城镇污水处理厂用地、运行及建设费用研究

汇总收集了国内已建城镇污水处理厂的大量资料,分析探讨了污水处理厂厂区占地面积、运行及建设费用与处理规模之间的关系,为今后污水处理厂的设计规划、工艺选择、建设费用分析等提供参考依据。研究表明污水处理厂厂区占地面积与处理规模可用函数表示,且具有较高的相关性。城镇污水处理厂所选用的工艺和处理规模对其运行成本有较大的影响,分别对大中小规模的污水处理厂在不同工艺下的运行成本进行分析,得出大规模污水处理厂的工艺选择对其运行成本影响不大;中规模污水处理厂易采用氧化沟工艺;小规模的污水处理厂适合采用SBR工艺。建设费用与污水处理规模有密切关系,由于建设费用受多种因素影响,又以江浙地区为例,对其建设费用与污水处理规模之间关系进行具体分析,对以上结论给予一定的补充。     

Multi-criterial evaluation of P-removal optimization in rural wastewater treatment plants for a sub-catchment of the Baltic Sea

Rural wastewater treatment plants (WWTP) are recognized as a significant phosphorous (P)-emission source in the German sub-catchments of the Baltic Sea. But enhancement of P-removal is cost intensive especially for small communities. This study proposes a concept to efficiently reduce P-emissions from WWTP by introducing low-cost non-constructional measures and assessing the resulting change of ambient water quality on a river basin scale. As case study, we choose the Warnow catchment in Mecklenburg-Vorpommern (Germany) where 76 % of WWTP-emissions originate from treatment plants without P-discharge limits. For these facilities, we evaluated two modification options: (1) optimization of enhanced biological Phosphorous removal (EBPR) in activated sludge systems (ASS) and/or (2) chemical precipitation (where EBPR is applicable). The total operational optimization potential in the Warnow catchment is about 20 %. Further improvements can only be applied by a chemical precipitation, with the drawback of increasing the wastewater disposal cost up to 6.5 euros CAP^?1a^?1. To prioritize relevant plants for improved P-removal we proposed two evaluation criteria: combining absolute emission, and impact on ambient water quality and costs.     

山地城市合流污水特细砂来源

对三峡库区山地城市合流制污水特细砂、管道沉积物、本地土壤等进行矿物成分分析表明，污水中特细砂矿物成分以石英、方解石，长石类为主，并含有少量云母、赤铁矿和石膏等矿物；认为特细砂主要来自周边砂壤质地土壤、风化岩石和地表沉积物；山地城市合流制管网（污水常规收集方式），山涧、边沟和冲沟（污水特殊收集方式）是细砂迁移的途径；生活污水和雨水是细砂迁移的载体；中亚热带湿润季风气候，加速成土母质主要是侏罗系紫色砂质岩、泥岩和石灰岩风化，而山地、丘陵地貌特征和充沛的雨量强化合流雨污水冲刷作用，导致水土流失加剧。因此，对于山地城市合流污水特细砂的治理，需要从合流制管网建设完善、水土流失防治、生活小区统一规划和污水处理厂除砂系统优化等多个方面进行控制。     

Models to Estimate Volatile Organic Hazardous Air Pollutant Emissions from Municipal Sewer Systems

Abstract

Emissions from municipal sewers are usually omitted from hazardous air pollutant (HAP) emission inventories. This omission may result from a lack of appreciation for the potential emission impact and/or from inadequate emission estimation procedures. This paper presents an analysis and comparison of the models available to estimate volatile organic HAP (VOHAP) emissions from sewers. Comparisons were made between the different theoretical foundations of the models, as well as between the emissions predicted by the models for a single sewer component. Sewer gas concentrations predicted by the models were also compared to measured sewer gas concentrations reported in the literature. Two of the models were compared in their ability to estimate sewer VOHAP emissions for a large U. S. city using National Pollution Discharge Effluent System data for the influent wastewater to the city's municipal wastewater treatment facilities. This estimate showed that, regardless of the model used, sewer emissions are a potentially significant source of VOHAP emissions in the urban environment. The choice of model, however, is thought to be less critical to sewer emission estimates than the source of sewer wastewater VOHAP concentration data.     

