Application domain for pesticide residues based on SRFs
Pesticides have been widely used since the mid-twentieth century for pest control. They are present in a wide range of physicochemical diversity and can be persistent in water, accumulated in sediments, and bio-accumulated in biota, which could cause potential environmental and health issue due to their potential toxicity to non-target organisms (Ccanccapa et al. 2016). The residual pesticide compounds were sampled from the water of the Ebro River Basin as the target pollutant, followed by a multi-dimensional assessment and analysis of the environmental risks of the pollutants. Basic data of pollutants in river water are shown in Table 1. The comparison of risk levels of pollutants in river basins using both methods are shown in Fig. 2.
Table 1
The half-life data of target pollutants in Ebro River and PNEC data table
Name of contaminant
|
CAS
|
Chemical formula
|
Half-life(d)
|
Half-life threshold(d)
|
C
|
MEC
(ng L− 1)
|
PNEC (ng L− 1)
|
Carbendazim
|
10605-21-7
|
C9H9N3O2
|
8
|
60
|
7.5
|
2.78
|
1.5
|
Fenitrothion
|
122-14-5
|
C9H12NO5PS
|
86.1
|
60
|
0.70
|
0.11
|
0.09
|
Hexythiazox
|
78587-05-0
|
C17H21ClN2O2S
|
24.6
|
60
|
2.44
|
7.41
|
6.1
|
Imazalil
|
35554-44-0
|
C14H14Cl2N2O
|
151
|
60
|
0.40
|
61.01
|
92
|
Metolachlor
|
51218-45-2
|
C15H22ClNO2
|
39
|
60
|
1.54
|
0.55
|
1
|
Prochloraz
|
67747-09-5
|
C15H16Cl3N3O2
|
60
|
60
|
1
|
15.59
|
18
|
Propazine
|
139-40-2
|
C9H16ClN5
|
90
|
60
|
0.67
|
0.14
|
40
|
Tebuconazole
|
107534-96-3
|
C16H22ClN3O
|
62
|
60
|
0.97
|
2.36
|
100
|
The results indicated that the risk levels for carbendazim (CARB), hexthiazole (HTZ) and imazalil in the pollutants were changed significantly. CARB is a broad-spectrum fungicide and used for foliar spraying, seed treatment and soil treatment (Mrinmay et al. 2019). After use, residues may subsequently appear in food, water, soil, or other media, and can also be absorbed by crops and passed along the food chain to humans. Exposure to CARB can lead to downregulation of humoral immune function and failure of spermatogenesis (Fang et al. 2010; Xiao et al. 2013). The risk of CTAB is reduced from high to medium by calculating and comparing the two methods, which can appropriately reduce the risk assessment of carbendazim. HTZ is an efficient and environmentally friendly acaricide. HTZ is also a widely used to control pests of a variety of food crops. According to the European Food Safety Authority (EFSA), EFSA recently proposed to increase the maximum residue limit of hexythiazox in tea from 0.05 mg/kg to 4 mg/kg, which to a certain extent can reflect the doubts about its environmental risk, and the risk should be appropriately reduced.
For all water samples obtained, SRF values were calculated to be below 0.1, indicating the presence of pesticides may cause a low risk to aquatic organisms with the exception for imazalil where an SRF value of 1.66 was observed, indicating that its presence may pose a high risk to aquatic organisms. These fungicides like imazalil have been used in some agribusinesses at concentrations up to 0.6-2 g L− 1 to control fungal infections during fruit and seed storage (Lozowicka et al. 2016). As a result, high amounts of imazalil residues were released during the washing step, producing high volume of contaminated wastewater (Carra et al. 2015; Karas et al. 2016; Ponce-Robles et al. 2017). Imazalil is also recommended for use as a fungicide by the Ministry of Agriculture in China. Although its toxicity is low, due to the high emission strongerenvironmental sustainability, the monitoring of its environmental emission should be further strengthened. In addition, the European Union's Food Safety Authority (EFSA) recommend that the potential environmental risk of azole drugs should be under close vigilance after reviewing the maximum Residue Limits (MRLS) for imazole in certain foods in On 30 October 2018.
