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International
OCCUPATIONAL AND
ENVIRONMENTAL MEDICINE
JESSICA A. HERZSTEIN, MD, MPH
President, Environmental Health Resources
Lexington, Massachusetts;
Corporate Medical Director, Air Products and Chemicals, Inc.
Allentown, Pennsylvania
WILLIAM B. BUNN III, MD, JD, MPH
Corporate Medical Director Director, Health
Management and Safety Navistar
International Corporation Chicago, Illinois
LORA E. FLEMING, MD, PhD, MPH, MSc
Associate Professor, Department of Epidemiology and Public Health
University of Miami School of Medicine Miami, Florida
J. MALCOLM HARRINGTON, MBBS, MSc
The Institute of Occupational Health, University of Birmingham
Birmingham, United Kingdom
JERRY JEYARATNAM, MBBS, MSc, PhD
Senior Fellow and Director
World Health Organization Collaborating Center for Occupational Health
Department of Community, Occupational, and Family Medicine
National University of Singapore
Republic of Singapore
IAN ROBERT GARDNER, MBBS, MPH
Program Director, Department of Health Safety and Environmental Management
IBM Asia Pacific
Sydney, New South Wales, Australia
St. Louis Baltimore Boston Carlsbad Chicago Minneapolis New York Philadelphia Portland
London Milan Sydney Tokyo Toronto
M Mosby
Solid Waste
SANDRA COINTREAU-LEVINE
Associate Contributors: James Listorti and Christine P. Furedy
CHAPTER OUTLINE
Background
Solid waste generation
Solid waste composition
Waste collection systems
Waste disposal systems
Solid waste management costs Health
and injury issues Availability of health
and injury data Air pollution disease
links
Bioaerosols
Particulates
Volatile organics
Lead Direct contact disease
links
HIV and hepatitis infection
Parasitic infections Water
contamination disease links Vector
disease links
Dengue fever
Leptospirosis, plague, and Hantavirus
Enteric bacteria Animal
feeding disease links
Trichinella spiral is
Taeniasis
Injuries
Collection injuries
Disposal injuries
Dump site slides and subsidence
Lifting-induced injuries
Vibration-induced injuries
Noise-induced injuries Summary and
recommendations
high-income countries began requiring open dumps to
be covered daily with soil to curtail vector access, thus
converting the dumps to controlled landfills. Since the
early 1970s, when it became apparent that even
controlled landfills were causing significant water
pollution, sanitary landfill technology has been developed and refined to provide barriers to pollutant
migration, as well as for leachate and gas management
systems.
In the past 2 decades, occupational health and safety
protection for solid waste facilities has become increasingly regulated to minimize work-related risks. For
example, most waste collection in developed countries
involves vehicles with low loading heights and easyto-lift plastic containers or bags. Waste sorting at
materials recovery facilities involves dust suppression,
conveyance enclosure, and ventilation-controlled work
environments, and workers are required to wear personal respiratory protection if working spaces do not
meet air standards set for occupational safety and health.
However, in developing countries the health-related
underpinnings of solid waste management still need to
be addressed. Even the minimal regulatory framework
that exists in most of these countries for environmental
protection and occupational health and safety is not
enforced. Solid waste workers and waste pickers are
directly exposed to health risk factors of fecal matter,
blood, volatile organics, air particulates, bioaerosols,
and hazardous chemicals. For waste pickers, living
adjacent to the dump site in poor housing conditions and
with minimal basic infrastructure for clean water and
sanitation often exacerbates these health risks.
BACKGROUND
Current standards and norms for handling municipal
solid wastes in industrialized countries have substantially reduced the occupational health and environmental effects from these wastes. About 3 decades ago,
620
Solid Waste Generation
Municipal solid waste is produced as a result of
economic productivity and consumption and includes
nonhazardous wastes from households, commercial
Solid Waste
621
establishments, institutions, markets, and industries.
Construction and demolition debris and yard wastes
typically are not included in the estimated waste
generation rate per capita of municipal solid waste, as
they are highly variable and skew quantity assessments.
Countries with higher incomes produce more waste per
capita and per employee, and their wastes have higher
proportions of packaging materials and recyclable
wastes. In low-income countries, less commercial and
industrial activity, as well as less institutional
activity, results in lower waste generation rates. In
countries where personal incomes are low, there is, of
necessity, extensive recycling at the source. Table 38-1
shows how waste generation rates vary by country
average income level and city size.
Middle class area with sewage-laden streets in Alexandria,
Egypt, during 1980s. Courtesy Daniel A. Okun.
Solid Waste Composition
Table 38-2 demonstrates how waste composition varies
by income levels. Because the solid waste of high-
Global Perspective on Solid Waste Quantities
Low-income country
Mixed urban waste: large city (kg/capita/day)
Mixed urban waste: medium city (kg/capita/day)
Residential waste (kg/capita/day)
0.50 to 0.75
0.35 to 0.65
0.25 to 0.45
Middle-income country
0.55 to 0.95
0.45 to 0.75
0.35 to 0.65
High-income country
0.75 to 1.8
0.65 to 1.5
0.55 to 1.0
Notes: World Bank country categorization by income is based on 1992 gross national product data. For purposes of this table, a medium city
is 100,000-500,000 residents; a large city is >500,000 residents; waste weight based on "wet received" (i.e., not dried).
