exposure assessment to heavy metals in the environment measures to eliminate or reduce the exposure...

Exposure Assessment to Heavy Metals in the Environment

Measures to Eliminate or Reduce the Exposure to Critical Receptors.

Maria de Lurdes Dinis

CIGAR, Geo-Environment and Resources Research Center

FEUP, Engineering Faculty, Porto University

Presentation overview• Introduction (heavy metals; sources; exposure);

• Natural and anthropogenic heavy metals sources;

• Possible ways of exposure to Cd, Hg, Pb;

• Generic health effects;

• European trend on heavy metals emissions;

• European heavy metals inventory;

– European countries emissions and the case of Portugal;

– Exposure assessment;

– Critical receptors.

• Measures to reduce or to eliminate the exposure;

• Closing remarks.

Introduction: heavy-metals

– Density > 5 g/cm3;

– Poisoning at low concentrations;

– Accumulate higher up the food chain;

– Hg, As, Cd, Pb, Cr, etc…..

– Naturally on earth’s crust;

– Many different applications (pipes, building materials, batteries, etc.);

– Past applications (no longer used): lead in gasoline, paints, and ceramic products, pipe solder, etc.;

Introduction - sources

– Mining;– Industrial production (foundries, smelters,

oil refineries, petrochemical plants, pesticide production chemical industry);

– Untreated sewage sludge;– Metal piping;– Traffic and combustion by-production coal

burning power plants.

• Pb, Hg, Cd a focus of International and EU action;– Persistent in the environment;– Long-residence time in atmosphere;– Subject to long-range transport processes.

Introduction

Natural sources - Cd, Hg, Pb

• Natural sources:– Earth crust (Cd, Hg, Pb);– Volcano activities (Cd, Hg);– Forest fires (Cd);– Degassing of the earth crust (Hg metallic);– Evaporation from natural water bodies (Hg).

Anthropogenic sources – Cd, Hg, Pb

• Anthropogenic sources:

– Energy sector: mineral oil and gas refineries, thermal power stations, other combustions installations;

– Production and processing of metals;

– Mineral industry: glass fibre, ceramic products, cement clinker in furnaces;

– Mining and related operations (Hg);

– Chemical industry; pharmaceutical Industry (Hg);

– Production explosives and pyrotechnics products (Pb);

– Waste and waste water treatment (disposal or recovery of hazardous waste, incineration of non-hazardous waste);

– Paper and wood production processing;

Exposure to Cd

• Cigarette smoking (not second-hand smokers);

• Releases into air and soils: smelting operations and incineration of municipal waste;

• Ingestion of Ni-Cd batteries (children);

• Ingestion of foods grown on soils contaminated: leafy vegetables are especially noted for Cd bio-concentration;

Exposure to Hg

• Metallic mercury: – Thermometers, barometers and instruments for measuring blood

pressure;– Electrochemical processes (electrode of mercury);– Dental amalgam (possibility of mercury vapor is released from

amalgam fillings, increase by chewing).

• Organic mercury (ex. Metylmercury):– Via food ingestion, fish and shellfish.

Exposure to Hg (cont.)Inorganic mercury:• Acute exposure inhalation - lung damage; • Chronic exposure - poisoning: neurological and psychological

symptoms;• Allergen, eczema.

Organic mercury:• Main symptoms relate to nervous system damage; • High doses lead to death, usually 2-4 weeks after onset of symptoms;• General population no significant health risks from methyl mercury

exposure, exception of certain groups with high fish consumption.

Exposure to Pb

• Leaded paints, plumbing fixtures, leaded gasoline, deterioration of leaded paint used in the past;

• Consumption of lead chips or paint dust (which tastes sweet) by children;

• Soldering, as an occupational or hobby exposure;• Vehicle exhaust, in soil and house dust;• Ingesting leafy vegetables grown in lead contaminated soil;• Releases into the air and onto soils by smelting operations.

Exposure to PbLow levels of lead in blood have been associated with:• Increased blood pressure;• Subtle decrements in cognitive performance;• Iron deficiency anemia.

