OR/17/056 Urban sources of groundwater pollution

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Lapworth, D J, Stuart, M E, Pedley, S, Nkhuwa, D C W, and Tijani, M N. 2017. A review of urban groundwater use and water quality challenges in Sub-Saharan Africa. British Geological Survey Internal Report, OR/17/056.

Introduction

Groundwater contamination can occur whenever there is a source releasing contaminants to the environment (Sililo et al., 2001[1]) (Table 4.1). The major sources of groundwater pollution include:

  • Municipal (sewer leakage, sewage effluent, sewage sludge, urban runoff, landfill, latrines, septic tanks);
  • Agricultural (leached salts, fertilisers, pesticides, animal wastes);
  • Industrial (process waters, water treatment, plant effluent, hydrocarbons, tank and pipeline leakage); and
  • Mining (solid wastes and liquid wastes) activities.
Table 4.1    Main sources of urban groundwater pollution in South Africa with
some of their characteristics (adapted from Sililo et al., 2001[1]).
Category Source Main pollutant Potential impact
Municipal Sewer leakage, septic tanks and latrines Nitrate, minerals, organic compounds, viruses and bacteria Health risk to users, eutrophication, odour and taste
Sewage effluent and sludge
Storm water runoff Bacteria and viruses, oils, grease, asbestos, heavy metals Health risk to water users
Solid waste disposal Inorganic minerals, organic compounds, heavy metals, bacteria and viruses Health risk to users, eutrophication, odour and taste
Cemeteries Nitrate, viruses and bacteria Health risk to water users
Peri-urban agriculture Livestock wastes Nitrate, ammonium, viruses and bacteria Health risk to water users
Pesticides Toxic/carcinogenic compounds Health risk to water users
Fertilisers Nitrogen, phosphorus Eutrophication, health risk to water users
Industrial Process plant and effluent Organic compounds, heavy metals Toxic/carcinogenic compounds
Industrial solid waste Inorganic minerals, organic compounds, heavy metals, bacteria and viruses Health risk to users, eutrophication, odour and taste
Leaking storage tanks Hydrocarbons, heavy metals Odour and taste
Chemical transport Hydrocarbons, chemicals Toxic/carcinogenic compounds
Pipeline leaks
Atmospheric deposition Vehicle emissions Acidic precipitation Acidification of groundwater and toxic leached heavy metals
Coal-fired power stations
Mining Tailings and stockpiles Acid drainage
File:OR17056fig4.1.jpg
Figure 4.1    Sources of faecal pollution within urban a) and rural b) settings (from Lawrence et al., 2001[2]).

Lawrence et al. (2001)[2] describe the various sources of faecal pollution in different settings and the pathways of these pollutants into groundwater (Figure 4.1). This simplified representation is valid for many groundwater contaminants and in peri-urban areas all of these sources of pollution may occur together. However, the figure does not show the processes of attenuation in the system that will reduce the concentration of contaminants reaching the water table. For microorganisms in faecal and other waste materials, the main barrier to their movement into groundwater is the unsaturated zone. Once into groundwater, however, a complex interaction of other physical, chemical and biological factors control the survival and mobility of the microorganisms (Mesquita et al., 2013[3]) and influence the distance that they can travel from the source. The causes of water quality contamination may be separated into those related to the production of contaminants at the source and those which govern their delivery into the water environment (Pegram et al., 1999[4]). In peri-urban environments they are primarily caused by infrastructure and services which are not adequate for the settlement characteristics, are poorly managed by the provider and/or poorly managed by the community.

Sanitation

Sanitation in peri-urban areas

Sanitation facilities in peri-urban areas largely take the form of on-site technologies such as pit latrines and pour-flush toilets. Reticulated systems are also an important source of contamination but these have very limited coverage overall in urban areas in SSA. On-site sanitation technologies, are often the cheapest and most appropriate forms of sanitation in rural and in urban areas. However in peri-urban areas the ground conditions give rise to poor drainage and risk of contaminated drinking water sources (Paterson et al., 2007[5]). High population densities result in a high liquid load. There are a number of current options:

  • A simple pit latrine consists of a seat or squatting hole over a pit, in which the human waste collects.
  • A VIP latrine has the addition of a screened vent pipe which extends from the pit to eliminate odours and flies.
  • A pour-flush toilet is similar to a cistern-flush toilet but with a shallower U-bend so that the toilet can be flushed by manually pouring a small amount (2–3 L) of water into the toilet pan. For on-site disposal, the toilet is connected to a pit.
  • Urine-diverting toilets. Sometimes referred to as EcoSan toilets, urine diverting systems separate the urine and the faeces in different compartments. The urine can be diluted and used as a liquid feed for plants; the faeces is digested for several months after which it can safely be used as a manure. Despite widespread marketing of EcoSan systems in Africa, the technology has a limited application.

For all these toilet types, apart from the Ecosan toilet, the pit is normally designed so that liquids disperse into the surrounding soil, while the solids accumulate and decompose over time, and can be safely removed after a few years for disposal or re-use on agricultural land. In practice, emptying pits is a considerable challenge in many peri-urban areas due to the difficult access for vacuuming trucks and other emptying machines, and the very mixed nature of the pit contents (often including rags and metal objects). As a result, the pit contents tend to accumulate and provide a constant source of contamination to groundwater.

Paterson et al. (2007)[5] suggest that a simplified (or condominial) sewerage system where a shallow possibly small diameter network of pipes takes the sewage elsewhere to be treated/disposed may be appropriate. This approach, using communities to install network, has been pioneered with some success in Pakistan by the Orangi Pilot Project (Gavini et al., 1985). For Bwaize III region of Kampala, Uganda, Katukiza et al. (2010)[6] present a technology selection method that takes into account social acceptance, technological applicability, economic and institutional aspects and health and environment benefit. These were a septic tank system, biogas toilet, compost pit and urine diversion dry toilet.