Global Perspective on Urban Solid Waste Characteristics
Composition of raw waste (by wet weight, %)
Vegetable/putrescible
Paper and carton
Plastic
Metal
Glass
Rubber, miscellaneous
Fines (sand, ash, broken glass)
Other characteristics:
Moisture
Density in trucks (kg/cm)
Lower heating (kcal/kg)
Low-income country
Middle-income country
High-income country
40 to 85
1 to 10
1 to 5
1 to 5
1 to 10
1 to 5
15 to 50
20 to 65
15 to 40
2 to 6
1 to 5
1 to 10
1 to 5
15 to 40
20 to 50
15 to 40
2 to 10
3 to 13
4 to 10
2 to 10
5 to 20
40 to 80
40 to 60
20 to 30
250 to 500
800 to 1100
170 to 330
1000 to 1300
100 to 1 70
1500 to 2700
Notes: World Bank country categorization by income is based on 1992 gross national product data. Compaction trucks achieve load densities
of 400 to 500 kg/cm. For self-sustained incineration, a year-round minimum greater than 1300 kcal/kg lower calorific value is needed; for
waste-to-energy plants, 2200 kcal/kg is the minimum calorific value desired; waste weight based on "wet received" (i.e., not dried).
622
Environmental Hazards and Populations
income countries contains a lower percentage of food
material, yard wastes, and other putrescible organics,
the resulting moisture content of the waste is lower and
the resulting calorific value higher. The waste of
developing countries does not have sufficient calorific
value to self-sustain incineration; that is, it will not burn
without the addition of fuel.
In high-income countries, hazardous wastes are
strictly regulated to be source segregated and separately
managed in secured transport, processing, and disposal
facilities. Despite the lower level of commercial,
industrial, and institutional activity in developing countries, their solid waste is not necessarily devoid of
hazardous wastes (defined as toxic, inflammatory,
reactive, explosive, or infectious, including such wastes
as the heavy metals in batteries, electroplating sludges,
paint solvents, pesticides, and infectious medical
wastes) because the regulatory framework and enforcement system to control such wastes are usually nonexistent or dysfunctional. Bloodied bandages, cotton
swabs, and syringes from hospitals are commonly found
within the mixed municipal solid waste collected in
developing countries. Hazardous solvents, adhesives,
plating materials, and pesticides from industries, as well
as hazardous asbestos products from construction and
demolition activity, are common.
In 1993, hazardous waste surveys conducted in
21 Latin American countries showed, as expected, that
the per person waste generation rate for industrial
hazardous waste sludges and solids is a function of the
country's level of industrialization, with the highest
rates (over 0.3 tons/person/year) in countries like
Mexico and Brazil, and the lowest rates (under 0.1
tons/person/year) in countries like Bolivia and Ecuador.
In most of these countries, more than 30% of the
hazardous industrial wastes are inappropriately discharged to open dumps and controlled landfills. Similarly, most of the hazardous medical wastes are being
co-disposed with general municipal solid waste in open
dumps and controlled landfills, seldom in sanitary
landfills with adequate protective measures.15
Human waste (i.e., fecal matter) is common in solid
waste, especially in developing countries (see Chapter
36). In high-income countries, most human waste is
handled in separate sewage and septic tank systems.
Nevertheless, a limited amount of human waste arrives
largely through disposable diapers. However, in developing countries, human waste is common in municipal
solid waste because of inadequate sanitation. In the
poorest of countries, people defecate along roadways
and on open lots, and the resulting street sweepings
contain feces. Open piles of uncollected solid waste
especially invite defecation; and, where buckets or bed
pans are used, the human waste is often placed in a
plastic bag before discarding it with the solid waste.
Even where there are latrines and toilets, it is common
practice to throw the used toilet tissue in the solid waste
dustbin. And finally, pumped seepage from septic tanks
and cesspits is commonly discharged at open dumps
because treatment facilities are seldom available for this
material.
Waste Collection Systems
In all but the most rural areas of high-income countries,
virtually all municipal solid wastes are collected.
Because of the relatively high cost of labor, loading
commonly is made as easy and as mechanized as
possible, thus minimizing occupational health and
injury risk. All waste is required to be fully contained,
either in a covered metal or plastic bin or within a plastic
bag. Occupational health and safety regulation limits the
size and weight of each container or bag.
Most low-income countries experience low levels of
collection service. Typically only 30% to 60% of the
municipal solid wastes are collected. Service levels in
middle-income countries are slightly higher; typically
50% to 80% of the wastes are collected. Because
uncollected wastes accumulate near homes and work
areas, city dwellers (and their domestic animals) in
low-income countries have much more direct contact
with wastes than city dwellers in high-income countries.
Municipal solid waste in developing countries commonly is collected through labor-intensive systems,
sometimes using handdrawn or animal-drawn carts. The
waste discharged for collection seldom is stored in a
plastic or metal container and covered with a lid, unless
unsuitably large oil drums are available. More typically,
the waste is placed on the ground directly, requiring that
it be shoveled by hand, or it is left in an open carton or
basket to be picked up by hand. In either case, the waste
awaiting collection is readily available to insect and
rodent vectors and to scavenging animals. Collection
workers in developing countries therefore have significantly more direct contact with solid waste than their
counterparts in high-income countries, who predominantly handle sealed plastic bags and covered dustbins.
