Perceived advantages of artisanal Aluminium cookware
In settings of poverty, such as in many parts of Africa, artisanal aluminium pots crafted from waste metal have high appeal. They are relatively inexpensive, and their heating times are shorter, leading to decreased use of fuels such as coal and wood, which in some areas are becoming increasingly scarce. Artisanal aluminium pots are light in weight, and relatively easy to carry around, for example by children and women, who most frequently bear the burden of cooking and collection of wood fuel. The cost is low due to the ready availability of waste aluminium to produce cooking pots, and the manufacturing technology is relatively simple. Aluminium pots are also fairly strong, durable and resistant to corrosion [3].
The production of artisanal Aluminium cookware in African settings
Artisanal aluminium cookware may be forged from a variety of waste metals, including motor car and bike engine parts, radiators, cans, construction materials and household appliances (Fig. 1) [4, 5]. The process of melting aluminium waste and crafting the pots is usually undertaken by a pair of individuals, or in small groups in a home setting [5, 6]. The work is laborious, and holds a risk of burn and other injuries, as well as exposure to air, dust and soil pollution. It may take as long as half a day for one or two men to make a single pot. The requirement for relatively low temperatures to melt the scrap aluminium has been associated with a high level of porosity in the final product. The non-standardization or subjectivity associated with the pot making process leads to a high defect rate, which may be costly for the pot makers in terms of both time and income. Field studies by the authors revealed that epoxy resins were sometimes used to fix small defects. Pots are often sold through direct sales or at local markets. In South Africa in recent years, there is anecdotal evidence that the production and use of artisanal pots is increasing, with the market growing from production and use in two provinces, to the current situation in which artisanal pots are available in at least six of South Africa’s nine provinces (Renee Street and Angela Mathee, personal communication). In parts of some African countries, the use of artisanal pots is pervasive, including in homes, schools, restaurants, for cooking of street foods and for catering at social gatherings, such as weddings and funerals, leading to a high potential for widespread and chronic exposure to lead and other toxic metals. Artisanal aluminium pots have also become a source of pride or considered a family heirloom, with names and signature designs being crafted onto the pots (Renée Street and Angela Mathee, personal communication) (Fig. 1).
Studies on leaching of metals from artisanal Aluminium cookware
Despite the widespread artisanal production and use of artisanal aluminium cooking pots, until relatively recently there has been a paucity of research undertaken to assess the concomitant lead exposure through the food pathway. A paper from 2010 points to artisanal cookware as a potential source of lead exposure in 500 pregnant women from Bangladesh. Lead concentrations measured in erythrocytes, urine, and breast milk were found to be relatively high, and the authors suggested that cooking pots may be an important source. Preliminary investigations found that up to 380 μg/L of lead was released into acidic solutions from artisanal cookware [7]. In Uganda, Mbabazi and colleagues [8] found that the highest rate of leaching of aluminium was from pots that had been locally made by artisans, relative to pots of factory origin. In Thailand, the blood lead levels of children whose food had been cooked in inexpensive pots without a quality assurance certificate was significantly elevated relative to those eating from certified cookware [9].
In a more detailed study of artisanal aluminium cookware undertaken in Cameroon, analyses of 26 pots obtained from four regions showed that while the lead content of the pots was relatively low (< 1000 ppm by X-ray fluorescence [XRF]), significant amounts of aluminium, lead and cadmium were released during dilute acetic acid extractions through boiling, and standing at ambient temperatures (up to 899 μg of lead/L). Associated calculations indicated that the lead level per serving could be as high as 260 μg. The authors postulated that daily use of such artisanal cookware may lead to chronic exposure to lead exceeding international public health guidelines, with concomitant health risks for households, especially children [10]. The Cameroonian study was followed up with a more extensive investigation of the metal content of 42 locally made pots from ten countries (Bangladesh, Guatemala, India, Indonesia, Ivory Coast, Kenya, Nepal, Philippines, Tanzania and Vietnam). XRF analyses showed detectable levels of lead in 86% (36/42) of the cookware items, and 11/42 or 26% of the cookware items had a lead content exceeding 0.1% or 1000 ppm. Thirty six percent (15/42) of the pots released a lead concentration of > 1 μg per serving after boiling for 2 h with a dilute (4%) acetic acid solution. The leaching tests showed that up to 177 μg of lead was released per serving [4]. Most recently, in a South African study of 20 artisanal aluminium pots, lead was detected in all samples of leachate collected after pot sections held at 95 °C for 2 h in a 3% acetic acid solution. The mean concentrations of lead in leachate exceeded the European Union maximum permissible level of 10 μg/L in 11 (55%) of samples in the first of a series of three migration tests. For individual pots, mean lead concentrations in leachate ranged from 31 to 2050 ppm [5]. The first three above mentioned leaching tests were done using assimilated cooking (acetic acid). A further study of artisanal aluminium pots from four African countries assessed the impact of artisanal cookware on contamination of food samples. The study assessed Al, As, Cd, Hg, and Pb exposure when preparing tomato and the other staple foods in stainless-steel compared with artisanal aluminium cookware. Using a concentration factor (CF), which measured the ratio between the metal content in the identical sample prepared with aluminum vs. stainless-steel cookware, the magnitude of the migration of Al and Pb from artisanal aluminium was noteworthy. For example, the mean CF for Pb was 18 mg/kg, with the highest CF for Pb at 26 mg/kg which was from artisanal cookware from Cameroon [11].