Pass rate of data from environmental water quality monitoring reaching Class A and Class B standards


Regardless of the action plan performance indicators or sustainable development indicators, the marine water quality standards are calculated and presented based on the rate in the past. The annual rate in the past is nearly 100%, showing a slightly loose standard. It is recommended that the water quality standards in our country should be revised based on foreign and the latest research data.







Indicator Details

Original indicator name: pass rate of data from marine environmental water quality monitoring and the number of estuaries with marine environmental quality reaching Class A and Class B standards


Marine pollution

PSBR model type

Pressure (P)

Corresponding targets


14.1 By 2025, prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution. 14.1.2 2020 quantitative target: maintain more than 99.5% of the water quality data reaching the standards in 8 of the testing items.

Aichi Biodiversity Targets

Target 8 By 2020, pollution, including from excess nutrients, has been brought to levels that are not detrimental to ecosystem function and biodiversity.


Many toxic metals can be found in the ocean including mercury, cadmium, lead, copper, and zinc, etc. These metal elements may exist alone or bind with organic compounds which becomes more toxic. For example, when mercury binds with carbon, it can form the neurotoxic compound methylmercury (CH3Hg). Although many metals naturally exist in the environment, the anthropogenic emissions caused by industrial and mining activities may increase the concentration of many toxins. If water quality data can be automatically and continuously monitored, a database of actual measured raw data should be built and made public online. This can be used to find the source of pollution, report it, and effectively stop illegal emissions of pollution.

Definition and Calculation

To calculate the pass rate of date from marine environmental water quality monitoring, we take water quality data from each monitoring station (including pH value, dissolved oxygen, heavy metal cadmium, lead, mercury, copper, zinc, total 7 items), and compare the result of each item with the water quality standards set for the marine environment category where the station belongs and tally the ones reaching standards.

$$ single item pass rate(\%)=\frac{times when water quality data reaching standard on one testing item}{times of water quality tested on one testing item}\times100\% $$

$$ total pass rate (\%)={\frac{times when water quality data reaching standard on all 7 testing items}{times of water quality tested on all 7 testing items}}{\times}100\% $$


According to the results of water quality monitoring in 2018, the total pass rate was 99.7%. Among them, the pass rate of pH value is 99.0%, the pass rate of dissolved oxygen is 99.5%, the pass rate of copper is 99.3%, and the pass rate of other items including heavy metals (cadmium, lead, zinc and mercury) is 100.0%.

Data Management Authorities

Ocean Conservation Administration (Environmental Protection Agency before 2018)

Data Source / URL

The Annual Report of Water Quality, on the website of Environmental Water Quality Information by Environmental Protection Administration, Executive Yuan.

Data Development Status


Data Providers

Environmental Protection Administration, Executive Yuan

Investigation Year