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sediment toxicity
Type of information:
other: EU Risk Assessment
Adequacy of study:
other information
other: EU Risk Assessment
Rationale for reliability incl. deficiencies:
other: No reliability is given as this is a summary entry for the EU RAR.

Data source

Referenceopen allclose all

Reference Type:
secondary source
Reference Type:
Waterborne and sediment-source toxicities of six organic chemicals to Grass shrimp (Palaemonetes pugio) and amphioxus (Branchiostoma caribaeum).
Clark JR et al.
Bibliographic source:
Arch. Environ. Contam. Toxicol., 16, 401-407.
Reference Type:
Effects of 1,2,4-trichlorobenzene on estuarine macrobenthic communities exposed via water and sediment.
Tagatz ME et al.
Bibliographic source:
Ecotoxicol. Environ. Safety, 10(3), 351-360.

Materials and methods

Principles of method if other than guideline:
EU Risk Assessment
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
EC Name:
Cas Number:
Molecular formula:

Results and discussion

Any other information on results incl. tables

EU Risk Assessment (2003):

Clark et al. (1987):

Clark et al. (1987) studied the waterborne and sediment-source toxicities to grass shrimp and

amphioxus. Both species are abundant in estuarine environment and are important in estuarine

food webs and detritus processing system. Amphioxus burrow into sediment along estuaries,

marine mudflats and sandy bottoms. Grass shrimps ingest detritus and sediment particles and

reside above the sediment water interface. The test sediment was 9:1 washed beach sand and

sediment dredged from Santa Rosa Sound. The mixture contained 0.5-1% organic matter. The

studies used 200 ml sediment in 3.8 l aquaria. The measured concentrations were 75-95% of

nominal concentrations in waterborne studies and 60-95% in sediment exposures. Sediments

containing 1,2,4-TCB at 10 mg/kg were not lethal to grass shrimp during 10 days of flow-through and no higher concentration were tested (Clark et al., 1987).


For amphioxus (Branchiostoma caribaeum), the 96-hour LC50for waterborne 1,2,4-TCB was

between 1.5 (0% mortality) and 10 mg/kg sediment (100% mortality). In the 10-day sediment

test, LC50was observed to be 200 mg/kg (NOEC: 75 mg/kg). Both tests were performed under

flow through conditions and results based on nominal values (Clark et al., 1987).



Tagatz et al. (1985):

The effects of 1,2,4-TCB on estuarine macrobenthic communities exposed via water and

sediments were studied in laboratory study (Tagatz et al., 1985) using sand-filled aquaria (clean silica sand at 5.5 cm height) under flow-through conditions. In one test, communities established by planktonic larvae entrained in continuously supplied unfiltered seawater for 50 days were exposed to 1,2,4-TCB for 6 days at the nominal concentrations 0.05, 0.5 and 5 mg/l. The lowest measured concentrations that affected the average numbers of individuals exposed via water were 0.04 mg/l for molluscs, 0.4 mg/l for arthropods and 4 mg/l for annelids, and the average number of species was significant lower than the control at 4 mg/l.


In a second test, 1,2,4-TCB was added to the sediment before 8 weeks of colonisation. The

concentrations in the sediment fluctuated during the exposure period: The nominal concentrations were 10, 100 and 1,000 mg/kg, the measured ranges were 4.3-<0.01 mg/kg,

97-2.1 mg/kg and 790-519 mg/kg sediment. After 8 weeks, the measured concentrations were

<0.01, 6.1 and 519 mg/kg, respectively, for sediment and 0.51, 12 and 74µg/l, respectively, for water. The lowest nominal concentration that affected the average numbers of individuals was 100 mg/kg for molluscs and echinoderms and 1,000 mg/kg sediment for arthropods and annelids. The average number of species was significantly lower than the control at=100 mg/kg sediment. Concentrations that affected community structure were usually two orders of magnitude lower for waterborne 1,2,4-TCB than for sediment-bound 1,2,4-TCB, but the same types of organisms were affected by each route of exposure. Most 1,2,4-TCB persisted in the sediment but some leached into the water throughout the 8-week exposure period (Tagatz et al., 1985).


In the study by Tagatz et al. (1985), the lowest measured concentration influencing the average number of individuals exposed via the water was 0.04 mg/l (this figure is an order of magnitude higher than the estimated PNECaquatic organisms). With exposure via the sediment, the lowest nominal concentration affecting the average number of individuals was 100 mg/kg sediment which after 8 weeks was measured to 6 mg/kg in sediment. The concentration in water was measured to be 12 to 74µg/l at the end of the study.



Clark et al. (1987) and Tagatz et al. (1985):

However,due to the uncertainties in these two studies, data cannot be used directly in the risk assessment for the sediment compartment, although especially the data from Tagatz et al. (1985) may indicatively be compared with the estimated PNECsedobtained by employing theequilibrium partitioning method of the TGD.

Applicant's summary and conclusion