Parkinson and Tayler (2003)[7] advocate a decentralised approach to wastewater treatment in peri-urban areas in low-income countries. Options include anaerobic treatment, waste stabilisation ponds and constructed wetlands.

Peri-urban agriculture

The pattern of peri-urban agriculture has common features across the continent, which is illustrated by examples of peri-urban cropping in Dar-es-Salaam, in the East, and Accra, in West Africa, shown Tables 4.2 and 4.3.

The intensification and expansion of agriculture brings many benefits and Jacobi et al. (2000)[8] state that due to urban and peri-urban agriculture Dar-es-Salaam is not short of food. Similarly in Zimbabwe, the yields from urban areas is greater than the yields from rural areas, where fertiliser use is limited (Brazier, 2012[9]). However, there are also associated risks to water resources. These can come from fertilisers, either synthetic or manure, and pesticides. Furthermore, if irrigation is not managed adequately there can also be risks of salinisation.

Animal wastes provide an important resource for agriculture, yet Harris et al. (2001)[10] report that around Kumasi, Ghana, although 80% of poultry manure was used in farming, the remainder can be dumped and burnt by the roadside and in Uganda poultry manure is mixed with brewery waste and used as cattle feed. In Niamey, Niger, peri-urban agriculture is characterised by fruit and vegetable production including cabbage, lettuce, tomato, carrot, onion, zucchini, sweet pepper, hot pepper, eggplant, French beans, melon, cucumber, cassava root, maize and strawberry (Andres and Lebailly, 2011[11]). During the hot season (March–May), market gardeners grow hot pepper, zucchini and cucumber. During the rainy season (June–September), they cultivate gumbo, melon and beans. During the dry season (October–February), they grow lettuce, cabbage, tomato, sweet pepper, beetroot, celery, carrot, and parsley. Fertiliser use can be high and comprises manure from the slaughter house or from local breeders and is supplemented with synthetic nitrogen, phosphorus and potassium (NPK) (Graefe et al., 2008[12]).

A survey of fertiliser use for urban and peri-urban agriculture in Namibia, (Dima et al., 2002[13]), where water is a limiting factor, showed that the most common type of fertiliser was digested human solid waste. Other sources were compost, household waste, inorganic fertilisers and fresh cow dung. Most fertiliser was applied once per year. The main pests were corn cricket, American bollworm, spiders, aphids and fungal attacks. Use of pesticides was very limited and the commonest method of control was hand picking. In Mekelle, Tigray, Ethiopia, urban and peri-urban agriculture is supported by an Urban Agricultural Office which provides hand dug wells for irrigation, technical support on seeds planting and fertilisers, and planting material and seedlings (Ashebir et al., 2007[14]). Several crops can be grown each year and both staples and vegetables are grown. The majority of farmers used both chemical and organic fertilisers.

In Bamako, Mali and Ouagadougou, Burkina Faso, the disposal of household waste also poses a challenge (Eaton and Hilhorst, 2003[15]). In both cities, waste is produced at an average of 0.6–0.7 kg/person/day. The composition of this varies considerably seasonally, with an increase in the amount of sand and dust during the dry season. Together with plastic, paper, metals and textiles, these inorganic components need to be separated out to allow safe recycling of organic matter. In both cities an informal private sector has established itself to collect waste. Organic solid waste is used for peri-urban agriculture by agreement, sometimes illicit, with waste disposal operatives. Farmers remove large inorganic objects and spread the waste on fields before the onset of the rainy season. The waste has an organic content of about 11%, nitrogen of about 0.3% and phosphorus 0.16%. Applications appear to be mainly on cereal crops.

Table 4.2    Peri-urban cropping in Dar-es-Salaam (after Jacobi et al., 2000[8]).
Zone Crop type Example Comment
High density area gardens (15–20% of houses typically 270 m2) Green leafy vegetables Sweet potato, cow pea, cassava and pumpkin Water limiting factor
Low density area gardens (4000 m2) Bigger plots often with tap
Community gardens Diverse
Urban area (65% of houses) Livestock production Cattle fed on public land and cut grass, poultry both extensive and intensive Growth of dairy cattle
Open space, unoccupied plots and river valleys Market orientated leafy vegetables Chinese cabbage Important in dry season when gardens water limited
Peri-urban Livestock Dairy cattle
Peri-urban typically 2 ha with 0.6 ha under vegetables and fruit Green and other vegetables, fruit, staples Maize, rice, cooking bananas, cassava, sweet and hot pepper, eggplant, okra, Being gradually swallowed up by urban area
Table 4.3    Peri-urban cropping in Accra, Ghana (after Asomani-Boateng, 2002[16]).
Zone Crop type Example Fertiliser Comment
Household Staples and fruit Maize, plantain, cassava and cocoyam, pineapples, mangoes, paw paw, orange, coconut palm oil Cow manure and chicken droppings
Vacant space including banks of streams and drains Vegetables Cauliflower, lettuce, cabbage, carrots, sweet peppers, French beans, peppers, beetroots, herbs, okra, peppers, tomatoes, eggplant and green leafy vegetables (ademe, ayoyo, gboma, busanga) Cow manure and chicken droppings
Synthetic fertilisers 		Streams and drains prone to flood
Peri-urban Fruit Pineapples, mangoes, paw paw, orange, coconut and palm oil Cow manure and chicken droppings
Synthetic fertilisers