As expected, after evaluating the worst-case scenario imazalil exhibited a high risk to aquatic organisms while the presence of carbendazim and hexythiazox posed a moderate risk to aquatic organisms. The presence of pesticide residues in the aquatic environment, particularly at high concentrations, may cause detrimental effects on aquatic organisms and eventually human beings.
Application Domain For Pfoas Based On Srfs
In this study, the surface water of Tianjin city was sampled for the risk assessment, and target pollutants included perfluorinated compounds and organophosphate. Basic data such as chemical formula and half-life of pollutants are shown in Table 2. The evaluation results are shown in Fig. 3.
Table 2
Perfluorinated compounds and organophosphate in Tianjin surface water
Compound
|
Abbr.
|
CAS
|
Chemical formula
|
Half-life(d)
|
Half-life threshold (d)
|
C
|
MEC
(ng L− 1)
|
PNEC (ng L− 1)
|
Perfluorrooctane sulphonate
|
PFOS
|
1763-23-1
|
C8HF17O3S
|
1.48E + 04
|
60
|
0.0041
|
1.61
|
1000
|
Perfluorooctanoic acid
|
FFOA
|
335-67-1
|
C8HO2F15
|
1.58E + 03
|
60
|
0.038
|
15.1
|
100000
|
Triethyl phosphate
|
TEP
|
78-40-0
|
C6H15O4P
|
4.90
|
60
|
12.24
|
1.683
|
9.0E + 05
|
Tri(2-ethylhexyl) phosphate
|
TEHP
|
78-42-2
|
C24H51O4P
|
4.23
|
60
|
14.18
|
47.4
|
5.0E + 05
|
Tri(2-chloroethyl) phosphate
|
TCEP
|
115-96-8
|
C6H12Cl3O4P
|
3.68
|
60
|
16.30
|
473.79
|
5.1E + 04
|
Tris(1-chloro-2-propyl) phosphate
|
TCPP
|
13674-84-5
|
C9H18Cl3O4P
|
3.68
|
60
|
16.30
|
6.3
|
4.5E + 04
|
Tris(1,3-dichloro-2-propyl) phosphate
|
TDCP
|
13674-87-8
|
C12H15Cl6O4P
|
4.08
|
60
|
14.71
|
3.249
|
3.9E + 04
|
Perfluorinated compounds (PFCs) have been recognized as emerging global pollutants and have attracted scientific and political attention worldwide (He et al. 2018). To date, PFCs have been found to be released into the environment and biological matrices through the use of PFC-containing products or through the degradation of their precursors. Due to their bioaccumulation and multiple toxicities, PFCs are persistent in the environment and widely present in wildlife and humans (Coperchini et al. 2015). Their presence in the environment poses a risk to ecosystems. Using both RQ and SRF methods of, the risk values of PFOS were found to be less than 1, and its risk level were changed from low to medium. The rise of PFOS levels in surface water may therefore affect aquatic ecosystems. The PFOA risk level was not changed. But the risk of PFCs contamination in surface water to ecosystem should draw more attention because of their bioaccumulation (Lu et al. 2019).
Organophosphate esters (OPEs) are widely used in plastics, textiles, building materials, lubricants, electronics and coatings due to their excellent physicochemical properties and high cost performance (Li et al. 2016). Although incidents of environmental contamination from OPE are rarely reported, they are ubiquitous in the environment as re-emerging contaminants considered to be potential health concerns, and research on the toxic effects of these chemicals is increasing. Bioaccumulation data and risk assessments of OPEs in aquatic organisms such as fish, algae and snails have been reported (Xing et al. 2019; Zha et al. 2018). The SRF values of TEP, TEHP, TCEP, TCPP, and TDCP in the organophosphate in the figure were all less than 1, indicating that there was no risk for aquatic organisms in the watershed.
