Environmental Toxicology

Question 1

what are the 3 forms of mercury

Answer 1

elemental Hg0, inorganic Hg+ ad Hg2+ and organic eg methyl mercury

Question 2

which forms of mercury are neurotoxic

Answer 2

elemental and organic

Question 3

whichform of mecury is toxic to the kidneys

Answer 3

inorganic

Question 4

which form is used in gold mining

Answer 4

elemental

Question 5

in which phase is elemental mercury very lipid soluble

Answer 5

vapour

Question 6

what allows elemental to accumulate in the CNS

Answer 6

its ability to penetrate the blood brain barrier

Question 7

what causes elemental to get trapped in cells due to poor lipid solubility

Answer 7

it is oxidised to Hg2+

Question 8

what is the symptomatic results of elemental mecury poisoning

Answer 8

tremour, change in personality, hallucinations

Question 9

which form is used as fungicides, in fur felting and electrochemical equipment

Answer 9

inorganic

Question 10

is inorganic very bioavailable from the gut

Answer 10

no- only 7% absorbed

Question 11

which organ is inorganic toxic to

Answer 11

GI tract

Question 12

what is the target organ of inorganic mercury

Answer 12

kidney

Question 13

what is inorganic mercurys effect on the kidney

Answer 13

it damages epithelial cells of the proximal convoluted tubules

Question 14

how can poisoning with organic mercury be treated

Answer 14

cysteine rich metallothionines which act as a buffer against toxicity

Question 15

what is organic mercury used as

Answer 15

fungisides and seed dressings

Question 16

which forms of organic mercury are lipophilic and very toxic

Answer 16

alkyl forms

Question 17

what does organic mercury poisoning cause

Answer 17

neurological damage

Question 18

how does organic mercury cross the blood brain barrier

Answer 18

L-type large amino acid transporter

Question 19

aside from elemental mercury, which other form is also convered to Hg2+ in cells in order to accumulate in the CNS

Answer 19

organic

Question 20

which form of mercury was minimata bay associated to

Answer 20

organic

Question 21

how many people were effected by minimata bay

Answer 21

12000

Question 22

how many people died as a result of the minimata bay disaster

Answer 22

1500

Question 23

what was minimata bay caused by

Answer 23

the discharge of 27 tonnes of effluent into the bay

Question 24

what was the effluent converted to in the sediment of the bay

Answer 24

methyl and dimethyl mercury

Question 25

what was the result of methy and dimethyl mercury entering the food chain at minimata bay

Answer 25

biomagnification and bioconcentration

Question 26

what are the symptoms experienced by those affected at minimata bay

Answer 26

memory loss, parathesia, difficulty speaking clearly, constricted visual field, ataxia, loss of muscle coordination

Question 27

what disease occurs in severe cases

Answer 27

cerebral palsy

Question 28

which proteins does methyl mercury bind covalently

Answer 28

those with an SH group

Question 29

how does the binding of proteins containing an SH group to methyl mercury convey toxicity

Answer 29

it inhibits activity of many enzymes

Question 30

which pathways in metabolism are inhibited by methyl mercury

Answer 30

krebs and glycolysis

Question 31

what is the result of methyl mercury disrupting mitochondrial electron transport

Answer 31

increased formation of reactive oxygen species

Question 32

what is the result of methyl mercury altering calcium homeostasis

Answer 32

activates calcium dependent endonucleases, proteases and lipases

Question 33

how does methyl mercury induce neuronal excitotoxicity

Answer 33

stimulating neuronal glutamate release

Question 34

where are toxins diluted

Answer 34

land sea air

Question 35

name a toxin which is of specific concern due to its chemical stability and lipid solubility

Answer 35

DDT