Biodegradation of phthalate esters in polluted soil by using organic amendment

This study investigated the biodegradation of the phthalate esters (PAEs) di-n-butyl phthalate (DBP) and di-(2-ethyl hexyl) phthalate (DEHP) in sludge and sludge-amended soil. DBP (100 mg kg^?1) and DEHP (100 mg kg^?1) were added to sewage sludge, which was subsequently added to soil. The results showed that sewage sludge can degrade PAEs and the addition of sewage sludge to soil enhanced PAE degradation. Sludge samples were separated into fractions with various particle size ranges, which spanned 0.1–0.45 μm to 500–2000 μm. The sludge fractions with smaller particle sizes demonstrated higher PAE degradation rates. However, when the different sludge fractions were added to soil, particle size had no significant effect on the rate of PAE degradation. The results from this study showed that microbial strains F4 (Rhodococcus sp.) and F8 (Microbacterium sp.) were constantly dominant in the mixtures of soil and sludge.     

Atmospheric deposition of phthalate esters in a subtropical city

In Chinese cities, air pollution has become a serious and aggravating environmental problem undermining the sustainability of urban ecosystems and the quality of urban life. Bulk atmospheric deposition samples were collected two-weekly, from February 2007 to January 2008, at three representative areas, one suburban and two urbanized, in the subtropical city, Guangzhou, China, to assess the deposition fluxes and seasonal variations of phthalate esters (PAEs). Sixteen PAE congeners in bulk deposition samples were measured and the depositional fluxes of ∑₁₆PAEs ranged from 3.41 to 190 μg m^?2 day^?1, and were highly affected by local anthropogenic activities. The significant relationship between PAEs and particulate depositional fluxes (correlation coefficient R² = 0.72, P < 0.001) showed PAEs are associated primarily with particles. Temporal flux variations of PAEs were influenced by seasonal changes in meteorological parameters, and the deposition fluxes of PAEs were obviously higher in wet season than in dry season. Diisobutyl phthalate (DiBP), Di-n-butyl phthalate (DnBP), and Di(2-ethylhexyl) phthalate (DEHP) dominated the PAE pattern in bulk depositions, which is consistent with a high consumption of the plasticizer market in China. PAE profiles in bulk deposition showed similarities exhibited in both time and space, and a weak increase of high molecular weight PAE (HMW PAE) contribution in the wet season compared to those in the dry season. Average atmospheric deposition fluxes of PAEs in the present study were significantly higher than those from other studies, reflecting strong anthropogenic inputs as a consequence of rapid industrial and urban development in the region.     

Preliminary toxicological assessment of phthalate esters from drinking water consumed in Portugal

This paper reports, for the first time, the concentrations of selected phthalates in drinking water consumed in Portugal. The use of bottled water in Portugal has increased in recent years. The main material for bottles is polyethylene terephthalate (PET). Its plasticizer components can contaminate water by leaching, and several scientific studies have evidenced potential health risks of phthalates to humans of all ages. With water being one of the most essential elements to human health and because it is consumed by ingestion, the evaluation of drinking water quality, with respect to phthalate contents, is important. This study tested seven commercial brands of bottled water consumed in Portugal, six PET and one glass (the most consumed) bottled water. Furthermore, tap water from Lisbon and three small neighbor cities was analyzed. Phthalates (di-n-butyl phthalate ester (DnBP), bis(2-ethylhexyl) phthalate ester (DEHP), and di-i-butyl phthalate ester (DIBP)) in water samples were quantified (PET and glass) by means of direct immersion solid-phase microextraction and ionic liquid gas chromatography associated with flame ionization detection or mass spectrometry due to their high boiling points and water solubility. The method utilized in this study showed a linear range for target phthalates between 0.02 and 6.5 μg L^?1, good precision and low limits of detection that were between 0.01 and 0.06 μg L^?1, and quantitation between 0.04 and 0.19 μg L^?1. Only three phthalates were detected in Portuguese drinking waters: dibutyl (DnBP), diisobutyl (DIBP), and di(ethylhexyl) phthalate (DEHP). Concentrations ranged between 0.06 and 6.5 μg L^?1 for DnBP, between 0.02 and 0.16 μg L^?1 for DEHP, and between 0.1 and 1.89 μg L^?1 for DIBP. The concentration of DEHP was found to be up to five times higher in PET than in glass bottled water. Surprisingly, all the three phthalates were detected in glass bottled water with the amount of DnBP being higher (6.5 μg L^?1) than in PET bottled water. These concentrations do not represent direct risk to human health. Regarding potable tap water, only DIBP and DEHP were detected. Two of the cities showed concentration of all three phthalates in their water below the limits of detection of the method. All the samples showed phthalate concentrations below 6 μg L^?1, the maximum admissible concentration in water established by the US Environmental Protection Agency. The concentrations measured in Portuguese bottled waters do not represent any risk for adult's health.     

