LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
produce large particle sizes. These large particles are needed for efficient delivery of the spray to
the surface being cleaned. This results in particle sizes that are much larger than the respirable
particle sizes used in testing and therefore would not be able to reach far into the lungs where
effects could occur. A study conducted for the Soap and Detergent Association (Battelle 1999)
measured the under 10 micron fraction delivered from 6 consumer product spray nozzles. The
overall mean (n=30) is 0.11% particles under 10 microns and the standard deviation is 0.21. The
very highest observation was 0.80% particles under 10 microns. This testing only captured the
spray particles that are under 600 microns, so the actual mean respirable particle percent of total
volume sprayed is less than 0.1%. The Battelle (1999) study also reported that for consumer spray
products in normal use conditions, the peak breathing zone concentration under 10 microns ranged
from 0.13-0.72 mg/m 3 . HERA (2004) reported that measurements of aerosol particles under 6.4
microns in size generated upon spraying with typical surface cleaning spray products resulted in a
product concentration of 0.35 mg/m 3 .
Inhalation of detergent dust during washing processes was modelled by HERA (2004) and found to
be 10-fold lower than the exposure from inhalation of aerosols from cleaning sprays. This estimate
is based on a study reporting an average release of 0.27 µg dust per cup of product used for machine
laundering (Hendricks, 1970). This is a conservative (protective) estimate as exposure from modern
compact/granular detergent formulations produced in agglomeration processes would be expected
to be much less.
These estimates of exposure to respirable particles from consumer and industrial products indicate
that inhalation is not a likely route of concern for human exposure (see SIAR Annex 1 and dossier
section 1.10B(b) and (c) for more information). 2
3 HUMAN HEALTH HAZARDS
3.1 Effects on Human Health
3.1.1 Toxicokinetics, Metabolism and Distribution
Studies in Animals
The absorption, distribution, metabolism and elimination of LAS has been studied in several
species, including rats, mice, guinea pigs, pigs, and rhesus monkeys (Debane 1978; Michael 1968;
Havermann and Menke 1959; Cresswell et al. 1978; Sunakawa et al. 1979). LAS was administered
either topically (i.e., dermally) or orally. Results showed that LAS can be absorbed from the
gastrointestinal tract. Absorbed LAS is then metabolized and excreted without accumulation in the
major tissues or fat.
Debane (1978) found that when 0.2 to 0.5% LAS was topically applied once to the back skin of rats
and guinea pigs, approximately 0.1 to 0.6% was absorbed. No accumulation was observed in
specific organs and LAS was quickly excreted in the urine after being metabolized. IPCS (1996)
notes that prolonged contact with the skin may compromise the integrity of the epidermal barrier,
thereby potentially permitting greater absorption from this route. Michael (1968) found that LAS
administered orally as an aqueous solution was readily absorbed from the gastrointestinal tract (80-
90% of the dose). Most of the absorbed dose was eliminated within 72 hours and 60-65% was
2 US EPA did not evaluate the modeling results in Annex 1 and therefore can make no conclusions regarding these
values.
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