WORKSHOP
ON MONITORING ENVIRONMENTAL
SOURCES, AND SETTING STANDARDS AND LEGISLATION
Moderator-Dr.
B. Sonawane; Panelists: Mr. D.C. Sharma, Dr. R. Parr, Dr. H. Falk,
Mr. Carter Brandon, Dr. R.K. Chandoke, Dr. D.G. Gajghate, Dr. M. Ahmed,
Dr.
T.K. Bandyopadhya, Dr.Shivalingaiah
The following
are summarized from the general discussions:
- Key sources
of exposure were listed:
Petrol
Lead in batteries
Lead smelting
in jewelry and artisan works
Milk
Infant formulae
Spices
Food stuff
Water
Cosmetics
General dust
Local industry
Cottage industry
Food colors
Pottery
Cooking utensils
Folk medicines
Lead based paints
and pigments
Lead pipes
Printing press
Fly ash
Recycling plastics
- Who is responsible
for what in India?
Foodstuff: The
Director General of Health Services the Prevention of Food Adulteration
Act (PFA) is responsible for the various standards of foodstuff.
Cookware: There
is no standard set and there is no regulatory agency that is monitoring
the standards for cookware. The Bureau of Indian Standards (BIS similar
to ASTM) has a few specifications for products and not for the production
process. But these are not strictly adhered to.
Water: There are
about 30 parameters, which are looked into by the Technical Advisory
Committee. They have to decide whether the wastewater has to go to
the surface or to a river. This can be under the control of the Central
Pollution Control Board (CPCB) or the State Pollution Control Board
(SPCB). Regarding drinking water the local government can be the advisory
committee and set a policy control. The same standards have to be
implemented for both urban and rural areas.
Air: This comes
under the control of Central Pollution Control Board (CPCB)
Soil: This also
can come under the control of Central Pollution Control Board (CPCB).
3. What do
we know about the level of lead in various sources and their contribution
to human exposure?
Information is
available with the industries and also the State Pollution Control
Board (SPCB) but they are not easily accessible. Information regarding
most of the small industries may not be available. Most of the organized
outlets of pollution come under supervision of the Central Pollution
Control Board (CPCB).
The impact of
most pollution sources on human beings and the link between exposure
and toxicity has not yet been clearly ascertained and communicated.
There is some limited data, but some more data needs to be collected.
Very little data is available regarding rural areas.
Data regarding
lead levels in milk is very much limited. Some suggested that studies
should be done on the lead levels in various sources.
Investigating
Environmental Lead Sources and Pathways
Dr.
Babasaheb R. Sonawane
Lead poisoning
is currently thought to be one of the most serious diseases of environmental
and occupational origin because of its high prevalence, environmental
pervasiveness, and persistence of toxicity in sensitive populations
throughout the world. A complete assessment of exposure in sensitive
populations requires knowledge of the multiple sources of exposure.
The conventional approach of identifying lead exposure to a single
source of high concentrations is not enough. A comprehensive review
of all multiple sources, both small and high exposures is needed in
assessing health risk.
It is critical
to understand contribution of natural concentrations of environmental
lead and the chronological record of anthropogenic contamination.
The major current environmental sources and pathways of lead exposure
in sensitive populations include but is not limited to air, dust,
soil and drinking water and food. Some of the current uses and sources
of lead to exposure include glazed pottery and utensils, cosmetics,
folk medicines, plumbing, paint pigments, solders, printing, pesticides,
fertilizers, batteries, plastics, lubricants, ceramics, machine alloys,
leaded gasoline and additives. Much of the lead released into the
environment is emitted into the atmosphere, dominated by emissions
from leaded gasoline. Emissions from other sources such as coal, wood
and oil combustion, mining, manufacturing, incineration, fertilizer
and cement production are also substantial. Lead contamination in
urban areas is often much greater than in rural areas. Environmental
lead contamination from combustion of leaded gasoline has been widely
documented in the United States and elsewhere. Lead enters air from
gasoline and from stationary emissions adding substantially to the
body burden of affected human populations. The removal of lead from
gasoline in the 1990 in the United States is one of the major public
health triumphs having an immediate impact on lead body burden of
general population. The mean blood concentration in children dropped
over from 14 ug/dl to 3 ug/dl between 1976 and 1994.