Waste Disposal Systems
In high-income countries, essentially all collected
wastes go to safe sanitary landfill, composting, materials
recovery, or incineration facilities that are designed and
operated to meet environmental protection standards.
Sanitary landfill is a disposal technology wherein solid
wastes are placed on impermeable soils that protect
Solid Waste
623
Global Perspective on Solid Waste Management Costs vs. Income
Low-income country
Middle-income country
High-income country
Average waste generation (mt/cap/yr)
0.2 mt
0.3 mt
0.6 mt
Average income based on GNP ($/cap/yr)
Collection cost ($/mt)
Transfer cost ($/mt)
Sanitary landfill cost ($/mt)
Total cost without transfer ($/mt)
Total cost with transfer ($/mt)
Cost as % of income
$370
$10-30
$3-8
$3-10
$13-40
$16-48
0.7-2.6%
$2,400
$30-70
$5-15
$8-15
$38-85
$43-100
0.5-1.3%
$22,000
$70-120
$15-20
$20-50
$90-170
$105-190
0.2-0.5%
Notes: World Bank country categorization based on 1992 gross national product data. $/mt = US dollars per metric ton; $/cap/yr = US dollars
per capita per year.
groundwater, underlaid with impermeable plastic membranes and drainage systems to collect contaminated
seepage (leachate) for treatment, and ventilated with gas
management systems. Within a sanitary landfill for
mixed municipal solid waste, each day's solid waste is
formed into a cell and covered with soil to minimize
water infiltration, mitigate odors, and limit vector
breeding.
Composting is a solid waste disposal technology
where the organic fraction of the waste is aerobically
decomposed by the natural microorganisms within the
waste. It involves enhancing the conditions necessary
for decomposition (e.g., nutrient, oxygen, and moisture
levels). Materials recovery facilities provide conveyance, sorting, and processing facilities that enable the
recovery of secondary materials such as paper, carton,
metal, and glass from solid waste.
In middle-income countries, probably less than 5% of
collected waste is deposited in sanitary landfills.
Roughly another 10% of collected waste is deposited in
controlled landfills. A controlled landfill offers less
environmental protection than a sanitary landfill. It has
only daily soil cover and perimeter drainage to minimize
leachate generation, but not the impermeable underlining and underdrainage, leachate treatment, and gas
collection systems required of sanitary landfills. Most
collected waste in middle-income countries is discharged to open dumps, which have no soil cover, burn
openly during dry seasons, and sometimes have steep
unstable side slopes.
Solid Waste Management Costs
Table 38-3 shows how solid waste collection, transport,
and sanitary landfill costs vary as a function of income.
In developing countries, while the per capita quantities
of wastes and labor costs are low, the costs of providing
solid waste management are not proportionately low.
Equipment capital costs and fuel costs in low-income
countries are comparable to those in high-income
countries, and sometimes are higher because of importation. The result, as seen in Table 38-3, is that solid
waste management cost is higher in low-income
countries when viewed as a percentage of personal
income. Given the proportionately high cost of full
service in developing countries and competing urban
infrastructure needs, the prevailing low levels of solid
waste service are likely to continue for at least another
decade.
HEALTH AND INJURY ISSUES
Population growth and economic development have
brought increasing amounts of solid waste to urban
areas. In most developing countries, the ever-increasing
quantities have overwhelmed local governments' capabilities to cope efficiently. Infectious medical wastes and
toxic industrial wastes in the solid waste mixture expose
waste handlers to a wide array of risks. In many of these
countries, waste pickers commonly find their livelihood
through sorting and recycling of secondary materials. A
majority of waste pickers usually are children and
women of childbearing age. Exhaust fumes of waste
collection trucks traveling to and from disposal sites,
dust from disposal operations, and open burning of
waste all contribute to occupational health problems
(Box 38-1). More removed environmental impacts, such
as downwind air pollution and downgradient water
pollution from solid waste disposal facilities, can affect
the surrounding population as well as the families of
waste pickers (Box 38-2).
A global relationship appears to exist between solid
waste handling and increasing health risk. The risk is
624
Environmental Hazards and Populations
BOX 38-1
BOX 38-2
OCCUPATIONAL HEALTH AND INJURY ISSUES
ENVIRONMENTAL HEALTH AND
INJURY ISSUES
Commonly reported occupational health and injury
issues in solid waste management include the following:
• Back and joint injuries from lifting heavy
waste-filled containers and driving heavy
landfill and loading equipment
• Respiratory illness from ingesting particulates,
bioaerosols, and volatile organics during
waste collection and from working in smoky
and dusty conditions at open dumps
• Infections from direct contact with contami
nated material, dog and rodent bites, or eating
of waste-fed animals
• Puncture wounds leading to tetanus, hepatitis,
and HIV infection
• Injuries at dumps due to surface subsidence,
underground fires, and slides
• Headaches and nausea from anoxic condi
tions where disposal sites have high methane,
carbon dioxide, and carbon monoxide con
centrations
• Lead poisoning from burning of materials
with lead-containing batteries, paints, and
solders
greatest in developing countries, where the contact
between the solid waste worker and waste is greatest and
the level of protection is least. From the information
available, most occupational health and injury problems
could be minimized by simple safety procedures that
cost little, and most adverse environmental effects could
be minimized by closing open dumps and implementing
sanitary landfills.
