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On December 22, 2021, China's Ministry of Ecology and Environment (MEE) published the HJ 1229-2021 Guidelines for Screening of Priority Assessment Chemical Substances[1] (Hereinafter referred to as the Guidelines), which took effect on January 1, 2022.
According to the Guidelines, chemical substances meeting any of the following criteria may be prioritized for environmental risk assessment.
1. PBT substances or vPvB substances, or highly suspected PBT or vPvB substances
PBT substances refer to substances that are persistent, bioaccumulative and toxic. vPvB substances refer to substances that are very persistent and very bioaccumulative.
According to Decision Method of Persistent, Bioaccumulative and Toxic Substances, and Very Persistent and Very Bioaccumulative Substances (GB/T 24782-2009)[2], the determination criteria for persistence, bioaccumulation and toxicity are listed in Table 1.
Persistence
Table 1 Determination criteria for persistent and very persistent substances[2]
Criteria for persistent (P) substances | Criteria for very persistent (vP) substances |
A substance that meets any of the following conditions is persistent: a) The half-life in seawater is longer than 60 d; b) The half-life in freshwater or river water is longer than 40 d; c) The half-life in marine sediments is longer than 180 d; d) The half-life in freshwater or river sediments is longer than 120 d; e) The half-life in soil is longer than 120 d. | A substance that meets any of the following conditions is very persistent: a) The half-life in seawater is longer than 60 d; b) The half-life in seawater or river water is longer than 60 d; c) The half-life in marine sediments is longer than 180 d; d) The half-life in freshwater or river sediments is longer than 180 d; e) The half-life in soil is longer than 180 d. |
If the half-life data is missing and the substance cannot be determined according to the criteria in Table 1, the substance may be determined using the screening criteria listed in Table 2.
Table 2 Screening criteria for persistent and very persistent substances[2]
Type of data | Endpoints | Results | Screening and determination of P |
Test data | Ready biodegradation test | Biodegradable | Non-P and non-vP |
Enhance ready biodegradat-ion test | Biodegradable | Non-P and non-vP | |
Inherent biodegradation: Zahn-Wellens test | With the DOC reduction method, the mineralization rate within 7 days is ≥70%, the logarithmic period does not exceed 3 days, the reduction is less than 15% before degradation occurs, and there is no pre-domesticated inoculation. | Non-P | |
Inherent biodegradation: MITI II test | With the respirometry (oxygen consumption), the mineralization rate within 14 days is ≥70%, the logarithmic period does not exceed 3 days, and there is no pre-domesticated inoculation. | Non-P | |
Predictive modelling | Biowin 2 (nonlinear model prediction) and Biowin 3 (final biodegradation time | Unrapid biodegradation (probability < 0.5)* and predicted time range for final biodegradation > 1 month (value < 2.2) | P |
Biowin 6 (MITI nonlinear model prediction) and Biowin 3 (final biodegradation time) | Unrapid biodegradation (probability < 0.5)* and predicted time range for final biodegradation > 1 month (value < 2.2) | P |
* The lower the probability, the faster the degradation.
Lack of rapid degradability is based on either a lack of ready biodegradability or other evidence of lack of rapid degradation. When no useful data on degradability are available, either experimentally determined or estimated data, the substance should be regarded as not rapidly degradable.
Bioaccumulation
Bioaccumulation can be determined based on bioconcentration factors (BCF). The data of both freshwater and marine organisms can be used.
Table 3 Determination criteria for bioaccumulative and very bioaccumulative substances[2]
Criteria for bioaccumulative (B) substances | Criteria for very bioaccumulative (vB) substances |
| BCF ≥2000 | BCF ≥5000 |
If the BCF data is missing and the substance cannot be determined according to the criteria in Table 3, the substance may be determined using the screening criteria listed in Table 4.
Table 4 Screening criteria for bioaccumulation[2]
Screening Criteria | Results |
n-octanol/water partition constant (lgKow)** ≦ 4.5 | Non-B and non-vB |
| Biomagnification factors (BMF) >1 | B or vB |
** The n-octanol/water partition constant (lgKow) is obtained through a test or quantitative structure-activity relationship (QSAR) method.
If the data for BCF and lgKow are both available for the substance, the measured lgKow values take precedence over estimated values and measured BCF values take precedence over lgKow values.