The magnitude
of lead exposure and the pathways through which it occurs vary from
country to country and are not very well characterized. Leaded gasoline
remains a major source of exposure in India and in many other developing
countries. All countries have many major point sources of lead emissions,
such as smelters, battery plants and scrap metal recovery facilities.
Systematic surveys of sources of lead and population at risk and their
blood lead levels have not been monitored in many developing countries.
It is difficult to identify and rank all sources of lead exposure.
Different sources of lead are often associated with different degrees
of lead poisoning in sensitive population.
The sensitive
populations include children, fetuses (via maternal exposure), and
pregnant women. There is a need for a continuous monitoring of lead
exposure. Biological markers of lead exposure such as blood lead,
urinary lead, and bone lead along with measurements of all sources
and pathways of exposure is essential to collect relevant data. The
current trend to using noninvasive or minimally invasive procedures
for blood, urine or bone with extra attention to contamination control.
Quality assurance and quality control to ensure reliability of data,
including use of scientifically and technically sound practices for
collection, transport, and storage of samples; laboratory analyses;
and the recording, reporting and interpretation of results are cornerstones
of the lead exposure monitoring and measurement of blood lead. Most
clinical and epidemiological research laboratories now involved in
measuring lead in environmental and biological materials use only
a few well studied analytical methods routinely and standardization
of analytical instruments and techniques are lacking. As the focus
of public health officials has turned to lower exposures, the errors
in detection has become more severe and the need for more careful
measurements has increased.
Sources
of Lead Poisoning Noted around the World
Dr.
Joel Schwartz
Dr. Schwartz began
his presentation with a question as to why we need to know the sources
and pathways of lead. The goal he said was primary prevention by reducing
exposure, which is possible only if the source of lead is known. He
then went on to give examples of studies pointing to evidence of presence
of lead in the environment. In connection with this, he referred to
Clane Patterson who in his work demonstrated that dust in most places
on earth had elemental abundance similar to the earth's crust as a
whole, with one exception - there was 1000 times more lead in the
dust.
He also referred
to studies conducted by Russ Flagel who looked at lead levels of mummified
bones of North American Indians and compared with age matched bones
of modern Americans who were never occupationally exposed and with
no history of lead poisoning, and concluded that the current levels
are 500-1000 times the pre-industrial concentrations.
Regarding the
sources of contamination, Dr. Schwartz referred to the following studies.
- Lead concentration
profile in snow strata of Northern Greenland: The data showed doubling
of lead levels in the snow every hundred years. There was a dramatic
change in the rate of increase in lead concentration around 1930,
which was attributed to introduction of tetra ethyl lead in gasoline.
- The Chicago
data showed a positive correlation between gasoline lead (billions
of grams per calendar quartile) and blood lead levels in microgram/dL.
In addition data from NHANES showed gasoline lead accounted for
more than half the lead in Americans in the 1970's.
- Children in
Mexico: Gasoline lead is a major problem in the developing world
as well. For example, Dr.Romieu looked at children in Mexico. She
found that blood lead levels increased15% per microgram per m3
of air lead, 33% for residence in high traffic areas, and 5% per
microgram of hand lead (much of it due to gasoline).
- Another Mexican
study showed that children’s blood lead levels varies with traffic
in neighborhoods. He explained that lead from the vehicular exhaust
has a bimodal distribution. One half of it is larger particles that
settle down at the ground level, the other half is of smaller particle
size (less than half micron) and remains air borne for days to weeks
depending on the weather conditions. The latter he said was a major
source from where lead is spread to the neighboring areas.
Apart from gasoline
the other sources of lead are:
· Industrial
Exposure
· Ceramics
· Folk Medicines/Eye
make-up
· Paint
· Others
Referring to ceramics
he said that a one-log increase in lead in glazed pottery was associated
with a 33% increase in children's blood lead level in Mexico. He also
pointed to another interesting study where lead content of yellow
pencils in Germany and Mexico were compared, the findings of which
were as follows:
|
Yellow
pencils in Germany
|
Yellow
pencils in Mexico
|
|
4.22 ppm
inside
|
63693 ppm
inside
|
|
1.55 ppm-in
outside paint
|
68114 ppm
in outside paint
|
Regarding folk
medicines being a source of lead, Dr. Schwartz indicated works of
Sarayan and co-workers-case reports in lead poisoning in US and Canada
in Indian migrants. The source in these migrants was traced to folk
medicines such as Maha Yogran Guggulu, Kandu and Ghusard.