Wastewater irrigation and soil amendment using household and human waste

The impact of wastewater irrigation has been well documented in several newly industrialised countries. For example in Mexico, there was a large study for DFID on irrigation using the effluent from Mexico City (CNA et al., 1998[17]). This scheme had been operating for many years with progressive extension of the irrigated area and a large rise in groundwater levels. Almost three quarters of the public supply groundwater sources in the main area exceeded the limit for nitrate-N (11.3 mg/L), about half for alkalinity and about one third for chloride. Most of the heavy metals were retained in the soil. Surveys of microbiological quality found between one third and one half of supplies were positive for faecal coliforms, with some >50 cfu/100mL. Levels fluctuated widely over time. Enterovirus was detected at three of the four sites where it was analysed and hepatitis and rotavirus were detected in springs in the area. In León, Mexico, irrigation with effluent containing a mixture of domestic and tannery effluent had also increased groundwater levels (Chilton et al., 1998[18]). Shallow groundwater was impacted mainly by salinity with concentrations of chloride of over 500 mg/L. Chromium from tannery effluent appeared to be almost all precipitated in sediments and lagoons of the wastewater distribution system and groundwater concentrations were not elevated above the background (Stuart and Milne, 2001[19]).

In Zambia, research on wastewater irrigation in the Mufulira and Kafue areas has focused on heavy metals in soils and crops (Kapungwe, 2013[20]). Crops were irrigated using both sewage and, in some areas, industrial wastewater containing copper mining effluent (Marshall et al., 2004[21]). Crops were shown to be contaminated with cadmium, copper, lead and zinc. This was similar to results from Zimbabwe (Muchuweti et al., 2006[22]). Mayeko (2008)[23] showed that the market gardeners of Kinshasa, Congo were exposed to chemical and microbiological contamination from the use of wastewater for irrigation. Water contained both heavy metals and microbiological contamination. Kulabako et al., (2009)[24] and Stevens et al., (2003)[25] investigated the use of novel, multi-stage, home-made trickle-filters, to treat kitchen and used bathing waters for use in household irrigation. The final effluent from these treatment systems was found to be suitable for small-scale urban agriculture.

Keraita et al. (2003)[26] reported the impact from the use of urban wastewater irrigation in and around Kumasi, Ghana. Due to inadequate waste treatment capacity surface and shallow groundwaters are being impacted by large volumes of untreated and partly treated waste water from the city. High nutrient concentrations (N and P) and microbiological counts were found in stream water receiving runoff from contaminated irrigation water as well as crops in Kumasi market which are a serious risk for consumers. In per-urban Kano, northern Nigeria, contamination of waters and soils on land used for food production is such that Binns et al. (2003)[27] question the long term sustainability of urban agriculture due to environmental and toxicological concerns. Economic pressures have also made it difficult to gain access to farmland and many farmers have diversified in order to survive (Maconachie and Binns, 2006[28]).

In Addis Ababa, Ethiopia, untreated wastewater is discharged directly to surface water which is used for irrigation by some farm households. Weldesilassie et al. (2009)[29] found that 88% of households reported that they benefited from wastewater as for some this was the only means for survival. The safe use of this resource was therefore considered valuable. However, Weldesilassie et al. (2011)[30] found that the cost of treating the health impact from worm infections alone made the use of poor quality water more expensive.

Cofie et al. (2005)[31] studied the use of human waste for urban agriculture in Tamale, Northern Ghana. Farmers used faecal sludge for cultivation of cereals, such as maize, sorghum and millet, sometimes combined with farmyard residues or chemical fertilisers. Sludge was discharged during the dry season to the field surface or to large pits and left to dry before spreading. Estimated nutrients applied were 455 kg/ha N, 61 kg/ha P and 121 kg/ha K as well as 1183 kg/ha additional organic carbon. Problems include odour, unacceptability of crops to the public and health problems in workers.

In Africa urban refuse comprises 50–90% organic material, and includes kitchen waste, food leftovers, rotten fruit and vegetables, leaves, crop residues and animal excreta and bones (Asomani-Boateng and Haight, 1999[32]). Most African countries have traditionally used such organic material as a soil improver. Promoting reuse on a large scale as a response to disposal problems requires decentralising of planning, waste separation, composting facilities and landuse planning. There are recognised health risks to both farmers and produce consumers, as well as threats to the environment in reuse due to the high faecal content of waste.

Industry

In newly industrialised countries the rate of industrialisation has been fast and the environmental problems more acute as natural attenuation processes have not yet had time to make an impact on environmental recovery (Morris et al., 2003[33]). Additional problems can occur in developing countries where regulations controlling waste disposal are not adequately enforced, control measures are not sufficient, and the resources to monitor discharges are non-existent or inadequate (Tallon et al., 2005[34]).

Chukwu (2008)[35] evaluated the impact on groundwater of abattoir waste in Minna, Nigeria, in two wells. Groundwater had elevated TDS and SS, pH, and low dissolved oxygen. Sangodoyin and Agbawhe (1992)[36] studied the pollution from abattoirs in the Ibadan area, Nigeria in both ground and surface water. Effluents consisted of a slurry of suspended solids, fat, blood, scraps of tissue and soluble material generally discharged to local streams without treatment. They also identified elevated phosphates from detergents in washdown water. In general groundwater appeared to be affected by effluent with increases in TDS.

Table 4.6 show the characteristics and composition of waste effluents from large and small industries in Nigeria which discharge mainly to surface water (e.g. Adebayo et al., 2007[37]; Kanu and Achi 2011[38]; Taiwo et al., 2010[39]). Olayinka and Alo (2004)[40] studied the impact of textile effluents on groundwater in parts of Lagos, Nigeria. These effluents had high BOD (100–390 mg/L) and COD (204–2000 mg/L) and pH (10–12 for one of the plants) and were highly coloured. Some wells within 25 m of the discharge were affected by elevated TDS and oxygen depletion due to high BOD TDS whilst those further away were not measurably affected. As a result of the contamination, groundwater wells close to the discharge had been abandoned by local residents.

