Pollution Monitoring Article

11/18/02
This article has many valuesfor the mission project.  It provides a foundation for many of the ideas for how to effectively monitor, incorporating scientific proof.  It also gives a method for performing tests on animals (such as the amphibia we will be using) that produces reliable data.  Although this information is new and there is not a great deal of support, tests like the ones we would be doing are what gives reproduceability to a method.

Assessment of Soil Contamination - a functional perspective. Van Straalen, Nico M. uBiodegredationu. Kluwer Academic Publishers, The Netherlands, 2002. 13: 41-52.

Summary
Many industrialized countries have encountered serious problems with soil contamination, especially in land that is intensely used.  Some sources of pollution in the Netherlands:

a) waste dumps: "industrial and household waste[s] may pollute the direct surroundings by surface dispersal and groundwater leaching of potentially hazard substances." (p. 41).
b) coal gas facilities - tar, which contains high concentrations of polycyclic aromatic hydrocarbons and cyanide.
c) gas stations - aliphatic and aromatic hydrocarbons, gas spills, etc
d) pesticides
e) various other chemicals from many different sources leak heavy metals, organochlorine compounds, etc.
Soil Protection Act (used in the Netherlands):
"Present use of soil should not impede any future use." (p. 42).

Functions recognized as uses of the soil:

a) soil as construction land
b) source of materials, such as ores
c) filter and buffer, preserving clean ground water
d) agriculture
e)"place where ecological functions are conducted that are relevant for the biosphere ingeneral." (42)
Ecotoxicology:
"... a science that deals with the ecological effects of potentially toxic substances in the environment." (42).  First concieved in 1969, originally applied to aquatic ecosystems only.  Methods of testing aquatic invertebrates, fish and algae developed.  Before 1995, only one internationally accepted test method for soil organisms - the earthworm artificial soil test.  Many new methods have been concieved since.
Traditional ecotoxicology method
toxicity tests: "organisms are exposed to a graded series of concentrations and effects are measured at each concentration.   The concentration corresponding to the maximallyaccepted effect is then estimated from the results by some regression technique and this may be expressed, for example, as EC10 (10% effect concentration) or EC50 (50% effect concentration). " (42-43).  This is called "inverse approach." (43).  Forward approach: concentration shows level of risk.  Problem both solve: how large is the risk from pollution? Drwaback of inverse approach: many complicating factors ("other pollutants, organic matter content, clay content, pH, microbial activity, age of pollution" [43]).  this may affect the toxicity.  Inverse gives approximation.  This is often useless in specific places because of site-specific factors.  Thus, the forward approach is more useful. (43)
Chapman et al (1986, 1990):
"sediment quality triad"- 3 pieces of info needed:
"1) chemical measurements of concentrations of pollutants,
  2) results of bioassays using samples from the field site, and
  3) field inventories of communities of organisms present at the site."
When categorized in a triangle, scores above a certain threshold indecate a problem that requires action.  "This approach has been relatively successful for sediment evaluations." (43)

Rutgers et al (2000):
"soil evaluations should be contingent on the inteded land use of the site" (43)

Bioassays - organisms are exposed to samples from a site and responses are observed under standardized conditions.

Van Gestel et al (2001)
"A combination of different bioassays is necessary; risk cannot be derived from effects on one group of organisms.  In addition, it is advised to conduct chronic bioassays using organisms exposed tin the soil itself, rather than short-term bioassays using organisms exposed to extracts from the soil." (43)
Polluted sites do not always have a control (reference site) which complicates this.

"Soil Health"
Ecosystem Health paradigm (Costanza et al, 1992). Ecologists and economists worked together to create "unifying concept of environmental management that would meet the needs felt with regulatory agencies to adopt a broader set of management goals than used at the time." (44).  From Costanza's book" "An ecological system is healthy and free from 'distress syndrome' if it is stable and sustainable..." (44).
One must use operational measures, mainly through indicators.  "...a complex concept such as ecosystem health cannot be measured as such, but that it can be approached through a series of indicators, each of which will measure a certain aspect..." (44).
Doran and Safley (1997)
"Soil health can be defined as 'the continued capacity of soil to function as a vital living system, within ecosystem and land-use boundaries, to sustain biological productivity, promote the quality of air and water environments, and maintain plant, animal and human health.'" (44)
Pankhurst et al (1997)
overview of various bioindicator approaches available to assess soil health.

Ecological theory - soil protection mostly involves functions; however, protecting structure might serve.  If all species present, all relationships unaffected, ecological functions constant.  However, there is an assymetrical relationship: protection of functions dues not require all structures, while protection of structures ensures protection of functions.
Lawton (1994) proposed 3 models of this relationship:

a) redundant species hypothesis - ecosystem functions are unaffected up to the point where only a small number of key species remains.  If one of these is lost, the system collapses.
b) rivet hypothesis - decrease of boidiversity, ecosystem function decreases proportionally (i.e. direct correlation)
c) idiosyncratic hypothesis - no relationship.
"general feeling among soil ecologists is that functional redundancy indeed plays a role in soil communities." (45)

Nordgren et al (1983)
study of heavy metal contamination showed considerable loss of species of fungi in a gradient of pollution around a metal smelting works.  However, soil respiration only was affected at high levels close to metal source.
Nevertheless, despite great efforts arising from the Rio convention, there is very little empirical evidence to support any of Lawton's hypotheses.

Naeem and Li (1997)
"ecosystem reliability": degree to which ecosystem functions are maintained over time.  Biodiversity is "ecological insurance." (45).  Must look therefore at biodiversity of species attributes instead of numbers.

Limiting Factors
soil microorganisms limited by "heterogeneity of nutrients and physicochemical factors." (46)
Less biodiversity directly affects overall rate of processing because capacity of each functional unit (species or species group) is "maximally deployed." Conversely, substrate limiting does not affect overall rate of processing; each functional unit can increase its share in the overall process. (Levine, 1989). [46]

Terrestrial Model Ecosystems
(Morgan and Knacker 1994, Edwards et al 1996, Verhoef 1996, Sheppard 1997)
allow enough complexity for interactions between organisms in tested soil, while still manageable and replicable.
Method:

a) use undistrubed soil columns from the field
b) include live vegetation growing on the soil
c) take column with several liters
"replicated systems are to be taken, for example in a site suspected of pollution and in a reference site, or along a gradient.  Differences in the performance of systems taken at different sites may be evidence of altered ecological functioning of the soil." (47)
TME's use forward approach.  Taken directly from field, so site specific as well.  Standardized incubation eliminates transient variables (such as temperature and humidity).  By measuring multiple things in each column of soil, better characterizations produced. (48)

Kersting (1984)
"Normalized operating range" (NOR) - in system of two variables: if system not perturbed, all combinations fall in NOR of system, or 95% confidence area of unperturbed areas.  "Normalized ecosystem strain" (NES) means the distance between a certain state and the center of the 95% confidence area, divided by the width of the confidence area at the same place.  NES is greater than unity when the system is out of the NOR.  NES takes many variables into account. (49)
TME and NOR approach developed similarly experimentally by Vanden Brink and Ter Braak (1999). (49)

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