Sorption behavior of dibutyl phthalate and dioctyl phthalate by aged refuse

Sorption is a fundamental process controlling the transformation, fate, degradation, and biological activity of hydrophobic organic contaminants in the environment. We investigated the kinetics, isotherms, and potential mechanisms for the sorption of two phthalic acid esters (PAEs), dibutyl phthalate (DBP) and dioctyl phthalate (DOP), on aged refuse. A two-compartment first-order model performed better than a one-compartment first-order model in describing the kinetic sorption of PAEs, with a fast sorption process dominating. Both the Freundlich and Dubinin–Astakhov (DA) models fit the sorption isotherms of DBP and DOP, with the DA model being of a better fit over the range of apparent equilibrium concentrations. The values of the fitting parameters (n, b, E) of the PAEs suggest nonlinear sorption characteristics. Higher predicted partition coefficient values and saturated sorption capacity existed in refuse containing larger quantities of organic matter. The sorption capacity of DOP was significantly higher than that of DBP. PAE sorption was dependent on liquid phase pH. Desorption hysteresis occurred in PAE desorption experiments, especially for the long-chain DOP. PAEs may therefore be a potential environmental risk in landfill.     

Spatial distribution and partitioning of polychlorinated biphenyl and organochlorine pesticide in water and sediment from Sarno River and Estuary,Southern Italy

The Sarno River is nicknamed “the most polluted river in Europe”. The main goal of this study is to enhance our knowledge on the Sarno River water and sediment quality and on its environmental impact on the gulf of Naples (Tyrrhenian Sea, Central Mediterranean Sea) in order to become a useful assessment tool for the regional administrations. For these reasons, 32 selected polychlorinated biphenyls (PCBs) and aldrin, α-BHC, β-BHC, δ-BHC, γ-BHC (lindane), 4,4′-DDD, 4,4′-DDE, 4,4′-DDT, dieldrin, endosulfan I, endosulfan II, endosulfan sulphate, endrin, endrin aldehyde, heptachlor, heptachlor epoxide (isomer B) and methoxychlor were determined in the water dissolved phase (DP), suspended particulate matter (SPM) and sediments. Total concentrations of PCBs ranged from 1.4 to 24.9 ng L^?1 in water (sum of DP and SPM) and from 1.01 to 42.54 ng g^?1 in sediment samples. The concentrations of total organochlorine pesticides (OCPs) obtained in water (sum of DP and SPM) ranged from 0.54 to 7.32 ng L^?1 and from 0.08 to 5.99 ng g^?1 in sediment samples. Contaminant discharges of PCBs and OCPs into the sea were calculated in about 1,247 g day^?1 (948 g day^?1 of PCBs and 326 g day^?1 of OCPs), showing that this river should account as one of the main contribution sources of PCBs and OCPs to the Tyrrhenian Sea.     

Tributyltin distribution and producing androgenic activity in water,sediment, and fish muscle

This study investigated the concentrations of Tributyltin (TBT) in water, sediment, and fish muscle samples taken from Kaohsiung Harbor and Kaoping River estuary, Taiwan. TBT concentrations in water and sediment samples ranged from less than 18.5 to 34.1 ng Sn L^?1 and from 2.44 to 29.7 ng Sn g^?1 weight per weight (w/w), respectively. Concentrations in the TBT‐contaminated fish muscle samples ranged from 10.8 to 79.6 ng Sn g^?1 w/w. The TBT concentrations in fish muscle were higher than those in water and sediment samples. The fish muscle/water TBT bioconcentration factor (BCF) ranged from 590 to 3363 L kg^?1. Additionally, the water samples were assessed for androgenic activity with an MCF7‐AR1 human breast cancer cell line. The androgenic activity ranged from 0.94 to 3.1 ng‐dihydrotestosterone per litre water (ng‐DHT L^?1). Higher concentrations of TBT in water and sediment samples occurred in the dry season, but the androgenic activity had higher values in the rainy season.     