Muffler life expectancy,
spark plug life expectancy and oil change intervals have more than
doubled in the case of unleaded fleets compared to leaded fleets.
The savings from these exceeded the cost of making gasoline without
lead. Hence, countries cannot afford to use leaded gasoline. To conclude,
Dr. Schwartz said that gasoline continues to be the common source
of lead and should be eliminated everywhere. In addition, each country
needs to investigate its local sources.
Roles
of National/State Governments
Dr.
R.K. Chandoke
The government
has the responsibility for organizing the institutional set-up for
the following:
- . Establishing
model agencies for lead pollution control
- Monitoring
of air, food, soil and water
- Need for Lead
Registries
- A comprehensive
manual on low cost lead screening program
- Establishment
of medical surveillance programs
- Seminars and
health and safety training classes in local languages for employees
and public
- workers
- Continuing
medical education (CME) sponsored by medical groups.
- Developing
and marketing resources to facilitate employers to have their own
lead poisoning prevention activities
- Environmental
medicine curriculum in universities
- Pre-market
testing of new chemicals and processes - a very good source of containment.
Lead should be
included as health hazard covered by insurance. Employees’ State Insurance
Corporation of India is the largest multidimensional social security
scheme in South East Asia. The scheme deals with an exclusive segment
of the population’s workers in the organized Sector Factories/ Establishment
employing minimum of 10 persons. E.S.I. Corporation deploys a larger
manpower of doctors (about 12,000), paramedical personnel over of
70,000 for the care of 330 lakhs people. Under the ESI Act, occupational
diseases are treated as employment injuries and insured persons suffering
from them are entitled to temporary and permanent disablement benefits.
It is important that the risks on their health from lead poisoning
are timely detected and remedial measures taken to protect their health.
Setting
of Standards and Priorities
Dr.
D.G.Gajghate
The sources of
lead exposure vary, depending on both current and previous patterns
of lead use in the country. The following analysis reveals some key
patterns in lead exposure:
Auto-exhaust:
Lead from petrol combustion is largely emitted from auto exhaust.
About 80 to 90 percent of lead in ambient air originated from combustion
of leaded gasoline. This is very important from health point of view
as fine particulate are responsible for quick absorption of lead in
the blood. In the last three years, the growth rate of gasoline consumption
has increased from 8 to 9 percent. This is due to very high production
of two-wheeler scooters, motor cycles and mopeds as well as cars.
With the implementation of 1991 emission norms and low leaded petrol
from 1994 and unleaded petrol from 1995 in four metro-cities, the
ambient lead levels has been reduced to some extent in the years 1995-97
as compared to the years 1991-94.
The average particulate
lead at Delhi, Mumbai, Calcutta and Chennai has been reduced by 12
- 20 %, according to some studies, after abatement policies. However,
other cities like, Ahmedabad, Hyderabad, Jaipur, Kanpur, Cochin and
Nagpur have reduced ambient lead levels only marginally after introduction
of low lead fuel in 1997.
With a view to
improving the lead air quality of cities a major program for improvement
of automotive fuels such as motor gasoline has been introduced in
the country in a phased manner. This includes the introduction of
unleaded petrol to meet the requirement of new, cleaner and low emission
vehicles fitted with the catalytic converter.
Industries:
Other sources of lead include the smelting and refining of non-ferrous
metal ores, refuse incineration and production of lead batteries and
cables which contribute 10 to 20 % lead in ambient air. For occupational
exposure to workers, lead smelters, small metal cottage industries,
and mining contribute as major sources of lead. Lead emission from
stationary sources such as non-ferrous smelters and battery plants
have to be reduced by stock control as particulate emission operation.
Indeed, such controls may be as important a strategy as vehicle emission
abatement. Severe lead pollution problems have occurred where emission
from single point sources in cities have caused excessive exposure
to large numbers of people living close to the facility.
General Sources:
Certain traditional practices using lead containing cosmetic and folk
medicines also expose significant populations to high levels of blood
lead. Pb content in blood and their exposure to Pb through air, food,
water, and dust should be assessed in each location of city. Some
Ayurvedic medicines and local cosmetics (Sindhoor and Kajal) are found
to be the cause of Pb poisoning to the users. Creating public awareness
and regulatory control may be the right steps to follow.
