Evaluation of Irrigation Water Quality Standards for Chromium using Material Flow Analysis and Risk Assessment
Date Issued
2005
Date
2005
Author(s)
Wang, Yi-Chen
DOI
zh-TW
Abstract
In recent years, chromium and its compounds are widely used in industries. For example, electroplate, stainless steel, leather tanning, textile dyeing process, and surface treatment which discharge wastewater, air pollution, and soil pollution cause irrigation water pollution and, indirectly, human health problem. The understanding of chromium’s distribution in the environment is the basis of risk management measures, since chromium is both useful and hazardous. Using material flow analysis and risk assessment, we can understand the role of chromium played in the interaction of economic system and environmental system, so as to seek resource circulation and reduce the risk.
The result shows that chromium is divided into 12 categories ranging from raw materials, materials, the use in factory, and products, including stainless steel products, catalyst, leather industry, surface treatment, dyeing, wood preservatives, alloy, corrosion inhibitor, textile, energy production, and laboratory chemicals. It is estimated that chromium is discharged to air 28 tons/year, to surface water 23 tons/year, and to soil 67 tons/year in Taiwan.
The goals of government’s irrigation water quality standards are to protect the crops and to maintain yields. However, the government sets the standards without considering human health risk assessment. In CalTOX multimedia and multimedia pathway model, the 0.1 mg/L chromium of irrigation water standard would cause the hazard quotient to be between 0.3~0.5 in 21 cities.
The inhalation carcinogenic risk of material flow is 2.32E-7 in northern area, 9.5E-8 in middle area, 6.1E-8 in southern area. Except for north part approaching to the traditional safe risk value, the risks of the other areas acceptable.
Using material flow estimation as environment pollution background values and adding it to 0.1 mg/L chromium of irrigation water standard to calculate hazard quotients, the results of Tainan city, Kaohsiung city, Taichung city are approaching to 1. Under the premise not to influence the human health, it is useful to reduce the polluting amount of the factory, or to consider stricter irrigation water quality standards.
Subjects
鉻
風險評估
物質流
灌溉水標準
chromium
risk assessment
material flow analysis
irrigation water quality standards
Type
thesis
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