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Tuesday, December 07, 2010

Industry urged to take precautions with triclosan

source cosmetics design-europe.com

By Andrew McDougall, 03-Dec-2010

Following various studies on the use of the antibacterial agent triclosan in consumer products, including oral care, experts are urging companies to remove it from their formulations as a precaution.

Elizabeth Salter Green, director of ChemTrust, a health and environmental body, explained that on a precautionary basis the chemical may not be safe to use at any level.

“It is important to stress that triclosan is not a dioxin, however concerns are that under certain circumstances it can develop the ability to disrupt hormones,” she told CosmeticsDesign-Europe.com.

Found in many consumer products

Triclosan is an ingredient added to many consumer products as an antibacterial ingredient.

It may be found in products such as antibacterial soaps and body washes, toothpastes, and some cosmetics. It is regulated by the U.S. Food and Drug Administration (FDA), and the European Union.

At this time, the FDA does not have evidence that triclosan added to antibacterial soaps and body washes provides extra health benefits over soap and water. However it stated that in 1997, reviewed extensive effectiveness data on triclosan in Colgate Total toothpaste showing that triclosan in this product was effective in preventing gingivitis.

Salter Green suggested that whilst one toxin may be harmless in a product individually, they may be dangerous if reacting together, suggesting that if there was no benefit for the toxin, it should be left out of the formulation.

Removed from GSK’s oral products

Oral care giant, GlaxoSmithKline, has removed triclosan from its Aquafresh and Sensodyne toothpastes, as well as its Corsodyl mouthwash, according to the University of Florida which has performed a study on the ingredient in sheep.

“If one eats the right foods and maintains correct dental hygiene, then triclosan, or other antibacterial agents are not needed,” explained Salter Green.

In the study by the University of Florida, researchers found that levels of triclosan were potentially damaging to the unborn foetus, if ingested by the carrying mother.

“We know it's a problem. But we just don't know how much of a problem. Triclosan can affect blood flow to the uterus, meaning the baby’s brain does not get the oxygen it needs,” said Professor Margaret James, who is the lead-author of the present study.

Discussing this particular study, Salter Green mentioned that a developing foetus in the uterus is extremely sensitive, and may be affected by disrupted hormone affecting brain development, metabolism, or the reproductive system.

Although this test was carried out on sheep, she explained that if the triclosan disrupts the hormone activity in an animal, whilst not being 100 per cent comparable, preserved hormonal evolution would suggest possible dangers to humans, and that the agent should be avoided if possible purely from a precautionary level.

comment

after wide spread use in sanitizers an increase in dioxine levels was experienced, leading to the conclusion that under some circumstances dioxines may be formed from triclosan.

FDA-fact sheet triclosan


What is triclosan?

Triclosan is an ingredient added to many consumer products to reduce or prevent bacterial contamination. It may be found in products such as clothing, kitchenware, furniture, and toys. It also may be added to antibacterial soaps and body washes, toothpastes, and some cosmetics—products regulated by the U.S. Food and Drug Administration (FDA).

What is known about the safety of triclosan?

Triclosan is not currently known to be hazardous to humans. But several scientific studies have come out since the last time FDA reviewed this ingredient that merit further review.

Animal studies have shown that triclosan alters hormone regulation. However, data showing effects in animals don’t always predict effects in humans. Other studies in bacteria have raised the possibility that triclosan contributes to making bacteria resistant to antibiotics.

In light of these studies, FDA is engaged in an ongoing scientific and regulatory review of this ingredient. FDA does not have sufficient safety evidence to recommend changing consumer use of products that contain triclosan at this time.

Does triclosan provide a benefit in consumer products?

For some consumer products, there is clear evidence that triclosan provides a benefit. In 1997, FDA reviewed extensive effectiveness data on triclosan in Colgate Total toothpaste. The evidence showed that triclosan in this product was effective in preventing gingivitis.

For other consumer products, FDA has not received evidence that the triclosan provides an extra benefit to health. At this time, the agency does not have evidence that triclosan in antibacterial soaps and body washes provides any benefit over washing with regular soap and water.

What consumers should know:

  • Triclosan is not known to be hazardous to humans.
  • FDA does not have sufficient safety evidence to recommend changing consumer use of products that contain triclosan at this time.
  • In light of questions raised by recent animal studies of triclosan, FDA is reviewing all of the available evidence on this ingredient’s safety in consumer products. FDA will communicate the findings of its review to the public in spring 2011.
  • At this time, FDA does not have evidence that triclosan added to antibacterial soaps and body washes provides extra health benefits over soap and water. Consumers concerned about using hand and body soaps with triclosan should wash with regular soap and water.
  • Consumers can check product labels to find out whether products contain triclosan.

