Experts’ Interpretation of the Technical Guide for Derivation of Marine Biological Water Quality Standards (Trial)
In order to protect the marine environment and promote the work of marine environmental standards, the Ministry of Ecology and Environment issued the Technical Guide for Derivation of Marine Biological Water Quality Standards (Trial) (HJ1260—2022) on July 18, 2022 (hereinafter referred to as the Guide). This is the first standard to guide and standardize the derivation of marine environmental standards in China, and relevant experts have answered relevant questions.
Q: What is the significance of the publication of the Guide for China’s marine environmental protection?
Researcher Yao Ziwei of National Marine Environmental Monitoring Center: Marine environmental benchmark is an important part of modern ecological environment governance system, and it is the basis and scientific basis for formulating China’s marine ecological environment quality standards, which can provide important support for China’s marine ecological environment risk assessment and emergency response.
The current Standard for Seawater Quality (GB3097—1997) has played an important role in the prevention and control of marine pollution in China, but when the standard was first formulated, it was based on one or more foreign seawater quality standards (marine life, senses, health, etc.). As for marine biological water quality standards, there are great differences between different countries and even the same country in different periods due to the differences in derivation methods and concerned species. When conditions permit, countries should carry out relevant benchmark research according to their own marine ecological environment characteristics.
The publication of the Guide is of great significance for strengthening the research of marine environmental standards in China, accelerating the transformation and application of research results, and improving the level of marine ecological environmental protection.
Q: Since the 1980s, some developed countries and international organizations have successively issued water quality standards for marine organisms. In contrast, what are the unique features of the Guide in terms of methods and technical requirements?
Researcher Wang Ying, National Marine Environmental Monitoring Center: Since 1980s, the environmental management departments of the United States, the European Union, the Netherlands, Australia/New Zealand and Canada and other countries and international organizations have successively issued technical guidelines for deriving water quality standards for protecting aquatic organisms (freshwater organisms and marine organisms) and water quality standards for protecting marine organisms according to their environmental management needs and water pollution status. In the process of compiling the Guide, domestic and foreign scientific research achievements were fully absorbed and used for reference.
Methodologically, it is stipulated that the species sensitivity distribution method is used to derive the water quality standards of marine organisms, which is the mainstream method to derive the water quality standards of freshwater and marine organisms in the world at present, and it is also the method stipulated in the Technical Guide for Deriving Water Quality Standards of Freshwater Organisms (HJ831—2022).
In terms of technical requirements, the characteristics and working basis of China’s marine ecosystem are fully considered: first, the toxicity data of marine species in China are required to be used to derive the water quality standards of marine organisms; Secondly, according to the species distribution of marine ecosystems in China, the minimum toxicity data requirements of "5 families and 8 species" based on the characteristics of marine biota in China are put forward; Thirdly, the calculation method of acute value/chronic value of the same effect is proposed, which solves the problem that different types of toxic effects have different weights and achieves the purpose of better protecting marine species in China. At present, only the European Union has put forward this technical requirement internationally.
Q: How to consider the minimum toxicity data requirements of "8 species in 5 families" based on the characteristics of marine biota in China?
Yan Zhenguang, researcher of china environmental science Research Institute: According to statistics, there are more than 3,000 species of microalgae and macroalgae in China, accounting for 11% of the total marine species in China; Arthropoda, Chordata, Annelida, Mollusca, Echinoderm and Rotifera are the main animal groups in China’s sea areas, with more than 17,000 species, accounting for 59% of the total marine species in China. The number of marine species in the above key groups of marine life in China accounts for more than 70% of the total marine species in China.
In order to make the derivation of marine biological water quality benchmark reflect the characteristics of marine ecosystem in China, it is a basic principle to determine the minimum toxicity data requirements for the derivation of the benchmark. The tested species in seawater should cover the key groups of marine organisms in China, which is embodied in the following aspects: 1 family of microalgae or macroalgae, 2 families of crustaceans in Arthropoda and 1 family of bony fishes in Chordata; Other phylum, such as annelids, molluscs, echinoderms, rotifers, etc., or an unused family among crustaceans and teleost fishes.