Prevention:
Lead pollution
is totally avoidable and a national program similar to malaria/small
pox eradication should be undertaken. Standard protocols should be
followed for collecting blood and source samples and for Pb analysis.
A major public awareness program should be launched through the print
media or through television by telecasting short films on various
aspects of vehicular pollution such as status, causes, effects and
measures for their prevention and control.
Summary
of Lead Poisoning Prevention in the United States
Dr.
Henry Falk
This presentation
focuses on the public health issues related to childhood lead poisoning
primarily in the United States, and also from an international perspective.
In 1991, the U.S. Department of Health and Human services (DHHS) issued
a strategic plan for the elimination of childhood lead poisoning to
be accomplished over a 20-year period. Implementation of this plan
required broad collaboration among key Federal agencies; the most
critical partnerships include HHS, the Environmental Protection Agency
(EPA), and Housing and Urban Development (HUD). Within HHS, the National
Institutes of Health (NIH) is the leading agency for health research,
while the Centers for Disease Control and Prevention (CDC) provides
guidance and funding for lead poisoning prevention activities at the
state and local levels.
Childhood exposure
to lead causes a graded series of health effects, from encephalopathy
and death in its most severe form to subclinical neurobehavioural
effects (most objectively measured by IQ testing) in its mildest form.
A coordinated series of cohort studies in young children, recently
evaluated by several metaanalyses, have quantified the low-level effects.
10 m g/dl of blood lead is now considered the level of concern
by all agencies working on this problem, although individual medical
evaluation and household environmental interventions begin at higher
levels.
The prevention
program started with the blood lead screening in Chicago between 1967-68,
where 9 urban areas, spanning over a population of 1,470,900 children
under 5 years of age were screened. Alarmingly high levels were found;
8.5% of the screened 28,000 children had blood lead levels above 50
ug/dl in 1967. Many subsequent national investigations in the US identified
sources as leaded vehicular exhaust from gasoline, food from soldered
cans, water from lead pipes, and household exposure via peeled and
deteriorating paints. The strategies for prevention included reduction
of lead hazards in homes, controlling the sources and pathways of
lead exposure and performing frequent screening funded by CDC, surveillance
of lead levels, and grants to state and local health departments.
Blood lead programs conducted by CDC and Public Health Service revealed
high raised lead levels in the 70’s and its steep drop in the subsequent
years.
With the removal
of lead from gasoline and from food cans, deteriorating lead paint
in housing remains the single most extensive and intractable source
in the U.S. High exposures now occur primarily among poor, minority
groups in older, inner cities. Since the remaining critical source
of lead is the home environment (paint, dust and surrounding soil),
regulatory approaches are less achievable than with gasoline or food
distribution, and a variety of new approaches are being used to maintain
pressure on the lowering of lead sources. Surveillance systems have
been developed at both the national and state levels to monitor trends
in blood levels and assess progress in the elimination of lead poisoning.
Data from the National Health and Nutrition Examination Surveys (II
and III) in the late 1970s and early 1990’s have documented an approximately
80% drop in childhood blood lead levels.
Treatment of individual
patients requires close coordination between the pediatrician/health
care provider and public health agencies that provide or assure the
housing, environmental and social services.
Screening guidelines
have evolved rapidly with the changing prevalence of childhood lead
poisoning. Current guidelines recommend a mix of universal and targeted
screening strategies, varying by geographic area and depending on
the level of exposure (as determined by percentage of old housing)
and prevalence of elevated blood levels (when such data are available).
Geographic information systems (GIS), utilizing census, housing, and
environmental data in the form of maps, are being developed for distribution
over the internet to provide state and local communities with sufficient
information (down to the zip code or census tract level) to assist
in local development of screening recommendations. Prevention effectiveness
research, including the screening techniques, educational and nutritional
guidelines, cost benefit analysis and primary prevention efforts,
were made by the CDC. As to prevention at home, the preventive measures
would be replacement of window sills, abatement and stabilization
of old paints and replacement with unleaded paint. Finally, the lead
exposure is being monitored by states at the local level in addition
to the national blood lead surveillance database.
New approaches
to diagnosis and treatment include the recent introduction of a portable,
hand-held instrument for rapid determination of blood lead levels
(particularly useful for field examinations or surveys), and the use
of the oral-chelating agent, succimer.