How can I tell if there is triclosan in a product that I am using?

Antibacterial soaps and body washes, and toothpastes are considered over-the-counter drugs. If an over-the-counter drug contains triclosan, it will be listed as an ingredient on the label, in the Drug Facts box. If a cosmetic contains triclosan, it will be included in the ingredient list on the product label.

What is FDA doing to evaluate the safety of triclosan?

We are engaged in an ongoing scientific and regulatory review of the safety of triclosan in FDA-regulated products. We also have partnered with other Federal Agencies to study the effects of this substance on animal and environmental health (see http://www.epa.gov/oppsrrd1/REDs/factsheets/triclosan_fs.htm; http://www.epa.gov/endo/).

FDA is working to incorporate the most up-to-date data and information into the regulations that govern the use of triclosan in consumer products. FDA will communicate the findings of its review to the public in spring 2011.

This article appears on FDA's Consumer Updates page, which features the latest on all FDA-regulated products.

Date Posted: April 8, 2010

Friday, December 03, 2010

new interest in surfactant enhanced soil clean-up

In the last years I only sporadically observed new abstracts on this topic.
In the latest issue of clu-in.org I found several of them. It seems interest in this topic is revitalizing.

the first is not associated with surfactants I think

ADVANCED METHODOLOGIES FOR THE TREATMENT OF HYDROCARBON CONTAMINATED SLUDGES FROM SOIL WASHING PROCESSES

Garcia Frutos, F.J., O. Escolano, R. Perez, A. Rubio, A. Gimeno, M.D. Fernandez, M. Babin, G. Carbonell, C. Perucha, and J. Laguna. First Spanish National Conference on Advances in Materials Recycling and Eco-Energy, Madrid, 12-13 November 2009. Paper S02-6, p 49-52, 2009

Fine products (silt-clay fractions) in sludge from soil washing plants following bulk soil treatment usually are highly contaminated. These fractions commonly are committed to landfill disposal or thermal destruction (in the case of organic contaminants). This paper presents the results of preliminary physical-chemical and bioremediation treatability tests carried out on a hydrocarbon-heavy sludge sample after bulk soil processing in a soil washing plant. To date, best results were obtained in two bioremediation processes tested at lab scale—landfarming and bioreactors—which decreased hydrocarbon levels by better than 50% in two months and one month, respectively. http://digital.csic.es/bitstream/10261/18607/1/S02_6.pdf

comment: reducing the very high contamination with spending time and money by only 50 % is really not worse the effort.


ULTRASOUND ASSISTED SOIL WASHING FOR REMOVAL OF DIESEL WITH SURFACTANT
Cho, S.-H., Y. Son, J. Cha, S.-G. Nam, M. Lim, and J. Khim, Korea Univ.
Proceedings of Symposium on Ultrasonic Electronics, Vol 30, p 147-148, 2009 [18-20 November 2009, Paper 1P4-31]

Mechanical mixing generally is a key process in conventional soil washing, sometimes accompanied by injection of anionic or non-ionic surfactants to enhance mass transfer of pollutants from soil to aqueous phase. Tests of the application of ultrasound to the washing process indicate a significant increase in removal efficiency. When the washing water or slurry was irradiated with ultrasound, cavitation events occurred, and sonochemical and sonophysical effects were induced. Sonophysical effects, such as micro jet and micro streaming, could enhance mass transfer of organic/inorganic pollutants from soil phase to aqueous phase. This paper describes the conduct and results of a study undertaken to compare an ultrasonic soil washing process with a conventional mechanical soil washing treatment to gain a better understanding of the mechanisms of each process. http://www.use-jp.org/USE2010/proceedings/USE09/pdf/1P4-31.pdf


TREATMENT OF FUEL-OIL CONTAMINATED SOILS BY BIODEGRADABLE SURFACTANT WASHING FOLLOWED BY FENTON-LIKE OXIDATION
Tsai, T.T. and C.M. Kao (National Sun Yat-Sen Univ., Taiwan); R.Y. Surampalli (U.S. EPA, Kansas City, KS); S. H. Liang (National Sun Yat-Sen Univ.).
Journal of Environmental Engineering, Vol 135 No 10, p 1015-1024, 2009