AVAILABILITY OF HEALTH AND INJURY DATA
Relatively few data are available on the health and
safety conditions of solid waste workers in the higherincome countries. One of the few good studies published from high-income countries was conducted by
the Danish National Institute of Occupational Health,
which provided a review of occupational health problems associated with collection of solid waste (domestic
only). The study found that in 1995 the relative risk (1.5)
among Denmark's solid waste collection workers for
occupational disease and injury was elevated when
compared to Denmark's total work force.48 The relative
Commonly reported environmental health and injury issues in solid waste management include the
following:
• Contaminated leachate and surface runoff
from land disposal facilities affecting downgradient ground and surface water quality
• Methane and carbon dioxide air emissions
from land disposal facilities adding to global
warming, thus increasing subsequent vectorborne disease abundance and pathogen
survival
• Volatile organic compounds and dioxins in air
emissions increasing cancer incidence and
psychological stress for those living near in
cinerators or land disposal facilities
• Animal feeding with solid waste, providing a
food chain path for transmitting disease
• Uncollected wastes that collect and hold wa
ter and clog drains, thus leading to stagnant
waters that encourage mosquito vector
abundance
• Uncollected wastes providing food and breed
ing sites for insect and rodent disease vectors
risk for solid waste workers and waste pickers in
developing countries is undoubtedly much higher.
Most of the developing country data discussed in this
chapter has not been published. The data are from direct
in-country observations and surveys, largely by local
physicians, health workers, and sociologists and documented in modest reports to their respective local
governments and health institutions. None appears to
qualify as true epidemiological studies and rarely do
they relate the incidence of injury or disease observed
to global country norms or control group observations.
For most of the information presented, this is a first
reporting in a comparative format and is indicative of
the hidden nature of the health risks suffered by solid
waste workers and the shadow life of the informal sector
waste pickers. As an example, data from Ghana provide
some indication of the differences in worker health and
safety between solid waste workers versus a group of
workers in construction45 (Box 38-3).
A number of health studies have been conducted in
India and Nepal16'21'26 (Table 38-4). Tuberculosis,
bronchitis, asthma, pneumonia, dysentery, parasites,
Solid Waste
BOX 38-3
ACCRA (GHANA) OCCUPATIONAL DATA
Health data from 1994 for the Accra Municipal Solid
Waste Department were reviewed and compared
with a local construction company. The solid waste
workers had a higher incidence of sick days, workrelated accidents, and mortality. The percentage of
people reporting sick during the year was 47.6% of
the total solid waste staff, versus only 33% of the total
construction staff. Sick days consumed 0.7% of the
total days among the solid waste staff, but only 0.5%
among the construction staff. Death occurred for
3.6% of the solid waste staff, but for only 0.6% of the
construction staff. One death among the solid waste
staff was directly work related. Lower incomes and
higher ages among solid waste staff may explain
some of these differences, but not all.45
and malnutrition are the most common diseases among
waste pickers based on health studies of waste pickers
conducted in Bangalore,Manohar, and New Delhi.26 Of
the 180 waste pickers surveyed at Calcutta's open
dumps in 1995, 40% had chronic cough, and 37%
jaundice; the average quarterly prevalence of diarrhea
was 85%; fever, 72%; cough and cold, 63%; eye
soreness or redness, 15%; and skin ulcers, 29%. 16
A study comparing waste pickers working at Calcutta's Dhapa dump in the 1980s with nearby farmers who
use organic solid waste as fertilizer showed that pickers
reported a higher prevalence of respiratory diseases
(71% vs. 34%), diarrhea (55% vs. 28%), and protozoal and helminthic infestation (32% vs. 12%).46 At
Bombay's open dump sites, 80% of solid waste workers
reported eye problems, 73% respiratory ailments, 51%
gastrointestinal ailments, 40% skin problems, and 22%
orthopedic ailments. Based on clinical examination,
90% had decreased visual acuity, and 27% had skin
lesions, of which 30% were determined to be directly
related to work.36
Women and children often make up a majority of
waste pickers at dump sites in developing countries (see
Chapter 32). Besides the implications for reproductive
toxicity described below, morbidity data from dump site
waste pickers in India suggest that waste picking
children have 2.5 times more risk of morbidity than
non-waste picking children from the same housing
areas. In 1991, 974 children below 16 years of age
were working at the largest dump site of Metro Manila
in the Philippines. Clinical examination of 194 children
625
Table 38-4
Katmandu, Nepal, Waste Pickers: Before and After
Waste Work Diseases21
Disease/reported symptoms
% Before
% After
Diarrhea
20
32
Dysentery
Parasitic diseases
Colds
Eye problems
Headache
11
18
48
6
3
27
45
86
18
23
showed that 30% had skin diseases (including rashes,
hypopigmentation, fungal infection, or boils) at the time
of examination. They also reported multiple respiratory symptoms including chronic cough (23%), chronic
phlegm production (18%), wheezing (25%), and shortness of breath (19%). Based on chest x-rays conducted
following the survey, in only 3% were these symptoms
attributable to residual or minimally active pulmonary
tuberculosis.1'56
AIR POLLUTION DISEASE LINKS
In developing countries, one of the major effects of
occupational and environmental exposure to solid waste
occurs in the respiratory system as a result of a wide
range of potentially toxic respiratory exposures (Box
38-4) (see also Chapter 30).