Polycyclic aromatic hydrocarbons in wastewater, WWTPs effluents and in the recipient waters of Beijing, China

In this study, surface water samples from the Wenyu River and the North Canal, effluent from major wastewater treatment plants (WWTPs) in Beijing, and wastewater from open sewers that discharge directly into the river system were collected and analyzed for 16 priority USEPA polycyclic aromatic hydrocarbons (PAHs). Concentrations of these 16 PAHs ranged from 193 to 1790 ng/L in river surface waters, 245 to 404 ng/L in WWTP effluents, and 431 to 2860 ng/L in the wastewater from the small sewers. The WWTP effluent was the main contributor of dissolved PAHs to the river, while wastewater from the small sewers contributed both dissolved and suspended particulate matter-associated PAH to the river as indicated by the high dissolved organic carbon and suspended particulate matter contents in the wastewater. Although the flow from each open sewer was small, a PAH discharge as high as 44 kg/year could occur into the river from these types of sewers. This amount was equivalent to about 22 % of the PAH loads discharged into the North Canal downstream from Beijing, whereas the remainder was mainly released by the major WWTPs in Beijing.     

膜生物反应器工艺污水处理厂设计进水水质的确定

城市污水处理厂进水水质是工程设计的基本参数,进水水质的测定分析对污水处理厂的设计具有重要意义。对无锡市城北污水处理厂的现状进水水质进行了调查和分析,提出按照水质指标浓度出现的频率确定污水处理厂设计进水水质的方法,并针对采用的膜生物反应器(MBR)工艺的特点,提出:(1)根据实测数据按照一定的保证概率可以用来确定城市污水处理厂设计进水水质;(2)为了使水质的确定更加符合设计工程的实际情况,根据实测数据分析确定设计进水水质指标时,一般还需要进行趋势性调整和季节性调整;(3)确定合理的指标浓度与流量,以此为依据进行反应池的工艺设计,同时要校核夏季温度高、浓度低、流量大和冬季温度低、浓度高、流量小的工况是否满足处理要求,然后取冬、夏季校核值以及未作季节性调整设计值中最不利情况作为设计值,才能充分保证出水达到处理要求。     

Perfluorochemicals in wastewater treatment plants and sediments in Hong Kong

The study reported in this paper examined the concentrations of nineteen perfluorochemicals (PFCs), including perfluoroalkyl sulfonates, carboxylates, and sulfonamides in samples collected from Hong Kong wastewater treatment plants (WWTPs) and sediments. The study was the first to use an external isolator column to assist in the quantification of PFCs in environmental samples without having to make internal modifications to a liquid chromatography system. Perfluorooctanesulfonate was found to be the dominant PFC pollutant in Hong Kong, and the WWTP sludge was the major sink of PFCs discharged from the urban areas. Compared to discharge influenced by industrial activities, much less perfluorooctanoate was found in waste streams. The significantly lower level of perfluorodecanesulfonate in WWTP sludge reflects the important influence of consumer products on PFC distribution. The dominance of even-chain length perfluoroalkyl carboxylates in all of the WWTP sludge samples investigated further suggests the strong aerobic degradation of fluorotelomer alcohols in WWTPs.     

Activated sludge systems removal efficiency of veterinary pharmaceuticals from slaughterhouse wastewater

The knowledge on the efficiency of wastewater treatment plants (WWTPs) from animal food production industry for the removal of both hormones and antibiotics of veterinary application is still very limited. These compounds have already been reported in different environmental compartments at levels that could have potential impacts on the ecosystems. This work aimed to evaluate the role of activated sludge in the removal of commonly used veterinary drugs, enrofloxacin (ENR), tetracycline (TET), and ceftiofur, from wastewater during a conventional treatment process. For that, a series of laboratory-controlled experiments using activated sludge were carried out in batch reactors. Sludge reactors with 100 μg/L initial drug charge presented removal rates of 68 % for ENR and 77 % for TET from the aqueous phase. Results indicated that sorption to sludge and to the wastewater organic matter was responsible for a significant percentage of drugs removal. Nevertheless, these removal rates still result in considerable concentrations in the aqueous phase that will pass through the WWTP to the receiving environment. Measuring only the dissolved fraction of pharmaceuticals in the WWTP effluents may underestimate the loading and risks to the aquatic environment.     

