LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals
LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals
LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals
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OECD SIDS <strong>LINEAR</strong> <strong>ALKYLBENZENE</strong> <strong>SULFONATE</strong> (<strong>LAS</strong>)<br />
(i)<br />
Reference: 1) Grieve, A.M. and Pitman, M.G. 1978. Salinity damage to Norfolk Island<br />
pines caused by surfactants. III. Evidence for stomatal penetration as the<br />
pathway of salt entry to leaves. Aust. J. Plant. Physiol. 5:397-413.<br />
2) Hamwijk, C. 2002. Literature study: Exposure and possible indirect<br />
effects of aerosol borne surfactants on coastal vegetation. TNO Chemistry<br />
report, Study number 02-4077/01. Prepared for CEFIC ERASM.<br />
Reliability: 4 Not assignable. Original studies were not directly reviewed.<br />
Species: Pinus halepensis (pine tree)<br />
Endpoint: Accumulation of <strong>LAS</strong> in plant tissues<br />
Exposure period: 2 minutes<br />
Method: The concentration of <strong>LAS</strong> tested was 1.7 x 10 -4 mol/kg, which is equivalent<br />
to 58 mg/L based on a C11.6 <strong>LAS</strong> with a molecular weight of 342. Three<br />
batches of ten 2-year old pine trees were immersed for 2 minutes in distilled<br />
water alone (batch 1), in <strong>LAS</strong>-distilled water (batch 2), or <strong>LAS</strong>-synthetic sea<br />
water (batch 3). The objective was to simulate the exposure to severe storms<br />
on the seashore. Only the aerial parts of the plants were immersed in a large<br />
volume container (50 x 50 x 8 cm) containing 1 L of the respective solutions.<br />
The root system was isolated with a plastic bag enclosure and not exposed<br />
directly to the solutions. Controls were run on ten plants. Trees were<br />
removed from the solutions and gently shaken to eliminate liquid droplets.<br />
Radiolabeled and control trees were kept in a greenhouse for 48 hours under<br />
a 16:8 day:night photoperiod, temperatures of 22° C (day):16° C (night), and<br />
a constant relative humidity. Before analysis, the trees were washed twice in<br />
distilled water for 1 minute while shaking to simulate rainfall. Trees were cut<br />
back at the soil surface and the aerial part divided into several parts for<br />
analysis (epicuticular wax from needles, dewaxed needles, and remaining<br />
plant material consisting of branches without needles and tree stem).<br />
Respective samples were extracted, prepared, and the radioactivity measured<br />
in each fraction using a liquid scintillation cocktail and spectrometer. For<br />
scanning electron microscopy, 48 hours after the exposure period ten needles<br />
from each of the five replicates of treated and control plants were cut into<br />
small segments and air dried, fixed on aluminium stubs with conductive glue<br />
and carbon coated. Axial surfaces were examined with a Stereoscan 90B<br />
electron microscope with 15 kV acceleration voltage.<br />
GLP: Yes [ ] No [X] ? [ ]<br />
Test substance: Stated by authors as <strong>LAS</strong> with an alkyl chain length of 12 carbons, with no<br />
further information. For our review, we have assumed this to be the typical<br />
European C11.6 <strong>LAS</strong> (average MW = 342). <strong>LAS</strong> was radiolabeled with 35 S in<br />
the sulphonate group attached to the phenyl ring and had a specific<br />
radioactivity of 8712 µCi/mol.<br />
Results: The amount of <strong>LAS</strong> (as a percent of total in solution; mean ± SD) found in<br />
each analyzed fraction of the trees and the wash water is shown below:<br />
Fraction<br />
Distilled water only<br />
(Batch 1 )<br />
<strong>LAS</strong>-distilled water<br />
(Batch 2 )<br />
<strong>LAS</strong>-seawater<br />
(Batch 3 )<br />
Epicuticular waxes ~ 0 0.18 ± 10 1.48 ± 1.03<br />
Dewaxed needles ~ 0 ~ 0 0.09 ± 0.16<br />
Remaining plant<br />
material<br />
~ 0 ~ 0 ~ 0<br />
Distilled water wash ~ 0 0.17 ± 0.06 1.41 ± 0.57<br />
The amount of uptake and percent of the total radioactivity incorporated in<br />
each fraction for the <strong>LAS</strong>-seawater and <strong>LAS</strong>-distilled water treatments are<br />
shown below:<br />
<strong>UNEP</strong> PUBLICATIONS 233