Bioaerosols
The elevated incidence of pulmonary diseases reported
among waste pickers is probably related to exposure to
biologically active agents (e.g., microorganisms and
their metabolites and toxins), volatile compounds, and
mold spores. Waste collection involves a physically
strenuous effort resulting in significantly higher pulmonary ventilation and a greater tendency to breathe
through the mouth instead of the nose. Over a study
period of 1984 to 1992, Danish solid waste collection
workers were reported to have a relative risk of 2.6 for
work-related allergic pulmonary diseases and 1.4 for
work-related nonallergic pulmonary diseases, as compared with the entire work force. Waste collectors in
Geneva had a 2.5 relative risk of acquiring chronic
bronchitis, according to studies during the mid-1970s.48
A study in Geneva found collection workers had a
high exposure to bioaerosols, mostly molds. Microorganism counts were between 10 4 and 10 5 cfu/m3
626
Environmental Hazards and Populations
BOX 38-4
OPEN DUMPS AND DECREASED LUNG
FUNCTION
At open dumps in Bombay the majority of waste
workers (73%) complained of aggravated symptoms
of cough and breathlessness during working hours.
Abnormal pulmonary function tests (PFTs) were presented in 23% of the dump site workers, and 26%
had restrictive patterns. Chest x-rays showed 17.5%
had nonspecific shadows consistent with posttuberculosis fibrosis, and about 11% presented reticulonodular shadows.36 PFTs were conducted on dump
site waste pickers and residents surrounding the
dump in Bangkok; 40% were below the normal
range. Individual and environmental tobacco exposure information did not explain the data.37
PFTs on 53% of children working at the largest
dump site at Metro Manila, Philippines, revealed
decreased pulmonary function compared to country
norms, especially the forced expiratory volume and
forced vital capacity.56
(cfu/m3 refers to the bioaerosol count in 1 cubic meter
of air) in immediate proximity to the waste collection
truck's loading hopper, and less than 103 cfu/m3 at a
distance of only 2 to 3 m away.48 A similar study in
Denmark found bioaerosols were as high as 106 and 107
cfu/m3 at the loading hopper and that waste collectors
carrying containers to the curb were exposed to only
25% of the bioaerosol count confronting collectors
emptying containers into the truck. When the trucks
were equipped with a cover over the loading hopper and
an exhaust to pull air under the cover, exposure levels
dropped substantially to fewer than 2 x 104 cfu/m3.48
Measurements at six materials recovery facilities in the
United States showed that airborne bacteria and fungi
concentrations measured inside the facilities were
roughly one order of magnitude higher than the levels
found outside the facility, with a wide variety of
pathogenic and nonpathogenic organisms identified.52
At two materials recovery facilities in Finland, airborne
bacteria and fungi concentrations were from 2 to 10
times higher than background concentrations.49 Similar
results were found at landfills in Liguria and Genoa
(Italy).30'31
Particulates
Waste collectors in developing countries are exposed to
significantly higher levels of diesel exhaust fumes than
their counterparts in high-income countries. Diesel
exhaust may play a potentiating role where waste
collection is conducted in high traffic density, especially
in developing countries where vehicle emissions are not
controlled. Some studies suggest a relationship between
diesel exhaust exposure, asthma, and decreasing lung
function.48
In Denmark in 1986, high particulate levels, including airborne bacteria, endotoxins, and fungi, led to 8
cases of bronchial asthma and 1 of chronic bronchitis
among 15 materials recovery plant workers at a new
plant.42 In Finland in 1989, dust concentrations at the
sorting stations of the materials recovery plants were as
high as 38 mg/m3 compared to an occupational health
standard of 10 mg/m3 for 15 minutes of exposure, while
dust levels within the incinerator were lower than the
occupational health standard.49In the United States in
1992, dust levels measured at six newly built materials
recovery facilities were found to be at least one order of
magnitude lower than worker protection standards.52
Dusts at open dumps and landfills, including hazardous
dusts such as asbestos and crystalline silica particles,
may be injurious to the respiratory system of solid waste
workers.61 Solid waste workers and waste pickers at
open dumps in developing countries suffer from smoke
generated by open burning and underground fires.
Volatile Organics
Because of their high vapor pressures and low solubilities, volatile organic compounds are present in solid
waste decomposition gases. One study identified 92
different volatile organic compounds in the headspace
loading area of solid waste collection trucks, including
alcohols, aldehydes, ketones, carboxylic acids, and
esters. Total volatile organic concentration varied from
0.9 to 8.1 mg/m3 in the loading area headspace.
Furthermore, sudden peaks in exposure are likely to
occur when the lids of waste containers are opened.48
Landfill decomposition gases have a number of trace
volatile organic compounds, some of which are potentially toxic (dichloromethane) and carcinogenic (benzene and vinyl chloride), as well as potentially affecting
the incidence of kidney disease (toluene) and leukemia
(benzene)13'51 (see Chapter 39). The U.S. government
estimated its municipal solid waste landfills released
approximately 200,000 tons/year of volatile organic
compounds, aside from methane.51 These trace constituents are normally at nontoxic concentrations, unless
significant quantities of hazardous wastes (solvents,
paints, pesticides, adhesives) are present.61 Elevated
levels of volatile organics were measured at the
Solid Waste
Bangkok dump site and were found to be higher by more
than an order of magnitude compared with nearby city
background levels, notably for toluene (700 |LLg/m3),
ethylbenzene (120 (Xg/m3), m-xylene and p-xylene
(330 |ig/m3), and o-xylene (110 |Hg/m3), as well as
benzene, methylene chloride, and methyl chloroform.37
In high-income countries, where incinerators now
have good pollution controls in place, air pollution
levels may be up to four times higher than background
within 1 to 2 km of an incinerator.18 In Japan in 1987,
stack emissions were analyzed from a continuously
operating modern incinerator and at a discontinuous
batch-type incinerator. Significant mutagenicity was
found in the stack gas, by using the Ames Salmonella/
microsomal mutagenicity bioassay test, and 13 polynuclear aromatic hydrocarbon compounds were identified. Similar results were reported in the United States.
