Global awareness of natural resource degradation and its negative consequences to human and environmental health has led to an increase in the volume of legislation and policies on these topics. In contrast to legal tools that were developed for the management of water and air quality, those addressing soil quality have only been established more recently. Within the larger framework of soil protection, the only international agreement that is considered binding is the United Nations Convention to Combat Desertification (UNCCD) of 1994 (Brandon, 2013).
The questionnaire distributed to soil pollution experts during preparation of this report was only returned by 31 percent of the countries. However, the responses for the section on legislative frameworks indicate that there are large gaps with respect to soil pollution. This may indicate either that legal instruments to manage soil pollution as a concept in itself is relatively new or that the experts who completed the questionnaires are not familiar with the legislative framework in their countries that may assist in addressing soil pollution. The limited information from the questionnaire responses was supplemented with a literature review and database search for applicable information.
Among the large number of international and regional agreements, a few exist that have relevance to soil contamination (Brandon, 2013). Although they do not deal directly with soil pollution, four international conventions address sources of soil pollution. These four conventions are the Basel Convention, Rotterdam Convention, Stockholm Convention and the Minamata Convention. The Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal was adopted in 1989 to stop the export of hazardous wastes to developing countries (Basel Convention, 2011). The Bamako Convention is the regional convention that bans the import of hazardous waste. It was brought into effect at the same time as the Basel Convention in order to ban such imports immediately. It is discussed in detail in section 12.5.2.
Before the 1990s Africa was particularly badly impacted by the trade in hazardous waste. In 1988, toxic waste trade between an Italian company and a Nigerian farmland owner was discovered (Kone, 2014; Ogbodo, 2010). Similar hazardous waste deals with Guinea-Bissau and Benin were also discovered prior to 1989 (Kone, 2014). The Basel Convention has been widely embraced by countries in sub-Saharan Africa and has already entered into force in 47 of the 48 countries in the region (Table 3). Nigeria was the first country to implement it in 1992, followed by Mauritius, Senegal, Seychelles and the United Republic of Tanzania in 1993. Angola and Sierra Leone did not implement the Convention until 2017 (Basel Convention, 2011).
The objectives of the Rotterdam Convention is the protection of the environment and human health through the responsible trade and use of hazardous chemicals (Rotterdam Convention, 2010). Prior to any consignment of chemicals listed under the Convention, the receiving country has to give its informed consent. The Convention may assist in the early detection of contaminated sites by requiring that details of hazardous chemicals be available in a national database (Brandon, 2013). After its initial adoption in Rotterdam in 1998, it was signed by only 18 countries in sub-Saharan Africa. Ratification began to gain momentum from 2001 and, to date, 43 countries in the region have brought the Convention into force. Indeed the only countries that have yet to ratify the Convention are Angola, Central Africa Republic, the Comoros, Seychelles, and South Sudan.
The Stockholm Convention on Persistent Organic Pollutants (POPs) was adopted in 2001 in Stockholm, Sweden and took effect on 17 May 2004 (Stockholm Convention, 2019). Stockpiles of POPs were reported to be present in several countries in the region such as Namibia, Niger, Senegal, Seychelles, South Africa, Sudan, the United Republic of Tanzania, Uganda and Zambia (Mansour, 2009). In the region, it was signed by 71 percent of the countries between 2001 and 2002 but took effect in 96 percent of countries between 2004 and 2012 (Stockholm Convention, 2019). In 2019, Equatorial Guinea is the most recent country of the region to ratify the Convention and has put it into force in 2020.
The Minamata Convention on Mercury was adopted in 2013 and entered into force on 16 August 2017 (Minamata Convention on Mercury, 2019). Artisanal and small-scale mining (ASM) uses mercury to extract gold from ore (Fritz et al., 2018). As ASM is the largest contributor to global mercury emissions, the Convention requires action by countries where ASM is widespread (Hilson et al., 2018).