Removal of antibiotics from urban wastewater by constructed wetland optimization

Seven mesocosm-scale constructed wetlands (CWs), differing in their design characteristics, were set up in the open air to assess their efficiency to remove antibiotics from urban raw wastewater. A conventional wastewater treatment plant (WWTP) was simultaneously monitored. The experiment took place in autumn. An analytical methodology including HPLC-MS/MS was developed to measure antibiotic concentrations in the soluble water fraction, in the suspended solids fraction and in the WWTP sludge. Considering the soluble water fraction, the only easily eliminated antibiotics in the WWTP were doxycycline (61 ± 38%) and sulfamethoxazole (60 ± 26%). All the studied types of CWs were efficient for the removal of sulfamethoxazole (59 ± 30-87 ± 41%), as found in the WWTP, and, in addition, they removed trimethoprim (65 ± 21-96 ± 29%). The elimination of other antibiotics in CWs was limited by the specific system-configuration: amoxicillin (45 ± 15%) was only eliminated by a free-water (FW) subsurface flow (SSF) CW planted with Typha angustifolia; doxycycline was removed in FW systems planted with T. angustifolia (65 ± 34-75 ± 40%), in a Phragmites australis-floating macrophytes system (62 ± 31%) and in conventional horizontal SSF-systems (71 ± 39%); clarithromycin was partially eliminated by an unplanted FW-SSF system (50 ± 18%); erythromycin could only be removed by a P. australis-horizontal SSF system (64 ± 30%); and ampicillin was eliminated by a T. angustifolia-floating macrophytes system (29 ± 4%). Lincomycin was not removed by any of the systems (WWTP or CWs). The presence or absence of plants, the vegetal species (T. angustifolia or P. australis), the flow type and the CW design characteristics regulated the specific removal mechanisms. Therefore, CWs are not an overall solution to remove antibiotics from urban wastewater during cold seasons. However, more studies are needed to assess their ability in warmer periods and to determine the behaviour of full-scale systems.     

The fate of dissolved organic carbon (DOC) in the wastewater treatment process and its importance in the removal of wastewater contaminants

Goal, Scope and Background Dissolved organic carbon (DOC) constitutes a parameter of organic pollution for waters and wastewaters, which is not so often studied, and it is not yet regulated by directives. The term ‘DOC’ is used for the fraction of organics that pass through a 0.45 μm pores’ size membrane. The type of wastewater plays an important role in the quality of DOC and it has been shown that DOC may contain aquatic humic substances, hydrophobic bases, hydrophobic neutrals, hydrophilic acids, hydrophilic bases and hydrophilic neutrals. The quality of the DOC is expected to affect its fate in a wastewater treatment plant (WWTP), since a considerable fraction of DOC is not biodegradable, and it may be released in the aquatic environment together with the treated effluent. In the present study, the occurrence of DOC during the wastewater treatment process is investigated and its removal rates during primary, secondary and overall treatment are being estimated. Furthermore, a correlation is being attempted between DOC and the concentrations of selected Persistent Organic Pollutants (POPs) and Heavy Metals (HMs) in the dissolved phase of wastewaters, to examine whether there are common sources for these pollution parameters in WWTPs. Also, DOC is being correlated with the partition coefficients of the above-mentioned pollutants in wastewater, in order to examine the effect of ‘solubility enhancement’ in WWTPs and to evaluate the result of this phenomenon in the efficiency of a WWTP to remove organic pollutants. Methods For the purposes of this study, 24-h composite wastewater samples were collected from the influent (raw wastewater, RW), the effluent of primary sedimentation tank (primary sedimentation effluent, PSE) and the effluent of secondary sedimentation tank (secondary sedimentation effluent, SSE). Samples were analyzed for the presence of 26 POPs (7 PCBs and 19 organochlorine pesticides), 8 HMs and DOC. Results and Discussion Mean concentrations of DOC in RW and PSE were at similar levels (∼ 70 mg l⁻¹), suggesting that primary treatment has a minor effect on the DOC content of wastewater. DOC concentrations in SSE were significantly lower (∼ 19 mg l⁻¹) as a result of the degradation of organic compounds in the biological reactor. Calculated removals of DOC were 0.8% in the primary treatment, 63% in the secondary treatment, and 69% in the overall treatment, exhibiting large differences from other organic pollution parameters, such as BOD and COD. The overall DOC removal was found to be independent from the DOC concentration in raw wastewater. Poor correlation was also observed between the DOC content and the concentrations of wastewater contaminants, such as persistent organic pollutants (POPs) and heavy metals (HMs), probably suggesting that their occurrence in WWTPs is due to different sources. A good negative linear relationship was revealed between DOC concentrations and the logarithms of the distribution coefficients (K _d) of various POPs and HMs between the solid and the liquid phases of wastewater. This relationship suggests that DOC facilitates hydrophobic pollutants to remain in the dissolved phase thus causing lower removal percentages during the treatment process. Conclusion DOC was measured at three stages of a municipal WWTP that receives mainly domestic wastewater and urban runoff. DOC concentrations in untreated and primarily treated wastewater were almost equal, and only after the secondary sedimentation there was a decrease. Concentrations and removal rates of DOC were in the same levels as in other WWTPs that receive municipal wastewater. The origin of DOC was found to be different to the one of POPs and of HMs, as no correlation was observed between the concentrations of DOC and the concentrations of these pollutants. On the contrary, DOC was found to have significant negative correlation with the K _d of all pollutants examined, suggesting that it plays an important role in the partitioning of those pollutants between the dissolved and the sorbed phase of wastewaters. This effect of DOC on partitioning can affect the ability of WWTPs to remove toxic pollutants, and that way it facilitates the discharge of those chemicals in the aquatic ecosystems together with the treated effluent. Recommendation By the results of this work it is shown that the presence of DOC in wastewaters can significantly affect the partition of hazardous pollutants between the dissolved and the sorbed phase. It is therefore of importance that this parameter is controlled more in wastewaters, since it can cause a decrease in the efficiency of WWTPs to remove quantitatively persistent pollutants.     