The results indicate that mutagenic potency is more
significantly affected by the completeness of combustion and by the effectiveness of pollution control
equipment than by the nature of the material being
burned. Results for solid waste and medical waste
incinerators were comparable to industrial and utility
boilers burning coal, wood, and oil.60 Chlorinated and
brominated dioxins and furans, considered among the
most hazardous substances created during incineration,
were found in Germany to be controllable through
controlled high temperature operating conditions and
flue gas cleaning.29
Lag periods of 15 to 30 years are generally assumed
for development of solid cancers as a result of exposure
to a cancer-inducing agent, and 5 to 15 years for
hematopoietic cancers.18 Cancer incidence in more than
14 million people living within 7.5 km of 72 solid waste
incinerators in Great Britain was examined from 1974
to 1984. Observed and baseline expected numbers of
cases were determined for each 1 km band from each
incinerator. Although the relative risk differences were
not high, the study determined that there was an
associated risk with distance from incinerators for all
solid cancers combined (stomach, colorectal, liver, and
lung cancers), but no evidence of increased risk for
lymphatic and hematopoietic cancers.18
In 1991, a large sanitary landfill in Quebec Province,
Canada, was studied for cancer incidence in residents
living near the site. In women, stomach and cervical
cancers were in excess; in men, stomach, liver, trachea,
bronchus, lung, and prostate cancers were increased. A
stronger association existed for cancer of the liver and
intrahepatic bile ducts than for the other cancers, with
relative risk elevated by nearly 80% in the closest
627
proximity (less than 4 km) and downwind. Analysis of
the landfill's gas showed at least 35 volatile organic
compounds were present in appreciable concentrations,
including suspected and known carcinogens—benzene,
vinyl chloride, methylene chloride, chloroform, 1,2dichlorethane, bromodichloromethane, tetrachloroethylene, 1,4-dichlorobenzene, 1,2-dibromoethane, and carbon tetrachloride.22
Also around the same Canadian landfill, the frequency of low birthweight children born to women
living proximal to the site was 20% greater.22 Data from
the Philippines indicate that teratogenicity may occur
near open dumps. At the Payatas dump site in Metro
Manila, out of 600 families living within V2 km of the
open dump, 3 infants were born with imperforate anuses
and 10 children had cerebral palsy. 8
Lead
High blood lead levels (mean 28 |ag/dl) are reported for
child waste pickers in Manila. More than 70% of
children working at Manila's largest dump site had
blood lead levels exceeding the World Health Organization's guideline of 20 |ig/dl. The average blood lead
levels of children in a Manila slum outside the zone
of influence of the dump site were significantly lower
(11 |Lig/dl).56
A study of incinerator workers in New York showed
a mean blood lead level of 11.0 |Hg/dl compared to
7.4 |ig/dl in a heating plant control group. Significantly
lower blood lead levels were found in workers who
reported consistent use of respiratory protection during
cleaning of the incinerator's air pollution control
precipitators.
41
DIRECT CONTACT DISEASE LINKS
Solid waste workers in high-income countries routinely
wear gloves and boots and handle only the bags or
containers where solid wastes are stored. On the other
hand, solid waste workers and waste pickers in developing countries touch the waste they collect or sort
through, and they typically are wearing only sandals.
Parasitic and enteric infections are common, and, to a
lesser extent, viral infections (see Chapter 20). Solid
waste collectors in Denmark had a relatively high risk
(6.0) of occupational disease from infectious diseases.48
Comparable information is not available from developing countries, but the substantially greater contact
between the solid waste worker and the waste in
developing countries should create an even higher
relative risk.
