LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
III. Purpose and Coverage of this Report
(1) Purpose
To provide high end to bounding estimates of the potential environmental and human exposure to LAS
from its manufacture and its use in consumer, commercial and industrial products in the United States to
complement an OECD SIDS Programme review of this category.
(2) Coverage
The report covers exposure from manufacturing and consumer/commercial/industrial use for all LAS
volumes produced and used in the United States.
IV. Summary
(1) Synthesis of Key Assessment Results
BACKGROUND: LAS is a mixture of closely related isomers and homologues covering several CAS
numbers, each containing an aromatic ring sulfonated at the para position and attached to a mostly linear
(87-98%) alkyl chain. It is an anionic surfactant that has been widely used since its 1964 introduction as
the primary cleaning agent in consumer/commercial/industrial laundry detergents and cleaning products.
This chemistry replaced branched alkylbenzene sulfonate (BABS), eliminating excessive foaming of
sewage treatment plants and receiving waters caused by the poor biodegradability of BABS.
RESULTS SUMMARY: Approximately 390,000 metric tons of LAS are consumed annually in North
America (United States and Canada combined). Production in Europe is approximately 400,000 metric
tons. Production in Japan is approximately 85,000 metric tons. About 78-97% of the LAS consumption
worldwide is in liquid, dry and tablet forms of laundry and fine fabric detergents. Another 2-10% is used
in dishwashing liquids, with the remainder used in other cleaners. The predominant disposal route for
these products is via wastewater. LAS is water soluble (250 g/L) and has low vapor pressure (3E-13 Pa).
The agglomeration process for production of modern powder/granular detergent formulations minimizes
the potential for inhalation of LAS from dust. LAS is effectively removed in biological wastewater
treatment (up to 99+%) and is rapidly and completely biodegraded (70-90+% in ≤28 days). It has low
potential for bioaccumulation (BCF - 87 L/kg), with rapid clearance. These characteristics help to
minimize the potential for human and environmental exposure. Engineering controls (e.g., exhaust
ventilation, dust collection) and personal protective equipment (e.g., protective clothing, eyewear, and
gloves) in place at facilities that manufacture liquid and dry materials sufficiently mitigate worker
exposure to LAS. The aquatic NOEC is 270 µg/L. Results of extensive environmental monitoring
evaluations in the United States indicate that measured surface water concentrations were generally below
50 µg/L for river water samples collected under low dilution (worst case) conditions below treatment plant
mixing zones and range from non-detect (