A bench-scale study was conducted to develop a two-stage remedial system consisting of surfactant washing followed by a Fenton-like oxidation process to remediate fuel-oil contaminated soils. The researchers also evaluated the effects of residual surfactant and soil organic matter (SOM) on the efficiency of Fenton-like oxidation; the effect of potassium dihydrogen phosphate (KH2PO4) addition on the stability of H2O2 and oxidation efficiency; and the possible oxidation products after the oxidation process. In the surfactant washing stage, a biodegradable surfactant, Simple Green (SG) at 50 g/L, was applied to flush fuel-oil contaminated soil having initial total petroleum hydrocarbons (TPHs) concentration of 50,000 mg/kg. Washing with 45 pore volumes (PVs) of SG followed by 25 PVs of deionized water achieved 90% TPH removal, dropping the soil TPH concentration from 50,000 to 4,950 mg/kg. In the Fenton-like oxidation stage at initial soil TPH concentration of ~4,950 mg/kg, TPH removal efficiency increased significantly with increased H2O2 concentrations. There was evidence that residual SG and SOM can compete with TPH for oxidants and thereby decrease oxidation efficiency; hence, an oxidation-sorption-desorption-oxidation scheme for soil TPH was observed in this experiment due to the initial sorption of TPH on SOM. Addition of 2.2 mM of KH2PO4 increased the stability and half-life of H2O2 but decreased TPH removal efficiency. The oxidation potential of the Fenton-like process was insufficient to oxidize fuel oil completely to nontoxic end products. The by-products observed after the oxidation process contained carboxyl groups with molecular weights similar to their parent compounds. Results indicate that the two-stage remedial system shows promise for future treatment of fuel-oil contaminated soil.

REMEDIATION OF DDT-CONTAMINATED SOIL USING OPTIMIZED MIXTURES OF SURFACTANTS AND A MIXING SYSTEM
Ghazali, M., E. McBean, H. Shen, W. Anderson, and P.-A. Dastous.
Remediation Journal, Vol 20 No 4, p 119-132, 2010

A surfactant-aided soil washing technique was studied as an alternative method for remediation of DDT-contaminated clayey soil. The ex situ process used both nonionic and anionic surfactants. A mixture of 1% nonionic surfactant (Brij 35) and 1% anionic surfactant (SDBS) removed more than 50% of DDT from soil in a flow-through system, whereas individual surfactants or other combinations of the surfactants exhibited lower removal efficiency. The use of a mixing system improved the soil washing process. A combination of 2% Brij 35 and 0.1% SDBS was found to be optimum, removing 70 to 80% of DDT. Prewashing the soil with tap water decreased the adsorption of surfactants to soil particles by 30 to 40%, and postwashing recovered 90% of the surfactants.


BENCH SCALE TREATABILITY STUDIES OF CONTAMINATED SOIL USING SOIL WASHING TECHNIQUE

Gupta, M.K., R.K. Srivastava, and A.K. Singh.
E-Journal of Chemistry, Vol 7 No 1, p 73-80, 2010

Surfactant washing is an ex situ process. The excavated contaminated soil can be heaped on plastic liners or other impermeable barriers and irrigated with washing solutions such as surfactant; alternatively, batch washing of the contaminated soil can be conducted in tanks or lined pits using continuous flows washing in countercurrent or normal modes. The authors applied soil washing using plain water enhanced with surfactants to a study of the remediation of soil contaminated with engine lubricant oil or a heavy metal. The engine oil was used at different percentages (by dry weight of the soil) to contaminate the soil artificially. The geotechnical properties of the soil underwent large modifications after mixing with the oil. Sorption experiments were conducted with cadmium metal in an aqueous medium at different initial concentrations of the metal and at varying pH values of the sorbing medium. For the remediation of contaminated soil matrices, a nonionic surfactant was used for the restoration of geotechnical properties of the soil samples contaminated with lubricant oil, while an anionic surfactant was employed to desorb cadmium from the contaminated soil matrix. The surfactant for soil contaminated with lubricant oil was able to restore properties up to 98% of those of virgin soil, while up to 54% cadmium was desorbed from the contaminated soil matrix in surfactant-aided desorption experiments. http://www.e-journals.in/PDF/V7N1/73-80.pdf

comment: As nonionic surfactant Triton X-100, as anionic Sodium Dodecyl Sulfate, selection seems to be based on scholarly aspects.
In my experience for mineral oil contaminated soil a mixture of anionic/nonionic works best, e.g. 3 parts Na Alkyl benzene sulfonate / 7 parts Synperonic 91/4



ELECTROKINETIC REMOVAL OF PETROLEUM HYDROCARBON FROM RESIDUAL CLAYEY SOIL FOLLOWING A WASHING PROCESS

Jeon, C.-S., J.-S. Yang, K.-J. Kim, and K. Baek.
CLEAN — Soil, Air, Water, Vol 38 No 2, Feb 2010