Toxicity
A substance that meets any of the following conditions is considered toxic:
Table 5 Determination criteria for toxicity[2]
Criteria for toxicity | Hazard class | |
a) The no observed effect concentration (NOEC) of marine or freshwater organisms<0.01 mg/L | Hazardous to the aquatic environment - chronic hazard[3] (Cat. 1) | |
b) The substance is classified as a carcinogen[4] | Carcinogenic | Carcinogenicity (Cat. 1A or 1B) |
Potentially carcinogenic | Carcinogenicity (Cat. 2) | |
c) The substance is classified as a teratogen[5] | Teratogenic | Reproductive toxicity (Cat. 1A, 1B) |
Potentially teratogenic | Reproductive toxicity (Cat. 2) | |
d) The substance is classified as a reproductive toxic substance[5] | Known/assumed to cause reproductive impairment and developmental toxicity to human | Reproductive toxicity (Cat. 1A, 1B) |
Likely to cause reproductive impairment and developmental toxicity to human | Reproductive toxicity (Cat. 2) | |
e)There is other evidence of chronic toxicity[1] [6] | Toxicity: substances that can cause severe, acute or chronic health risks and even death after inhalation, intake, or skin penetration. | Specific target organ toxicity (repeated exposure) (Cat. 1, 2) |
| Harmfulness: substances that can cause limited health risks after inhalation, intake, or skin penetration.
A substance or preparation is classified as harmful when the observable effects meet the following conditions:
a) LD50 (rats, oral) ≦50 mg/kg (bw/d);
b) LD50 (rat or rabbit, skin) ≦100 mg/kg (bw/d);
c) LC50 (rat, inhalation) ≦0.25 mg/L (6h/d). | ||
If the required data is missing and the substance cannot be determined according to the criteria in Table 5, the substance may be determined using the screening criteria listed in Table 6.
Table 6 Screening criteria for toxicity[2]
Type of data | Screening Criteria | Results |
Short-term aquatic toxicity (algae, daphnia, fish) | Half maximal inhibitory concentration (IC50) or median lethal concentration (LC50)≥0.1 mg/L | Not toxic |
Half maximal inhibitory concentration (IC50) or median lethal concentration (LC50)<0.1 mg/L | Potentially toxic | |
Half maximal inhibitory concentration (IC50) or median lethal concentration (LC50)<0.01 mg/L | Toxic | |
| Avian toxicity (Subchronic /chronic toxicity or reproductive toxicity) | Long-term NOEC<30 mg/kg (food) | Toxic |
2. Substances with carcinogenicity, mutagenicity and reproductive toxicity (CMRs), or highly suspected CMRs
Under GB 30000.23-2013 Part 23: Carcinogenicity[4], GB 30000.22-2013 Part 22: Germ cell mutagenicity[7], and GB 30000.24-2013 Part 24: Reproductive toxicity[5], substances classified as carcinogenicity (Cat. 1), mutagenicity (Cat. 1) or reproductive toxicity (Cat. 1) or highly suspected CMRs shall be priority considerations for PACs.
3. PT or BT substances
For persistent and toxic (PT) and bioaccumulative and toxic (BT) substances, they should possess toxicity above Cat. 2 for carcinogenicity, germ cell mutagenicity, reproductive toxicity, specific target organ toxicity (repeated exposure) or chronic aquatic hazard according to GB 30000 standards.
4. Endocrine disrupting chemicals (EDCs) or substances suspected of endocrine disruption
There are no unified definitions for endocrine disrupting chemicals (EDCs). Currently, the most academically recognized ones are from US Environmental Protection Agency (EPA) and World Health Organization/ International Programme on Chemical Safety (WHO/IPCS).
EDCs are defined by EPA as “an exogenous agent that interferes with synthesis, secretion, transport, metabolism, binding action, or elimination of natural blood-borne hormones that are present in the body and are responsible for homeostasis, reproduction, and developmental process.”
The group of molecules identified as endocrine disrupting chemicals is highly heterogeneous and can generally be classified according to their origins or endocrine disrupting effect.
Currently, the international community has listed 15 substances identified with the potential to interfere with human endocrine, which will be put under control. They include substances like perfluoroalkyl, bisphenol A, phthalates, organophosphorus pesticides, etc.
Companies should pay close attention to the latest information on EDCs as they play a crucial role in future research on the impact of environmental factors on human health.
5. Other highly suspected hazardous chemicals
Substances with highly suspected specific target organ toxicity (repeated exposure)[6] or chronic aquatic hazard[3] shall be priority considerations for PACs.
6. Chemicals with evidence or potential risk of environmental exposure
Chemical substances with evidence of environmental exposure, such as substances detected in environmental media, or substances detected in organisms that are caused by environmental exposure.
Chemical substances with potential risks for environmental exposure, such as chemicals produced or used in large quantities or volumes, chemicals that are widely dispersed in public, etc.
Companies should pay attention to products that have frequent interactions with consumers and are often associated with environmental exposure activities, such as detergents, cleaners, disinfectants, coolants, cosmetics, flavors and fragrances, air spray products, textile dyes, household paints, coatings, adhesives, lubricants, etc.