Current status and historical variations of phthalate ester (PAE) contamination in the sediments from a large Chinese lake (Lake Chaohu)

The residual levels of phthalate esters (PAEs) in the surface and two core sediments from Lake Chaohu were measured with a gas chromatograph–mass spectrometer (GC–MS). The temporal–spatial distributions, compositions of PAEs, and their effecting factors were investigated. The results indicated that di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), and di(2-ethylhexyl) phthalate (DEHP) were three dominant PAE components in both the surface and core sediments. The residual level of total detected PAEs (∑PAEs) in the surface sediments (2.146?±?2.255 μg/g dw) was lower than that in the western core sediments (10.615?±?9.733 μg/g) and in the eastern core sediments (5.109?±?4.741 μg/g). The average content of ∑PAEs in the surface sediments from the inflow rivers (4.128?±?1.738 μg/g dw) was an order of magnitude higher than those from the lake (0.323?±?0.093 μg/g dw), and there were similar PAE compositions between the lake and inflow rivers. This finding means that there were important effects of PAE input from the inflow rivers on the compositions and distributions of PAEs in the surface sediments. An increasing trend was found for the residual levels of ΣPAEs, DnBP, and DIBP from the bottom to the surface in both the western and eastern core sediments. Increasing PAE usage with the population growth, urbanization, and industrial and agricultural development in Lake Chaohu watershed would result in the increasing production of PAEs and their resulting presence in the sediments. The significant positive relationships were also found between the PAE contents and the percentage of sand particles, as well as TOC contents in the sediment cores.     

Occurrence and microbial degradation of phthalate esters in Taiwan river sediments

Concentrations and microbial degradation rates were measured for eight phthalate esters (PAEs) found in 14 surface water and six sediment samples taken from rivers in Taiwan. The tested PAEs were diethyl phthalate (DEP), dipropyl phthalate (DPP), di-n-butyl phthalate (DBP), diphenyl phthalate (DPhP), benzylbutyl phthalate (BBP), dihexyl phthalate (DHP), dicyclohexyl phthalate (DCP), and di-(2-ethylhexyl) phthalate (DEHP). In all samples, concentrations of DEHP and DBP were found to be higher than the other six PAEs. DEHP concentrations in the water and sediment samples ranged from ND to 18.5 μg/l and 0.5 to 23.9 μg/g, respectively; for DBP the concentration ranges were 1.0–13.5 μg/l and 0.3–30.3 μg/g, respectively. Concentrations of DHP, BBP, DCP and DPhP were below detection limits. Under aerobic conditions, average degradation half-lives for DEP, DPP, DBP, DPhP, BBP, DHP, DCP and DEHP were measured as 2.5, 2.8, 2.9, 2.6, 3.1, 9.7, 11.1 and 14.8 days, respectively; under anaerobic conditions, respective average half-lives were measured as 33.6, 25.7, 14.4, 14.6, 19.3, 24.1, 26.4 and 34.7 days. In other words, under aerobic conditions we found that DEP, DPP, DBP, DPhP and BBP were easily degraded, but DEHP was difficult to degrade; under anaerobic conditions, DBP, DPhP and BBP were easily degraded, but DEP and DEHP were difficult to degrade. Aerobic degradation rates were up to 10 times faster than anaerobic degradation rates.     

Distribution,possible sources,and health risk assessment of SVOC pollution in small streams in Pearl River Delta,China

The pollution levels of typical semivolatile organic compounds (SVOCs) consisting of 15 polycyclic aromatic hydrocarbons (PAHs), 20 organic chlorinated pesticides (OCPs), and 15 phthalate esters (PAEs) were investigated in small rivers running through the flourishing cities in Pearl River Delta region, China. The concentrations of ∑15PAHs were 2.0–48 ng/L and 29–1.2?×?10³ ng/g in the water and sediment samples, respectively. The ∑20OCPs were 6.6–57 ng/L and 9.3–6.0?×?10² ng/g in the water and sediment samples, respectively. The concentrations of ∑15PAEs were much higher both in the water and sediments. The partition process of the detected SVOCs between the water and sediment did not reach the equilibrium state at most of the sites when sampling. The combustion of petroleum products and coal was the major source of the detected PAHs. The OCPs were mainly historical residue, whereas the new inputs of dichlorodiphenyltrichloroethane (DDT), chlordane, and endosulfan were possible at several sites. The industrial and domestic sewage were the major source for the PAEs; storm water runoff accelerated the input of PAEs. No chronic risk of the SVOCs was identified by a health risk assessment through daily water consumption, except for the ∑20OCPs that might cause cancer at several sites. Nevertheless, the integrated health risk of the SVOCs should not be neglected and need intensive investigations.     

