Chapter 5 - Metal Contaminants Flashcards
- Varies in toxicity depending upon its chemical
form - A byproduct of refining gold and other metals
- A normal component of the earth’s crust
- Used in pesticides, wood preservatives, and
in manufacturing processes - Exposure can come from ingestion and
inhalation.
aresenic
sources of arsenic
- wood preservative
- manufacture of ammunitions
- pesticides
- fertilizers
- combustion of fossil fuels
- animal feed additive
standard for arsenic
10 micrograms per liter of drinking water
health effects of arsenic exposure
- skin, bladder, kidney, and liver cancer when ingested
- lung cancer when inhaled
- periphreal vascular disease
- cerebrovascular disease
- cardiovascular disease
- biabetes
- pregnancy issues
health effects of arsenic exposure
- GI distress
- decreased blood cell production
- periphery nervous disorders
- fetal malformations
- cancer
- Black-foot disease
disease commonly associated with arsenic exposure
Black-foot disease
- Used widely in industry because of its special
properties (lighter than aluminum and
stronger than steel) - Employees in the metal processing industry
most likely to be exposed - Inhalation is the most common method of
exposure - Class A carcinogen
beryllium
sources of beryllium
- oil
- space and air crafts
- golf clubs
- dental bridges and plates
- relays and switches
- metal alloys
health effects of beryllium exposure
- chronic beryllium disease
- shortness of breath
- persistent cough
- fatigue
- night sweats
- chest and joint pain
- loss of appetite
- Occupational exposure comes
from the production of nickel batteries, zinc smelting, manufacture of paint
pigments, soldering, and from employment in
metal factories. - bioaccumulates in shellfish and is
found in some species of mushrooms
cadmium
sources of cadmium
- automobile and aircraft construction
- burning of municiple waste
- rechargeable batteries
- solar cells
- phosphate fertilizers
- pigments for plastic
- cement
health effects of cadmium exposure
- Osteoporosis in women
- Height loss in men
- Kidney damage
- Elevated blood pressure
- Cardiovascular diseases
- “Itai-Itai” disease (after a Japanese word
meaning “severe pain” in the joints and spine)
health effects of cadmium exposure
- GI distress
- kidney damage/failure
- decreased fetal birth weight
- inhibition of spermatogenesis
- respiratory system damage
- fragile bones
- amenia
disease commonly associated with cadmium exposure
Itai-Itai disease
Naturally occurring element in the earth’s
crust (e.g., in rocks, soils, and materials of
volcanic origin)
chromium
most common forms of chromium
- chromium (0)
- chromium (III)
- chromium (VI)
form of chromium that is an essential nutrient
chromium (III)
form of chromium that is a carcinogen
chromium (VI)
health effects of chromium (VI) exposure
- Digestive problems
- kidney and liver damage
- skin ulcers
- respiratory problems, for example,
nose bleeds, perforation of the nasal septum,
and runny nose.
as pH increases, what happens to the % sorped of chromium?
it decreases
- naturally ocurring metal that is highly toxic
- released as a by-product of industrial processes
- microorganisms can transfer small amounts
mercury
sources of mercury
industrial processes
health effects of mercury exposure
- at low levels, is a hazard because it become deposited in lakes, rivers, and other bodies of water
- can be ingested from exposed fish
- Mad Hatter syndrome - excitability, delirium, hallucinations
- Minamata diseas - trembling, loss of motor control, partial paralysis (methylmercury)
sources of lead
- leaded gasoline
- tap water from soldered pipes
- painted surfaces on older buildings
health effects of lead exposure
- central nervous system (CNS) effects
- lead poisoning
sources of nickel
- constituents of the earth’s crust
- production of appliances and tools
- nickel-cadmium batteries
health effects of nickel exposure
- nickel allergy
- cardiovascular-related and renal diseases
- fibrosis of the lungs
- carcinogenic action
sources of copper
- electrical wiring
- cookware
- metal alloys
- paint
- fungicide
- landfill leachate
health effects of copper exposure
- irritation of nose and throat
- nausea and vomiting
- kidney and liver damage
- growth inhibition
- leaf chlorosis
What soil type has the highest heavy metal binding capacity (HMBC)?
Georgia clay
how does biotransformation occur in plants?
chelation and complexation
what mechanisms allow microorganisms to break down heavy metals?
reduction and oxidation
- cystein-rich proteins
- low molecular weight
metallothioneins
- non-ribosomally synthesized proteins
- consist only of glutamine, cysteine, and glycine
phytochelatins
what do metallothioneins and phytochelatins do for plants and animals?
- transport intert heavy metals to plant vacuoles for storage
- transport heavy metals to the kidneys for excretion
how do crustaceans help reduce toxicity?
store heavy metals in concentrations in the hepatopancreas
what does bacteria and fungi efficiently transform metals in to?
micronutrients
how do bacteria and fungi efficiently transform metals into micronutrients?
ligand exchange and oxidation-reduction
through what mechanism is Mn (II) transformed into Mn (IV)?
oxidation
through what mechanism is Fe (II) transformed into Fe (III)?
oxidation
through what mechanism is Co (III) transformed into Co (II)?
reduction
through what mechanism is AsO2^- transformed into AsO2^4-?
reduction
through what mechanism is Se^0 transformed into SeO3^2?
oxidation
through what mechanism is As (III) transformed into As (V)?
arsentite -> arsenate
oxidation
aresenic oxiding bacteria
all aresenic oxidizers contains the As (III) oxidase gene ____.
aoxB
helps catalyze arsenite oxidation
What metal is required by most organisms in cellular functions but is toxic in high concentrations?
selenium (Se IV)
What can Cromium be reduced to?
it can be reduced from Cr (VI) to Cr (III)
