Wed, Apr 04, 2018 - Page 8 News List

Organic farming needs regulating

By Tseng Kuo-jin 曾國珍

Taiwanese who want to promote their produce as “organic” need government-approved certification to ensure they meet the environmental standards for organic farming. Soil and irrigation water quality must meet certain criteria and be certified before organic agricultural products are grown and sold. These requirements are essential to help guarantee food safety.

The Organic Agricultural Product and Organic Agricultural Processed Product Certification Management Regulations (有機農產品及有機農產加工品驗證管理辦法), last amended in 2015, stipulate the allowable level of heavy metal content in soil.

Heavy metals, such as cadmium, chromium, copper, nickel, lead and zinc, are measured by their “bioavailable forms” in soil.

Bioavailability in this evaluation refers to the approximate levels of heavy metals in soil which plants absorb and use for their growth.

According to the basic principles of edaphology — the study of agricultural soil — crops absorb minerals in “bioavailable forms” from the soil no matter whether these minerals are essential, beneficial or unnecessary for their growth.

The efficiency of the absorption process is determined by different physical, chemical and biological conditions of the soil.

The process of absorbing heavy metal ions is no exception.

Once the density of the minerals in the soil exceeds a certain level, it might become toxic for the plants and affect the health of their root system.

If plants absorb heavy metals in excessive amounts, then they can become toxic if consumed; cadmium-contaminated rice being a pertinent example.

The standards for allowable heavy metal content in soils have been complied with for many years and organic agricultural products in Taiwan have never been found to exceed the permissible heavy metal levels stipulated by the Ministry of Health and Welfare.

The standards that measure allowable heavy metal content in terms of the amounts of their “bioavailable forms” in soil are effective in controlling the quality of farmland soil for organic agricultural farming.

However, the Council of Agriculture on Jan. 3 announced a policy to help facilitate farming and issued a notice saying that many regulations would be amended.

As for the environmental conditions for practicing organic farming, in the proposed amendment the standards for heavy metal density in farmland soil and irrigation water were to be changed from bioavailability-based measurement back to criteria set in the management standard of heavy metal content in farmland of edible crops, as regulated by the Environmental Protection Administration (EPA).

The level of heavy metals in soil and irrigation water would only need to be below the criteria designated by the irrigation and soil pollution control standards.

The proposed amendment significantly loosens standards for organic farming.

This is a source of much concern due to its relevance to the issue of food safety.

Zinc is a case in point. The 2015 version of the regulations stipulates that the concentration of zinc in soil must be under 50 parts per million (ppm) and must be measured based on its bioavailability.

This methodology is lax because zinc levels in hundreds of soil samples — covering all kinds of farming soil — were all found to be under 30ppm.

However, the assessment of heavy metal content in soil according to the EPA regulation adopts another methodology known as the aqua regia digest.

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