A study was conducted of total petroleum hydrocarbon (TPH) removal from residual clayey soil using an electrokinetic process following a washing procedure. Eight electrokinetic experiments were carried out to investigate the characteristics of TPH removal. When 0.1 M MgSO4 or 0.1 M NaOH was used as an electrolyte, the electric current increased rapidly within the first 100 or 200 h, respectively. A negatively charged soil surface resulted in a more negative zeta potential and greater electroosmotic flow toward the cathode. The accumulated electroosmotic flow was higher when using 0.1 M NaOH as the anolyte-purging solution than when using 0.1 M MgSO4. Although the energy consumption for the two purging solutions was similar, the efficiencies of TPH removal when 0.1 M MgSO4 and 0.1 M NaOH with surfactant were used were 0 and 39, respectively, because the electroosmotic flow rate increased with TPH removal efficiency. When 5 isopropyl alcohol was used as a circulation solution, the electric current increased, but the TPH removal was similar to that using water. In terms of energy consumption, the use of a surfactant-enhanced electrokinetic process with NaOH as electrolyte was effective in removing TPHs from low-permeability soil. http://onlinelibrary.wiley.com/doi/10.1002/clen.200900190/pdf


REMOVAL OF HIGH CONCENTRATIONS OF POLYCYCLIC AROMATIC HYDROCARBONS FROM CONTAMINATED SOIL BY BIODIESEL
Jinbao Wu, Zongqiang Gong, Liyan Zheng, Yanli Yi, Jinghua Jin, Xiaojun Li and Peijun Li
Frontiers of Environmental Science & Engineering in China, [online prior to print publication] 2010
Solubilizing experiments were carried out to evaluate the ability of biodiesel to remove PAHs from highly contaminated manufactured gas plant (MGP) and PAH-spiked soils alongside applications of hydroxypropyl-beta-cyclodextrin (HPCD) and tween 80 as comparisons. Biodiesel displayed the highest solubilities for phenanthrene (420.7 mg/L), pyrene (541.0 mg/L), and benzo(a)pyrene (436.3 mg/L). These corresponded to several-fold increases relative to 10% HPCD and tween 80. Biodiesel showed a good efficiency for PAH removal from the spiked and MGP soils for both low- and high-molecular-weight PAHs at high concentrations. Biodiesel was a more effective agent for PAH removal from the spiked soils compared with HPCD and tween 80; it achieved over 77.9% removal of individual PAHs. Tween 80 also showed comparable capability with biodiesel for PAH solubilization at a concentration of 10% for the spiked soils. Biodiesel solubilized a wider range of PAHs than HPCD and tween 80 for the MPG soils. At PAH concentrations of 229.6 and 996.9 mg/kg, biodiesel removed >80% of total PAHs. The investigators observed a significant difference between PAH removals from the spiked and field MGP soils: PAH removals from the MGP soil by HPCD and tween 80 were much lower than those from the spiked soil. These results demonstrate the potential for utilizing biodiesel for remediation of highly PAH-contaminated soil.

comment: Though biodiesel worked best (I experienced the same), it works when used as 100 %. Clean-up of biodiesel for recycling proved difficult, with activated carbon it will be costly. For PAH extraction I would suggest a combination of about 1 part carboxymethyl cellulose / 9 Part Synperonic 91/4.


WASHING OF FIELD WEATHERED CRUDE OIL CONTAMINATED SOIL WITH AN ENVIRONMENTALLY COMPATIBLE SURFACTANT, ALKYL POLYGLUCOSIDE
Han, M., G. Ji, and J. Ni, Peking Univ., Beijing, China.
Chemosphere, Vol 76 No 5, p 579-86, 2009
Weathered crude oil-contaminated soils are much more difficult to remediate than those freshly contaminated. Although surfactant-enhanced ex situ soil washing can be used to remediate the weathered soils, surfactant toxicity is a major concern. A class of green surfactants, alkyl polyglucosides (APGs), was tested for washing field-weathered soils with relatively high oil concentration (123 mg/g dry soil) from an oilfield in China. APG1214, characterized with a longer alkyl chain, was more effective than APG0810 for removing crude oil. Addition of inorganic sodium salts to the APG1214 solution further improved crude oil removal efficiency. Washing parameters (temperature, washing time, agitation speed, and solution/soil ratio) were investigated, further optimized, and integrated with an orthogonal design. Under optimum conditions, removal efficiency reached 97%. GC/MS analysis showed that the proportion of small n-alkanes (C(16) to C(23)) in residual crude oil gradually increased, which helped to interpret the oil removal mechanism. Removal of large n-alkanes was achieved from the synergy between APG1214 and inorganic salts, which was the opposite of the effect when they were added separately. This study presents a promising technique for remediation of weathered crude oil-contaminated soils with ecologically compatible surfactant and provides guidelines for its practical application.