m2)

Mollusk abundance (No./m2)

Oligochaete abundance (No./m2)

Dominant populations (No./m2)

  Baetis sp. (mayfly)

  Isonychia sp. (mayfly)

  Stenonema sp. (mayfly)

  Thienemannimyla sp. (chironomid)

  Tanytarsus sp. (chironomid)

  Cricotopus sp. (chironomid)

  Polypedilum sp. (chironomid)

  Reotanytarsus sp. (chironomid)

  Naididae (aquatic worm)

NS

NS

--

NS

-

NS

NS

NS

NS

NS

--

b

---

NS

---

++

+

+

NS

NS

--

-

--

---

---

++

+

+

293

927

293

927

293

a Plus (+) and minus (-) signs indicate whether the response significantly increased or decreased from the control condition (± = 0.05). The strength to the response was graded as slight (+/-), moderate (++/--), or great (+++/---) based on statistical analyses.  NS indicates not significant. bTaxon too low in abundance, emerged.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
A model ecosystem NOEC (no-observed-effect-concentration) was concluded to be 293 ug/L based on measured water column exposure and adjusted to 268 ug/L by the bioavailability model.
Executive summary:

An integrated model stream ecosystem fate and effects study of a C12LAS homologue, with a high content (35.7%) of its most hydrophobic and toxic 2-phenyl isomer, was performed in the summer and fall of 1996 in Procter and Gambles Experimental Stream facility.  The study addressed responses of periphytic microbes, immature benthic fauna including abundance and drift, and emergence of adult insects in a 56-day exposure.  A model ecosystem NOEC (no-observed-effect-concentration) was concluded to be 293 microgram/L based on measured water column exposure and adjusted to 268 microgram/L by the bioavailability model.