The Minamata Convention is therefore highly relevant to sub-Saharan Africa, where ASM contributes significantly to the economies of at least 23 countries in the region. Gold is the main metal mined by this method in all of these countries except in Angola (Fritz et al., 2018). In Angola, oil extraction and diamond mining constitute the main extractive industries. This might explain why the high level of ratification of the Basel, Stockholm and Rotterdam Conventions by countries in the region is not replicated with the Minamata Convention. It has been signed by 75 percent of countries between 2013 and 2014 and ratified or acceded by 66 percent between 2014 and 2019 (Minamata Convention on Mercury, 2019). However, it is worth noting that of the 34 countries that have ratified the Minamata Convention in sub-Saharan Africa, six only did so in 2019 and the United Republic of Tanzania ratified it in 2020.
Further details on the ratification and implementation of the Basel, Rotterdam, Stockholm, and Minamata Convention in sub-Saharan Africa are presented in Table 3.
Although no regional convention on soil protection currently exists (Brandon, 2013), there are two African treaties that can be linked to soil conservation and prevention of soil pollution. Shortly after the international adoption of the Basel Convention on 22 March 1989 (Basel Convention, 2011), the Bamako Convention on the Ban of the Import to Africa and the Control of Transboundary Movement and Management of Hazardous Wastes within Africa was the continent’s first collective effort on this issue within its regional boundaries (Agbor, 2016). It was adopted on 30 January 1991 but did not enter into force until 1998 (African Union, 2003). Its main objectives are to stop the import of hazardous waste from other parts of the world and the management of wastes already present in Africa (African Union, 2003; Papu-Zamxaka, Harpham and Mathee, 2010). It includes a consideration of the relevant sections of the conclusions of the Stockholm Conference of 1972 and the Basel Convention of 1989 (African Union, 2003). This was an important step forward to prevent African countries from becoming a dump site for other countries with stringent waste laws (Agbor, 2016; Papu-Zamxaka, Harpham and Mathee, 2010).
The Bamako Convention is credited for including a broader range of hazardous and potentially hazardous wastes, including radioactive waste. It aims to prohibit all imports of hazardous waste, even when masked as a source of income through recycling (Agbor, 2016). In spite of its commendable intentions, it has entered into force in only half of the countries in sub-Saharan Africa (African Union, 2003). In an attempt to accelerate the slow progress in implementing the Bamako Convention, the Libreville Declaration on Health and Environment in Africa was formulated and signed in Gabon in 2008 (World Health Organization, 2008).
This declaration was signed by 53 African countries, 48 of which are from the sub-Saharan African region (listed in Table 4) (World Health Organization, 2008). It raises the concern that more than 2.4 million deaths annually are caused by avoidable environmental issues in Africa. It also emphasized that the Bamako Convention, that was supposed to stop the harmful impacts of hazardous waste on the continent, had not been implemented since its drafting in 1991. The commitments of the Libreville Declaration signatories include the establishment of different legislative framework levels, capacity building to address the issues, initiation and coordination of applied research. It also commits to effective implementation and the establishment of monitoring and evaluation at the national level (World Health Organization, 2008). WHO commends the Libreville Declaration for contributing to the advancement of African policies to address the adverse effects of environmental pollution on human health (World Health Organization, 2018). In support of the agreement of the Bamako Convention, the African Union established the African Court of Justice and Human Rights in 2004 (African Court on Human and Peoples’ Rights, 2019). This court has jurisdiction to prosecute the illegal trading of hazardous wastes and present it as an international crime committed on the African continent (Agbor, 2016).
The revised African Convention on the Conservation of Nature and Natural Resources was signed in Maputo in 2003, thereby superseding the original one that was signed in Algiers in 1968 (African Union, 2003). The revised convention recognizes the polluting effects of hazardous wastes and other toxic and radioactive substances and requires that they be addressed through prevention, mitigation and elimination (Brandon, 2013). Article VI of the Convention calls for agricultural practices that will control erosion and pollution resulting from agricultural activities. Parties must also ensure that all other land uses, such as mining and waste disposal, do not cause land degradation, including pollution. Although the revised convention has already been signed in 2003, its entry into force is even slower than that of the Bamako Convention. It has entered into force in only 16 countries in sub-Saharan Africa between 2004 and 2019 (listed in Table 4) (African Union, 2003). It was adopted in 2017.
Further details on the regional agreements with impact on soil pollution prevention in sub-Saharan Africa can be found in Table 4.