Co-design of experimental nature-based solutions for decentralized dry-weather runoff treatment retrofitted in a densely urbanized area in Central America

The quality of water in many urban rivers in Latin America is increasingly degrading due to wastewater and runoff discharges from urban sprawl. Due to deficits in sanitary drainage systems, greywater is discharged to the stormwater drainage network generating a continuous dry-weather runoff that reaches rivers without treatment. One of the main challenges in the region is to achieve sustainable management of urban runoff for the recovery of rivers ecosystem integrity. However, retrofitting conventional centralized wastewater drainage networks into the existing urban grid represents important social, economic and technical challenges. This paper presents an alternative adaptive methodology for the design of Nature-based Solutions for decentralized urban runoff treatment. Through this study, technical solutions commonly used for stormwater management were adapted for dry-weather runoff treatment and co-designed for the particular conditions of a representative study area, considering space availability as the main constraining factor for retrofitting in urban areas. The application of a co-design process in a dense neighbourhood of the Great Metropolitan area of Costa Rica brought to light valuable insights about conditions that could be hindering the implementation of NBS infrastructures in Latin America.     

Illicit drugs in Canadian municipal wastewater and estimates of community drug use

In this study of wastewater treatment plants in three Canadian cities, selected illicit drugs, including cocaine and its major metabolite, benzoylecgonine (BE), amphetamine, methamphetamine and ecstasy (i.e. MDMA) were detected in untreated wastewater. Cocaine was the most widely used illicit drug at a median level for the 3 cities of 15.7 doses per day per 1000 people. For the other drugs, the median doses per day per 1000 people were 1.8 for amphetamine, 4.5 for methamphetamine and 0.4 for ecstasy. Methamphetamine use was highest in the largest city and cocaine use was lowest in the smallest city. Removal of the illicit drugs by wastewater treatment was generally >50%, except in a WWTP that uses primary treatment. The community consumption estimate for ecstasy in the present study is far below published estimates of the prevalence of ecstasy use among the Canadian population, which may be due to only occasional use of ecstasy.     

