Pollution Control Strategies Research Articles

Biodegradation of Dibutyl Phthalate by the New Strain Acinetobacter baumannii DP-2.

Optimizing the culture conditions of DBP degradation by bacteria and investigating its biodegradation pathways have a great importance to develop effective PAEs pollution control strategies. In this study, we investigated the cultivation condition optimization, degradation kinetics, and degradation pathways of a newly isolated dibutyl phthalate (DBP) degradation strain, which was isolated from activated sludge and identified as Acinetobacter baumannii DP-2 via morphological observation, biochemical identification, and 16S rDNA sequence analysis. The degradation conditions were optimized based on the results of single-factor experiments and response surface optimization experiments. The DBP degradation rate of Acinetobacter baumannii DP-2 reached up to 85.86% when the inoculation amount was 17.14%, the DBP concentration was 9.81 mg·L−1 and the NaCl concentration was 5 g·L−1. The GC-MS analysis results indicated that the intermediate metabolites of Acinetobacter baumannii DP-2 mainly consisted of DMP, MBP, PA, and benzoic acid derivatives, which confirmed the degradation pathway from DBP to PA under aerobic pathway and then to BA under anaerobic pathway. In summary, Acinetobacter baumannii DP-2 shows great potential for the degradation of DBP in contaminated soils.

The role of sources and meteorology in driving PM2.5-bound chlorine

The role of chloride in atmospheric chemistry received increased attention over recent years. Given the primary and chemical-active nature of PM2.5-bound chlorine (p-Cl-), it makes sense to get to know the sources and processes of p-Cl-. The temporal behavior of observed p-Cl- concentration based on 1-h high resolution exhibited seasonal variation of high in winter, low in summer and diurnal variation of high in the morning, low in afternoon. Meteorological normalization technique based on random forest was used to disentangle the effects of emission changes which affected the seasonal variation and meteorology which was related to diurnal variation on p-Cl-. Generalized additive model (GAM) identified RH and temperature as the key meteorological factors of p-Cl- generation, and p-Cl- pollution was serious under the condition of low temperature and high RH. Dispersion-normalized positive matrix factorization (DN-PMF) was used to apportion the p-Cl- to its sources, finding that coal combustion was the main source of p-Cl-, followed by biomass burning and industrial process emissions. Our results will provide the basis for further analysis the causes of p-Cl- pollution and composite air pollution control strategies.

Water Quality Status of Jatigede Reservoir Sumedang Regency, West Java

With the captured fisheries sector as a livelihood for residents around Jatigede, it is feared that water quality will decline. Another function of the Jatigede Reservoir is to irrigate irrigation canals, control floods, source PLTA power, and raw water to serve the people of Sumedang, Indramayu, and Cirebon city. The intended purpose is to determine the quality of water in the Jatigede Reservoir. This research was carried out in Jatigede Reservoir from November 2020 to August 2021, using the survey method. The method of determining the location used a purposive sampling method, carried out at five stations representing Jatigede Reservoir. The water quality parameters used are temperature, pH, dissolved oxygen, and brightness. The results of observations of water quality in Jatigede Reservoir with temperatures ranging from 28°C-29°C, pH ranging from 6.67–8.35, dissolved oxygen ranging from 6.8–7.83 mg/l and brightness ranging from 70-93.8 cm indicate that the water quality of the Jatigede Reservoir is still categorized into good water quality and is ideal for capture fisheries sector activities in the Jatigede Reservoir. The results of the status of water quality in the waters of the Jatigede Reservoir are included in the category of Fulfill Quality Standards to Lightly Polluted, and the average Pollution Index value ranges from 1.75 to 3.01 in class II water quality standards and 0.86-1.94 in class III water quality standards. Water quality in Jatigede Reservoir during the research was influenced by the input of river flow in the form of organic and inorganic waste. Water pollution control strategies can be carried out by increasing the inventory and identification of pollutant sources, improving waste management, determining the capacity of the pollution load, increasing knowledge and community participation in waste management, increasing supervision of wastewater development, and improving water quality monitoring.

