using algae to help establish numeric water quality ...classification. algae can be used to develop...
TRANSCRIPT
![Page 1: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/1.jpg)
Using Algae to Help Establish Numeric Water Quality Criteria and
Nutrient Reduction Targets
Scott L. RollinsSpokane Falls Community College and
University of California, Santa Cruz
13th Annual Meeting of the California Aquatic Bioassessment Workgroup
This document may not be copied, reproduced, or distributed without permission of the author.
![Page 2: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/2.jpg)
Nutrients as a Stressor
● Nutrients (nitrogen and phosphorus) are one of the leading causes of water quality impairment in the U.S.
● Because N and P are naturally found at varying concentrations in the environment, development of nutrient criteria/reduction targets are challenging
![Page 3: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/3.jpg)
Nutrient Criteria Guidance• U.S. E.P.A. has
developed nutrient criteria guidance documents
• Numeric criteria recommendations have also been published for use by states and tribes if they choose not to develop their own
Nutrient Concentration
![Page 4: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/4.jpg)
Nutrient Criteria Guidance
• Most of these published numbers are based on the lower 25th percentile of the measured nutrient concentrations
• This would mean that 75% of all streams fail to meet numeric standards
Nutrient Concentration
![Page 5: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/5.jpg)
U.S. Environmental Protection Agency Guidance for Nutrient Criteria
Development
Existing Work
Reference-basedApproach
Observed Nutrient-Response Relationships
Benchmarks(Candidate Nutrient
Criteria)
Classification
![Page 6: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/6.jpg)
Algae Can Be Used to Develop Criteria Using Each of These
Approaches
![Page 7: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/7.jpg)
Using Algae to Develop Criteria• Algae respond directly to nutrients• Species assemblages are diverse and
respond differentially to nutrients• Algae influence several numeric and
narrative water quality standards (e.g., biostimulation, DO, pH)
• Algae are directly or indirectly related to multiple beneficial uses
• Algae provide a more reliable indicator of excess nutrients than one-time water column measurements of nutrients
![Page 8: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/8.jpg)
U.S. Environmental Protection Agency Guidance for Nutrient Criteria
Development
Existing Work
Reference-basedApproach
Observed Nutrient-Response Relationships
Benchmarks(Candidate Nutrient
Criteria)
Classification
![Page 9: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/9.jpg)
Defining “Reference”
● “Reference” is poorly defined, but is generally interpreted to mean pristine, minimally disturbed, or pre-European settlement
● This may be over-protective and may not provide for assimilative capacity of the system
● Others ways of defining expected conditions have been developed
![Page 10: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/10.jpg)
U.S. Environmental Protection Agency Guidance for Nutrient Criteria
Development
Existing Work
Reference-basedApproach
Observed Nutrient-Response Relationships
Benchmarks(Candidate Nutrient
Criteria)
Classification
![Page 11: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/11.jpg)
Stream Classification
• Standard Method– Geospatial Classifications
(e.g., Bailey’s or Omernik’s Ecoregions)
• Species Composition Approach to Classification– No/minimal a priori
assumptions regarding geospatial constraints on species composition
– Species composition defines the classes
![Page 12: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/12.jpg)
![Page 13: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/13.jpg)
Channel Length
Precipitation
% Urban Land Use
% Crop Land Use
Total Phosphorus
Site-specific Expectations:An Alternative to Classification
![Page 14: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/14.jpg)
U.S. Environmental Protection Agency Guidance for Nutrient Criteria
Development
Existing Work
Reference-basedApproach
Observed Nutrient-Response Relationships
Benchmarks(Candidate Nutrient
Criteria)
Classification
![Page 15: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/15.jpg)
Inferring Reference TP Concentration
Channel Length
Precipitation
% Urban Land Use
% Crop Land Use
Expected TP at
0 crop & urban= 0
= 0
Datafroma new
site
![Page 16: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/16.jpg)
U.S. Environmental Protection Agency Guidance for Nutrient Criteria
Development
Existing Work
Reference-basedApproach
