Quaternary ammonium compounds, bis(C16-18 and C18-unsatd. alkyl)dimethyl, chlorides

Endpoint summary

Additional information

Read across from structurally similar Quats (DHTDMAC, DODMAC) can be applied.

In the EU Risk Assessment DODMAC (EU, 2002) Monitoring data are given. These values reflect the situation of the Sewage treatment plants as well as of sediments of the year of collection (mostly 1980 to 1990). From 1990 to date these concentrations have dropped strongly.

For the interpretation of the following monitoring data, it has to be considered that (if not otherwise noted) the figures stand for total concentrations, i.e. no distinction has been made between the "dissolved" (in reality: included in vesicles) and the adsorbed fractions.

Waste water and treatment plants

In 1979 DHTDMAC was analysed in a wwtp in Dülmen (Germany), which receives a high proportion (> 95%) of domestic sewage. An overall removal rate of about 94% was found during primary settlement, aerobic treatment and secondary settlement. The average concentra­tions were 1.57 mg/l in raw sewage and 0.09 mg/l in the effluent. In activated sludge 8.3 g DHTDMAC/kg dry solid was detected. The river below outfall contained 0.03-0.12 mg/l (0.07 mg/l) (Topping & Waters, 1982).

In a wwtp in Alderly Edge (UK) which also receives mainly municipal sewage, a total removal rate of >95% was found (average concentrations: 1.38 mg/l in raw sewage, 0.04 mg/l in secondary effluent). In activated sludge 3 g DHTDMAC/kg dry solid was detected. The con­centrations are lower than in Dülmen because of the lower use of softeners in UK (Topping & Waters, 1982).

DHTDMAC was measured in the biological treatment plant of Lüdinghausen (Germany) by 5 laboratories in 1987. Generally, the results were in good agreement. The average values are 830 µg/l in the raw sewage, 30 µg/l in the final effluent (corresponding to 96% removal), and 3.3 g/kg in the wasted sludge. The fraction of municipal and industrial waste waters are not reported (Gerike et al., 1994).

During several monitoring studies in the USA, the wwtp elimination was calculated from mea­sured influent and effluent concentrations. The removal rates were 19-32% (Æ26%) for 4 primary treatment plants, 44-94% (Æ72%) for 5 trickling filter plants, and 89-98% (Æ94%) for 5 activated sludge plants (Versteeg et al., 1992).

In 1984 and 1985, ditallow dimethyl ammonium chloride (DTDMAC) and its impurity monotallow trimethyl ammonium chloride (MTTMAC) were measured in the production site's effluent and in influent and effluent of the public owned treatment work in Lima (Ohio, USA) which receives the producer's sewage (Hopping, 1987). We assume that the detected substance is DHTDMAC in reality. The results were as follows [µg/l]:

Table 3.1.2.1a: Measurements of DTDMAC and MTTMAC concentration (average values)

Year	Sample point	DTDMAC	MTTMAC
1984	Plant waste	552,000	51,900
	POTW influent	3,650	410
	POTW effluent	63	<10
	Removal	98%	>98%
1985	Plant waste	280,000-520,000 (av. 53,000)	13,000-33,000 (av. 24,000)
	POTW influent	3,000-7,300 (av. 4,430)	270-590 (av. 370)
	POTW effluent	62-120 (av. 91)	<10-33 (av.20)
	Removal	98%	95%

In 1988, DHTDMAC was measured in wasted activated sludge from the treatment plant in Koblenz (Germany). With 14 measurements, concentrations of 8.8-9.2 g/kg were detected (Hellmann, 1989).

From 1991 to 1994, DHTDMAC was repeatedly measured in digested sewage sludge of 5 Swiss municipal treatment plants. In 1991, the concentrations were in the range of 2.57 to 5.87 g/kg dry sludge. Until 1994, they dropped to 0.15 to 0.30 g/kg because of the widely replacement of the substance (Fernandez et al., 1996).

Based on the monitoring studies cited above, an elimination rate of 95% in biological treatment plants is used for the following exposure calculations.

Based on measurements at different sites of treatment plants, ECETOC (1993) estimated the DHTDMAC fractions being adsorbed onto primary sludge to 31% and onto wasted activated sludge to 24%. In the regional exposure assessment, it is assumed that in all 55% of the used substance is adsorbed and reaches agricultural soils during use of sludge as fertilizer.

 

Rivers, suspended matter and sediments

In 1981, DHTDMAC was measured at 30 locations at the Rhine and its tributaries. At every location, 2 grab samples were taken: in the first the bulk concentration was measured, while in the second the suspended matter was allowed to settle down during 2 weeks and afterwards the DHTDMAC concentration in the overlying water was measured. The bulk concentrations were found to be in the range between 4-92 µg/l with an average of 19 µg/l, the average fraction adsorbed onto suspended matter was found to be 27%. The concentration of suspended solids was in the range of 9 to 72 mg/l with an average of 22 mg/l (Kappeler, 1982).

In the river Rhine near Bonn, DHTDMAC was detected in concentrations of 6-12 µg/l (no further data available) (Schneider & Levsen, 1986).

The pollution of suspended particles in the river Rhine was examined by Hellmann, 1995. The DHTDMAC concentrations decreased from about 200 mg/kg in 1982 to 25-50 mg/kg in 1994. In the same period the German DHTDMAC consumption for softeners had dropped by more than 90% (cf. section 2). It was found that the DHTDMAC concentrations in 1993/94 were not reciprocal to the river flow as it would be expected. Detailed hydrological studies showed that the DHTDMAC loads rise strongly with increasing river flows. As the reason raising of sediments and rinsing of agricul­tural soil during strong rainfalls are stated. These soils and sediments are loaded with historical DHTDMAC emissions. The results reveal that DHTDMAC adsorbed onto soil and sediments is not or very slowly degraded.

In a sediment sample from the German river Saar, 220 mg DHTDMAC per kg (unknown if dry or wet weight) were detected in 1988 (Hellmann, 1989).

DHTDMAC was detected in the Spain river Llobregat being highly polluted with waste water from surfactants and pesticide industries. No concentration is reported (Rivera, 1987).

From March 1990 to June 1991, DTDMAC concentrations between 2 and 34 µg/l were measured in 6 different rivers in the Netherlands (van Leeuwen et al., 1992). We assume that the detected substance is DHTDMAC in reality.

In 1990, the following DHTDMAC concentrations were measured in Dutch rivers: 15-25 (Æ 20) µg/l in large rivers, 22-52 (Æ30) µg/l in rivers, 11-48 (Æ27) µg/l in tributaries, 15-116 (Æ43) µg/l in canals and 17-114 (Æ56) µg/l in polders (ECETOC, 1993).

 

Furthermore the following monitoring data (DHTDMAC) without further information are available:

Table 3.1.2.1b: Monitoring data (DHTDMAC):

Medium	Country	Concentration	Year	Reference
Main - suspended solids	Germany	11 - 201 (av.85) mg/kg	1989 - 90	Klotz, 1990
Elbe - suspended solids	Germany	av.20 mg/kg	1990	Hellmann, 1990
Weser - suspended solids	Germany	80-100 mg/kg	1990	Hellmann, 1990
Niederrhein - suspended solids	Germany	50-150 mg/kg	1990	Hellmann, 1990
3 rivers (sediments)	Belgium	11-67 mg/kg	1987	ECETOC, 1993
Rhein at Iffezheim (sediments)	Germany	78 mg/kg	1987	Klotz, 1990