Estimates of PM2.5 concentrations spatiotemporal evolution across China considering aerosol components in the context of the Reform and Opening-up

With astonishing and rapid development in China since the Reform and Opening-up in 1978, serious air pollution has become a great challenge. A better understanding of the response of PM2.5 pollution to socioeconomic development after the Reform and Opening-up policy is benefit for pollution control. However, heterogeneous influences of biophysical and socioeconomic activities on PM2.5 pollution pose great challenges in statistical simulation of PM2.5. Few statistical model regards aerosol species as the explanatory variables for heterogeneous formation mechanism to retrieve PM2.5 concentration. In this research, monthly PM2.5 concentration in China during 1980–2020 was reconstructed by a novel statistical strategy considering aerosol components (AC-RF). Three cross-validation (CV) methods, sample-based CV, spatial-based CV and temporal-based CV results indicated satisfactory performance of AC-RF model with correlation coefficient (R) of 0.92, 0.90, 0.86, respectively. A three-stage concluded on PM2.5 concentration annual variation in China was drawn as followed: Before 2000, PM2.5 level in China represented smooth evolution and mainly influenced by natural events with polluted region locating in Xinjiang province, North China and Central China. Since 2000, PM2.5 concentration increased to high level in the context of rapid socioeconomic development. Severe air pollution covered Jing-Jin-Ji agglomeration, Central China and Sichuan Basin. During 2012–2020, PM2.5 declined and polluted region shrank, which was benefited by the strictest-ever air pollution control measures. Based on aerosol components analysis, sulfate aerosol exhibited the most significant increase trend in recent 40 years and black aerosol variation is the most closely related to PM2.5 pollution. In conclusion, unsustainable development is the culprit for air quality deterioration. Strict and continuous air pollution control strategies are effective for air quality improvement.

Modelling the role of institutional quality on carbon emissions in Sub-Saharan African countries

The motivation of this study stems from the United Nations Sustainable Development Goals on clean and responsible energy consumption, climate change mitigation and sustainable economic growth (UN-SDGs-7, 11, 12 and 13). The present study examines the impact of institutional quality on CO2 emissions in the presence of the Environmental Kuznets Curve (EKC) framework using data on CO2 emissions and the six dimensions of institutional quality from the World Governance Indicators (WGI). The current study focuses on selected 30 Sub-Saharan African (SSA) countries over the annual period from 2000 to 2021. The EKC hypothesis revealed CO2 emissions are substantially reduced by corruption control, regulatory quality, and the rule of law. Findings from the Dumitrescu and Hurlin causality test showed a one-way causality running from CO2 emissions to industrialization. Similar uni-directional causality is observed between economic growth, and energy consumption. On the other hand, we observed a two-way causality flow from CO2 emissions to population growth and all indices of institutional quality over the investigated period. These findings indicate that government agencies should efficiently implement acceptable strategies for pollution control and enact public benefit environmental regulations in the form of a healthier climate for the entire population.

The role of source emissions in sulfate formation pathways based on chemical thermodynamics and kinetics model

Sulfate is a major PM2.5 constituent and poses a significant threat to ecosystems and human health, which has attracted lots of attention to the sulfate formation mechanism. In recent years, there has been great scientific interest in the multiphase oxidation of SO2 in aqueous aerosol particles. Many factors are involved in the reaction process, including precursor SO2, oxidants/catalysts, and aerosol acidity, which are three channels closely related to the source emission. The conjoint analysis of source emissions and sulfate aqueous formation can provide a scientific basis for designing effective strategies, though the related research is extremely limited. Here, we applied an improved solute strength-dependent chemical Thermodynamics & Kinetics model (for aqueous pathway contribution) and the Partial Target Transformation-Positive matrix factor model (for source apportionment) to explore the role of source emission in sulfate aqueous formation. The results indicated H2O2 aqueous oxidation was the dominant pathway (65.9 %), and secondary nitrate source may grow together with sulfate formation from H2O2 pathway. H2O2 and TMI pathways were related to higher SOR (sulfur oxidation rate). TMI pathway was significant in summer (54.6 %) and increased with secondary sources and vehicle exhaust. NO2 pathway was more significant at low secondary source and high coal combustion (higher contribution of NO2 pathway appeared in winter, 24.7 %). While high formation rate of the O3 pathway always occurred at low source levels. Coal combustion and vehicle exhaust showed obvious effects on sulfate aqueous formation. Notably, aerosol acidity is a significant factor related to sources and plays a key role in sulfate formation. The result also suggested aerosol pH may be more important than the amounts of substances involved in the oxidation reaction. The findings in this work can provide useful information for better understanding sulfate aqueous formation and offer a scientific basis for designing strategies for air pollution control and sulfate mitigation.

