Metals as Environmental Pollutants

Question 1

Lead

Answer 1

Readily absorbed
Binds to sulfahydryl groups on proteins

Interferes with Ca2+ metabolism

Hematologic, skeletal, neurologic, GI, and renal toxicities

House paints & gasoline back in the day
Flaking lead paint

Tx when blood levels > 45ug/dL

Increases chondrogenesis & delays cartilage mineralization

Inhibits Delta-aminolevulinic acid dehydratase & ferrochelatase
-Therefore increase protoporphyrin levels

Microcytic hypochromic anemia

Question 2

Symptoms of Lead poisoning

Answer 2

Brain:
Adult- Headache, memory loss
Child: Encephalopathy, mental deterioration

Gingiva- lead line

Blood:
Anemia, red cell basophilic stripping

Peripheral N.:
Adult- demylination

Kidney:
Chronic tubuolinterstitial disease

GI tract:
-Abdominal pain

Bones:
Child: Radiodense deposits in epiphyses

Blood and bone marrow changes
-Inhibition of ferrochelatase –> ring sideroblasts, red cell precursors with iron-laden mito
Peripheral demyelinating neurophathy

Question 3

Lead Morphology

Answer 3

Blood and bone marrow changes
-Inhibition of ferrochelatase –> ring sideroblasts, red cell precursors with iron-laden mito

Peripheral demyelinating neurophathy

• Extensors of wrist and fingers affected
• Paralysis of peroneal muscles –> foot drop

GI –> poorly localized abdominal pain

Kidneys- Proximal tubular damage, gout

Question 4

Mercury

Answer 4

Binds to sulfahydryl groups in proteins

Damage to CNS & Kidney

Pigment in cave paintings, cosmetic, tx for syphilis, component of diuretics

1) Metallic mercury (elemental mercury)
2) Inorganic mercury (mercuric chloride)
3) Organic mercury (methyl mercury)

In contaminated fish, hazard in dental workers, earth’s crust

Question 5

Symptoms of mercury posioning

Answer 5

Inhalation:

• Tremor
• Gingivitis
• Bizarre behavior “Mad Hatter”

Minamata disease

• Cerebral palsy
• Deafness
• Blindness
• Mental retardation
• CNS defects in children in utero

Question 6

Arsenic

Answer 6

Affects GI tract, NS, skin, and heart

“King of poisons”

Indian and chinese herbal medicine

Arsenic trioxide tx for acute promyelocytic leukemia

Question 7

Symptoms of arsenic poisoning

Answer 7

Acute GI, cardiovascular, and CNS toxicities that are often fatal

Affects ox-phos, since trivalent arsenic replaces phosphates in ATP

Parasthesias, numbness, pain (2-8 wks after exposure)
Chronic exposure –> hyperpigmentation & hyperkeratosis
Increased risk of cancer in lungs, bladder and skin

Induced by light –> tumors in palms and soles

Question 8

Cadmium

Answer 8

Toxic to kidneys

Mining, electroplating, batteries, soil, fertilizers

Uptake into cells via ZIP8 (transporter for zinc)

Question 9

Symptoms of Cadmium

Answer 9

Obstructive lung disease
Necrosis of alveolar epithelial cells

Renal tubular damage –> end stage renal disease

Ca2+ loss
Osteoporosis
Osteomalacia

ROS