Determination of estrogenic compounds in wastewater using liquid chromatography-tandem mass spectrometry with electrospray and atmospheric pressure photoionization following desalting extraction

Two complementary LC-MS ionization methods, electrospray (ESI) and atmospheric pressure photoionization (APPI), have been optimized to determine three natural estrogenic compounds (estrone, 17beta-estradiol and estriol) and two synthetic estrogenic compounds (17alpha-ethynylestradiol and diethylstilbestrol) in the influent and effluent of wastewater treatment plants (WWTPs). The wastewater samples were first subjected to solid-phase extraction coupled with desalting extraction to remove matrix interference. The analytes were then detected using liquid chromatography-tandem mass spectrometry (LC-MS-MS) with ESI and dopant-assisted (DA) APPI to evaluate the ion suppression effect and to complement the detection and quantification of estrogenic compounds in complex wastewater samples. The average ion suppression factors for the extracts of the WWTP influent analyzed using ESI and APPI were 52+/-5% and 27+/-7%, respectively. The sensitivity and ionization efficiency of the LC-ESI-MS-MS system decreased dramatically when a complex matrix was present in the WWTP influent sample. Estrogenic compounds could be detected in the WWTP influent and effluent samples at concentrations below the parts-per-billion level. The lower detection limits obtained when using ESI and the higher matrix tolerance of the APPI method allowed the complete quantification of estrogenic compounds in very complex samples in a complementary manner.     

Impact of wastewater treatment plants on receiving surface waters and a tentative risk evaluation: the case of estrogens and beta blockers

Five estrogenic hormones (unconjugated?+?conjugated fractions) and 10 beta blockers were analyzed in three wastewater treatment plant (WWTP) effluents and receiving river waters in the area of Lyon, France. In the different samples, only two estrogens were quantified: estrone and estriol. Some beta blockers, such as atenolol, acebutolol, and sotalol, were almost always quantified, but others, e.g., betaxolol, nadolol, and oxprenolol were rarely quantified. Concentrations measured in river waters were in the nanogram per liter range for estrogens and between 0.3 and 210 ng/L for beta blockers depending on the substance and the distance from the WWTP outfall. The impact of the WWTP on the receiving rivers was studied and showed a clear increase in concentrations near the WWTP outfall. For estrogens, the persistence in surface waters was not evaluated given the low concentrations levels (around 1 ng/L). For beta blockers, concentrations measured downstream of the WWTP outfall were up to 16 times higher than those measured upstream. Also, the persistence of metoprolol, nadolol, and propranolol was noted even 2 km downstream of the WWTP outfall. The comparison of beta blocker fingerprints in the samples collected in effluent and in the river also showed the impact of WWTP outfall on surface waters. Finally, a tentative environmental risk evaluation was performed on 15 sites by calculating the ratio of receiving water concentrations to predicted non-effect concentrations (PNEC). For estrogens, a total PNEC of 5 ng/L was considered and these substances were not linked to any potential environmental risk (only one site showed an environmental risk ratio above 1). Unfortunately, few PNECs are available and risk evaluation was only possible for 4 of the 10 beta blockers studied: acebutolol, atenolol, metoprolol, and propranolol. Only propranolol presented a ratio near or above 1, showing a possible environmental risk for 4 receiving waters out of 15.     

Stochastic modeling of chemical oxygen demand transformations in gravity sewers.

Wastewater quality characteristics in terms of biomass, its substrates, and the corresponding kinetic and stoichiometric parameters were determined based on 109 wastewater samples originating from five different campaigns in four different sewer networks. Quality parameters were determined by model calibration of measured wastewater oxygen uptake rates applying a model that describes the aerobic breakdown of wastewater organic matter. Thereafter, the distributions of the parameters were analyzed. Two of the five datasets were obtained at the upstream end of a five-km-long, intercepting gravity sewer. For each of these upstream wastewater samples, downstream samples were collected with a delay corresponding to the residence time. The upstream distributions of the wastewater composition were used as boundary conditions for a Monte Carlo simulation. The calculated downstream distributions were compared to the measured downstream distributions and good agreement was observed.     

合流制排水系统溢流污染就地调蓄处理控制技术研究

在对高效混合絮凝斜板沉淀工艺进行现场中试的基础上,将化学强化处理工艺与调蓄池相结合,针对上海市某合流制排水系统,进行调蓄/沉淀池的概念设计,提出主要设计参数,利用计算流体力学(CFD)模型对调蓄/沉淀池进行优化设计.试验和模拟结果表明,调蓄/沉淀池与单纯的调蓄池相比具有更好的溢流污染控制效果和效益/造价比.     