Kualitas Air Sungai

This study aims to analyze the water quality of the Barumun river in Pinang City based on water quality criteria and formulate a pollution control strategy that needs to be implemented. The method used is descriptive and quantitative by analyzing river water quality status based on the pollution index. The results showed that the PI value of Barumun river water ranged from 0.82 to 1.71. The recommended pollution control strategies are: 1) maintaining river border protection zones involving environmental cadres and green communities in monitoring; 2) supervision and control of water pollution along the river; 3) improving monitoring of river water quality and supervision of wastewater discharge into rivers; 4) the granting of a wastewater disposal permit (IPLC) to the river must pay attention to the condition of the capacity of the river's pollution load capacity and enforce environmental laws against business actors who violate the established environmental quality standards. In conclusion, the Barumun River in Kota Pinang has decreased in quality, with the status of water quality being lightly polluted. The recommendations for water pollution control strategies that need to be implemented are progressive strategies.
 Keywords: Water Quality, Water Pollution Control, Water Quality Status

Assessment of the effect of meteorological and emission variations on winter PM2.5 over the North China Plain in the three-year action plan against air pollution in 2018–2020

Air quality in Beijing-Tianjin-Hebei and its surrounding regions has been significantly improved during the Three-Year Action Plan for Winning the Battle Against Air Pollution from 2018 to 2020. The PM2.5 concentration can be significantly influenced by meteorological conditions, and the effectiveness of anthropogenic emissions reduction on PM2.5 over the North China Plain remains unclear. In this study, the Nested Air Quality Model System (NAQPMS) and observations were used to quantitatively examine the contribution of meteorological and emission variations to autumn-winter (November to February) PM2.5 concentrations in Beijing and its surrounding regions from 2018 to 2020. The model reproduced the temporal evolution of atmospheric pollutants and components well. The results showed that the observed mean PM2.5 concentrations during the winter were reduced by 15% and 29% in 2019 and 2020, respectively, compared with that in 2018. In 2019, the meteorological conditions over the Beijing-Tianjin-Hebei (BTH) region were poor, causing an increase of PM2.5 by 7.6% in BTH and 11% in Beijing; therefore, the control of air pollutant emission compensated for the unfavorable influence of meteorology and emission reduction was the decisive factor for PM2.5 reduction; In 2020, the meteorological conditions were relatively favorable, and the changes in meteorological factors and emission reduction led to a decrease in PM2.5 concentration by 18.6% and 10.5%, respectively, compared to 2018. Emission reduction also contributed to decrease in nitrate, ammonium, organic matter, element carbon and precursors. This work confirmed the obvious environmental benefit of pollution control measures from 2018 to 2020. There was obvious regional heterogeneity in the effect of meteorology and the impact of adverse meteorological conditions should be considered during the formulation of air pollution control measures. The results can serve as a reference for the formulation of air quality objectives or the evaluation of the environmental effect of pollution control schemes.

Grid computing method for atmospheric environmental capacity coupled with ventilation coefficient using CALPUFF simulation and GIS spatial analysis technology

ABSTRACT Atmospheric environmental issues have evolved from point source pollution to regional pollution, leading to controlling specific air pollutant emissions. A-value method has been found suitable for estimating large-scale atmospheric environmental capacity rather than small-scale, resulting in the inaccuracy of developing air pollution control strategy. This study proposed a grid computing method based on the CALPUFF modelling system and GIS spatial analysis tool. The meteorological data from the MM5 model were used to simulate the spatial distribution of air pollutants. The meteorological flow field data was used to simulate the ventilation coefficient. The A value was revised with the simulated to achieve accurate results of atmospheric environment capacity. The credibility was verified by applying this method to Fengtai District, Beijing, China. The research area was divided into small partitions via the ArcGIS spatial analysis tool. The simulation results agreed well with the observation data from actual monitoring stations, even for the PM10 concentration with the most significant error (MRE: 7.05%−13.28%, RMSE: 11.62–17.89, R 2: 0.84–0.90). The GIS spatial analysis tools were applied to match the underlying surface types and overcome the restrictions of administrative boundary management. The study proposed four schemes to achieve differentiated air pollutant emission reduction and develop suitable control strategies. Furthermore, this method can be applied on different scales of natural geographic boundaries and realize the precise spatial management of atmospheric environmental capacity.

