The safety of soil for use in cosmetics, medicinal purposes, geophagia and pottery have not been well explored. The arrival of modern cosmetics did not change the reliance on soil for dermatological beautification (Matike, Ekosse & Ngole 2010) as traditional use of soil for cosmetic purposes is still a common practice among many African communities (Matike et al. 2010). African women, especially those who reside in rural areas, also use local soils for photo-protection (Matike, Ekosse & Ngole 2011). These mix red soil (ibomvu in isiZulu) or white soil (umcako in isiZulu) with water to produce a paste that is applied onto the face (Dlova et al. 2013). Red soil paste is also applied onto traditional incisions or scars to aid in fast healing (Magwa 2006). Here, soil used for cosmetics is mainly distinguished by colour, with white and red soil being preferred.

Geophagia is the intentional ingestion of earth material (Mathee et al. 2014), which dates back historically in African communities (Phakoago 2017). A variety of reasons for practising geophagia include religious, nutritional and medicinal benefits, enhancement of personal appearance, pregnancy-related cravings and enjoyment of the taste, texture or smell of the soil (Mathee et al. 2014). The prevalence of geophagia differs widely but is still practised in many parts of the world. Geophagic soils across the African continent are unique in origin. While vendors in South Africa get geophagic soils from the wilds of mountains, valleys and riversides, those from Kenya and Tanzania source them from termite mounds (Phakoago 2017). The physical properties of soil such as their texture, structure, colour, smell and taste play an important role during selection (Ekosse, DE Jager & Ngole 2010). Our study sought to understand whether users were aware of the dangers posed by soil use and whether they had strategies to curb them.

Pottery and the construction of houses are among other practices that utilise local soil. In South Africa, there are many different types of traditional housing structures. In the Eastern Cape, a traditional hut can be built using wooden poles, with gaps between poles filled using a strong type of grass then plastered with soil. Other traditional huts can be built using stones that are then plastered with soil (Makaka & Meyer 2006). In the KwaZulu-Natal (KZN) province, there are still homesteads built with mud blocks and painted with an earthy coloured finish (umcako or ibomvu) (Mhlaba 2009). Research indicates that pottery vessels as ancient times were used for cooking, water storage and sorghum beer brewing (Fowler 2011). Potters in Umsinga district, KZN use clay (ubumba in isiZulu) to make vessels. These clays are sampled from dry stream beds, with soil types that include reddish-brown Rensburg and Katspruit calcareous soils (Fowler 2011). With all these vast uses, it is important to know how safe soil is to users. Mpuchane et al. (2010) investigated cosmetic soils from Swaziland, Botswana and South Africa and found only 14 of the 102 soil samples to have faecal coliform contamination. Bisi-Johnson, Obi and Ekosse (2010), also reported geophagia to have a range of health complications such as constipation, stomach cramps, parasitic infestation and dental damage. The aim of the study was thus to assess non-agricultural soil uses practised by people in selected communities of uMgungundlovu district and how they ensure safety for use. This was performed through a survey in three communities using questionnaires and key informant interviews. Specific objectives included:

More females than males participated in the survey. This was because men thought women were more knowledgeable about non-agricultural soil uses because these practices were usually undertaken by women. All interviewees were at least 18 years of age, because people below 18 were considered rather unknowledgeable as far as soil uses are concerned. The older generation also had low numbers, with users being mostly between 18 and 50 years. This could be because most soil users are women, who consume it (because of cravings developed during pregnancy) or use it for cosmetic purposes to enhance their beauty. S’khosana (2017) in a study in uMzinyathi and uMgungundlovu showed cravings to be the main reason for practising geophagy by women. The reasons for practising geophagia that we observed in the survey was mostly cravings or simple enjoyment. Songca et al. (2010) in a study to understand the demographic characteristics associated with geophagia also found that consumers had strong cravings for soil. The literacy level of participants was mostly secondary education, while there were very few people with no formal education. The study showed common soil uses to be cosmetics and geophagy, with construction and medicinal uses being not that popular, while pottery did not appear to be practised at all in the studied areas. Cosmetic soil was mostly used as sunscreen or a skin cleanser, but in some cases, soil was applied by traditional trainees for ritual purposes such as umemulo. Dlova et al. (2013) suggested that women use soil as a sunscreen because they cannot afford commercial products. Elandskop and KwaNxamalala are semi-rural areas where women are often involved in chores such as gardening that exposes them to UV light, so they apply a soil paste to protect them from the sun. This shows that although users might not have the scientific knowledge, they have an understanding that soil offers some protection or can serve as a cleanser to their skin. There is evidence to show that soil is a common ingredient in toners and cleansers that are used commercially in beauty spars. Smit (2011) in a study of textural properties of soil used as cleanser by traditional trainees showed that 50% – 70% of the soil samples had particle diameters of 2 µm – 20 µm, which were similar to those of clay mixtures used for cleansing in commercial Thermal Centres. Common colours of soil applied on skin by users were white and red. Mpuchane (2010) reported these colours together with yellow, grey and brown to be commonly used in several modern cosmetics products such as face powders, lip gloss, eye shadow and blushers; as they influence the sun screening and toning abilities of such products.