Symptoms, Children:• Mental retardation; language; cognitive function; balance; behavior;

school behavior.

Exposure to high levels (adults or children):• Brain and kidney damage and ultimately cause death.

Pb health effectsLead may accumulate in bone and lie dormant for years, and then pose a

threat later in life during events such as pregnancy, lactation, osteoporosis, and hyperthyroidism and, which mobilizes stores of lead in bones.

• Inhalation: up to 50% of inhaled inorganic lead absorbed in the lungs.• Ingestion: adults take up 10–15% of lead in food, whereas children

may absorb up to 50% via the gastrointestinal tract.• Accumulated in the skeleton;• Half-life of lead in blood is about 1 month and in the skeleton 20–30

years. • Inorganic lead - probable human carcinogens (U.S. EPA);• Organic lead - not sufficient information (U.S. EPA);

Cd health effectsVery long half-life in the body (10 to 30 years) and can build

up over a long time

Adults• Cd and Cd compounds are known human carcinogen (EPA);• Inhalation – lungs (carcinogen risk);• Ingestion food, water contaminated (toxicity risk):

– Long-term low levels exposure: kidneys disease, lung damage and fragile bones.

Children• Similar to adults: kidney, lung and bone damage;• Based animal studies:

– > Cd absorption; more susceptive to a loss of bone and decreases bone strength;– Exposure during pregnancy: affects behaviour and learning ability, reduce body

weight and affect skeleton.

Hg health effects• Nervous system;

• Metylmercury and metallic vapors (more concern);

• Exposure to high levels of metallic, inorganic or organic mercury – permanently damage brain, kidneys, developing fetus;

CHILDREN

• It passes to from mother to fetus and through breast milk;

• Brain damaged, mental retardation, coordination problems, blindness and inability to speak;

• Problems nervous and digestive system and kidney damage.

EU countries Trend

– Progress reducing point source emissions (Cd, Pb):• Technologies improvements (incinerators, metal refining,

smelting industries);• Closing older facilities.

– Progress reducing point source emissions (Hg):• Improved controls on mercury cells used in industrial processes;• Replacement old mercury cells by diaphragm or membrane

cells;• Decline of coal use across Europe as a result of fuel switching.

EU Countries trend on emissionsSince 1990: – With fiscal and regulatory measures EU Member

States have completely phased out the use of leaded petrol;

– Emissions from the transport sector decreased about 95%.

Between 1990/2007: – Decrease : 56% Cd; 57% Hg; 88% Pb;– Sources (2007): energy related sources:

fuel combustion from public power and heat generating industrial facilities);– Still - Road transport contribute up to 25% Pb emissions.

European database: E-PRTR

• EPRT-European Pollutant Release and Transfer Registry: register provides easily accessible key environmental data from industrial facilities;

• It contains data on main pollutant releases to air, water and land industrial facilities across the E.U. countries;

• First report in 2009 corresponds to emission data 2007;

• Next report in 2010 will cover 2008 data; data will continue to be updated on an annual basis; report covering emission from 2 years previous;

– Total annual emission releases normal operations and accidents;

– Releases and transfers must be reported ONLY if the emissions of a facility are above the activity and pollutant thresholds set out in the European Directives 91/689/EEC and 96/61/EC.

http://prtr.ec.europa.eu/Home.aspx

Heavy-metals European emissions

• Data 2007 for 27 countries extracted:– Austria, Belgium, Bulgaria, Cyprus,

Czech Republic, Germany, Denmark, Estonia, Greece, Spain, Finland, France, Spain, France, Hungary, Ireland, Italy, Latvia, Luxembourg, Netherlands, Poland, Portugal, Romania, Sweden, Slovenia, Slovakia, United Kingdom.

– Portugal emissions to air, water, soil: Cd, Hg, Pb.