Spatial-temporal characterization of air pollutants using a hybrid deep learning/Kriging model incorporated with a weather normalization technique

A scarce distribution of the PM2.5 chemical compositions monitors reduces the applicability of scientific information for policymakers to assess the effectiveness of air pollution control strategies. There is an urgent need for a spatial-temporal prediction model for characterizing PM2.5 chemical compositions to assess exposure risks and develop effective air pollutants reduction strategies. In this study, the spatial-temporal variations of NO3− and SO42− were characterized using a hybrid multi-step ahead neural network (MSA-NN)/Kriging model in the urban areas with limited PM2.5 constituents monitoring stations. A meteorological normalization technique was further applied to develop a de-weather model to investigate temporal variations of air pollutants during the level 3 COVID-19 alert in central Taiwan. The MSA-NN algorithm could predict 94% and 91% of NO3− and SO42−, respectively, at the t+1-time horizon predictions. Based on the predicted results using the present de-weather model, the reduction in primary emissions attributed to the impact of COVID-19 during the level 3 alert was found to dominate the temporal air pollutant concentrations in central Taiwan. The present model could provide applicable and accurate high resolution of spatial-temporal NO3− and SO42− datasets in an area with limited PM2.5 chemical composition measurement. The present model could also be potentially applied to facilitate hotspot identification and human exposure assessment. The present Artificial Neural Network-based de-weather model is applicable to predict meteorological normalized time series air pollutant concentrations, which could be used to verify the effects of the meteorological parameters and primary emissions on the variations in air quality during the implementation of a specific air quality control strategy or changes in anthropogenic activities.

Estimation of Agricultural Non-point Source TN and TP Export Coefficients Based on Soil Loss

Taking the Yellow River Delta as a typical research area, we constructed a coastal agricultural TN and TP non-point source pollution estimating model by analyzing the relationship between the surface soil pollutant loss risks and the monitored pollutant flux into the sea. On this basis, TN and TP non-point source export coefficients of paddy fields, irrigated land, and dry land were calculated, and the verification showed that the estimated export coefficients were acceptable. In the study area, the TN and TP export coefficients into the sea of arable land were 18.33 kg·(hm2·a)-1 and 1.02 kg·(hm2·a)-1, respectively. The agricultural non-point source pollution loads of arable land were relatively high in summer. The sub-basins with larger agricultural non-point source pollution loads were mainly located in the control areas of the Zhimai River, Guangli River, and Xiaodao River. The administrative regions with larger total agricultural TN and TP loads were mainly in the northern Huanghekou Town and Yong'an Town, and areas with larger loads per unit area were in the southwest. Therefore, it is necessary to pay more attention to the temporal effects of agricultural non-point source pollution, simultaneously coordinate the social and economic development, and formulate comprehensive agricultural non-point source pollution prevention and control strategies from the perspective of sub-basins and administrative units. This will allow us to improve the offshore pollution status from the perspective of land and sea coordination.

A Stackelberg game model with tax for regional air pollution control

The command-and-control regulation is likely inefficient and costly. This study investigates a regional pollution control scheme with tax (RPCST) under which the central government sets the tax rate under a given pollutant reduction quota and local governments determine their pollution removal rates based on the central government’s policy. First, a one-leader-multi-follower (OLMF) Stackelberg game model is formulated, in which the central government is the leader and the local governments are the followers. Then, a procedure based on bilevel programming and relaxation method is applied to solve the OLMF model. Finally, a case study analyzing the SO2 reduction of the Yangtze River Delta in China is conducted to demonstrate the effectiveness of the RPCST. The results show that RPCST works better than the current command-and-control scheme. Our analysis provides a guideline for governments to design optimal tax schemes to effectively solve the regional air pollution crisis.