628
Environmental Hazards and Populations
HIV and Hepatitis Infection
The United States reported 31 health-care workers who
were infected with HIV by contaminated puncture
wounds, but no incidence in housekeeping workers. The
risk of HIV infection after puncture has been estimated
to be about 0.3%. However, the risk of HBV infection
from a comparable injury was estimated to be at least 10
times higher, or 3% or more. Solid waste workers in the
United States are currently estimated to have a risk of
contaminated puncture that is roughly l/1000th the risk
level of hospital nurses.65 Studies in 1990 in Genoa,
Italy, showed solid waste workers had a higher prevalence of HBsAg carriers (2.9%) compared to the general
population (2.0%), as well as more anti-HBs and
anti-HBc positive subjects (13.8%) versus the general
population (11.8%).30
Parasitic Infections
Studies of stool samples from solid waste workers in
India showed 98% were positive for parasites, especially Trichuris trichium (a human whipworm) and
Ascaris lumbricoides (a human roundworm), whereas
only 33% of the control group were positive.6 Similarly,
stool specimens collected from children working at or
whose family members work at the dump site in
Bangkok, Thailand, showed that 65% were infected by
one or more parasites. Hookworm (Ancyclostoma
duodenale or Necator americanus) was the most
prevalent (14%) of the helminthic infections, and
Giardia lamblia (a flagellate protozoon) was the most
prevalent (44%) protozoan infection.37 In stool samples
from child waste pickers at Manila's largest dump site,
nearly 98% had T. trichiura, A. lumbricoides, or both.56
WATER CONTAMINATION DISEASE LINKS
Rainfall that runs over solid waste, or percolates through
solid waste, extracts dissolved and suspended constituents and thus becomes a contaminated liquid called
leachate. Leachate typically has high concentrations of
dissolved organics, total dissolved solids, ammonia,
nitrate, phosphate, chloride, calcium, potassium, sulfate,
and iron, as well as heavy metals (commonly including
lead, zinc, cadmium, and nickel).59'64 Leachate also
contains high numbers of fecal bacteria, while viruses
seldom survive because of their sensitivity to the low pH
values common to leachate.5 Downgradient users of
leachate-contaminated groundwaters can potentially be
exposed to significant dissolved contaminant levels, but
seldom do pathogenic microorganisms migrate in most
soils (except sand) due to filtration, ion-exchange, and
adsorption-attenuative mechanisms.59 In the case o
direct discharge of leachate to a surface water from \
land disposal site, downgradient users can also b(
exposed to disease organisms in their bathing, food
irrigation, and drinking water supply, as well as through
eating contaminated aquatic organisms.
VECTOR DISEASE LINKS
Solid waste can provide the perfect breeding ground and
continuous habitation for a number of disease vectors,
ranging from rodents to mosquitos (see Chapter 20).
These vectors can then spread diseases not only to solid
waste workers and pickers but also to the surrounding
resident populations.
Dengue Fever
Dengue fever is spread by the Aedes aegypti mosquito,
which favors small, clean water pools for breeding,
including containers, tires, and tin cans found in waste
piles.40 In towns with poor solid waste collection
service, a high correlation exists between dengue fever
and households with disposable containers and tires
littering open lands, as these containers hold rain water
and provided breeding sites.4'40'44'62
Leptospirosis, Plague, and Hantavirus
Rodents breed and feed in uncollected solid waste and
at open dumps.40 Their numbers are related to the
available food supply, as well as to the extent of pest
control supported in city budgets.43 Leptospirosis is
spread by exposure to rodent urine. Bubonic plaque is
spread by rodent fleas; more than 2000 cases were
reported in 1993 and 1994, the highest total since global
data were first compiled in 1954 and a fourfold increase
over 1990.63 In 1996 in El Bolson, a small Argentine
resort town, an outbreak of Hantavirus, a disease spread
by contact with rodent droppings or inhaling dust
contaminated with rodent urine, killed 10 people.54
Enteric Bacteria
In Tarn we, Myanmar (Burma), in 1989, houseflies were
captured in different parts of the city and during different seasons. Enteric bacteria were isolated more frequently in flies from refuse dumps, latrines, and animal
pens, with highest counts in the hot/wet season.32
ANIMAL FEEDING DISEASE LINKS
Domestic animals (e.g., cows, goats, pigs, chickens,
horses) are present at most open dumps in developing
Solid Waste
countries, and animal infection is likely. The presence of
human and animal fecal matter, as well as slaughter
waste, raises concern about disease (such as mad cow
disease, which necessitated the selective slaughter of
hundreds of thousands of cattle in 1996) being spread
when animals eat the infected flesh of other animals.12
Trichinella spiralis
Trichinosis is rare unless animals that are natural hosts
(e.g., pigs, bears, boars, badgers) to Trichinella spiralis
are fed with raw meat.11'53 Recent studies from 31 farms in
Oahu, Hawaii, showed that pigs testing positive for T.
spiralis were found only on farms feeding garbage to
pigs.17 T. spiralis increased in Soviet-bloc countries
including Latvia, Belorussia, and Georgia from the late
1970s through the 1980s, in part because of access of
animals to raw meat in domestic garbage at open
dumps.5 In 1985, more than 400 rats at a pig farm in
the United States were found to be infected with T.