Industrial Activity EU 27 Countries(Cd emissions and compounds)

Facilities Air Cd

WaterCd

SoilCd

Energy Sector 142 5,72 t 986 kg -

Mineral oil and gas refineries 24 992 kg - -

Thermal power stations and other combustion facilities

117 3,72 t - -

Production And Processing Metals 128 9,5 t 2,10 kg 209 kg

Mineral Industry 97 1,79 ton 892 kg -

Chemical Industry 34 653 kg 964 kg 30,2 kg

Waste And Waste Water Treatment 160 218 kg 10,9 t 1,20 t

Paper And Wood Production Processing 61 509 kg 1,03 ton 102 kg

Animal And Vegetable Products From The Food And Beverage Sector

9 47,8 kg 85 kg 128 kg

Other Activities 6 26,3 kg 53,4 kg -

TOTAL 637 18,3 t 17 t 1,67 t

Industrial Activity EU 27 Countries(Hg emissions and compounds)

Facilities Air Hg

Water Hg

Soil Hg

Energy Sector 249 19,8 ton 4,65 ton 2,7 kg

Mineral oil and gas refineries 28 940 kg 125 kg -


216 18,5 t 4,25 kg 2,70 kg

Production And Processing Metals 87 4,63 t 456 kg 9,49 kg

Mineral Industry 113 3,99 t 113 kg -

Chemical Industry 76 614 t 1,82 t -

Waste And Waste Water Treatment 282 1,19 t 3,31 t 232 kg

Paper And Wood Production Processing 41 199 kg 100 kg 27,3 kg


4 - 3,58 kg 23,3 kg

Other Activities 4 26,3 t 4,35 kg -

TOTAL 856 36 t 10,5 t 295 kg

Industrial Activity EU 27 Countries(Pb emissions and compounds)

Facilities Air Pb

WaterPb

SoilPb

Energy Sector 84 80,7 t 21,6 t -

Mineral oil and gas refineries 14 2,14 t 3,57 t


68 61,1 t 18,0 t -

Production And Processing Metals 185 398,3 t 22,1 t 18,8 t

Mineral Industry 86 60,9 t 33,0 t -

Chemical Industry 51 2,34 t 8,54 ton 749 kg

Waste And Waste Water Treatment 364 5,41 t 124 t 44,7 t

Paper And Wood Production Processing 59 3,17 t 3,20 t 1,98 t


10 - 190 kg 1,93 t

Other Activities 6 421 kg -

TOTAL 845 551,74 t 213 t 68,2 t

Air Water Soil

Cd Cd Cd

France = 2,96 ton Spain = 3,98 ton U. K.= 1,16 ton

Finland = 2,94 ton Poland = 3,26 ton France = 261 kg

Spain = 2,94 ton Italy = Romania = 1,23 ton Germany = 214 kg

Air Water Soil

Hg Hg Hg

Germany = 7,64 ton Italy = 4,20 ton U.K. = 158 kg

Spain = 4,25 ton Poland = 2,47 ton Hungary = 105 kg

Poland = 3,84 ton Spain = 1,01 ton Germany = 32,9 kg

Air Water Soil

Pb Pb Pb

Germany = 68,2 ton Poland = 99,2 ton France = 10,3 ton

France = 60,6 ton Finland = 16,9 ton Germany = 8,46 ton

Belgium = 55,7 ton Italy = 9,8 ton n.a.

Cd, Hg, Pb emissions per EU State Member, 2007

European Emissions• Sources Hg:

– 50% Coal Combustions Thermal Power Plants;– 17% Chemical industry - industrial scale production of organic and

inorganic chemicals;

< 4 % each

European Emissions• Sources Cd:

– 51% Production and processing of metals;– 20% Thermal power stations and other combustion installations;– 10% Mineral industry.

< 7 % each

European Emissions• Sources Pb:

– 72% Production and processing of metals;– 11% thermal power stations and other combustion installations;– 11% mineral industry.