Developed and developing countries follow different approached to legislation on polluted land, ranging from a specific and comprehensive approach in several developed countries to a broad and indirect approach through the environmental framework law in developing countries. Comprehensive legislation provides detailed procedures ranging from the identification of contaminated sites to their remediation and final monitoring (Brandon, 2013). Within the group of countries with extensive specific legislation on contaminated sites, Brandon (2013) identified three main drivers for the development of such legislation, namely:
In order to provide a more thorough overview of the current national legislative frameworks for soil pollution in sub-Saharan Africa, a keyword search was conducted on the FAOLEX database. This search was supplemented by keyword searches in Google and Google Scholar. The keyword combinations used were “soil pollution”, “soil contamination”, “soil conservation”, “environmental” and “waste” in conjunction with the name of each country. From the results, only examples of legislation and regulations were included and not guidelines or strategic plans. The legislation had to include at least an aspect of soil pollution, for example sources of soil pollution such as waste or pesticides or include sections on liability for pollution caused by a land use such as mining. The results are presented in Table 5Error! Reference source not found. below.
None of the countries in the region has a specific soil pollution act that can be used as a legal tool to enforce the prevention and treatment of soil pollution through a judicial system. Only two countries, Burundi and Namibia, have specific legal instruments for the prevention and management of soil pollution. In Burundi, soil pollution is addressed in the Decree on Soil Conservation and Use of 1958 and in Namibia by the Soil Conservation Act of 2001. Other legislation that can address sources of soil pollution such as waste, agrochemicals and mining are also considered relevant in the prevention and addressing of soil pollution. Only three countries in the region have no legal instruments or regulations that aim to combat soil pollution: Eritrea, Somalia and South Sudan.
An example of legislation that is relevant to soil pollution, is the Dangerous Chemicals Control Act, No. 16 of 2004 of Mauritius. The objective of the Act is the protection of human and environmental health through the prevention of negative impacts caused by dangerous chemicals. Chapter 3 of the Act excludes substances such as explosives, dangerous drugs, radioactive substances and pharmaceutical products by referring to the Acts that are responsible for the legislation of these substances. This Act is considered progressive in the region as it provides lists of dangerous chemicals according to different schedules. The first schedule lists 422 dangerous chemicals that should be handled in accordance with the specification of the Act. The second schedule lists the prohibited chemicals, categorized under industrial chemicals and agricultural chemicals. While it addresses the negative impacts on the environment, it only provides toxicity classification criteria for aquatic environments and does not address terrestrial environments that may protect soil organisms (FAOLEX, 2019).
Further details on the national legislation addressing soil pollution prevention and management are presented in Table 5.
It should be noted that three countries in the region, Burkina Faso, South Africa and the United Republic of Tanzania, include specific reference values for soil contaminants in the above-mentioned legislation (FAOLEX, 2019). While Burkina Faso and South Africa have different values for each trace element for different land uses, only one set of limits is available for trace elements in soil in the United Republic of Tanzania (Table 6). As illustrated in Table 6, higher soil concentrations of trace elements such as cadmium, cobalt, copper and nickel are allowed in areas of industrial land use than in areas zoned for agricultural use.
In comparison to the Canadian reference values (Table 6), higher concentrations of hexavalent chromium, nickel and vanadium in soil are considered acceptable in the three sub-Saharan Africa countries. While the highest allowable concentration of hexavalent chromium in soil in Canada is 1.4 mg/kg for industrial areas, it is 40 mg/kg for industrial sites in South Africa. No concentration limits are specified for industrial sites in either Burkina Faso or the United Republic of Tanzania. For hexavalent chromium, the Tanzanian guidelines provide only an upper limit of 100 mg/kg. The Tanzanian contamination limits are the only data set in the region that specifies a test methodology for the determination of trace elements in soil samples. The ISO 11047:1998 methodology is prescribed for all the listed trace elements except arsenic, selenium and molybdenum for which there is currently no stipulated reference methodology. Only the South African list contains threshold limits for both hexavalent and trivalent chromium but, unlike the other countries’ list, no contamination limits for selenium (FAOLEX, 2019).