Profiles and risk assessment of phthalate acid esters (PAEs) in drinking water sources and treatment plants,East China

This study is the first report describing the occurrence of 15 phthalate acid esters (PAEs) in the three typical water sources of YiXing City, Taihu Upper-River Basin, East China. The fate of target PAEs in the Jiubin drinking water treatment plant (JTP) was also analyzed. The amounts of Σ₁₅PAE in the Hengshan (HS), Youche (YC), and Xijiu (XJ) water sources were relatively moderate, with mean values of 360, 357, and 697 ng L⁻¹, respectively. Bis(2-ethylhexyl) phthalate (DEHP) dominated the PAE concentration, making up 80% of the 15 total PAEs. The highest levels of Σ₁₅PAE were found in HS, YC, and XJ in March 2015, January 2015, and July 2014, respectively. The occurrence and concentrations of these compounds were spatially dependent, and the mean concentrations of Σ₁₅PAE in HS, YC, and XJ samples increased from the surface layer to the bottom layer with varied percentage increases. The removal efficiency of the PAEs in the finished water varied markedly, and the removal of PAEs by the JTP ranged from 12.8 to 64.5%. The potential ecosystem risk assessment indicated that the risk of PAEs was relatively low in these three water sources. However, risks posed by PAEs due to drinking water still exist; therefore, special attention should be paid to source control in the JTP, and advanced treatment processes for drinking water supplies should be implemented.

     

Occurrence of phthalates in sediment and biota: relationship to aquatic factors and the biota-sediment accumulation factor

Phthalate compounds in sediments and fishes were investigated in 17 Taiwan's rivers to determine the relationships between phthalate levels in sediment and aquatic factors, and biota-sediment accumulation factor (BSAF) for phthalates. Mean concentrations (range) of di(2-ethylhexyl) phthalate (DEHP), butyl benzyl phthalate (BBzP) and di-n-butyl phthalate (DBP) in sediment at low-flow season were 4.1 (<0.05-46.5), 0.22 (<0.05-3.1) and 0.14 (<0.05-1.3)mgkg(-1)dw; those at high-flow season were 1.2 (<0.05-13.1), 0.13 (<0.05-0.27) and 0.09 (<0.05-0.22)mgkg(-1)dw, respectively. Trace levels of dimethyl phthalate (DMP), diethyl phthalate (DEP) and di-n-octyl phthalate (DOP) in sediment were found in both seasons. Concentrations of DEHP in sediments were significantly affected by temperature, suspended solids, ammonia-nitrogen, and chemical oxygen demand. The highest concentration of DEHP in fish samples were found in Liza subviridis (253.9mgkg(-1)dw) and Oreochromis miloticus niloticus (129.5mgkg(-1)dw). BSAF of DEHP in L. subviridis (13.8-40.9) and O. miloticus niloticus (2.4-28.5) were higher than those in other fish species, indicating that the living habits of fish and physical-chemical properties of phthalates, like logKow, may influence the bioavailability of phthalates in fish. Our data suggested that DEHP level in river sediments were influenced by water quality parameters due to their effects on the biodegradation processes, and that the DEHP level in fish was affected by fish habitat and physiochemical properties of polluted contaminants.     

