Endocrine Distrupting Chemicals EDC

Question 1

Issues

Answer 1

hormone impacts, humans (sex ratio), bird (nest change, pairing behaviour), amphibians & reptiles (under-developed organs), fish population skewed, imposex (molluscs)

Question 2

Identifying

Answer 2

not direct, different types and properties

Question 3

Disruption: Endocrine system

Answer 3

hormone production, chemical messengers, genes in DNA activation

Question 4

Disruption: Non-hormone chemicals

Answer 4

interference

Question 5

Disruption: EDC mimic natural hormones

Answer 5

receptor sites blocked, promote receptor site numbers

Question 6

Impacts

Answer 6

oestrogenic - (APEs), pasticisers. Androgenic (TBT). Distrupting - Hg, Cd, Pb, lindane

Question 7

Evaluation Schemes

Answer 7

Toxicity data? -> NOT EDC, Whole organism study, Screening (QSAR, in vitro) -> Wild life effect study - determine no effect concentration

Question 8

QSAR Model

Answer 8

quantitative structure-activity relationship, 100’s EDC identified, controls implemented, begin with priority substances

Question 9

Research Example - APEs alkylphenol ethoxylates

Answer 9

Industrial non-ionic surfactants: 80%, domestic & industrial cleaning products, formulations (paper & plastic industries)

Question 10

Europe

Answer 10

voluntary ban UK - IPPC control

Question 11

Industrial effluent

Answer 11

sewage treatment works transport

Question 12

APE Degradation: Ethoxylate chain

Answer 12

temperature dependent loss/shortening of chain, 0% @ 15 degrees, 50% @ 20 degrees, 100% @ 28 degrees

Question 13

APE Degradation: Increased ED

Answer 13

Impacts with short chain

Question 14

APE Degradation: Residue

Answer 14

alkylphenol persistent

Question 15

APE Biogeochemical Cycling

Answer 15

High distribution coefficient (Kd), degradation in river sediment?, environ. conc?, cycling within estuaries?

Question 16

APE Behavior: Water

Answer 16

Conc. - <1ug/l, low degredation rate - dissolved form, low estuarine reactivity?

Question 17

APE Behaviour: Sediment

Answer 17

Concn - 0.1-3000 ug/kg, UK <50ug/kg, high sorptive capacity, upper sediment layers permit APE degradation 90% over 100 days, low sediment (low O2) - slow, degradation rates, APs persists

Question 18

APE Determination Analytical task: Seperate analyte

Answer 18

sample matrix (sediment/suspended solid 1 or water 2), extraction (soxhlet 2 or solid phase extraction SPE 1)

Question 19

APE Determination Analytical task: Pre-concentration Example

Answer 19

Sample 0.5 dm3 10ugdm-3 -> SPE column (80% efficient) 4ug -> Solvent 5cm3 (4ug in 0.005 dm3) 4x1000/5 = 800 ugdm-3

Question 20

APE Determination Analytical task: Analyse quantitatively

Answer 20

HPLC-Flourescence - very sensitive, low analyte concentrations, seperate analyte from residual matrix

Question 21

Energy graph

Answer 21

photon energy, e- excited go up energy level then go back down. Energy in is not equal Energy out

Question 22

Flourescence

Answer 22

Incident light in E1 then Flourescent light out E2, spectroscopy E1>E2. Measure at 90 degrees to incident, detect photons -> sensitive

Question 23

Summary: SPE (C2, ethylacetate eluent)

Answer 23

10-20X pre-concentration

Question 24

Summary: HPLC

Answer 24

NH2 column

Question 25

Summary: Flourescence detection

Answer 25

230nm excitation, 300 nm emission (detection limit 10ugdm-3)

Question 26

SPE-HPLC-Flourescence system for:

Answer 26

low environmental concentration (1-10 ugdm-3), difficult, varying matrix

Question 27

EDC in Environment: Chemicals

Answer 27

range & effect not completely understood/quantified

Question 28

EDC in Environment: Environmental input

Answer 28

varied, non-uniform approach to controls

Question 29

EDC in Environment: Environmental cycling

Answer 29

concentration & cycling known to some extent, some unkown EDC environmental persistence unclear

Question 30

Future model? Environmental chemistry

Answer 30

Interface with other (science & non-science) sectors