< 6 % each

Portugal heavy metal emissions to the

environment

Industrial Activity - Portugal(Cd emissions and compounds)

Facilities Air Water Soil

Energy Sector 6 325 kg - -



4 80 kg - -

Production And Processing Metals 3 280 kg 15,6 kg -

Mineral Industry 3 78 kg - -

Chemical Industry 1 0 94,3 kg -

Waste And Waste Water Treatment 3 11 kg 536 kg -

Paper And Wood Production Processing 7 364 kg 6,4 0 kg -


3 27 kg 62,7 kg 31,5 kg

Other Activities 2 13 kg 15,3 kg

TOTAL 29 1,10 ton 730 kg 31,5 kg

Industrial Activity - Portugal(Hg emissions and compounds)


ENERGY SECTOR 4 432 kg - -



3 294 kg - -

PRODUCTION AND PROCESSING METALS

1 87 kg - -

MINERAL INDUSTRY 2 39 kg - -

CHEMICAL INDUSTRY 1 - 1,8 kg -

WASTE AND WASTE WATER TREATMENT

3 - 111 kg -

PAPER AND WOOD PRODUCTION PROCESSING

4 73 kg - -

OTHER ACTIVITIES 1 13 kg 15,3 kg -

TOTAL 16 644 kg 113 kg -

Industrial Activity - Portugal(Pb emissions and compounds)


ENERGY SECTOR 2 1,27 ton - -



1 774 kg - -

PRODUCTION AND PROCESSING METALS

4 5 ton 288 kg -

MINERAL INDUSTRY 3 1,06 ton 29,1 kg -

WASTE AND WASTE WATER TREATMENT

3 - 1,61 ton -

PAPER AND WOOD PRODUCTION PROCESSING

3 250 kg 62,6 kg -

ANIMAL AND VEGETABLE PRODUCTS FROM THE FOOD AND BEVERAGE SECTOR

1 - 80,4 kg -

TOTAL 16 7,59 ton 2,07 ton -

Exposure assessment

• Many different sources, multipathways and multiple chemicals exposure at same time;

• Assessment protocols are based on the assumption that exposure to chemicals occurs, as well as their effects, in isolation from each other:

– Usually the normal procedure is to perform an exposure assessment by

calculating the dose resulting for each one of the present chemicals.

– We study mercury in isolation; we study cadmium in isolation …..

Exposure assessment

• Chemical speciation of metals determines their uptake, absorption and subsequent metabolism – important influence in their toxicity;

– Substantial differences in the toxic potential of metal compounds due to oxidation state of the metal and the solubility of the compound;

– Little information about the chemical speciation of metals to which humans are exposed in ambient air, drinking water or in the diet;

Exposure assessment

• Some health effects are linked with a specific route of exposure (lung cancer – inhalation);

– However, most health effects associated with metals exposure are systemic (response that affects the whole body), and not linked to a specific route of exposure, although it may influence systemic dose.

• Also, absorption of different metals dependent both on the form in which metal is present in the exposure medium and also the route of exposure;

• Very little investigation of combined metals exposure; it appears no practical alternative to treating the health impacts of different metals as being additive.

Example• Data for environmental emissions from 17 Portuguese facilities (thermal

power plants and combustion facilities) were extracted from the European inventory database.

Pollutant/Chemical Releases AirCO2 17 293 000

tN2O 251 tAs and compounds 346 kgCd and compounds 80 kgCr and Compounds 418 kgCu and compounds 148 kgHg and compounds 294 kgNi and compounds 4,57 tPb and compounds 774 kgZn and compounds 341 kgPM10 1 384 tHCl and inorganic compounds 163 tCO 800 tHF and inorganic compounds 127 tNon-methane volatile compounds

458 t

NOx/NO2 52 935 tSOx/SO2 83 195 tBenzene 1,79 t

Exposure Assessment

Who is or will be, exposed to what, when, where and for how long? (intensity, frequency, exposure period, and pathway of

contaminants: soil, water, air);

• Site characterization (source: release rate, release time, …);

• Identification of exposed populations - critical receptors;

• Identification of exposure pathways;

• Heavy metals concentrations and releases, transport and fate;

• Estimation of exposure concentrations for each pathway;

• Estimation of contaminants intake each pathway;

• Dose estimative and risk characterization.

Exposure pathways from airborne routine discharges of a coal-fired power plant

Resuspension

Exposure scenario: Subsistence farmers, adults and children.

