Aquatic toxicity, of surfactants

The presence of surfactants and their biodegradation products in different environmental compartments can invoke a negative effect on the biota. The ecotoxicity of surfactants to aquatic life has been summarised in the scientific literature [1—5]. Nevertheless, some information is still lacking in relation to the aquatic toxicity of surfactants, especially knowledge regarding the toxicity of the degradation products, the effect of surfactants on marine species, the ecotoxicity of mixtures of chemical compounds with surfactants, the relationship between toxicity and chemical residue and the effect of surfactant presence in specific environmental compartments (water, particulate matter, pore-water, sediment). 

Roberts, D. W. (1991) QSAR issues in aquatic toxicity of surfactants. Sci. Total Environ, 109/110, 557-68. 

Obviously this is not just another book in the series my involvement as co-editor of the book, together with my two old friends, Thomas Knepper and Pirn de Voogt, makes this book rather special to me. Everything started in 1996 when I first met separately with Thomas and afterwards with Pirn and we decided to establish a consortium covering the analysis, behaviour and toxicity of surfactants in the aquatic environment. 

TOXICITY OF SURFACTANTS FOR AQUATIC LIFE Julian Blasco, Miriam Hampel and Ignacio Moreno-Garrido... 

This chapter presents a summary of the available information regarding the toxicity of surfactants in the aquatic environment and also the new data with special emphasis on the marine environment, the use of microalgae and early life-stages of fish in toxicity assays. In the last few years, one aspect related to the impact of biodegradation products of surfactants in the environment has acquired a significant relevance—the estrogenic effect—and this subject is treated in depth in Chapter 7.3 of this book. 

Fig. 2 Environmental assessment of surfactants is based on values of biodegradation and aquatic toxicity. A surfactant must lie within the shaded areas in order to meet the OECD regulatory directives...

Uppgard L, Sjostrom M, Wold S. Multivariate quantitative structure-activity relationships for the aquatic toxicity of alkyl polyglucosides. Tenside, Surfactants, Detergents 2000 37(2) 131-8. 

Table 4 Aquatic toxicity of some anionic surfactants ...

There are different types of emulsion breakers and inhibitors, some of which are best used when little water is present, which is referred to as a closed system, and others that are best used on the open water, referred to as an open system. For example, some contain surfactants that are very soluble in water and are best used in closed systems so that they are not lost to the water column. Others contain polymers that have a low water solubility and thus are best used on open water. The aquatic toxicity of the products also varies widely. 

The separate determination of homologous and isomeric compounds is absolutely necessary in order to assess the aquatic toxicity of a surfactant because biodegradability and aquatic toxicity are strongly... 

Seen as a whole, there are many data available on the aquatic toxicity of anionic surfactants, mainly for acute... 

Data for acute aquatic toxicity against daphnia are found in Table 22.11, with a clear indication that also soaps as surface-active compounds display a toxicity similar to synthetic surfactants. The aquatic toxicity of soaps depends considerably on the water hardness. 

Table 22.18. Chronic aquatic toxicity of nonionic surfactants...

Lewis, M. A., Chronic and sublethal toxicities of surfactants to aquatic animals a review and risk assessment. Water Res., 25, 101-113 (1991). 

Hodges G, Roberts DW, Marshall SJ, Dearden JC (2006) The aquatic toxicity of anionic surfactants to Dophnia magna—a comparative QSAR study of linear alkylbenzene sulphonates and ester sulphonates. Chemospheie 63 1443-1450... 

To a large extent, surfactant choices control the toxicity of raw textile wastewater [39]. Surfactants vary in their aquatic toxicity as well as treatability depending on specific features of the molecular structure. Moore reported that aquatic toxicity correlates with hydrophyllic/lipophyllic balance of the surfactant. He also determined that water hardness is a contributing factor in aquatic toxicity of... 

Although the data are limited, the aquatic toxicity of dialkyl sulfosuc-cinates does not indicate unusual toxicity for a surfactant. The LC50 for rainbow trout is 28 mg/L [59]. 

TABLE 4 Aquatic Toxicity of Gemini Arginine-Based Surfactants... 

Aquatic toxicity of SMEs is significantly affected by the chain length of the aUcyl group. As the chain length increases, the toxicity increases. Drozd published reported LCjg values of various surfactants tested on fish and invertebrates [25]. The C12 SME data ratings are practically nontoxic according to the U.S. Fish and Wildlife Service. Other surfactants listed, such as LAS, AOS, and alcohol... 

The acute aquatic toxicity of the major degradation intermediate (Fig. 13) was determined under static conditions on both rainbow trout and daphnid with replicate groups of 10 organisms. The results of this study are summarized in Table 4. As seen from these resnlts, the control effluent had no effect on the rainbow trout or the daphnid. The biodegradation products from the activated sludge treated with C,g alkyidiphenyl oxide disulfonate (20 ppm initial concentration) had no effect on the rainbow tront or daphnid. The fact that the disulfonated surfactant, when added directly to the effluent, is toxic to fish is consistent with other sul-fonated surfactants [25,26],... 

The aquatic toxicity of a chemical depends not only on its intrinsic toxicity but also on its biodegration rate. Chemicals which are toxic but are degraded at a rapid rate may not affect aquatic life. However, most fluorinated surfactants are biochemically stable and their aquatic toxicity is not reduced by degradation. 

The aquatic toxicity of fluorinated surfactants has been studied by Knaack and Walther [16]. The biochemical oxygen demand of three fluorinated surfactants was measured by the Warburg method, using a mixed bacterial culture. The fluorinated surfactants tested were the following ... 

Prescher et al. [17] studied the aquatic toxicities of four fluorinated surfactants to guppy Poecilia reticulata) and green algae (Monoraphidium griffithif). 

The aquatic toxicity of fluorinated surfactants to fish has been related to their high surface tension. The very sensitive orfes Leuciscus idus melanotus) have tolerated as much as 20 mg/L of tetraethylammonium perfluorooctanesul-fonate for 70 h without noticeable effects. However, when the concentration of the surfactant was increased to a level where the surface tension started to drop markedly, toxic effects were immediately observed [7]. 

Lewis MA, Suprenant D (1983) Comparative acute toxicities of surfactants to aquatic invertebrates. Ecotoxicol Environ Saf 7 313-322... 

Nonionic surfactants and phenoUc resins based on alkylphenols are mature markets and only moderate growth in these derivatives is expected. Concerns over the biodegradabiUty and toxicity of these alkylphenol derivatives to aquatic species may limit their use in the future. The use of alkylphenols in the production of both polymer additives and monomers for engineering plastics is expected to show above average growth as plastics continue to replace traditional building materials. 

Both approaches are useful and they are also complementary because it is important to know where a chemical that may be best in its class falls out with respect to hazard. For example, a surfactant that is best in its class will be rapidly biodegradable, but most surfactants have some aquatic toxicity because they are surface active. However, surfactants as a class are typically close to the green end of the hazard spectrum because they tend to have low hazard ratings for most other endpoints. It is also possible to have chemicals that are best in their class but that are still problematic. For example, some dioxin congeners are less toxic than others but one would not presume that a dioxin congener that is best in its class is green . Concurrent use of the best in class approach with the absence of hazard approach is also important because it drives continual advancement within a class toward the ideal green chemistry. Once innovation occurs and a chemical or product is developed that meets the same or better performance criteria with lower hazard, what was once considered best in class shifts. 

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