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Survey of chemical substances in kohl and henna products
1 Introduction
1.1 Background
The purpose of the project is to perform a survey of kohl and henna products on the Danish market.
Foreign studies on kohl and henna products have shown that the products may contain harmful substances, which are prohibited in cosmetic products. For instance, in a study by Lekouch et al. (2001) a
high concentration of lead in kohl products: 54 to 89%, and a lower concentration in henna products: 0.2 to 1.2%, was measured. It could also be mentioned that Hardy et al. (2004) and Illes (2000) found
that besides galena (lead sulphide, PbS) stibnite (antimony sulphide, Sb2S5) was a major component in kohl products.
The purpose is also to clarify whether the consumers are exposed to lead or other metals based on a screening survey. The study starts with a quantitative analysis of lead and a screening for other elements
such as e.g. antimony, arsenic, cadmium, gold, iron, copper, cobalt, mercury, manganese, nickel, sulphur, and zinc in kohl and henna products.
1.1.1 Kohl
The traditional eye cosmetic to be put around the eyes is commonly known as kohl. Other names may be used such as kajal, al-kahl or surma. In Western cultures, the name eye liner may be more common
although names as kohl and kajal often are included in the product name.
The kohl products previously analysed for their contents have typically been local products from for instance Marocco, Egypt, Saudi Arabia, India and Pakistan (e.g. Al-Ashban et al. 2004, Al-Hazzaa and
Krahn 1995, Hardy et al. 1998 and 2004, Lekouch et al. 2001, Nir et al. 1992, Parry and Eaton 1991).
Al-Ashban et al. (2004) collected 107 kohl samples from different regions of Saudi Arabia and analysed for the presence of lead. Lead levels up to 53% (530 mg/g) were detected in some kohl samples.
Al-Hazzaa and Krahn (1995) analysed the elements in 21 kohl products from Saudi Arabia, India and the Middle East. Seven products did not contain lead while 4 contained between 2.9 and 34.1% lead
and 10 products contained more than 84% lead.
Hardy et al. (2004) analysed 18 kohl samples, all purchased in Cairo and eleven of them originated in Egypt. The main component of six samples (4 from Egypt and 2 from India) was found to be galena
(PbS). For a further ten samples, the main component was found to be one of the following: amorphous carbon, calcite (CaCO3), cuprite (copper(I)oxide, Cu2O), goethite (FeO(OH)), elemental silicon or
talc (Mg3Si4O10(OH)2). For the last two samples the main component of each was an unknown amorphous organic compound.
In Oman, 47 samples of kohl products were collected, 15 contained lead. Of the lead containing samples 4 originated from India. The remaining 11 samples from India contained, besides lead, amorphous
carbon, iron, zinc and calcium (Hardy et al. 1998).
Several studies have found increased levels of lead in the blood of infants to whom kohl was applied (e.g. Alkhawajah 1992, Al-Saleh et al. 1999, Nir et al. 1992, Rahbar et al. 2002, Shaltout et al.
1981). Also in adult users of kohl, increased lead blood levels have been observed following the use of kohl (Warley et al. 1968, Al-Ashban et al. 2004).
Some of the inorganic or organic colorants present or potentially present in the products are prohibited in cosmetic products. Inorganic colorants may contain heavy metals, which besides the already
mentioned lead, for instance could be antimony, arsenic, cadmium, chromium, mercury, selenium, strontium lactate, -nitrate and –polycarboxylate, tellur, thallium and zirconium.
The toxic effects of lead to humans are well studied. The recognition that children are especially sensitive to very low levels of lead has caused several studies in situations where children could be exposed to
lead (e.g. Mojdehi and Gurtner 1996, Rahbar et al. 2002, Shaltout et al. 1981). Chronic exposure to lead that could result in as low blood lead levels as e.g. 10 µg/dl blood or less may cause mental
deterioration, learning disabilities or behavioural abnormalities in children (Vaishnav 2001).
It has been observed that while adults absorb approx. 11% of the lead that reaches the stomach-intestine system it is 30 to 75% for children. By exposure via inhalation approx. 50% is absorbed while less
than 1% of lead is absorbed by skin contact (Farley 1998).
In 1992, WHO has set a provisional tolerable weekly intake value (PTWI) of lead to 25 µg/kg body weight for both children and adults. The PTWI value was previously 50 µg/kg bodyweight for adults but
was reduced based on the desire to reduce the lead load to unborn children.
In USA, kohl is not allowed as cosmetic. In USA, kohl is defined as colour additive and not allowed to be used in cosmetics (FDA 1996, 2001). However, it is noted that products may use the name kohl
without containing kohl and FDA recommends the consumer carefully to check the ingredients list (FDA 2001).
1.1.2 Henna
Henna like kohl is used traditionally in the decoration of women. Extracts from dried powdered leaves of the henna plant (shrub) has been used for centuries by women in the East for the dying of hair. Since
1890 the use has been widely distributed to Europe for the dying of hair. Most common is the use for dying of hair where many shades may be obtained by mixing with leaves from other plants such as e.g.
indigo (Indigofera sp.). For the coloration of skin and nails, the powder can be mixed with lucerne or catechu, which is a brown coloured substance made from the sap of the Indian tree Black catechu
(Acacia catechu). The powder is mixed and made into a paste with hot water. The paste is applied to the area desired to be dyed and left on for a few hours (Grieve 1971).