The minimum toxicity data requirements of 8 species are mainly considered from the following two aspects: from the point of view of mathematical statistics, the more species, the better the model effect; From the point of view of the robustness of species sensitivity distribution model and the reliability of reference value, if the toxicity data covers key biological groups, then the uncertainty of reference value based on more than 8 species is within the acceptable range. There are eight criteria for evaluating the number of species as "good" in the minimum toxicity data requirements of the Australian/New Zealand Technical Guidelines for Derivation of Water Quality Standards.
At the same time, from the perspective of protecting marine biodiversity and marine ecology, it is clear that alien invasive species should not be used as a benchmark to deduce the tested species, such as marine microalgae that produce microcystins and Spartina alterniflora that compete with native species for nutrition.
Q: We have noticed that there are great differences in the exposure time of different kinds of marine life in the Guide. How do you consider it?
Professor Tan Qiaoguo of Xiamen University: Based on the standard testing methods of marine ecotoxicology at home and abroad, in order to protect marine species in China more pertinently, on the basis of analyzing the life history and reproductive characteristics of different types of marine species, the Guide puts forward the differential exposure time for 7 categories and 43 families of marine organisms such as algae, rotifers, annelids, molluscs, arthropods, echinoderms and chordates. According to the acute toxicity test, the generation cycle of Brachionus plicatilis is only about 2 days, and it is recommended that its exposure time should not be longer than 48 hours. For most arthropods and fish, the generation cycle is long, and the exposure time is recommended to be no more than 96 hours. According to the chronic toxicity test, the generation cycle of cladocera such as Daphnia mongolica is 5-7 days, and the exposure time is recommended to be no less than 5 days. However, the generation cycle of fish such as medaka can reach 3-4 months, and it is recommended that its exposure time should be no less than 21 days.
Q: As the vice chairman of the National Expert Committee on Environmental Standards, I would like you to talk about what work needs to be promoted in the field of marine environmental standards in China during the 14 th Five-Year Plan period.
Researcher Wang Juying, National Marine Environmental Monitoring Center: Marine environmental standards mainly include marine biological water quality standards and sediment quality standards for protecting marine ecosystems, nutrient standards for preventing water eutrophication, and people’s health standards for consuming seafood and marine recreational water.
China’s marine environmental benchmark research began in 1980s, and made some progress. For example, related research provided direct technical support for the formulation of Marine Sediment Quality (GB18668—2002); The national "863" special project "Research on Key Technologies for Determining the Threshold of Marine Environmental Effects of Typical Organic Pollutants from Land-based Sewage Discharges into the Sea" and the marine public welfare scientific research special project "Research and Formulation of Offshore Seawater Quality Standards/Standards" won the first prize and the second prize of the Marine Engineering Science and Technology Award respectively.
China’s sea area spans temperate zone, subtropical zone and tropical zone, and the marine ecosystem is diverse. From the perspective of protecting China’s marine ecosystem, during the Tenth Five-Year Plan period, based on protecting the integrity of China’s marine ecosystem, we should speed up the research and construction of China’s seawater quality benchmark system, develop the target pollutant marine biological water quality benchmark that has an important impact on China’s marine ecological environment quality, carry out the ecological risk threshold research of new pollutants such as endocrine disruptors, and develop the nutrient water quality benchmark of key sea areas such as Bohai Sea and South China Sea based on classification and zoning.
Experts in the field of marine environmental benchmark research in China are distributed in different institutions. In order to ensure the smooth progress of the marine environmental benchmark work in the 14th Five-Year Plan, we should give full play to the role of the National Environmental Benchmark Expert Committee as a think tank platform, and the superior research teams in the United Nations should work together to organize joint research. Through cooperation in a wider space and at a higher level, we will contribute wisdom and strength to the marine environmental benchmark work in China, better serve the marine ecological environmental protection in China, and meet the urgent need to speed up the modernization of the ecological civilization governance system and governance capacity.