Application domain for endocrine disruptors based on SRFs
Endocrine disruptors (EDs) are compounds that cause great environmental problems. EDs are a large group of substances of natural or anthropogenic origin that interfere with an organism's endocrine system. They interact with estrogen receptors to enhance or inhibit the normal function of the hormone, potentially leading to adverse effects such as sterility and species extinction in aquatic organisms (Filipkowska and Lubecki 2016; Tijani et al. 2016). Although such pollutants are usually present in the environment in low concentrations, some of them are toxic per liter concentrations (Teixeira et al. 2021). Their adverse effects leading to certain cancers and other non-communicable diseases such as diabetes and adverse effects on aquatic life populations have been reported (Olaniyan and Okoh 2020). In this study, endocrine disruptors in surface water of Xiang Jiang River were used as target pollutants to evaluate their environmental risks. Related pollutant data are shown in Table 3. RQ and SRF methods were used to calculate the risk value of each pollutant of endocrine disruptors in Xiang Jiang River. The comparison results are shown in Fig. 4.
Table 3
Endocrine disruptors in surface water of Xiang Jiang River, China
Name of contaminant
|
CAS
|
Chemical formula
|
Half-life(d)
|
Half-life threshold(d)
|
C
|
MEC
(ng L− 1)
|
PNEC (ng L− 1)
|
Progesterone
|
57-83-0
|
C21H30O2
|
666.66
|
60
|
0.09
|
8.1
|
415
|
Testosterone
|
58-22-0
|
C19H28O2
|
1.17E + 04
|
60
|
5.1E-03
|
6.5
|
100
|
Androstenedione
|
1963-5-8
|
C19H26O2
|
1.12E + 03
|
60
|
5.4E-02
|
4.4
|
14
|
Estrone
|
53-16-7
|
C18H22O2
|
1.06E + 05
|
60
|
5.7E-04
|
51.33
|
6
|
Bisphenol A
|
1980-5-7
|
C15H16O2
|
4.02E + 06
|
60
|
1.5E-05
|
30.9
|
2000
|
The lack of regulated monitoring has resulted in increasing concentrations of micropollutants in the environment and increased public concern about the presence of endocrine disrupting compounds in surface waters. In order to remove these compounds, appropriate identification and evaluation methods need to be employed. The risk values were significantly changed for progesterone, testosterone, androstenedione and bisphenol A from low to high risk using the SRF method. Chronic exposure to testosterone at lower concentrations can cause endocrine disruption in aquatic animals (Appa et al. 2018). In addition, environmental pollutant levels of estrogen may contribute to breast cancer in women, prostate cancer in men, and reproductive system abnormalities in men (Sutaswiriya et al. 2021). Androstenedione belongs to steroidal androgens. It mainly comes from the excrement and urine of livestock and poultry as well as the discharge of wastewater from paper mills and urban sewage treatment plants. The continuous discharge of pollution sources leads to the male phenomenon of fish in some areas, which has a strong negative impact on species richness and ecological balance, and raises the environmental risk.
Bisphenol A (BPA) is a well-known endocrine disrupting compound commonly found in industrial wastewater and wastewater treatment plants (Godiya and Park 2022). The widespread use of BPA in the plastics industry has led to its widespread distribution in the environment and to inevitable human exposure to the substance through dietary and non-dietary sources (Geens et al. 2012; Usman and Ahmed 2016). Previous studies have shown that BPA can be detected in dust, surface water, industrial sewage, sediment and soil. BPA can interact with estrogen and nuclear receptors to varying degrees, interfering with their natural expression, thereby acting as endocrine disruptors. There is good evidence that BPA at 1–10 µg ml− 1 is acutely toxic to freshwater and marine species, and this disturbance can adversely affect reproductive and metabolic functions. This has prompted strict EU regulations on the use of BPA in some industrial products, leading to the widespread use of its structural and functional analogs in manufacturing, such as bisphenol AF (BPAF) (Artham and Doble, 2012; Mouneimne et al. 2017; Chen et al. 2021). Combining the persistence level and the exposure effect, the risk assessment level is high, so the release of BPA in the water environment and its further identification are still worthy of attention.