Professor D. D. Poudel. The Founder of the Asta-Ja Framework
Asta-Ja is a theoretically grounded grassroots-based planning and management framework for conservation, development, and utilization of natural and human resources. Asta-Ja means eight of the Nepali letter “Ja” [Jal (water), Jamin (land), Jungle (forest), Jadibuti (medicinal and aromatic plants), Janashakti (manpower), Janawar, (animals), Jarajuri (crop plants), and Jalabayu (climate)].
Asta-Ja promotes accelerated economic growth and socio-economic transformation of the nation. It is a scientific, holistic, systematic, self-reliant, and multidisciplinary framework for the conservation, development, and utilization of Asta-Ja resources.
The eight elements of the Asta-Ja system are very intricately linked and strongly connected. Hence, it is important to have sustainable conservation and development of each of the eight elements of Asta-Ja for better functioning of the entire system.
Asta-Ja Framework emphasizes community capacity-building, self-reliant, and national, regional, and local level planning and development of environmental and natural resources for socio-economic transformation of the nation.
Asta-Ja is the backbone of Nepal’s economy. Therefore, the best governance of Asta-Ja is the ultimate goal of a government.
We discussed Environmental Impact Assessment (EIA) and Ecological Risk Assessment (ERA), two common environmental analysis techniques, in earlier series. We will discuss Environmental Site Assessment (ESA) in this series.
As urbanization, industrialization, construction, and disposal of toxic substances and hazardous waste continue to rise, number of sites that require environmental assessment with respect to human health and environmental risks and take necessary measures to mitigate these risks becomes more and more compulsion.
For example, a Petrol Pump site with leaking underground storage tanks (USTs) may have significant environmental impact due to the leaks of petroleum product and toxic substances.
Petroleum leaks from storage tanks would contaminate soils, indoor air, surface water and groundwater.
Various contaminants from leaking petroleum tanks include methyl tertiary butyl ether (MTBE), benzene, toluene, ethylbenzene, xylene (BTEX), polycyclic aromatic hydrocarbons (PAHs), total combustible hydrocarbon (TCH), volatile organic chemicals (VOCs), petroleum hydrocarbons (PHCs), and many other toxic chemicals.
These toxic substances are found to have caused cancer, decreased immune system, heart diseases, and have affected the lungs, kidneys, and central nervous system.
Therefore, it is important to keep track of petroleum USTs to prevent their leakages and monitor soil, water, and indoor air quality in sites where petroleum leakages are expected.
This is just an example of why Environmental Site Assessment and remediation of contaminated site is necessary.
Environmental Site Assessment (ESA):
Human health and environmental risks from a contaminated site depends on many factors including the condition and type of the receptors, site conditions, fate and transport of contaminants, concentration of the contaminants, and exposure of the receptors.
Harmful effects of contaminants to the receptors, which are based on the scientific theories and behaviours of the contaminants that the scientists had knowledge of when establishing exposure and toxicity relationship, may change with the new scientific learning on the environmental behaviour and toxicity of the chemicals.
Development of new investigation technologies and methods allow scientists to establish new exposure and toxicity relationship.
When the exposure and toxicity risks shown is unacceptable against established criteria then remedial actions should be taken. Risk assessment requires the identification of source-pathway-target linkage.
A three-phase approach, consisting of site characterization, exposure assessment, toxicity assessment, risk characterization, and remediation, is often used in the ESA and remediation of a contaminated site.
Phase – I This phase involves initial investigations and preliminary risks assessment. Various activities carried out at this stage are site description, describing the nature and extent of contamination, and historic activities that may be sources of contamination.
A description of local topography and geology, drainage, surface cover, vegetation, status of ground water, approximate depth to water table, proximity to surface water, and proximity to drinking water supplies is done.
In addition, annual rainfall, flood potential, land and water use for the nearby areas, existence of any regulations and policy measures are assessed.
Any other environmental information that is relevant to risk assessment is collected.
Causes and effects of pollution are established. Preliminary risk assessment may involve establishing background exposures, route of exposures, does-effect relationship, eco-toxicological risks, bioavailability of the contaminants, and the combined effects.