Table 4.4    Types of waste effluents generated by
selected industries in Nigeria (after Kanu and Achi, 2011[38]).
Type of waste Type of industry
Oxygen-consuming Brewery, dairy, distillery, packaging, pulp and paper mill, tannery, textiles
High suspended solids Brewery, coal washing, iron and steel, distillery, pulp and paper mill, palm oil mill
High dissolved solids Chemical plant, tannery, water softening
Oil and grease Laundry, metal finishing, oil field, petroleum refinery, tannery, palm oil mill
Coloured Pulp and paper mill, tannery, textile dying, palm oil mill
Acid Chemical plant, coal mine, iron and steel, sulphite pulp
Alkaline Chemical plant, laundry, tannery, textile finishing mill
Hot effluent Bottle washing, laundry, power plant
Table 4.5    Industrial pollutants (after Kanu and Achi, 2011[38]) .
Industry Compounds found in receiving waters
Pharmaceutical and personal care Antibiotics, lipid regulators, anti-inflammatories, antiepileptics, tranquilizers, and cosmetic ingredients containing oil and grease
Soap and detergent Alkyl sulphates, high BOD & COD, oil and grease
Paper Sugars and lignocelluloses,
Fertiliser Ammonium-nitrogen, urea, nitrate-nitrogen, orthophosphate- phosphorus
Textile — sizing and desizing Starch, waxes, carboxymethyl cellulose(CMC), polyvinyl alcohol (PVA), wetting agents, , fats, waxes, pectins
Textile — bleaching and mercerising Sodium hypochlorite, Cl2, NaOH, H2O2, acids, surfactants, NaSiO2 sodium phosphate, cotton wax
Textile — dying and printing Dyestuffs urea, reducing agents, oxidizing agents, acetic acid, detergents, wetting agents, pastes, urea, starches, gums, oils, binders, acids, thickeners, cross-linkers, reducing agents, alkali
Brewing Carbohydrates and nitrogen
Tanning Cr, oxidising agents, Cl, fats
Palm oil milling Carbohydrates and nitrogenous compounds giving high BOD & COD, oil, fatty acids, low pH

Chukwu (2008)[35] evaluated the impact on groundwater of abattoir waste in Minna, Nigeria, in two wells. Groundwater had elevated TDS and SS, pH, and low dissolved oxygen. Sangodoyin and Agbawhe (1992)[36] studied the pollution from abattoirs in the Ibadan area, Nigeria in both ground and surface water. Effluents consisted of a slurry of suspended solids, fat, blood, scraps of tissue and soluble material generally discharged to local streams without treatment. They also identified elevated phosphates from detergents in washdown water. In general groundwater appeared to be affected by effluent with increases in TDS.

Table 4.6    Industrial effluent quality in Nigeria
(after Adebayo et al., 2007[37] and Taiwo et al., 2010[39]).
Parameter Lagos
(textile) 		Lagos (brewery) Kaduna (mixed) Port Harcourt (mixed)
Temperature (C) 27.6 30.3 30
pH 7.6 4.8
Conductivity (mS/cm) 761 1157
Alkalinity (mg/L) 767 445
Nitrate (mg/L) 4.0 362
Ammonium (mg/L) 1.0
Phosphate (mg/L) 1.0 836
Total hardness (mg/L) 1233 4083
Oil and grease (mg/L) 20 0 7 2343
BOD (mg/L) 534 1352 300 4374
COD (mg/L) 850 2253 1800
H2S (mg/L) 17.2 130 0.6

Managed aquifer recharge (mar) and fuel storage

The recharge of groundwater using treated wastewater was studied in an area of Addis Ababa (Abiye et al., 2009[41]). Treated wastewater from the Kaliti plant was discharged to the Little Akaki River overlying the Akaki wellfield. The work showed that the soil was able to remove most contaminants from infiltrating wastewater and that MAR would be a feasible method to improve groundwater resources. This is likely to be particularly relevant in more arid urban zones in SSA.

Sources of pollution at a typical petrol station in Nigeria include leakage from underground storage tanks, spills during loading and other operations and dumping of waste, commonly in shallow pits (Nganje et al., 2007[42]). In a survey of petrol stations and mechanics workshops around Calabar, Nigeria found concentrations of total hydrocarbons and total polyaromatic hydrocarbons to be higher than the WHO drinking water guideline values in groundwater. These were found by factor analysis to be associated with poor yard practice and waste management.

Solid waste disposal

Solid waste characteristics

Urban solid waste creates large environmental problems in Africa; the generation of waste has increased considerably in the last 3 decades (Yhdego, 1988[43]). To an extent, this is a consequence of the growth in urban populations, but the problem is compounded by the lack of resources and infrastructure to cope with growing amount of waste leading to uncontrolled disposal into water courses and other convenient areas (Carrillo et al., 1985[44]; Yhdego, 1995[45]). In Dar-es-Salaam it was reported that over 80% of the wastes produced were left in open pits, streets, markets or storm water drainage channels (Yhdego, 1995[45]). In Tanga, Tanzania, all types of solid waste were disposed in an old partially flooded sand quarry close to a residential area (Mato, 1999[46]). Wastes may be treated partially by uncontrolled burning. Scavenging is widespread and uncontrolled. There is evident pollution of both ground and surface water.