Pollution fingerprinting of two southwestern estuaries in Ghana

The present study assessed the pollution fingerprints of two estuaries (Pra and Ankobra) in the Southwestern region of Ghana. Contaminations of sediments in the two estuaries were evaluated for particle size distribution, total organic matter, microplastics, nitrate-nitrogen, phosphorous, and metals. The results revealed the mean concentration of microplastics particles in Pra as follows: fibre (14.22 ± 4.99); sheet (24.44 ± 13.21); fragment (38.00 ± 25.47); bead (4.22 ± 4.84); and in Ankobra as follows: fibre (13.00 ± 7.56); sheet (20.60 ± 12.59); fragment (8.70 ± 11.22); bead (3.30 ± 4.14). Metal concentrations were in the order Fe > As > Zn > Cu > Pb; concentrations of Cd and Hg were below the detection limit. Pb, Cu, and Zn were within Interim Marine Sediment Quality Guidelines except for Fe and As. The respective order of contamination factor and geo-accumulation index of the metals were As > Fe > Zn > Pb > Cu and As > Fe > Pb > Cu. The pollution load index recorded for Pra and Ankobra estuaries were 1.94 and 2.71, respectively, suggesting deterioration of the estuaries due to metal pollution. The principal component analysis indicated that pollution fingerprinting is strongly influenced by Fe, Cu, As, Zn, silt, and sand associated with illegal artisanal gold mining activities. Thus, the findings from this study imply that the levels of pollution recorded could have deleterious impact on human health and the communities that depend on the services rendered by the estuaries. There is the need to adopt strategies for pollution control to protect these fragile ecosystems that support livelihoods.

Discrepancies in ozone levels and temporal variations between urban and rural North China Plain

Effective emission reductions of some primary pollutants have brought down aerosol loadings but led to increasing relative importance of secondary pollutants, as was indicated by the rising O3 levels during warm seasons within urban and suburban areas of China, which has received much attention in recent years, especially in the North China Plain (NCP). This has raised serious concerns on its agricultural impacts, which were mainly evaluated based upon O3 model simulations or urban/suburban measurements due to a lack in long-term rural observations. In this study, we present highly valuable continuous O3 observations at a rural NCP site during 2013–2019. Compared to nearby urban/suburban sites, which experienced increased O3 levels, rural observations exhibited decreasing O3 mole fractions. While O3 mole fractions and AOT40 widely increased at urban/suburban NCP sites from 2013 to 2019, O3 observations in the rural NCP site (GC) revealed decreases, especially during summer and autumn with greater rates for AOT40. A reassessment of O3 agricultural impacts in the NCP region was performed using rural observations, resulting in wheat, maize and soybean averaged relative yield losses of 37 ± 14, 8 ± 4 and 30 ± 13% yr–1, respectively. O3 impacts on crop yields and resulting economic losses did not increase as was suggested by previous estimations based on urban/suburban O3 data. Our analyses indicated high overestimations (i.e., average relative differences in estimated crop production loss reaching 53%, 112% and 75%, respectively, for wheat, maize, and soybean). Despite alleviated O3 agricultural impacts, the total economic cost loss in Hebei province still took up 0.89% of the gross domestic production (3.47 × 1012 USD) in Hebei province. Since the China National Environmental Monitoring Center mainly aims at monitoring O3 levels in populated areas, observation sites representative of agricultural regions are lacking across China. The current study highlights the urgent necessity for the establishment of rural O3 observation networks and encourages extensive field experiments on exposure–response relationships of different crops varieties to O3 for more accurate agricultural impact evaluations. Additionally, explorations into the underlying mechanisms behind the reversed O3 temporal variation between rural and urban areas should be conducted for future development of pollution control strategies.

Development and assessment of inventory of air pollutants that deteriorate the air quality in Indian megacity Bengaluru

Air pollution in Indian megacities has been exceeding national and international standards. Indian megacity ‘Bengaluru’ is one amongst them where the identification of sources of air pollutants that contribute to the deterioration of air quality in cities and their spatio-temporal variability has become paramount importance. In this paper, we have made an attempt to develop a high resolution (∼0.4 km × ∼0.4 km) emission inventory of eight major pollutants for South-Asian megacity Bengaluru for 2020. The study quantifies the emission load from all possible sources in the city using megacity scenarios and bottom-up approach. The estimated annual emission for PM2.5, PM10, CO, NOx, SO2, VOC, BC and OC over Bengaluru are found to be 62.2 Gg/yr, 113.9 Gg/yr, 447.5 Gg/yr, 294.5 Gg/yr, 194.9 Gg/yr, 393.8 Gg/yr, 22.9 Gg/yr, and 36.5 Gg/yr respectively. The transport sector remains the dominating source of all pollutants. The unattended anthropogenic sources like windblown road dust, municipality solid waste burning are emerging sectors in the identified emission hotspots. Both traditionally dominating sectors like transport and industries play an acute role in the deteriorating air quality across the megacity. This developed new surface emission dataset will be a critical tool for air quality study and to frame pollution control strategies.