The CDC has recently
collaborated in international lead investigations in Russia, China,
Egypt/Middle East, Mexico/Latin America, India and elsewhere. Lead
exposures differ by country, depending on gasoline use, local industry,
consumer products, methods of food preparation, and a variety of other
factors. The potential for significant population exposures to children
in rapidly industrializing countries remains very high.
Dr Falk explained
the need for a National plan. He gave three main reasons for it:
1.The problem
is of national scope, particularly in children, and there is widespread
occurrence of low level lead exposure.
2. The solution
is national. National plans have been executed in the US where levels
of lead in petrol and paint have been regulated. Attention is drawn
to the fact that the sources of lead in developing countries are widespread
-in gasoline, paint, and food cans etc, -- as shown by national surveys.
3. Because it
requires tremendous coordinated effort to reduce elements which foster
the use of lead.
Dr. Falk explained
the strategies used in the US to tackle this problem. He said that
environmental programs were adopted as this would help solve the problem.
This job was taken up by the Environmental Protection Agency (EPA),
resulting in gradual phasing out of lead in gasoline, decreased lead
levels in the air coming from smelting and other industries, and decreased
lead levels in the soil and water. All these needed monitoring enforcement,
regulation and cost analysis. The food industry was involved and they
were advised to reduce the use of lead in food cans, ceramics, china
dish, etc. All these were done at the Federal level. State Governments,
Housing Departments, Health Communities, and NGOs all need to be involved
to educate the public. Family physicians and social and occupational
agencies also play an important role.
Dr. Falk mentioned
that in the 70’s it was difficult to educate and convince people of
the lead problem. But now the need is to identify the extent of the
problem, health research, the type of studies to be done, the equipment
to be used, the need to tackle nutritional inadequacies and enforcement
of regulations are the areas that are given more importance.
He also presented
a few slides indicating the decreasing level of blood lead in the
children of the United States, and hoped that by the year 2002, lead
levels would be minimal and by 2011 lead would be more or less fully
eliminated.
Conclusions
and Recommendations
The following
recommendations were made by the workshop participants:
For many populations
in developing countries human exposure to lead is excessive, produces
diseases that are preventable, and it must be reduced. Currently available
information suggests that lead levels pose significant hazards to
the health of infants and children. Leaded gasoline remains a major
source of exposure. Hence, prevention of lead exposure should be the
priority of the government at the national, state and local levels.
The strategy to prevent lead exposure will require both political
and economic measures involving public health professionals, workers,
industries, political leaders and other stakeholders. The initial
cost of reducing lead exposure is generally short-term, but the cost
of not reducing lead exposure is enormous. The importance of information
sharing within the country and with other countries needs very little
mention. Some of the critical steps outlined below to develop and
implement the national action plan will require real commitment of
resources.
The vast amount
of information available on lead's persistence and adverse health
effects at low exposure levels provide a compelling basis for an aggressive
national program of lead removal from the environment. As a practical
matter, no society should risk health of their infants and children.
As a result, priorities must be set. They may include (1) identification
of sources of the highest lead exposure and susceptible population
at risk (2) establishment of cost-effective methods of minimizing
those exposures, (3) use of administrative actions and financial incentives/tax
breaks to ensure the success of national policy goals.
The following
key recommendations were put forward by the panel:
- Need to identify
some additional data especially regarding lead levels in milk, tap
water, etc.
- Need for epidemiological
studies to identify important sources.
- Need for coordination
of data
- Need for regulatory
agencies with respect to cookware, pottery etc.
- Need for establishing
a national task force involving the following: government,
industry, NGO's, Citizens’ groups.
- Need for a
National/State Web site providing information regarding lead levels
and toxicity. The established national task force should monitor
it.
- Need to phase-out
lead in gasoline and the elimination of lead in ceramic
glazes, paints, occupational settings, consumer products, plumbing,
and solder on food cans.
- Need for regulatory
enforcement for limiting workplace exposure to lead.
- Need for implementation
of appropriate public health initiatives such as surveillance of
high-risk populations, environmental monitoring and education of
the public and training of health care professionals.
- Need for research
on control technologies targeted towards prevention of lead exposure.
- Need for development
and support of infrastructure to train medical professionals to
intervene in cases of lead poisoning/toxicity.
- Need for mass
educational campaign targeting parents on the dangers of lead exposure.