Table 4.7    Waste generation rate and origins (from Guerrero et al., 2013[47]).
Country GDP (US$) Year of study City Waste arriving at disposal site Waste generation rate (kg/capita/day)
Ethiopia 344 2009 Addis Abba H,O,M,I,S 0.32
Kenya 738 2009 Nakuru H,O,C,M,A,I, S 0.50
Malawi 326 2009 Lilongwe H 0.50
South Africa 5786 2009 Pretoria H,O,C,M,S 0.65
South Africa 5786 2009 Langeberg H,O,C,M,A,I,S 0.65
South Africa 5786 2009 Emfuleni H C,I 0.60
Tanzania 509 2010 Dar-es-Salaam H,O,M,A,I, S 0.50
Zambia 985 2010 Lusaka H,O,C,A,I,S 0.37

H = household, O = offices & schools, C = construction, M = healthcare, A = agriculture, I = industry, S = shops

In many African countries the collection of waste is haphazard and inefficient (Yhdego, 1988[43]). In addition, hazardous and non-hazardous wastes are often disposed of without separation (Carrillo et al., 1985[44]) creating a risk to the health of the local population, the workers who collect the waste and those who make a living by scavaging from waste disposal sites. The main sources of solid waste in the urban areas of Tanzania are domestic, commercial activities, industries, streets and markets. The composition ofwastes is primarily vegetables and other putrescible matter with very high moisture content. (Yhdego, 1995[45]). Guerrero et al. (2013)[47] found a similar pattern for a number of cities in SSA, see Table 4.7.

Leachate quality varies through the lifetime of a landfill and after its closure (Klinck and Stuart, 1999[48]). During the early stages leachate is acidic and high in volatile fatty acids and pathogens. It may also contain mobilised heavy metals, ammonium and organic carbon. As waste degradation progresses conditions become anaerobic and the methanogenic phase is initiated. The majority of the remaining organic compounds are high molecular weight and leachate is characterised by low BOD. Ammonium remains high but falling redox potential immobilises many metals as sulphides. The health hazards of poor waste disposal are long-established. Klinck and Stuart (1999)[48] list human faecal matter; industrial waste; decomposition products from the waste, inorganic macro-components, heavy metals, dissolved organic matter expressed as COD or TOC including methane and volatile fatty acids and anthropogenic organic compounds; smoke from waste burning including polyaromatic hydrocarbons and dioxins. Stuart and Klinck (1998)[49] provide indicative leachate quality for a range of landfills from newly developing countries, including where waste is periodically burnt.

Disposal practices

In many countries of SSA, the disposal of waste is poorly regulated and enforced. As a result, substantial quantities of waste are disposed of illegally and without any consideration of the human and environmental health consequences (Carrillo et al., 1985[44]). In areas of Nairobi, Kenya, dump sites were selected for convenience, not appropriateness based on environmental risks (Henry et al., 2006[50]). Figure 4.2 shows the changes in municipal solid waste generation and collection capacity for Nairobi, Kenya, between 1972–2004. In Addis Ababa, Ethiopia, 56% of households surveyed deposited their waste in to plastic bags, 19% just dumped it in open spaces, waterways and around their home and 6% burnt it causing significant air pollution (Mazhindu et al., 2012[51]).

Table 4.8    Components of industrial solid waste in Dar-es-Salaam
in order of rate of generation (after Mbuligwe and Kaseva, 2006[52]).
Solid waste component Rate (t/a) Major source
Glass cullets 13903 Breweries, distilleries, soft drink manufacturers
Bottle caps 9389 Soft/alcoholic drink manufacturers
Grain bran 4717 Grain millers
Spent grain and yeast 3638 Breweries
Packaging materials 2194 Soft drinks, breweries, distilleries, vegetable oil refining etc
Spent bleaching earth 1889 Food, beverages, vegetable refining
Plastics and rubber 1884 Plastic and rubber industries
Dust/soil 603 Grain millers, paint manufacturing
Peelings and crushed spent seeds 481 Fruit and vegetable canning
Waste/discarded paper 295 Pulp and paper industries
Scrap metal 252 Fabricated and basic metal industries
Sludge 140 Food, beverages, vegetable refining, paint manufacturing
Sand and discarded tiles 43 Tile manufacturers
Rejected plastic bottles 36 Bottled drinking water manufacturers, pharmaceutical industry
Foam 7.1 Foam mattress manufacturers

However, there are some notable exceptions. Industrial solid waste in Dar-es-Salaam is stored in open air piles, bins, masonry enclosures and silos (Mbuligwe and Kaseva, 2006[52]). Waste is partially segregated since it tends to be stored near the industry type that produced it. Some edible oils, paper and pulp, glass, plastics and batteries are formally segregated as there is some recycling. About 60% is collected and transported by the municipal authorities. The main components are shown in Table 4.8.

The disposal of medical waste presents challenges such as the spread of contagious diseases and impact to water resources (Nkhuwa et al., 2008[53]). An inventory of the medical waste from health centres in Lusaka, Zambia found:

  • Infectious waste, such as bandages, swabs and disposable equipment
  • Pathological waste, such as tissue, organs, blood and body fluids
  • Sharp equipment including needles
  • Pharmaceutical waste
  • Radioactive waste
  • Other, such as kitchen, bed linen, paper

The majority of this waste was disposed in refuse pits (paper, plastic, kitchen waste), and placenta pits (treated with sulphuric acid to create more space). Some waste (drugs, sharps, swabs etc) was sent for incineration, but the cost of incineration and inadequate temperatures achieved by the incinerators meant that potentially incineratable wastes were found in open pits.