Strategi Pengendalian Pencemaran Sungai Siak yang Berkelanjutan Menggunakan Pendekatan Multi Criteria Decision Making (MCDM)

The main objective of the research is to establish a sustainable Siak River pollution management strategy, in an effort to accelerate (quick win) the strategic policy of Siak River pollution management which is one of the National Strategic category rivers located in the Sumatra Region based on Presidential Decree No. 12 of 2012 concerning the Determination of the River Basin, because the Siak River has a very large function and role in regional and economic development both locally, regionally and nationally. The approach method used is Multi Criteria Decision Making (MCDM) with the selected method of Analytical Hierarchy Process (AHP). The primary data is in the form of questionnaire data with the aim of being assessed by experts (expert judgment) who are considered competent in assessing the processing of Siak River pollution. Seven respondents identified who have the potential and are representative to contribute to obtaining expert judgment recommendations consist of Universities represented by the University of Riau (UR), the Riau Province Environmental Agency (BLH), the Sumatran Ecoregion Development Control Center, Non-Governmental Organizations (NGO) Jikalahari, Center for Watershed Management (BPDAS) Indragiri Rokan. Regional Research and Development Agency for Riau Province and the River Basin Center (BWS) III Sumatra. The main results of the study stated that the Siak River water pollution control strategy using the AHP approach sequentially was to rearrange the spatial function, determine the pollution load capacity (DTBP), coordination of stakeholder synergies, program socialization and counseling, supervision and monitoring, law enforcement and development. Wastewater Treatment Plant (WTP).

Pollution Index Analysis and Water Pollution Control Strategy in Berenyok River, Tanjung Karang, Mataram City

Berenyok river is one of the water sources in Tanjung Karang, Mataram city, categorised as Class 2 for its designation. Thus, preserving the quality of water in the Berenyok river is crucial. This study aims to determine the water quality, calculate the Pollution Index (PI), and set control strategies for the Berenyok river. The study uses quantitative methods such as laboratory analysis for the water quality and PI calculation using a formula based on the Decree of the Minister of Environment No.115/2003 on determining water quality status. Meanwhile, the Strengths, Weakness, Opportunities, and Threats (SWOT) analysis generates recommendations for water pollution control strategies. The sampling locations are located in two sampling points (upstream and downstream of the Berenyok river) during bright daylight and the river's normal flow. Based on analysis results, the Berenyok river is defined as lightly polluted as the concentrations of several chemical parameters exceed the maximum limit, such as BOD, and PO3-P. It is also verified by high concentration of total coliform, namely 540,000 MPN/100mL (upstream) and 1,600,000 MPN/100mL (downstream). Thus, recommendations for water pollution control strategies are substantial for the Berenyok river.

Vertical distributions and potential sources of wintertime atmospheric pollutants and the corresponding ozone production on the coast of Bohai Sea

This study investigated the wintertime vertical distributions and source areas of aerosols, NO2, and HCHO in a coastal city of Dongying from December 2020 to March 2021, using ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) and a potential source contribution function (PSCF) model, respectively. Moreover, the chemical production sensitivity of O3 at different height layers was analyzed using HCHO/NO2 ratios. The results revealed that the wintertime averaged highest concentrations of aerosol (1.25 km−1), NO2 (14.81 ppb), and HCHO (2.32 ppb) were mainly distributed at the surface layer, 100–200 m layer, and 200–300 m layer, respectively. Regarding the diurnal cycles, high concentrations of aerosol (>1.4 km−1) and NO2 (>16.0 ppb) usually appeared in the early morning and late afternoon, while high concentrations of HCHO (>2.5 ppb) usually occurred during 12:00–15:00. The PSCF model revealed that the wintertime aerosol mainly originated from Shandong, northern Jiangsu, Korea, and the northwestern Mongolian Plateau. Below 200 m, NO2 was mainly from western Shandong, whereas above 600 m, it was mainly from northern Shandong and the Beijing-Tianjin-Hebei (BTH) region. The corresponding sources for HCHO were central and southern Shandong (below 200 m) and northern Shandong, northern Jiangsu, and southeastern BTH (above 600 m). In addition, the chemical production sensitivity of O3 below 100 m was observed only in the VOC-limited regime. The percentages of O3 production under the NOx-limited, NOx-VOC-limited, and VOC-limited regimes were 10.75% (31.18%), 4.30% (19.35%), and 84.95% (49.47%) at the 500–600 m (900–1000 m) layer. This study has guiding significance for the coordinated control of PM2.5 and O3, and can assist in the implementation of regional joint prevention and control strategies for air pollutants.

