Zinc sulphide

Toxicity to other aquatic organisms

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:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: High quality large scale field study, extensively described.

Data source

Reference

Reference Type:

publication

Title:

Use of field data to support European water framework directive quality standards for dissolved metals

Author:

Crane M, Kwok KWH, Wells C, Whitehouse P and Lui GCS.

Year:

2007

Bibliographic source:

Environm. Science and technology 41,5014-5021

Materials and methods

Test guideline

Qualifier:

no guideline required

Principles of method if other than guideline:

Spatially matched measurements of benthic macroinvertebrate family richness and measured dissolved metal concentrations were compared over two sampling periods spanning all regions from England and Wales.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Zinc

EC Number:

231-175-3

EC Name:

Zinc

Cas Number:

7440-66-6

IUPAC Name:

zinc

Details on test material:

results expressed as dissolved Zn++ concentrations.

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

dissolved concentrations were mean values for the 3 months before macroinvertebrate samples were taken, based on monthly sampling (n=3). if dissolved concentration was below detection limit, half the detection limit was taken as concentration.

Test solutions

Vehicle:

no

Details on test solutions:

field data on environmental waters

Test organisms

Test organisms (species):

other: macroinvertebrate communities and families of Ephemeroptera, Plecoptera and Trichoptera were assessed.

Details on test organisms:

In addition to the EQI, on benthic macroinvertebrate communities, also families of Ephemeroptera, Plecoptera and Trichoptera were assessed, as these families of aquatic insects are known to be sensitive to metal toxicity.

Study design

Test type:

other: field study with benthic macroinvertebrates and insects

Water media type:

freshwater

Limit test:

no

Test conditions

Hardness:

varying, UK waters

Test temperature:

ambient field temperature

pH:

varying, UK waters

Dissolved oxygen:

ambient.

Nominal and measured concentrations:

measured dissolved concentrations were used in the analysis

Details on test conditions:

field study

Results and discussion

Effect concentrations

Dose descriptor:

NOEC

Effect conc.:

> 20 - < 27 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

other: benthic macroinvertebrate structure and insect family richness

Remarks on result:

other: values given are the 95% confidence intervals calculated on the toxicity threshold values

Details on results:

data were plotted as log dissolved metal concentrations against biological effects metrics to determine effect thresholds of the EQI scores, number of Ephemeroptera families, Plecoptera and Trichopetra families.

Reported statistics and error estimates:

Effect thresholds were determined by using 2 statistical approaches:
-quantile regression: the concentration at which quantiles were significantly decreasing with 10% was used to define the threshold;
-piecewise ("broken stick") regression: two lines are used to describe the data, joining at a breakpoint, which is considered the toxicity threshold. lines are described using least squares analysis, the breakpoint is at the concentration where the sum of squared errors was at minimum.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Highly relevant field study very useful to check the protection level provided by the HC5 following from statistical extrapolation of single species test data.

Executive summary:

Measured dissolved zinc concentrations in UK waters were compared with benthic macroinvertebrate communities and family richnness of several taxonomic groups of water insects. The extensive analysis comprised data from 291 sampling sites, and 448 samples.The field data demonstrate that the water quality standards for zinc, expressed as dissolved metal, should be set in the range between 20 and 27 µg /l. This study is highly relevant to check the protective power of the statistically derived HC5, used for PNEC setting. The results confirm that the HC5 following from the single species tests is protective for the ecosystem as a whole.