Nkhuwa et al. (2008)[53] showed that for the health centres studied in Lusaka local groundwater quality was compromised by coliforms, TDS and high COD, but this could not necessarily be separated from other local sources in the area. In a study in Owerri, Nigeria, Arukwe et al. (2012)[54] found solid waste disposal to be a source of a range of emerging groundwater contaminants including phthalate plasticisers, polycyclic musks, bisphenol A and UV filters.

File:OR17056fig4.2.jpg
Figure 4.2    Municipal solid waste (MSW) generation and collection in Nairobi, Kenya (after Henry et al., 2006[50]).

Cemeteries

Although cemeteries have the potential to pollute groundwater, there have been very few published studies that have assessed this potential. The number and variety of pollutants is extensive, ranging from the mineral, organic and biological decomposition products from the bodies, to the chemicals used for embalming the bodies and treating and preserving the coffins. Engelbrecht (1998)[55] studied a municipal cemetery site in the Western Cape, South Africa. This was situated on unconsolidated sands in the same geological succession as the local aquifer. Groundwater was sampled using specially drilled well points and analysed for a range of microbiological parameters, inorganic species and organic carbon. Groundwater was extremely polluted compared to water in the surrounding area with elevated concentrations of potassium, ammonium, TON, organic carbon, phosphate and a higher pH. Elevated concentrations of faecal coliforms, Escherichia coli, faecal streptococci and Staphylococcus aureus (an organism that colonises the skin and nasal passages of humans) were also measured. The impact of pathogens from cemeteries on the underlying groundwater has also been reported by Trick and co-workers (Trick et al., 2005[56]).

Their study of a working cemetery in the UK detected pathogens in the groundwater even with an unsaturated zone thickness of between two and three metres. However, the vulnerability the groundwater to pathogen contamination from the unsaturated zone will be dependent on the soil composition, and so it is difficult to extrapolate from this report to other environments. A more recent study of soil samples taken from a cemetery in Guateng, South Africa, identified elevated concentrations of minerals and metals that could pose a risk to human health if they were transferred into the groundwater (Jonker and Olivier, 2012). These studies show the importance of cemeteries as a source of contamination to groundwater, and highlight the risks to drinking water sources in peri-urban areas of SSA where on-plot burial is occasionally practiced (e.g. Zume 2011).