Microbial source tracking of fecal contamination in stormwater runoff.

Concerns over fecal contamination in stormwater canals have promoted the need for pollution control strategies, including the use of microbial source tracking, to identify fecal contamination in the Greater New Orleans Area. Surface water samples were collected over a 12-month period at five canal locations within Jefferson Parish, Louisiana. Quantitative polymerase chain reaction and the IDEXX method were used to assess the concentrations of coliforms, Escherichia coli (E. coli) and human fecal 183 bacteroides (HF183) in stormwater samples. A 100% positive detection rate of total coliforms and E. coli was observed across all tested sites. Despite the closeness of the five sites, when averaged across all sampling time points, Kruskal-Wallis tests indicated that E. coli was present at significantly different concentrations in these locations (χ2(5) = 19.8, p = 0.0005). HF183 was detected in 62% of the water samples collected during the stormwater sampling. Without further testing for HF183 markers, the conclusion from this study would have been that fecal contamination from an unknown source was always present at varying levels during the study period. Analysis of HF183 markers therefore adds another layer of conclusions to the results deductible from E. coli concentrations. A 100% E. coli detection rate, high E. coli concentrations coupled with low rates of HF183 detection particularly at the Esplanade, Poplar Street, and Bonnabel Boat Launch sites, the sites closest to the lake outlet, throughout the study period, indicate that fecal contamination at these stormwater canal sites comes primarily from non-human sources. However, the Metairie Road and Napoleon Avenue sites, which have the highest HF183 detection rates, on top of chronic pollution by other non-human sources, are also influenced by human fecal pollution, possibly because of human development and faulty infrastructure. This study highlights the advantages of the use of microbial source-tracking methods to complement traditional indicator bacteria.

Human activities changed organic carbon transport in Chinese rivers during 2004-2018

Rivers serve as regulators of global climate by releasing greenhouse gases, burying particulate carbon, and connecting different ecosystem carbon pools. However, long-term organic carbon (OC) transport features across different Asian rivers are not well known due to unavailable data. Based on routinely monitored environmental and hydrological data during 2004-2018, this study investigated the spatiotemporal variations in dissolved (DOC) and particulate OC (POC) transport across 41 rivers in China. Across different rivers, both DOC (1.35 – 16.8 mg/L) and POC (0.27 – 4.48 mg/L) concentrations covered wide ranges. The DOC content was high in the north and low in the south, with significantly higher (t test, p < 0.01) values for rivers north of 30°N (5.39 ± 3.66 mg/L vs. 2.39 ± 1.14 mg/L). Human activities greatly influenced the riverine DOC and POC distributions. The riverine ammonia nitrogen (NH+ 4-N) content was positively correlated with DOC (r = 0.81 and p < 0.01) and explained 85.59% of its spatial variation. High vegetation coverage had significant effects on decreasing the riverine POC content, with r = -0.55 and p < 0.05. During 2004-2018, water pollution prevention and control strategies decreased DOC concentrations in 60.98% of rivers; meanwhile, anthropogenic vegetation restoration and dam construction led to POC content decreases in 90.48% of rivers. Importantly, along with DOC and POC changes, increasing DOC/POC ratios were found in 90.48% of the rivers, with 42.86% being significant, which indicated that Chinese rivers are losing their Asian features of low DOC/POC ratios due to artificial disturbance. This study is significant for accurately quantifying greenhouse gas emissions, carbon burial, and OC export to estuaries by Chinese rivers.