Phase II This phase involves detailed field investigations, quantification of the risks, and the preparation of ESA report.
Various field investigation techniques may involve surficial sampling of vegetation, surface water, and soils from contaminated areas; subsurface sampling of soil vapors, soil and groundwater; geophysical investigations for buried objects and/or contamination plumes; chemical analytical testing; and longer term monitoring of surface water, soils, gas, and groundwater.
Many high-tech laboratory analytical instruments and capability may be necessary at this phase.
Some of these analytical methods may include Ground Penetrating Radar (GPR), Electromagnetic (EM) Induction, Infrared Monitor (IR), Seismic Reflection and Refraction, Flame Ionization Detector (FID), Photoionization Detector (PID)), Direct push, Drilling, Soil gas Survey; Immunoassay Test Kits, Colorimetric kits, Fluorescence analyzers, Laser induced fluorescence/cone penetrometer, X-ray fluorescence (XRF), Long path FTIR-organics, PLM (Polarized Light Microscopy), and X-ray fluorescence (XRF).
Specific technical guidelines and standard methods for the assessment of contaminated sites must be developed and followed. Risks are quantified based on the results from field investigation and laboratory determination.
The ESA report is prepared.
Phase – III The Phase-III in ESA is a feasibility study or investigation of remediation technologies or practices for the remediation of a contaminated site.
Requirement for remediation or corrective actions will be based on Phase II results.
Various engineering and ecological remediation techniques could be tested. Remediation plan is developed involving local stakeholders and concerned governmental agencies.
Further field and laboratory investigations may be necessary. Appropriate remediation design is developed.
Remediation of a Contaminated Site:
There are several ex-situ and in-situ techniques employed in remediating contaminated sites.
We can find ex-situ techniques such as excavating the contaminated soils and bringing it to a facility for driving off volatile organics and destroying other contaminants.
Vacuum extraction and temperature treatment are some of the techniques used in ex-situ treatment.
Ex-situ treatments are costly but effective. In-situ techniques are usually preferred ones in which treated soils are in place and are less costly and less destructive.
Some of the common in-situ treatments that are used for the removal of contaminants from the soils include water flushing, leaching, vacuum extraction and heating.
Pyrolysis technology includes heating soil at temperature of 1,400-2,000 oC and decomposing or volatilizing organic matters.
The stem produced through heating is treated.
Plants such as prairie grass, sunflower, and spring wildflowers are used for treating contaminated soils, and the technique is called phytoremediation.
Plants remediate contaminated soils through hyperaccumulation or through enhanced rhizosphere phytoremediation.
Hyperaccumulating plants take up the contaminants from soils and accumulate them in their tissues, which are harvested and removed.
Soil contaminated with Ni, Zn and certain organics such as TNT (trinitrotoluene) can be remediated using hyperaccumulating plants.
In some cases, plant roots exude certain carbon compounds, which enhance microbial activities in the rhizosphere and decompose the contaminants.
Applying voltage at the two sides of soil forming electric gradient and attracting heavy metals, a technique called electrokinetic remediation, electromigration, electroosmotic flow, or electrophoresis is a new evolving technique in the remediation of contaminated soils.
Another technique of remediating contaminated soils include the use of N and P fertilizer and maintaining appropriate C/N ratio so that naturally occurring microorganisms can degrade the contaminants (biostimulation).
Treatment of contaminated groundwater is much difficult. Certain surfactants such as Quaternary Ammonium Compounds (QACs) are applied to form organoclays to attract nonpolar organic molecules in groundwater and hold them until they degrade.
Certain bacteria can also be inoculated in the polluted zone of groundwater (bioaugmentation) to breakdown contaminants and remove as harmless gas.
Soil and groundwater contaminated sites continue to increase as urbanization, industrialization, and improper disposal of municipal and industrial solid waste, hazardous substances, and leaking underground storage tanks (USTs) continue to rise.
Environmental consequences of such contamination including public health impacts and ecological risks often are very heavy and threatening.
Therefore, it is important for environmental programs and scientific community in Nepal to pay sufficient attention to such contamination and build capacity in remediating contaminated sites.
In part 8 of this series, this author will discuss the issue of natural resource ownership in Nepal.