References

  1. ↑ Jump up to: 1.0 1.1 SILILO, O T N, SAAYMAN, I C, and FEY, M V. 2001. Groundwater vulnerability to pollution in urban catchments Water Research Commission, WRC Project No 1008/1/01.
  2. ↑ Jump up to: 2.0 2.1 LAWRENCE, A R, MACDONALD, D M J, HOWARD, A G, BARRETT, M H, PEDLEY, S, AHMED, K M, and NALUBEGA, M. 2001. ARGOSS — Guidelines for assessing the risk to groundwater from on-site sanitation. British Geological Survey Commissioned Report, CR/01/142.
  3. ↑ MESQUITA, S, NOBLE, R T, and WURBS, R. 2013. Recent developments in monitoring of microbiological indicators of water quality across a range of water types. Water Resources Planning, Development and Management, 29–53.
  4. ↑ PEGRAM, G C, QUIBELL, G, and HINSCH, M. 1999. The nonpoint source impacts of peri-urban settlements in South Africa: Implications for their management. Water Science and Technology, Vol. 39, 283–290.
  5. ↑ Jump up to: 5.0 5.1 PATERSON, C, MARA, D, and CURTIS, T. 2007. Pro-poor sanitation technologies. Geoforum, Vol. 38, 901–907.
  6. ↑ KATUKIZA, A Y, RONTELTAP, M, OLEJA, A, NIWAGABA, C B, KANSIIME, F, and LENS, P N L. 2010. Selection of sustainable sanitation technologies for urban slums — A case of Bwaise III in Kampala, Uganda. Science of The Total Environment, Vol. 409, 52-62.
  7. ↑ PARKINSON, J, and TAYLER, K. 2003. Decentralized wastewater management in peri-urban areas in low-income countries. Environment and Urbanization, Vol. 15, 75–90.
  8. ↑ Jump up to: 8.0 8.1 JACOBI, P, AMEND, J, and KIANGO, S. 2000. Urban agriculture in Dar es Salaam: providing an indispensible part of the diet. 257–283 in Growing cities, growing food: Urban agriculture on the policy agenda.
  9. ↑ BRAZIER, A. 2012. Conflicts over urban agriculture in Harare, Zimbabwe. Royal African Society. http://africanarguments.org/2012/07/10/conflicts-over-urban-agriculture-in-harare-zimbabwe/
  10. ↑ HARRIS, P J C, ALLISON, M, SMITH, G, KINDNESS, H M, and KELLEY, J. 2001. The potential use of waste stream products for soil amelioration in peri-urban interface agricultural systems. 1–28 in Waste composting for urban and peri-urban agriculture: Closing the rural-urban nutrient cycle in Sub-Saharan Africa. DRECHSEL, P, and KUNZE, D (editors). (IWMI & FAO.)
  11. ↑ ANDRES, L, and LEBAILLY, P. 2011. Peri-urban agriculture: The case of market gardening in Niamey,Niger. African Review of Economics and Finance, Vol. 3, 68–79.
  12. ↑ GRAEFE, S, SCHLECHT, E, and BUERKERT, A. 2008. Opportunities and challenges of urban and peri-urban agriculture in Niamey, Niger. Outlook on Agriculture, Vol. 37, 47–56.
  13. ↑ DIMA, S J, OGUNMOKUN, A A, and NANTANGA, T. 2002. The status of urban and peri-urban agriculture, Windhoek and Oshakati, Namibia. IP & FAO (Windhoek).
  14. ↑ ASHEBIR, D, PASQUINI, M, and BIHON, W. 2007. Urban agriculture in Mekelle, Tigray state, Ethiopia: Principal characteristics, opportunities and constraints for further research and development. Cities, Vol. 24, 218–228.
  15. ↑ EATON, D, and HILHORST, T. 2003. Opportunities for managing solid waste flows in the periurban interface of Bamako and Ouagadougou. Environment and Urbanization, Vol. 15, 53–64.
  16. ↑ ASOMANI-BOATENG, R. 2002. Urban cultivation in Accra: an examination of the nature, practices, problems, potentials and urban planning implications. Habitat International, Vol. 26, 591–607.
  17. ↑ CNA, BGS, LSHTM, and UB. 1998. Impact of wastewater reuse on groundwater in the Mezquital Valley, Mexico. Final report to DFID. British Geological Survey Technical Report WC/98/42.
  18. ↑ CHILTON, P J, STUART, M E, ESCOLERO, O, MARKS, R J, GONZÁLEZ, A, and MILNE, C J. 1998. Groundwater recharge and pollutant transport beneath wastewater irrigation: The case of León, Mexico. 153–168 in Groundwater Pollution, Aquifer Recharge and Vulnerability. ROBINS, N S (editor). Special Publication 130. (London: Geological Society.)
  19. ↑ STUART, M E, and MILNE, C J. 2001. The risk to groundwater from wastewater irrigation using high chromium tannery effluent. Environmental Geochemistry and Health, Vol. 23, 247–251.
  20. ↑ KAPUNGWE, E M. 2013. Heavy metal contaminated water, soils and crops in peri urban wastewater irrigation farming in Mufulira and Kafue Towns in Zambia. Journal of Geography and Geology, Vol. 5.
  21. ↑ MARSHALL, B, BOWYER-BOWER, T, CHISALA, B H, KAPUNGWE, E M, AGRAWAL, M, AGRAWAL, R, and SHARMA, R. 2004. Contaminated irrigation water and food safety for the urban and peri-urban poor: Appropriate measures for monitoring and control from field research in India and Zambia. Department for International Development (DFID) Main Inception Report: DFID project No.R8160. (London).
  22. ↑ MUCHUWETI, M, BIRKETT, J W, CHINYANGA, E, ZVAUYA, R, SCRIMSHAW, M D, and LESTER, J N. 2006. Heavy metal content of vegetables irrigated with mixtures of wastewater and sewage sludge in Zimbabwe: Implications for human health. Agriculture, Ecosystems & Environment, Vol. 112, 41–48.
  23. ↑ MAYEKO, K K. 2008. Wastewater use and urban agriculture in Kinshasa, DR Congo. Agriculture in urban planning. REDWOOD, M (editor). (Earthscan/IDRC.)
  24. ↑ KULABAKO, R, KINOBE, J, MUJUNGA, J, S.OLWENYI, and SLEYTR, K. 2009. Greywater use in peri-urban households in Kitgum,Uganda. Sustainable Sanitation Practice, Vol. 1, 16–24.
  25. ↑ STEVENS, M, ASHBOLT, N, and CUNLIFFE, D. 2003. Review of coliforms as microbial indicators of drinking water quality. Report to Government of Australia: National Health and Medical Research Council, ISBN 1864961651.
  26. ↑ KERAITA, B, DRECHSEL, P, and AMOAH, P. 2003. Influence of urban wastewater on stream water quality and agriculture in and around Kumasi, Ghana. Environment and Urbanization, Vol. 15, 171–178.
  27. ↑ BINNS, J A, MACONACHIE, R A, and TANKO, A I. 2003. Water, land and health in urban and peri-urban food production: the case of Kano, Nigeria. Land Degradation & Development, Vol. 14, 431–444.
  28. ↑ MACONACHIE, R A, and BINNS, T. 2006. Sustainability under threat? The dynamics of environmental change and food production in peri-urban Kano, northern Nigeria. Land Degradation & Development, Vol. 17, 159–171.