Observed Nutrient-Response Relationships
Benchmarks(Candidate Nutrient
Criteria)
Classification
![Page 17: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/17.jpg)
Typical Stressor-Response Relationship
Intensity of Stressor (e.g., dose)
Res
pons
e (e
.g.,
% m
orta
lity)
Point Estimates (e.g., LD10, LD50)
![Page 18: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/18.jpg)
Typical Stressor-Response Relationship
Intensity of Stressor (e.g., dose)
Res
pons
e (e
.g.,
% m
orta
lity)
Point Estimates (e.g., LD10, LD50)
Threshold Region
Acceptable Conditions
Unacceptable Conditions
Threshold Point Estimate
![Page 19: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/19.jpg)
Quantifying the Threshold
● Algae respond at very low levels in the laboratory; laboratory settings also exclude other potentially important ecological factors
● Use of observational field data in some capacity is probably necessary
● Thresholds can be determined with associated uncertainty, allowing interpretation of the “risk of exceeding the threshold”– Bootstrapping– Bayesian
![Page 20: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/20.jpg)
Ris
k of
Exc
eedi
ng T
hres
hold
TP-Chlorophyll Relationship Observed in Michigan Streams and Rivers
![Page 21: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/21.jpg)
U.S. Environmental Protection Agency Guidance for Nutrient Criteria
Development
Existing Work
Reference-basedApproach
Observed Nutrient-Response Relationships
Benchmarks(Candidate Nutrient
Criteria)
Classification
![Page 22: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/22.jpg)
Bayesian Inference
Prior InformationThe Prior
Pr(model)
DataThe Likelihood
Pr(data|model)
Updated KnowledgeThe Posterior
Pr(model|data)
![Page 23: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/23.jpg)
U.S. Environmental Protection Agency Guidance for Nutrient Criteria
Development
Existing Work
Reference-basedApproach
Observed Nutrient-Response Relationships
Benchmarks(Candidate Nutrient
Criteria)
Classification
![Page 24: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/24.jpg)
Prior Threshold Information
● Threshold (from Dodds et al. 2002)– 30 μg TP/L
● Mean chlorophyll below the threshold (estimated from Nieuwenhuyse and Jones 1996)– 1.2 μg chla/L– 13.3 μg chla/L
![Page 25: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/25.jpg)
Effects-based Information
![Page 26: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/26.jpg)
Integrating the Information● Thresholds provides an effects-based
information
● Inference models provide expected referencelevels of TP and a site-specific “classification”
● Both methods can integrate previous research using Bayesian statistics
● How can the information be integrated to create a TP benchmark (candidate nutrient criterion)?
![Page 27: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/27.jpg)
Relative Risk Framework
● Relative risk (RR) measures the influence of some risk factor on a specified outcome
● In epidemiology, RR is calculated as the incidence rate among individuals exposed to the risk factor, divided by the incidence rate in those not exposed to the risk factor– E.g., smokers are X times more likely to die from
lung cancer than non-smokers
![Page 28: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/28.jpg)
Relative Risk for Developing Nutrient Benchmarks
● What is the risk of exceeding the TP-chlorophyll threshold at current TP levels, relative to the probability of exceeding the threshold at reference levels of TP?
● At what level of TP is the probability of exceeding the threshold to equal the probability of exceeding the threshold at reference levels of TP?
![Page 29: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/29.jpg)
Calculating Relative Risk
Current RR = Probability threshold has been passed at current TP Probability of exceeding the threshold at reference TP
RR = 1 = Probability of exceeding the threshold at reference TP
Benchmark is set at TP level where RR = 1
![Page 30: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/30.jpg)
Example: Cass River, Michigan
![Page 31: Using Algae to Help Establish Numeric Water Quality ...Classification. Algae Can Be Used to Develop Criteria Using Each of These Approaches. Using Algae to Develop Criteria • Algae](https://reader034.vdocuments.us/reader034/viewer/2022052010/601f923548aadb09127f0734/html5/thumbnails/31.jpg)
Summary
● This approach provides a formal method for integrating various sources of information recommended by the USEPA for nutrient criteria development
● The method acknowledges uncertainty in predictions, which is vital for making informed management decisions
● Relative risk is a value that is easy to explain to policy makers and stakeholders