Design of control strategies for nutrient removal in a biological wastewater treatment process

Wastewater treatment plants (WWTP) are highly non-linear operations concerned with huge disturbances in flow rate and concentration of pollutants with uncertainties in the composition of influent wastewater. In this work, the activated sludge process model with seven reactor configuration in the ASM3bioP framework is used to achieve simultaneous removal of nitrogen and phosphorus. A total of 8 control approaches are designed and implemented in the advanced simulation framework for assessment of the performance. The performance of the WWTP (effluent quality index and global plant performance) and the operational costs are also evaluated to compare the control approaches. Additionally, this paper reports a comparison among proportional integral (PI) control, fuzzy logic control, and model-based predictive control (MPC) configurations framework. The simulation outcomes indicated that all three control approaches were able to enhance the performance of WWTP when compared with open loop operation.

     

模糊综合评价在氧化沟能耗评价中的应用

在对环太湖流域4座采用氧化沟工艺的城市污水处理厂进行能耗调研的基础上,以吨水位能耗(E)、生化段装机容量(η)、有机物去除量(ΔCOD)、氨氮去除量(ΔNH3-N)、总磷去除量(ΔTP)作为评价氧化沟法城市污水厂能耗的指标,结合隶属度函数,应用单因素模糊综合评价法对所调研的污水处理厂进行能耗水平定量评价。得出A污水处理厂的能耗级别为二级,B和C污水处理厂的能耗级别为三级,D污水处理厂能耗级别为五级。级别越高能耗越大。     

Wastewater treatment plants (WWTPs) as a source of sediment contamination by toxic organic pollutants and fecal sterols in a semi-enclosed bay in Korea

Toxic organic contaminants and a macrobenthic community were assayed in sediments collected near a wastewater treatment plant (WWTP) outfall to assess the impact of WWTP discharges on an aquatic environment. Average concentrations of toxic organic contaminants in sediments from 20 locations were 96.7ng TEQ/kg dry matter for PCDD/Fs, 1.84ng TEQ/kg dry matter for dioxin-like PCBs, 29.1microg/kg dry matter for PBDEs, 411microg/kg dry matter for nonylphenols, 1021microg/kg dry matter for fecal sterols, and 928microg/kg dry matter for PAHs. Concentrations of all the organic contaminants and fecal sterols varied widely and there was a clear decrease in concentration gradients with increasing distances from the WWTP outfall. This result suggests that WWTP activities contribute to contamination by organic chemicals. A survey of benthic organisms showed the dominance of a few polychaete species, indicating a deterioration of the macrobenthic community by the WWTP discharge. Non-parametric multidimensional scaling (MDS) ordination and Spearman correlation analyses showed that organic contamination is associated with the benthic community structure. For polychaete species, the sensitive species for organic contaminants was Paraprionospio pinnata, while contaminant-tolerant species were Spiochaetopterus koreana and Capitella capitata. BIOENV analyses of all locations suggested PCDDs and PCDFs as the major contaminants influencing the structure of the macrobenthic community. The present study highlights that continuous WWTP discharges contribute to severe organic contamination and risks for the benthic community in an aquatic ecosystem.     

Acidic pharmaceuticals in domestic wastewater and receiving water from hyper-urbanization city of China (Shanghai): environmental release and ecological risk

The occurrence, behavior, and release of five acidic pharmaceuticals, including ibuprofen (IBP), naproxen (NPX), ketoprofen (KEP), diclofenac (DFC), and clofibric acid (CA), have been investigated along the different units in a tertiary-level domestic wastewater treatment plant (WWTP) in hyper-urbanization city of China (Shanghai). IBP was the most abundant chemicals among the measured in raw wastewater. The loads of the acidic pharmaceuticals in the WWTP influent ranged from 7.5 to 414 mg/day/1,000 inh, which were lower than those reported in the developed countries suggesting a less per capita consumption of pharmaceuticals in Shanghai. IBP obtained by highest removal (87 %); NPX and KEP were also significantly removed (69–76 %). However, DFC and CA were only moderately removed by 37–53 %, respectively. Biodegradation seemed to play a key role in the elimination of the studied pharmaceuticals except for DFC and CA. An annual release of acidic pharmaceuticals was estimated at 1,499 and 61.7 kg/year through wastewater and sludge, respectively, from Shanghai. Highest pharmaceuticals concentrations were detected in the effluent discharge point of the WWTP, indicating that WWTP effluent is the main source of the acidic pharmaceuticals to its receiving river. Preliminary results indicated that only DFC in river had a high risk to aquatic organisms. Nevertheless, the joint toxicity effects of these chemicals are needed to further investigate.