  29. ↑ WELDESILASSIE, A B, FRÖR, O, BOELEE, E, and DABBERT, S. 2009. The economic value of improved wastewater irrigation: a contingent valuation study in Addis Ababa, Ethiopia. Journal of Agricultural and Resource Economics, Vol. 34, 428–449.
  30. ↑ WELDESILASSIE, A B, BOELEE, E, DRECHSEL, P, and DABBERT, S. 2011. Wastewater use in crop production in peri-urban areas of Addis Ababa: impacts on health in farm households. Environment and Development Economics, Vol. 16, 25–49.
  31. ↑ COFIE, O O, KRANJAC-BERISAVLJEVIC, G, and DRECHSEL, P. 2005. The use of human waste for peri-urban agriculture in Northern Ghana. Renewable Agriculture and Food Systems, Vol. 20, 73–80.
  32. ↑ ASOMANI-BOATENG, R, and HAIGHT, M. 1999. Reusing organic solid waste in urban farming in African cities: a challenge for urban planners. Third World Planning Review, Vol. 21, 411.
  33. ↑ MORRIS, B L, LAWRENCE, A R, CHILTON, P J, ADAMS, B, CALOW, R C, and KLINCK, B A. 2003. Groundwater and its susceptibility to degradation: a global assessment of the problem and options for management. UNEP Early Warning & Assessment Rpt. Series, RS 03–3 (Nairobi, Kenya).
  34. ↑ TALLON, P, MAGAJNA, B, LOFRANCO, C, and LEUNG, K T. 2005. Microbial indicators of faecal contamination in water: a current perspective. Water, Air, and Soil Pollution, Vol. 166, 139–166.
  35. ↑ Jump up to: 35.0 35.1 CHUKWU, O. 2008. Analysis of groundwater pollution from abbatoir waste in Minna, Nigeria. Research Journal of Dairy Sciences, Vol. 2, 74–79.
  36. ↑ Jump up to: 36.0 36.1 SANGODOYIN, A Y, and AGBAWHE, O M. 1992. Environmental study on surface and groundwater pollutants from abattoir effluents. Bioresource Technology, Vol. 41, 193–200. Cite error: Invalid <ref> tag; name "Sangodoyin 1992" defined multiple times with different content
  37. ↑ Jump up to: 37.0 37.1 ADEBAYO, O T, BALOGUN, A M, and OLUBIYI, O A. 2007. Chemical analysis of some industrial effluents that discharge into Lagos Lagoon, Nigeria. Research journal of Environmental sciences, Vol. 1, 196–199.
  38. ↑ Jump up to: 38.0 38.1 38.2 KANU, I, and ACHI, O K. 2011. Industrial effluents and their impact on water quality of receiving waters in Nigeria. Journal of Applied Technology in Environmental Sanitation, Vol. 1, 75–86.
  39. ↑ Jump up to: 39.0 39.1 TAIWO, A, OLUJIMI, O, BAMGBOSE, O, and AROWOLO, T. 2010. Surface water quality monitoring in Nigeria: a situational analysis and future management strategy. J Sustain Manag, Vol. 2, 301–320.
  40. ↑ OLAYINKA, K O, and ALO, B I. 2004. Studies on industrial pollution in Nigeria: The effect of textile effluents on the quality of groundwater in some parts of Lagos. Nigerian Journal of Health and Biomedical Sciences, Vol. 3, 44–50.
  41. ↑ ABIYE, T, SULIEMAN, H, and AYALEW, M. 2009. Use of treated wastewater for managed aquifer recharge in highly populated urban centers: a case study in Addis Ababa, Ethiopia. Environmental Geology, Vol. 58, 55–59.
  42. ↑ NGANJE, T N, EDET, A E, and EKWERE, S J. 2007. Concentrations of heavy metals and hydrocarbons in groundwater near petrol stations and mechanic workshops in Calabar metropolis, southeastern Nigeria. Environmental Geosciences, Vol. 14, 15–29.
  43. ↑ Jump up to: 43.0 43.1 YHDEGO, M. 1988. Urban solid waste management in Tanzania. Waste Management & Research, Vol. 6, 175-180.
  44. ↑ Jump up to: 44.0 44.1 44.2 CARRILLO, M, ESTRADA, E, and HAZEN, T C. 1985. Survival and enumeration of the fecal indicators Bifidobacterium adolescentis and Escherichia coli in a tropical rain forest watershed. Applied and Environmental Microbiology, Vol. 50, 468–476.
  45. ↑ Jump up to: 45.0 45.1 45.2 YHDEGO, M. 1995. Urban solid waste management in Tanzania Issues, concepts and challenges. Resources, Conservation and Recycling, Vol. 14, 1–10.
  46. ↑ MATO, R R A M. 1999. Environmental implications involving the establishment of sanitary landfills in five municipalities in Tanzania: the case of Tanga municipality. Resources, Conservation and Recycling, Vol. 25, 1–16.
  47. ↑ Jump up to: 47.0 47.1 GUERRERO, L A, MAAS, G, and HOGLAND, W. 2013. Solid waste management challenges for cities in developing countries. Waste Management, Vol. 33, 220–232. Cite error: Invalid <ref> tag; name "Guerrero 2013" defined multiple times with different content
  48. ↑ Jump up to: 48.0 48.1 KLINCK, B A, and STUART, M E. 1999. Human health risk in relation to landfill leachate. Final report to DFID. British Geological Survey Technical Report, WC/99/17.
  49. ↑ STUART, M E, and KLINCK, B A. 1998. A catalogue of leachate quality for selected landfills from newly industrialised countries. Report to DFID. British Geological Survey Technical Report, WC/98/49.
  50. ↑ Jump up to: 50.0 50.1 HENRY, R K, YONGSHENG, Z, and JUN, D. 2006. Municipal solid waste management challenges in developing countries — Kenyan case study. Waste Management, Vol. 26, 92–100.
  51. ↑ MAZHINDU, E, GUMBO, T, and GONDO, T. 2012. Waste management threats to human health and urban aquatic habitats — A case study of Addis Ababa, Ethiopia. 21–54 in Waste management — An integrated vision.
  52. ↑ Jump up to: 52.0 52.1 MBULIGWE, S E, and KASEVA, M E. 2006. Assessment of industrial solid waste management and resource recovery practices in Tanzania. Resources, Conservation and Recycling, Vol. 47, 260–276.
  53. ↑ Jump up to: 53.0 53.1 NKHUWA, D C W, KAFULA, T, and AHMED, A H. 2008. A preliminary inventory of hazardous medical waste disposal systems and their influence on groundwater quality in Lusaka. Medical Journal of Zambia, Vol. 35, 129–138.
  54. ↑ ARUKWE, A, EGGEN, T, and MÖDER, M. 2012. Solid waste deposits as a significant source of contaminants of emerging concern to the aquatic and terrestrial environments — A developing country case study from Owerri, Nigeria. Science of The Total Environment, Vol. 438, 94–102.
  55. ↑ ENGELBRECHT, J F P. 1998. Groundwater pollution from cemeteries. The Water Institute of Southern Africa. Biennal Conference and Exhibition, Vol. 1, 1–8.
  56. ↑ TRICK, J, KLINCK, B, COOMBS, P, NOY, D, and WILLIAMS, G. 2005. Burial sites and their impact on groundwater. IAHS PUBLICATION, Vol. 297, 36.
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