spiralis.39
Taeniasis
Taeniasis is an infection caused by the adult stage
of tapeworm Taenia saginata (beef tapeworm) and
Taenia solium (pork or dog tapeworm). Cysticercosis
is an infection caused by the larvae stage of tapeworm
T. solium from pigs. In developing countries, the prevailing practice of grazing domestic animals and living
with freely roaming dogs on open dumps creates an
infection risk.20'38 Researchers determined that canine
tapeworm infects 76% of dogs living on discarded raw
meat or organs.55
INJURIES
Collection Injuries
In 1995 the relative risk for occupation accidents among
Denmark's waste collectors was about 5.6, compared to
Denmark's total work force. The most commonly
reported accidents among Danish waste collectors were
fractures, sprains, wounds, soft tissue injuries, and
chemical burns.48 Two decades earlier, a study in New
York City showed that solid waste workers had 20 times
more injuries than all other laborers; the U.S. average
for solid waste-related injuries was 10 times that for all
industry.10'27 A Brazilian study reported annual accident
levels of about 7 per 10 waste collectors.48
Disposal Injuries
In 1994 in Liguria, Italy, a region with 11 active landfills
for municipal solid waste, there were 10 occupation
629
injuries out of 100 sanitary landfill workers studied.31
For the 180 waste pickers at Calcutta's main open dump,
in 1995 the quarterly cut injury prevalence was 69%,
pin prick was 33%, and eye injury was 16%. Also, 49%
of waste pickers reported they had received dog bites
and 16% had received rat bites at the dump. 16 In
Bangkok, 88% of waste pickers reported being injured
by glass, 73% by needles, 30% by bamboo, and 25% by
metal.37 Roughly 82% of the dump site waste pickers
surveyed in Katmandu, Nepal, stated they had received
wounds to the leg, and 70% had received wounds to the
hand.21
Dump Site Slides and Subsidence
Open dumps often have side slopes of waste that are
steep and unstable, and underground fires are common and create underground cavities. In 1993 in
Istanbul, a large displacement of the waste mass
occurred (about 1.2 million cubic meters). The slide
engulfed 11 homes and killed 39 people. 34 Similarly,
in 1994 in Oportino, Spain, a man was killed and 250
residents evacuated because of a solid waste slide.3
Landfill slides have been responsible for child deaths in
a couple of cities in India.7 Child deaths from landfill
equipment also have been reported in Indonesia and the
Philippines.35'56
Lifting-induced Injuries
Waste collection work is characterized by heavy lifting.
Loading weights and heights in some developing
countries are not regulated, making the potential for
injury greater. Substantial risk exists for low back pain
and musculoskeletal disorders of the neck, shoulders,
and arms. Records from the United States reveal that
musculoskeletal restrictions due to arthritis were four
times as common for waste collectors as for general
laborers. From 1984 to 1992, the relative risk for
musculoskeletal problems among Danish waste collectors was 1.9.48 Relative energetic loads, expressed as
oxygen consumption, are typically high for waste
collectors, and coronary-related disease events were
twice as common among U.S. waste collectors as for
general laborers.10
Vibration-induced Injuries
German studies found that the effect of vibration on
drivers of landfill equipment is significant. Spinal
injuries experienced by landfill equipment operators
develop from higher than average degeneration of the
vertebrae and intense vibration of hands and arms from
operating the equipment levels. 61 A study of landfill
630
Environmental Hazards and Populations
personnel in Liguria, Italy, found 18 workers had
lumbago (low back pain).31
Noise-induced Injuries
Noise levels from processing equipment in materials
recovery facilities in the United States often have been
found to exceed Occupational Safety and Health
Administration (OSHA) action levels for worker pro-
BOX38-5
RECOMMENDATIONS REGARDING SOLID
WASTE WORKERS
• Provide clean drinking water and washing and
sanitation facilities for solid waste workers and
waste pickers
• Prohibit children and domestic animals from
entering solid waste disposal sites
• Provide vaccination for hepatitis A and B, teta
nus, polio, and typhoid and provide annual
medical examinations
• Provide education on personal hygiene and on
the safe care and feeding of domestic livestock
and pets
• Provide protective clothing, glasses, shoes or
boots, and gloves to all solid waste workers and
waste pickers
• Require respiratory protection, such as face
masks, at waste processing facilities
• Provide conveyance belts or tables that facilitate
sorting
• Improve the source storage of solid wastes in
bags and covered dustbins and limit the weight
of containers that are manually loaded
• Provide hearing protection for workers in the
vicinity of heavy equipment and waste process
ing operations
• Provide health and safety plans for all solid
waste processing and disposal facilities, includ
ing operational procedures for waste handling
and emergency procedures of first aid and
evacuation
• Implement source segregation of nonhazardous
recyclable wastes and hazardous wastes
• Avoid steep, unstable slopes at disposal sites and
provide backup chimes for landfill equipment
• Develop training materials on occupational and
environmental health and injury issues of solid
waste management that are suitable for distribu
tion to countries of various income levels and
sociocultural conditions
tection. Equipment in developing countries is not
required to address noise safety standards and noise
levels are expected to be higher.
SUMMARY AND RECOMMENDATIONS
This discussion of health and injury effects shows that
it is difficult to distinguish between occupational and
environmental risks in developing countries, since many
people who are not solid waste personnel live and work
in the immediate proximity of large piles of solid waste,
whether uncollected accumulations, clandestine dumps,
or official land disposal sites. Improved solid waste
collection in developing countries would decrease the
population exposed to risk, and measures are needed to
improve the work environment for those who make their
livelihood from collecting, sorting, or otherwise handling waste.
The people involved in solid waste management in
developing countries would benefit significantly if a few
modest steps were taken to protect their health, as
outlined in Box 38-5. In addition, every developing
country needs to adopt a plan to upgrade open dumps to
controlled landfills. Emergency measures are necessary
to curtail underground fires by placing soil daily on
waste to help prevent surface collapse and resulting
injuries.
Every city needs to implement record keeping on the
health of its solid waste workers, including the informal
waste pickers and recyclers. Rather than having open
access of waste pickers to solid waste disposal sites, all
solid waste workers should be registered and participate
in a regular vaccination and health examination program. Local medical schools and occupational health
institutes need to be encouraged to study the health of
solid waste workers in comparison with appropriate
baseline control populations, since true epidemiological
data are sorely lacking for this sector.
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