Incineration is a practical alternative to landfilling plastic waste. However, there are increasing concerns about the possibility of hazardous chemicals, such as halogenated additives and polyvinyl chloridebecause the combustion of plastics releases dioxins, furans and polychlorinated biphenyls (PCBs) into the atmosphere during the process [32]. Gilpin et al. [33] highlighted some compounds released during PVC incineration, including acetaldehyde, benzaldehyde, formaldehyde, phosgene, polychlorinated dibenzo-dioxin, hydrochloric acid, propylene and vinyl chloride, among others. Some of the health effects of these compounds include damaging the nervous system, causing lesions, eye and respiratory tract irritation and carcinogenic effects adversely affecting the bone marrow, the liver and the immune system [33]. In addition, the released substances settle on the soil and plants as black carbon, ashes, and many powders, with the potency to drift to the marine environment and when rain falls, some of these toxic composites permeate the soil, pollute the aquifers, or plants cultivated around this soil absorb them and further integrate them into the food chain [34].

Contrary to recycling and landfilling, incineration of plastic is less commonly used for waste management due to its higher immediate possibility for pollution. The only benefit from plastic incineration is the recovery of energy [35] but plastics can be recycled by converting recovered scraps into usable materials. However, since most plastics are non-biodegradable, the best effort will be to reduce waste productions, effectively reuse waste and then recycle [36].

Plastic recycling is an essential part of the global effort toward the reduction of the 8 million tons of plastic debris that empties into the ocean yearly [37], although the plastic recycling terminology is complicated due to its recycling and recovery systems [38]. There are four types of recycling techniques, and the primary technique is one which mechanically reprocesses plastics into an equally strong new product. The next one is called the secondary technique, and it is the mechanical reprocessing of plastics into a product with lesser qualities. The third, which is called the tertiary technique, revolves around the recovery of the chemical elements of the plastics, and the last recovers the chemical constituents of the plastics. Whatever method is used to recycle plastic, the smelting of various sorts of materials often results in phase separation like that of oil and water, and the result is the reason for the structural weakness in the finished product(s), which is accountable for the limited use of these polymer sequences [39]. This is the situation with polypropylene and polyethylene, the two most regularly produced plastics, which has reduced their recycling potential [40]. Despite this, the volume of post-consumer recycled plastics has grown since 1990, albeit it is low in comparison to other products, such as corrugated fiberboard (about 70%) and newspaper (nearly 80%) [41]. As documented by Geyer et al. [42] in 2015, about 9% of the world’s 6.3 billion tonnes of plastic garbage were recycled, while the other 12% and 79% were burnt and landfilled, respectively. The global rate of recycling in 2016, however, increased to over 14% of total plastic waste [43], with countries such as Japan, a major contributor, increasing waste recycling from 39% in 1996 to 83% in 2014 [44,45].

3. The Environmental and Health Impact of Plastic Waste Disposal in South African Townships

This section discusses the environmental and health impact of plastic waste disposal in South African townships as retrieved from secondary sources.

3.1. Environmental Impact

The increased human population impacts the distribution of plastic waste, and this can ultimately lead to pollution of the environment, which is evident in the decline of the natural environment [53], mortality of aquatic organisms [54] and blockage of sewage systems, especially in third world countries [55], thereby resulting in breeding grounds for mosquitoes and other disease-causing vectors as well as foul odours [56], reduced aeration and water percolation, causing reduced productivity in agricultural lands [57,58].

3.2. Health Impact

Plastic polymers are commonly assumed to be harmless, yet they pose little risk to society; however, diverse types of additives, as well as residual monomers presumably preserved from these polymers, are speculated to be the source of the health risks. [45]. Most of the plastic additives are known endocrine disruptors and carcinogens [65], and these chemicals harm humans primarily through skin contact (linked to dermatitis), ingestion and inhalation [66]. Microplastics are vital toxins that can form complexes in the food chain after being consumed by a variety of marine and freshwater life, resulting in a variety of health problems [67]. When and if consumed, animals exposed to plastic additives and microplastics can be harmful to humans, and through the detection of environmental contaminants, biomonitoring investigations on human tissues have indicated that plastic elements are found in the human species [68]. All the above are not just localised but global issues and hence applicable to South African townships.

Between 1994 and 2009, consumption of fish in South Africa increased by over 26%, posing human health risks because the ingestion of some aquatic species might trigger the transmission of microplastics, toxins and microorganisms to humans [69]. Ref. [70] research conducted for the World Health Organization (WHO) regarding the risk of microplastics to humans showed that there is inadequate data to draw firm conclusions on nanoparticle toxicity as no reliable evidence suggests it is a concern. However, subject to the dependence of the population on seafood, a varied amount of plastics has been quantified to have been ingested from such food groups as mussels and shrimp in fifty countries in Europe, the Persian Gulf and China [71]. These food groups are taken whole, unlike fish, which is normally cleaned first to eliminate microplastics from the digestive system. For South Africa, edible marine organisms that have been researched for microplastics are brown mussels [72] and four species of estuarial fish [73], but data on levels of transferal of microplastics from edible aquatic species to humans were unavailable for South Africa. [74] discovered that people who ingest a variety of marine species, including filter feeders(e.g., mussels and oysters), may be exposed to microplastics.

Microplastics have been found in human faeces in several investigations, with most particles (90 per cent) being expelled [75]. Some particles may go from the stomach to the lymphatic and circulatory systems, whereas others are more likely to pass through cell tissues, the blood-brain barrier and the placenta [76]. The human body reacts to these particles by triggering immunosuppression, immunological activation and aberrant inflammatory responses [77]. Unfortunately, there is a void in the literature in South Africa at the time of this study, but considering the level of dietary seafood content of a significant section of the country’s population, this area should be prioritised for future research. In humans, however, air inhalation and drinking water appear to be the primary pathways of microplastic uptake, with ingestion as a secondary route [70]. Waste (including plastic) burning is identified in townships by Mngomezulu [50], Nkosi [78] and Muchapondwa [79], and the particles produced by this can be inhaled or ingested when they settle on the water. Microplastics are classified as harmful vectors because they may enable chemical transfer in food types consumed by humans; hence, the chemical ingestion related to microplastics may be a greater concern than the intake of the plastics themselves.

4. Recommendations

With the ongoing concerns over global warming, countries are working to reduce environmental and health challenges caused by plastic waste by lowering the manufacture of plastics and plastic products, prohibiting excessive packaging, litter collection and recycling. In contributing to this, herein recommends the need to enforce realistic policies. It is also essential for the government to implement and enforce regulations that will check processes of manufacturing, consuming, using and the final disposal of plastics. To prevent zero diversion to landfills and indiscriminate disposal to the environment, the 3Rs, reduce, reuse, and recycle must be employed at all stages. Waste management plays a major role in reducing the toxic effects of plastic wastes on public health and the environment, and hence there is a necessity for the advancement of practices that will ensure proper plastic waste collection, treatment and disposal.

Furthermore, the general populace must be educated on the potential health and environmental effects of plastic waste pollution as this will help towards reducing the pollution rate and conserve the quality of the natural environment. Also, bioplastics is a plastic produced from cellulose that is made of wood pulp by a British chemist in the 1850s, and if manufacturers can embrace its use, the problem of plastic waste generation and the accompanying environmental and public health effects can be handled. Furthermore, biodegradability with little or no toxic residue will also aid in protecting the ecosystem from the dangers of traditional plastic wastes.