Medicinal soil is mainly practised by traditional healers to heal incisions. These are scars made by a sharp object in the face to show which clan one belongs to. Here red soil is applied to heal the incisions or wounds in general (Magwa 2006). Matike et al. (2011) also highlighted the vast uses of soil by traditional initiates to include it serving as a deep cleanser, toner or for identification purposes during initiation. As discussed, users also apply soil to treat skin problems such as acne and rashes, while the use of soil to treat indigestion is less common. Bisi-Johnson et al. (2013) reported that soils containing minerals such as aluminosilicate, kaolinite or montmorillonite commonly had a glue-like property that promoted attachment of microorganisms and nutrients. This might explain their effectiveness in treating ailments, but more work needs to be carried out on this.

The survey showed that respondents in all areas sourced soil from different places, with cosmetic soil mainly sampled from mountains or bought already processed from vendors. A few users also collected it from riverbanks and roadsides. Matike et al. (2010) found that users collected soil samples from riverbanks and roadsides for cosmetic use. Dlova et al. (2013) in a study in Durban again found the most common source of soil for cosmetic use to be near riverbanks. Soil used as geophagia was mainly collected by the roadside in excavations opened during road construction as well as from mountains, while a few users in the study areas bought it directly from vendors. In a study in Limpopo, Mpanama respondents also collected geophagic soil from mountains (Phakoago 2017).

In the case of sampling techniques, most geophagic soils were sampled by digging using a knife, spade, hand- hoe or selective handpicking in all areas. A study by Msibi (2014) also found that most consumers collected soil by digging using a knife. Soil processing was mainly performed for cosmetic soil, while for geophagia, respondents consumed the soil directly as is without processing it. After collection, the soil used for cosmetics was treated by boiling with water in an effort to lower pathogenic microbial populations, as users believe the heat from the boiled water is effective in killing pathogens. This was also done to make the soil smoother when applying.

According to the respondents, there are side effects associated with the different soil uses. Cosmetic soil use, for example, may cause skin blemishes, irritation and dryness. These side effects are worsened by over-application of the soil paste or applying it without it having been mixed with lotion. According to the respondents, geophagic soils may cause constipation, appendicitis and gallstones. Msibi (2014) as well as Phakoago (2017) also observed that geophagic soil caused severe constipation by binding with mucus inside the intestines.

These findings indicate that the study managed to provide an overview of soil uses, with users convinced that their storage and handling techniques (boiling, burning and baking) made the soil safe for use. However, the limitation of the research was that it was mostly performed in peri-urban areas because these were easily accessible from the university. More uses such as pottery could have been explored in deeper rural areas. In short, the study found that in addition to enjoyment of geophagic soil, users felt selected soils were an effective sunscreen and skin cleanser and were safe for use as long as heat treatment (and sometimes the addition of lotion to prevent dryness) was performed for cosmetic soil. Some users even suggested that soil use was effective at treating wounds and other skin ailments such as acne and rashes. Respondents highlighted that care should be taken, however, not to over-consume geophagic soil (as it could cause problems of constipation and development of gallstones among others), while over-applying cosmetic soil could cause skin dryness.

The study revealed that soil use for non-agricultural purposes is still common practice, with women users applying it as a sunscreen or conditioner or consuming it for enjoyment, while males use it in construction. Traditionally, soil is applied during ceremonies and rituals, while medicinal use to treat traditional incisions or wounds was not very common. With all our study areas being peri-urban, pottery was not practised at all. Pottery use might be a practise that is common in deeper rural areas, so more research on this could be directed there. In an attempt to ensure safety for use of cosmetic soil, users process the soil through heat treatment, for example boiling, burning or baking before use. Users believe such pre-treatment is effective in reducing microbial contaminants in soil. Users are aware of the health challenges (constipation, skin irritations etc.) associated with consuming soil but strongly believe that their pre-treatment methods decontaminate soil so that it is safe for use. More comparative analysis on microbial (particularly of pathogens) and heavy metal loads before and after heat treatment of the soils to ensure effectiveness of safety measures employed by users have been probed in a separate study. The validity of effectiveness of soil to treat ailments such as skin rashes, acne, wounds, indigestion and diarrhoea needs further investigation.