Exposure pathway:Soil and dust inhalation;Meat and milk ingestion;Leafy vegetables ingestion.

Cd and children as critical receptors

• Expected to be similar to the effects seen in adults (kidney, lung, and bone damage depending on the route of exposure).

BASED ON ANIMAL STUDIES:

– Younger animals absorb more cadmium than adults;

– Younger animals are more predisposed than adults to a loss of bone and decreased bone strength from exposure to cadmium;

– Babies of animals exposed to high levels of cadmium during pregnancy had changes in behavior and learning ability;

– High enough exposures to cadmium before birth can reduce body weight and affect the skeleton.

Hg and children as critical receptors

• Of greatest concern global scale is the sensitivity of fetal and infant nervous system to low-level mercury toxicity.

• Infants and children especially vulnerable to the acute, sub-acute and chronic effects of ingestion of chemical hazards (higher doses): children consume more food per kilogram of body weight than adults;

• Children’s developing organs and tissues are more vulnerable to the toxic effects of certain chemicals;

• With greater exposure and more severe health effects, chemicals in food are more harmful to children than adults.

Pb and children as critical receptors

• A number of issues still remain “unresolved” Pb toxicity in children:

– The risk posed to the fetus caused by mobilization of long-lived skeletal stores of Pb in pregnant women;

– Recent research has clearly demonstrated that maternal bone lead stores are mobilized at an accelerated rate during pregnancy and lactation: associated with lower birth weight, growth rate, and mental development;

– And since Pb stored in bones persist for decades it is possible that it can remain a threat to fetal health many years after environmental exposure had actually been reduced or stopped.

Measures: eliminate or reduce exposure

Main goals at individual level:

– Limit exposure;

– Decrease absorption with dietary suggestions may help inhibit intake and uptake of cadmium, mercury and lead:

• ex. Fe reduces uptake of Cd and Pb; • Ca reduces the uptake of Cd; • high sulfur foods such onions and garlic probably help the body blocking

uptake and decreasing retention of many toxic metals.

– Decrease release of stored metals;

– Protect vulnerable tissues;

How to achieve main goalsIndustrial level – several measures were suggested to reduce metals

emissions to the air [ESPREME, report project FP6]:

Primary Measures: for processes of fuel combustion for energy production purposes: fuel supply measures and combustion modifications:

1. Technical measures: heavy metals minimization content in fuels and raw materials; technology and fuel switching towards methods generating lower or zero HM emissions; installations modifications.

2. Non-technical measures: higher surveillance procedures, reducing

consumption of heavy metals contain/releasing products and good housekeeping of environment of heavy metals releasing processes.

How to achieve main goalsIndustrial level – several measures were suggested to reduce metals

emissions to the air:

Secondary Measures:

1. Particulate control techniques: electrostatic precipitators, fabric filters,

ceramic filters, cyclones and multi-cyclones, wet scrubbers;

2. Absorption techniques to heavy metals emissions reduction;

3. Nitrogen oxide reduction methods (Hg reduction);

4. Adsorption methods (activated carbon, aluminosilicate based sorbents,

impregnated sorbents,…) and,

5. ….

– Further progress have been made in assessing sources and emissions to environment, country and regional (European) level;

– The reason of continuous reduction of heavy metals emissions during the last four decades: better knowledge of HM sources, emissions, pathways, and fate in the environment;

– Developing efficient control emission equipment has resulted in more efficient regulatory efforts to reduce HM emissions from anthropogenic sources;

Closing remarks

– Coal combustion is still the major source for the HM (except Pb);

– Largest power plants are becoming more and more efficiently controlled: tighter efforts to reduce emissions by mainly changing and improving their technology;

– However, emissions from residential units are still being largely uncontrolled: emissions reduction can be achieved by replacing these units by central heating plants burning natural and biogas instead of coal;

– Alternative renewable energy sources in Europe will surely contribute to continuous reduce emissions from combustion of coal;

– European directives also has an important role in pressure industry in order to reduce emissions.

Closing remarks

Thank you

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