Dust
Under certain circumstances, starch dust may represent an explosion hazard. Workers pouring sacks of potato starch and maize starch have been exposed to airborne dust in the range of 115-200 mg/m3 (OSHA, 2005). Repeated or prolonged contact with skin may cause dermatitis (NIOSH, 2004).
Starch production
Starch production is an industrial process that consumes energy and water, and yields wastewater and by-products. In 2012, a study carried out for the European Starch Industry Association concluded that, for the process leading to native starch (not including cultivation), the use of electricity and heat (the latter necessary for drying and concentration) were the major contributors to the carbon footprint, while water use was the main contributor to water depletion. Additives were not a contributor to the environmental impact for native starch, but did contribute to the impact for other products like liquid glucose. The study noted that the widespread use in Europe of cogeneration (combined heat & power) systems mitigated the effects of energy consumption and that waste production was reduced. Most starch by-products in Europe are indeed from plant sources, have an economic value and are not discarded or burned (Vercalsteren et al., 2012).
Starch production from roots and tubers, which includes washing and peeling operations, requires particularly large quantities of water. For instance, the European potato starch industry release of wastewater has been reported to be equivalent to the wastewater production of 2.9 million people (Mikkelsen, 2006). In cassava production, a ton of starch generates approximately 10 to 20 m3 of wastewater with high organic loading (P 0.2-0.6 kg and N 3-10 kg) (DWI, 2006). A cassava starch production unit processing 100 t of tubers per day may output 47 t of fresh by-products, which may cause environmental problems when left in the surroundings of processing plants or carelessly disposed of (Aro et al., 2010). In Nigeria, for example, cassava wastes are mainly left to rot away or burned off to create space for the accumulation of a new generation of waste heaps, emitting carbon dioxide and producing a strong offensive smell (Aro et al., 2010; Adebayo, 2008). Cassava peels (high amounts of cyanogenic glucosides) and pomace (large amounts of biodegradable organic matter) may cause surface water pollution especially if they are stored under heavy rain or simply disposed of in surface waters (Pandey et al., 2000; Cereda et al., 1996; Barana et al., 2000). The presence of a large processor or of a high concentration of small processors can cause the eutrophication of slow moving water systems, notably during the dry season (FAO, 2001). However, cassava processing does not appear to affect groundwater supply, except perhaps in the immediate surroundings of processing units due to leachates filtering through the soil (FAO, 2001). Water depletion can be minimized by the adoption of processing technologies suitable for the water resources available (FAO, 2001). Generally, the long-term and broad-based impact of cassava processing on the environment can be corrected by proper waste management (FAO, 2001), and the use of cassava by-products as feedstuffs or as an alternative substrate for biotechnological processes in way to alleviate environmental issues (Pandey et al., 2000).