Detergents are made from Branched Alkyl Benzene Sulphonic acid (BAB/ABS, brand name Conco AAS) and Linear Alky Benzene Sulphonic acid (LAB/LAS, brand name Santomerse). These are high production volume (>1, 000,000 pounds per annum) chemicals, which compete well with soap both in price and performance. These ionic surfactants are used in cleaning products for home, institutional and industrial use (also in agricultural products, textiles, paints, and personnel (including children) products. Commercial products usually contain 60 – 90% and consumer products 5 – 30% BAB/LAB. At one time most of these applications were all dependent on soap as the surface-active agent. The commercial BAB/LAB products are mixtures of various alkyl chain lengths, typically from about C10 to C14. Manufacturing process of BAB/LAB emits benzene, which is known carcinogen and known reproductive toxin. BAB was developed in early 1930s and being inexpensive became an instant success for use in powdered laundry detergents, replacing soaps. However, these were found to cause foaming problems in sewage/waste water treatment plants and in the environment. BAS surfactant began to accumulate in remote streams, waterfalls and fountains as BAB entered into waste flow patterns. The synthetic detergents were thought to be more resistant than soap to degradation in sewage treatment plants. The degradation process was found to be slow and incomplete due to the interruption of bacterial two-carbon oxidation at a time by the branched alkyl (3-carbon oxidation) in the hydrocarbon chain (C10 – C12). This led to search for development of biodegradable straight chain chemicals for use in detergents.

The light colored viscous liquid LAB was introduced in 1965 as a replacement for BAB. Though pure LAB solutions have average foaming properties but the alkaline mixtures of LAB are considered excellent, next to soap. LAB is complex mixture of closely related homologues and isomers.

Because of the enormous amounts of LAB consumed each year (2 million tons in 1990), serious concerns have been raised and studies are in progress to examine the biodegradation of major co-products of commercial mixtures of LAB surfactants. Di-alkyl tetralin-sulphonates (DATS) and methyl-branched isomers of LAB (iso-LAB),

which account for up to 15% of LAB, have been reported to be resistant to primary degradation. Studies have indicated the non-biodegradability of 40 – 60% of DATS and iso-LAB. On the basis of LAB consumption and the results of these studies, it has been estimated that 200,000 tons of refractory organics is dispersed each year in the environment as a result of the use of these surfactants.

Under the High Production Volume Chemical Challenge Program, LAS/ABS (LAB/BAB) Consortium’s partial submission to US EPA in December 2002 provides the following information:
(a) 28 days biodegradation of LAB (mixtures) & BAB (derivatives) 71% and
(b) 64.73%, respectively.
Acute oral for LAB (mixtures) 1300 – 1836 mg/kg and for BAB (derivatives) 520 – 1080 mg/kg. Both types of chemicals cause skin irritation.

Further studies by LAS/ABS Consortium are in progress in USA and a final submission is likely to be made to USA EPA some time this year. International Program on Chemical Safety (ICS), World Health Organization (WHO), so far has not evaluated the different alkyl benzene sulfonates and their effect on environment. Based on 1000 lbs of surfactants, laboratory tests (including aerobic degradation, industrial, atmospheric and water borne wastes and energy consumption in manufacturing process and waste disposal) seem to support the use of methyl ethyl sulfonates (MES) and fatty alcohol sulfonates (FAS) over LAB.

In view of above, the following suggestions have been made to Pakistan Environmental Protection Agency (Pak-EPA) for consideration regarding ban on use of BAB and LAB in Detergents:

1. Both LAB & BAB may not be banned in the country for 2 – 3 years.
2. Meanwhile an assessment should be made regarding consumption of LAB and BAB by industry in the country. Industry may also be advised to look into use of MES/FAS to replace BAB/LAB.
3. In view of the LAB/BAB consumption in the country and the results of the on-going studies on LAB/BAB biodegradation, environmental and health impacts, either of LAB/BAB or both may be banned.
4. Industry may be assisted with offer of incentives and technical know-how to replace LAB/BAB with MES/FAS.