In the series of henna products, some mixed products exist containing among others p-phenylenediamine (CAS no. 106-50-3) and lawsone (2-hydroxy-1,4-naphthoquinone, CAS no. 83-72-7).
p-Phenylenediamine is used with an oxidation agent in oxidatively based hair dyeing preparations. p-Phenylenediamine has by the Scientific Committee on Cosmetics been evaluated to be a strong contact
allergen (SCCNFP 2002a).
Lawsone naturally occurs in henna and is evaluated to be mutagenic in vitro and in vivo in some animal studies and, therefore, to fulfil the criteria to be classified as a category 3: mutagen (SCCNFP
2002b). The Scientific Committee evaluating the studies concluded that lawsone had a genotoxicity/mutagenicity potential and that therefore no safe threshold for lawsone could be established (SCCNFP
2004).
The henna products are therefore also analysed for their content of p-phenylenediamine and lawsone.
In Denmark, henna products have previously been analysed for their content of p-phenylenediamine and lawsone. Four henna products were analysed p-Phenylenediamine was not present in any of the
products and lawsone was found in only 1 product at the concentration 0.24% (Rastogi et al. 2003).
1.2 Use
Kohl and henna products are both product groups within cosmetics that traditionally have been widely used in Southern Europe, North Africa, the Middle East and parts of Asia among women, children and
babies as cosmetic and for medical purposes. The use of both product types are assumed to be widely distributed among the Danish population. Based on a Dutch study (Bremmer et al. 2002) it is assumed
that an average of 10% of the population uses kohl or eyeliner on a daily basis.
1.3 Product description
1.3.1 Kohl
Kohl is an eye makeup product. The Arabian name for eye makeup is ”kohl”. Kohl exists as a black or greyish powder, cake or liquid aimed to be applied on the skin in close vicinity to the eyes (Illes
2000). Kohl is often mixed with other chemical substances and is applied to eyebrows, skin area around the eyes or in the treatment of skin diseases in infants (Lekouch et al. 2001, Hardy 1998 and 2004).
Kohl products entail a few products as powders but most products exist in a more or less solid form. The product is applied around the eyes with a brush, stick or pencil.
1.3.2 Henna
Henna is a powder or a plant extract from plants or the genus Lawsonia. Typically Lawsonia inermis is used but Lawsonia alba is also mentioned in this context. The henna plant is a small shrub existing
naturally in Western Asia and North Africa. The leaves are picked, dried and grinded to powdered henna. The colouring agent in the henna leaves is called lawsone.
Some henna products claim to be of pure botanical origin and as lawsone is a natural constituent of the plant the substance will be present. The concentration is usually stipulated as less than 0.5 to 1% of
lawsone in so-called natural products. Some of the marketed products may be added chemical substances such as phenylenediamines or the entire henna product may be synthetically manufactured.
Henna used in hair care and for hair dyeing is often used as an alternative to permanent chemical hair dyeing. However, the colour nuances of henna is normally limited to the darker shades.
During the survey products were obtained that presented as ”black Henna” with the notion that another plant was included (Indigo: Indigofera tinctoria). Indigo is claimed not to contain lawsone. At the
other end of the colour scale with a minimum of colour was obtained a ”Henna neutral” declared to contain the plant Cassia auriculata, which also is claimed not to contain lawsone.
The henna powder usually consisting of grinded dry powdered plant parts is used by mixing the powder with hot boiling water stirred to a paste. After a certain cooling period the hot paste is massaged into
the dry hair and skull of the head where it is left for approximately 45 to 90 minutes before flushing / washing. Sometimes it is recommended to use a special balsam for a following fixation of the colour
making it last longer. Hair dyed with henna usually keeps the colour for the duration of approximately 30 days.
Henna as colorant in temporary tattoos
Henna is traditionally red but for temporary henna tattoos (skin stains) a black henna is used. This henna is added other colorants such as para-phenylenediamine which results in the black colour. These
temporary tattoos are not included in the project although both the trade association SPT and the Scientific Committee SCCNFP (SCCNFP 2003) has the opinion that the use of temporary tattoos may be
the cause to problems with henna hair dyeing. The argument is supported by several studies (e.g. Läuchl et al. 2001, Marcoux et al. 2002, Neri et al. 2002, Schultz and Mahler 2002, Temesvari et al.
2002).
Lawsone
The substance lawsone (INCI name lawsone, CAS no. 83-72-7) exists as mentioned in the dried leaves of Lawsonia inermis (CAS no. 84988-66-9) at a concentration up to 1%. The substance may also
be chemically manufactured as: 2-hydroxy-1,4-naphthoquinon.
Lawsone is suggested to be used as a non-oxidising colouring agent for hair dyeing at a maximum concentration of 1.5% (typical concentration 1.26%) in the finished cosmetic product (SCCNFP 2001).
The Scientific Committee on Cosmetic products has evaluated several studies on the substance and concluded that lawsone was not suitable for use as a non-oxidising colouring agent for hair dyeing and
gave lawsone a classification 2A: the available data support the conclusion that the substance constitutes a health hazard (SCCNFP 2002b).
1.4 Consumer target group
The consumers of kohl products are usually women. The use of black decorations around the eyes is often observable in Danish women and is very widely used by ethnic women who traditionally use such
products.
The users of henna products are likewise often women. The use is assumed widely distributed among the entire population.
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Version 1.0 September 2005, © Danish Environmental Protection Agency
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