Diphosphoric acid, copper salt

Additional ecotoxological information

Administrative data

Endpoint:

additional ecotoxicological information

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

other: PdD thesis

Title:

Les effets du cuivre sur la structure et le fonctionnement des ecosystemes aquatiques: une etude en mesocosmes lotiques; Effects of copper on structure and function of freshwater ecosystems: a lotic mesocosms study

Author:

Roussel, H.

Year:

2005

Bibliographic source:

These, Université Toulouse III - Paul Sabatier, U. F. R. Sciences de la Vie et de la Terre

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Freshwater mesocosm study, covering different trophic levels

GLP compliance:

no

Type of study / information:

Freshwater mesocosm, covering different trophic levels

Test material

Test material information

Constituent 1

Reference substance name:

Copper sulphate

EC Number:

231-847-6

EC Name:

Copper sulphate

Cas Number:

7758-98-7

Molecular formula:

Cu.H2O4S

IUPAC Name:

copper(2+) sulfate

Specific details on test material used for the study:

Cu2+ as delivered as CuSO4

Results and discussion

Any other information on results incl. tables

Results showed, in the 75 µg/L treatment, a decreased abundance of macrophytes, zooplankton, macroinvertebrates and an increased abundance of periphyton, emerging insects and fish. Taxa richness was lowered in all communities in the 75 µg/L treatment. The Principal Response Curve analyses, showed that copper at 25 and 75 µg/L altered community structure of all communities. Functioning of the leaf decomposition was altered at 75 µg/L. Aquatic hyphomycetes showed functional redundancy in their ability to degrade leaf litter. Copper direct toxic effects propagated within the trophic levels lead to indirect positive or negative effects. To help disentangling all these effects a food web model based on functional groups was build and qualitatively analyzed with loop analyses. Factors other than trophic interactions probably played an important role in structuring the ecosystem (tolerance, seasonal benefit, habitat availability, external invasion, access to more resources such as light or nutrient etc.). In conclusion, this study highlighted the interest of studying both ecosystem structure and function to identify a range of responses as symptoms of ecosystem dysfunctions. Considering all those results, a NOEAEC ecosystem was set at 5 µg/L (and 4 µg/l as dissolved).

Applicant's summary and conclusion

Conclusions:

Considering all results, a NOEC ecosystem was set up at 5 μg Cu/L for fresh water ecosystems.

Executive summary:

During 18 months, environmentally realistic concentrations of copper (0, 5, 25 and 75 µg/L) where applied on 12 outdoor mesocosms of 20 m long (using tapwater) with 2 distint regions having a different depth. Copper concentrations at the end of the 18 month period were at the respective concentrations 17, 22, 80 and 196 mg Cu/kg dry weight. No organic carbon measurements are reported during the study. Copper effects on the ecosystem functioning included endpoints of relevance to the sediment compartment: leaf decomposition, fungi richness and sporulation as well as evaluations of macrophyte and macro-invertebrate populations. The results showed decreased leaf litter decomposition, decreased sporulation of fungi and decreased abundance/richness of litter associated invertebrates in the 75µg Cu/L enclosure. The data also showed increased abundance of macrophytes, periphyton and emerging insects at 75µg Cu/L. The NOEC and LOEC for the litterbag decomposition were therefore set at respectively 25 µg Cu/L and 75 µg Cu/L (nominal concentrations). The NOEC/LOEC levels are higher than the NOEC/LOEC derived for the pelagic compartment (set at 5 and 25 µg Cu/L). The results can be used to compare the protectiveness of single -species PNECS to multi-species systems. These results therefore confirm that the NOEC of the pelagic compartment is protective for the benthic community. The results also demonstrated a low sensitivity of stickleback (predating fish), supportive to the consideration of waterborne exposures as most sensitive exposure route.

 

The aim of this project was to evaluate the effects of copper on the structure and function of freshwater ecosystems. To achieve this goal, the use of experimental streams called mesocosms allowed to realize ecologically realistic study while controlling many parameters (contaminant exposure, water and sediment quality, antecedent of biotic and abiotic material, etc.). During 18 months, environmentally realistic concentrations of copper (0, 5, 25 and 75μg/L) where applied on 12 outdoor mesocosms of 20 m long. Community structure of phytoplankton, periphyton, macrophytes, zooplankton, macroinvertebrates, emerging insects, aquatic hyphomycètes and population dynamics of three-spined sticklebacks was monitored. Copper effects on the ecosystem functioning was studied through (1) the leaf decomposition process and (2) the buildup of a food web model followed by qualitative loop analyses. Results showed, in the 75μg/L treatment, a decreased abundance of macrophytes, zooplankton, macroinvertebrates and an increased abundance of periphyton, hyphomycetes, emerging insects and fish. Taxa richness was lowered in all communities in the 75μg/L treatment. The Principal Response Curve analyses, showed that copper at 25 and 75μg/L altered community structure of all communities. Functioning of the leaf decomposition was altered at 75μg/L. Aquatic hyphomycetes showed functional redundancy in their ability to degrade leaf litter. Copper direct toxic effects propagated within the trophic levels and leaded to indirect positive or negative effects. To help disentangling all these effects a food web model based on functional groups was build and qualitatively analyzed with loop analyses. Factors other than trophic interactions probably played an important role in structuring the ecosystem (tolerance, seasonal benefit, habitat availability, external invasion, access to more resources such as light or nutrient etc.). In conclusion, this study highlighted the interest of studying both ecosystem structure and function to identify a range of responses as symptoms of ecosystem dysfunctions. Considering all those results, a NOEC ecosystem was set up at 5μg/L for fresh water ecosystems.