Download - Endocrine Disrupting Compounds:

Endocrine Disrupting Compounds:

General Overview and Impact on Freshwater Biology

SCAP Water Issues Committee Meeting

May 5, 2011

Photo by Judy Gibson From: Jenkins et al., 2009 P

The Endocrine System

• All vertebrates possess an endocrine system which consists of- Glands: Secrete hormones

- Receptors: Detect and react to hormones




• The endocrine system is responsible for biochemical signals that insure proper function of the body throughout the life cycle.




• The endocrine system is responsible for biochemical signals that insure proper function of the body throughout the life cycle.

• Endocrine disrupting compounds (EDCs) mimic natural hormones and can bind with hormone receptors – disrupting normal endocrine function

NonylphenolDegradation product of nonionic surfactants (detergents)

17-EstradiolNatural hormone

Endocrine Disrupting Compounds

• Exogenous Compounds-compounds (molecules) that originate outside of living organisms

• Encompass a variety of chemical classes including pesticides, pharmaceuticals, plastisizers, flame retardents, hormones, cleaning products, personal care products

• Many are organic wastewater contaminants (OWCs) and some are contaminants of emerging concern (CECs)

• Primary focus has been on the EDCs “estrogenic effects”-where EDCs mimic the hormone estrogen

• Estrogen receptors are essentially the same among most vertebrates

EDCs Widespread in the Environment

EDC Common Use

Alkylphenol ethoxylates (APEs) and their degradation products

Industrial and household nonionic surfactants (detergents)

Bisphenol-A (BPA) Most widely used plasticizer (softener) in the US

17-ethynyl estradiol (EE2)

Synthetic estrogen used in most birth control and hormone replacement drugs

Organochloride pesticides (OCPs)

Pesticides, herbicides and fungicides used by industry and household consumers (ex: DDT)-banned since

Phthalates Ubiquitous component of leachable plastics

Polyaromatic hydrocarbons (PAHs)

Nonvolatile hydrocarbons present in oils and petroleum-based lubricants

Polychlorinated biphenyls (PCBs)

Oils used primarily in transformers (ex: Aroclor)-banned since 1976

Triclosan and degradation products

Common ingredient of soaps and personal/household disinfectants

EDC Release to Freshwater Systems

• Discharge from wastewater treatment plants (WWTPs)APEs, Hormones (e.g. EE2), Triclosan, BPA, Pharmaceuticals

• Agricultural wastewater dischargesHormones

• Urban and agricultural runoffPAHs, OCPs

• Industrial dischargesAPEs, BPA, Phthalates

Primary release mechanisms:

Impacts on Freshwater Biology

Observations led to years of research to determine cause of abnormalities

Abnormally high incidence of intersex fish observed downstream from WWTPs in late 1970s

Field studies:

• Confirmed correlation between proximity to treated effluent and sexual disruption

• Measured concentrations of EDCs in rivers and treated wastewater effluent-detected at parts per billion (g/L) to parts per trillion (ng/L)

Laboratory studies:

• Examined estrogenic effects of individual EDCs on fish and other biota

• Determined potency (i.e. estrogenic activity) of individual EDCs (e.g. EE2 found to cause feminization at 1.2 ng/L)


Rodgers-Gray et al. 2001

− Possession of both male and female germ cells

− Males in possession of “female-like” gonadal tissue and reproductive ducts

− Increased levels of female-specific protein vitellogenin (VTG)

− Reduced sperm density

Evidence of sexual disruption includes:


Rodgers-Gray et al. 2001

Exposure of juvenile wild roach to sewage treatment water effluent (STWE) of various dilutions resulted in dose-dependent and sustained feminization of reproductive ducts in males

− Possession of both male and female germ cells

− Males in possession of “female-like” gonadal tissue and reproductive ducts

− Increased levels of female-specific protein vitellogenin (VTG)

− Reduced sperm density

Evidence of sexual disruption includes:

Many EDCs bioconcentration in higher trophic level organisms such as fish, allowing for exposure even when aqueous concentrations are very low

Impacts on Freshwater Biota

• Aqueous concentration

• Partition (i.e. does it prefer to sorb into sediments or does it remain in the aqueous phase?)

• Degree of bioconcentration

• Estrogenic activity

• Degradation pathways

The impact of individual EDCs is primarily a function of the compound’s chemical properties and the extent of its use in human activity

Factors To Consider:

Bisphenol-A

DDTPossible treatment options will also depend on chemical properties

Factors Effecting EDCs’ Biological ImpactComparison of Common EDCs:

EDC Sorption Degradation Bio-concentrationEstrogenic

ActivityPossible

Treatment Options

APEs Moderate Bio-aerobic & anaerobic

Moderate High Sorption, oxidation, reduction

BPA Moderate Bio-aerobic & Photo

Moderate High Biodeg. Photodeg.

EE2 Strong Bio-aerobic Strong Very High Sorption, Oxidation

OCPs Moderate Bio & Photo are minimal

Very Strong Low to Moderate Sorption, Photodeg. Oxidation

Phthaltes Weak Bio-aerobic Weak Moderate Biodeg., Oxidation

PAHs Strong Bio-aerobic & Photo

Highly Variable Moderate to High Sorption, Oxidation

PCBs Strong Bio & Photo are minimal

Strong Moderate to High Sorption, Photodeg. Oxidation

Triclosan Moderate Photo, Bio is disputed

Dioxin biproducts strongly bioconcentrate

Moderate (for Dioxins + Furans)

Sorption, Oxidation, Possibly Reduction

EDCs in the Santa Ana RiverIssue: To what extent to EDCs in the SAR impact the reproductive ability of the Santa Ana Sucker

Gross et al., 2004:

•Measured concentrations of OWCs including APEs and EE2 in effluent of four WWTPs and in river water along the SAR.

•APE metabolites detected in all effluents/at all locations-max concentrations of 19.6 parts per billion (g/L) in effluent upstream of Prado Dam

•EE2 not detected in river or effluent water at detection limit of 2 parts per trillion (ng/L)

•Significant downstream attenuation of compounds observed

Recent studies from the SAR basin provide insight into this issue:

EDCs in the Santa Ana RiverIssue: To what extent to EDCs in the SAR impact the reproductive ability of the Santa Ana Sucker

Jenkins et al., 2009:

•Detected OWCs, including EDCs, in aquatic biota and water in the SAR basin along a gradient of proximity to WWTP effluent (including one control site).

•Conducted in vitro assays of sexual parameters of western mosquitofish (proxy for santa ana sucker)

•Results indicate endocrine disruption in the form of altered hormone ratios in both sexes and secondary sex characteristics in males

Recent studies from the SAR basin provide insight into this issue:

Summary

• EDCs are exogenous compounds that encompass a variety of chemical classes and derive from numerous areas of human activity

• Mimic hormones, in particular estrogen, and bind to endocrine receptors thereby interfering with normal endocrine function

• Treated effluent is an important conduit of EDCs to the environment

• Fate, transport and biological impact is a function of chemical properties and extent of human use

• Large body of evidence that exposure to EDCs causes endocrine disruption in riverine fish, including mosquito fish in the Santa Ana River

• On-going research further investigates link between EDCs and reproductive impairment in aquatic biota