1,2,4-trichlorobenzene

Sediment toxicity

Link to relevant study record(s)

Reference

Endpoint:

sediment toxicity, other

Type of information:

other: EU Risk Assessment

Adequacy of study:

other information

Reliability:

other: EU Risk Assessment

Rationale for reliability incl. deficiencies:

other: No reliability is given as this is a summary entry for the EU RAR.

Principles of method if other than guideline:

EU Risk Assessment

GLP compliance:

not specified

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.

Executive summary:

EU Risk Assessment (2003):

Clark et al., (1987)

For amphioxus (Branchiostoma caribaeum), the 96-hour LC₅₀ for waterborne 1,2,4-TCB was between 1.5 (0% mortality) and 10 mg/kg sediment (100% mortality). In the 10-day sediment test, LC₅₀ was observed to be 200 mg/kg (NOEC: 75 mg/kg). Both tests were performed under flow through conditions and results based on nominal values.

 

Tagatz et al. (1985):

In the study the lowest measured concentration influencing the average number of individuals exposed via the water was 0.04 mg/l 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.

Description of key information

For transported isolated intermediates according to REACh, Article 18, this endpoint is not a data requirement. However, data is available for this endpoint and is thus reported under the guidance of "all available data".

 

EU Risk Assessment (2003):
Clark et al., (1987)
For amphioxus (Branchiostoma caribaeum), the 96-hour LC50 for waterborne 1,2,4-TCB was between 1.5 (0% mortality) and 10 mg/kg sediment (100% mortality). In the 10-day sediment test, LC50 was observed to be 200 mg/kg (NOEC: 75 mg/kg). Both tests were performed under flow through conditions and results based on nominal values.
Tagatz et al. (1985):
In the study the lowest measured concentration influencing the average number of individuals exposed via the water was 0.04 mg/l 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.