Transcript TOXIC SUBSTANCES ENSC 202 Stephanie DiBetitto, Josh Fontaine, and Rebecca Zeyzus LCB’s Proposed Toxic Substance Problems.

TOXIC SUBSTANCES
ENSC 202
Stephanie DiBetitto, Josh Fontaine,
and Rebecca Zeyzus
LCB’s Proposed Toxic Substance Problems
3 Subcategories of Toxic Substances
• Heavy Metals
• Organochlorines: PCBs, dioxin, DDT
• Others: VOCs, PAHs, phthalates
Substances within these subcategories are
posing threats to the LCB
Problem
• Many sources (industry, deposition,
agriculture, WWTP, etc.)
• Many sources contributed from outside LCB
• Transported through ecosystems
• Synergistic effects
• Harmful to many areas of life
• Can be persistent within the environment
Objectives
• To evaluate negative impacts of the
substances of concern
• To identify and document the toxic
substances’ source, and their modes of
transport between habitats and through
ecosystems
• To examine the risk presented within the
habitats and the link between the sources and
toxins persisting within the environment
Goal/ Purpose
• To understand the potential risk posed by the
three subcategories of toxic substances within
ecosystems
• Apply the findings to a relative risk model for
the Lake Champlain Basin in the future
(Methyl- Hg)
• NIOSH REL: 0.05 mg/m3
• NIOSH REL: 0.050 mg/m3
Figure 2. Surface sample trace metal concentrations (from partial digestion) and TEL,
ER-L, PEL, ER-M values. The height of the bar represents the trace metal concentration
or guideline value in gg−1. The stations are arranged in roughly a north-south orientation.
(Lacey et al., 2001)
Figure 7. Core samples: trace metal concentrations from partial digestion (g g−1) versus depth
(cm)below sediment/water interface. The cores are presented in roughly a northwest-southeast
transect (Lacey et al., 2001)
General Findings: Organochlorines
• Significantly impact the environment and
human health at low concentrations
• Highly toxic
• Highly mobile
• Persistent
• Hydrophobic
• Lipophilic  bioaccumulate
• Endocrine disruptors
Sources: Organochlorines
•
•
•
•
*Atmospheric Deposition
Agricultural and Urban Runoff
Waste Water Treatment
Industrial Waste Discharges
Chemical Characteristics:
Organochlorines
•
•
•
•
Semi- volatile
Low vapor pressure
Undergo diffusion, advection, and convection
Co-exist in both gas and particle phases, cycle
through the atmosphere and earth’s surface
• These processes allow for OCs to be absorbed
from the gas phase by water, soil, plant surface
and snow and become available within a range of
ecosystems and habitats
• Arguably most detrimental to natural systems
Forest Ecosystems: Organochlorines
• Persist in forests due to deposition
• Pollutants in the air are adsorbed to leaf and
needle surfaces
• Leaf litter transports contaminants to the soil
• Different soil horizons undergo alternate
responses due to processes like degradation,
dissolution, adsorption, and evaporation
• Remain in the A-horizon due to its acidic
properties in pine forests
Waterways: Organochlorines
• Agricultural Runoff
• Rivers are the largest receptacles of pesticide
waste and agricultural runoff
• Enter river systems through surface run-off
from urban areas
• Bioavailable to the organisms living in the
river
• Generally found in densely populated areas
(target estuaries and coastal marine
ecosystems)
Effects of Organochlorines in the Lake
Champlain Basin
•
•
•
•
•
•
•
•
PCBs and dioxins
NIOSH REL: Ca
Found in sediment
Low levels of PCBs throughout the lake- bioaccumulates
Concentration of PCBs exceeds U.S. FDA for fish and EPA
guidelines for humans
Largest single source of contaminant from Georgia Pacific
sludge bed in Cumberland Bay
Dioxin brought to LCB from pesticide runoff (agriculture)
Both PCBs and dioxin primarily transported from wind
currents depositing substances from sources outside of the
basin
Fish advisories are a result of the elevated concentrations,
promote safe fish consumption and protect human health
(Lake Champlain Basin Program, 2011)
NIOSH REL: 1.5 mg/m3
NIOSH REL: 1400 mg/m3
NIOSH REL: Ca
Factors to consider
•
•
•
•
•
•
Input duration
Mass loading
Predator- prey relationships
Sensitivity of species
Flushing time
In mammals may consider gender, age, diet,
health condition, reproduction status, and the
season determine the effect posed on the
mammal
• *Risk = product of many factors
Effects Filter
Source
Effect
Agriculture
1
Urban
1
WWTP
1
Dams
0
Roads
1
Fisheries
0
Marinas
1
Forested Area
0.5
Industrial
1
Parks
1
External
1
Logical link between sources and stressor
Source Impact Filter*
Source
Impact
Agriculture
2
Urban
2
WWTP
2
Dams
0
Roads
1
Fisheries
0
Marinas
1
Forested Area
0
Industrial
2
Parks
0.5
External
2
Logical link between the effect of the source on the stressor
Habitat Impacts Filter*
Habitat
Impacts
Lakes/ Ponds
1
Rivers/ Streams
1.5
Developed Areas
0.5
Forest
0.5
Herbaceous
0.5
Agriculture
1
Wetlands
1
<6ft
2
>6ft
1
Stressors logical link to the habitat
Uncertainty
• Input frequency and intensity unquantified
• Effect on aquatic organisms dependent on
exposure severity and the physiochemical
properties of the parent compound and the
products it is transformed into
• Synergisms between chemicals within
environment and amongst each other
Conclusions
• An abundance of toxins entering the Lake
from outside the basin via deposition
• Primary sources of toxins include industrial
and agricultural runoff and WWTP
• Bioaccumulative and persistent properties of
these substances increase risk
Recommendations
• Education, Advisories
• Disposal
• Monitor sediments, find trends in changes
over time
• Revolution
THE END
WARNING: This is what happens when toxins get into the
Lake (featured above, Champ taking a dip in the LCB)