Assessment of Organochlorine Pesticide Residues in Water,Sediment, and Fish of the Songhua River,China

This study examined residual concentrations and associated ecological risks of the organochlorine pesticides (OCPs) hexa- chlorocyclohexane (HCH) and dichloro-diphenyl-trichloroethane (DDT) in water, sediment, and fish of the Songhua River in Zhaoyuan County, China. In June 2012, 10 water, 10 sediment, and 20 fish samples were collected. Residual concentrations of ΣHCH and ΣDDT ranged from 10.0–35.59 ng L^?1 (mean 28.03 ± 11.66 ng L^?1) and 5.12–39.66 ng L^?1 (mean 32.36 ± 11.58 ng L^?1) for water. Residual concentrations of ΣHCH and ΣDDT ranged from 0.52–3.00 ng g^?1 (mean 2.04 ± 0.73 ng g^?1) and 0.34–3.41 ng g^?1 (mean 2.38 ± 0.92 ng g^?1) for sediment. The ratios of α-HCH/γ-HCH were close to 1 at the majority of sampling points, indicating considerable new pollution from the use of lindane. The ratios of p,p′-DDE + p,p′-DDD/ΣDDT were less than 0.5, indicating recent inputs from DDT impurities in dicofol. All HCH and DDT isomers except for p,p′-DDD were detected in fish tissue samples, but the associated ecological risks were estimated to be below levels of concern. The study revealed a historical usage of OCPs in the Zhaoyuan section of the Songhua River and new OCP from the use of lindane and dicofol.     

Effects of hydromorphology and riparian vegetation on the sediment quality of agricultural low-order streams: consequences for stream restoration

Intensive agricultural land use imposes multiple pressures on streams. More specifically, the loading of streams with nutrient-enriched soil from surrounding crop fields may deteriorate the sediment quality. The current study aimed to find out whether stream restoration may be an effective tool to improve the sediment quality of agricultural headwater streams. We compared nine stream reaches representing different morphological types (forested meandering reaches vs. deforested channelized reaches) regarding sediment structure, sedimentary nutrient and organic matter concentrations, and benthic microbial respiration. Main differences among reach types were found in grain sizes. Meandering reaches featured larger mean grain sizes (50–70 μm) and a thicker oxygenated surface layer (8 cm) than channelized reaches (40 μm, 5 cm). Total phosphorous amounted for up to 1,500 μg?g^?1 DW at retentive channelized reaches and 850–1,050 μg?g^?1 DW at the others. While N-NH₄ accumulated in the sediments (60–180 μg?g^?1 DW), N-NO₃ concentrations were generally low (2–5 μg?g^?1 DW). Benthic respiration was high at all sites (10–20 g O₂ m^?2?day^?1). Our study shows that both hydromorphology and bank vegetation may influence the sediment quality of agricultural streams, though effects are often small and spatially restricted. To increase the efficiency of stream restoration in agricultural landscapes, nutrient and sediment delivery to stream channels need to be minimized by mitigating soil erosion in the catchment.     

Effects of diethylphthalate and di-(2-ethyl)hexylphthalate on the physiology and ultrastructure of cucumber seedlings

Phthalic acid esters (PAEs) are one kind of persistent organic pollutants. This study was conducted to investigate the effects of diethylphthalate (DEP) and di(2-ethyl)hexylphthalate (DEHP) with different concentrations (0, 30, 50, 100, and 200 mg L^?1) on early seedling growth of Cucumis sativus L. Physiological, biochemical, and ultrastructure of seedling leaves were examined for 7-day exposure. The three antioxidant enzymes’ activities was stimulated at low-DEP treatments and decreased under higher levels (>200 mg L^?1) compared to the controls. Furthermore, MDA and H₂O₂ gradually enhanced with the elevation of DEP and DEHP concentration. Significant impact on the chloroplast and mitochondrion was visible, possibly as a consequence of free radical generation. DEP induced bigger and more starch grains in chloroplasts than DEHP. This study concluded that the effects of DEP and DEHP on cucumber seedlings represented the adverse impacts of DEP and DEHP on the ecosystem and agricultural production. The environmental harm caused by DEP was severer than DEHP.     

Anaerobic degradation of diethyl phthalate, di-n-butyl phthalate, and di-(2-ethylhexyl) phthalate from river sediment in Taiwan

We investigated anaerobic degradation rates for three phthalate esters (PAEs), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), and di-(2-ethylhexyl) phthalate (DEHP), from river sediment in Taiwan. The respective anaerobic degradation rate constants for DEP, DBP, and DEHP were observed as 0.045, 0.074, and 0.027 1/day, with respective half-lives of 15.4, 9.4, and 25.7 days under optimal conditions of 30 °C and pH 7.0. Anaerobic degradation rates were enhanced by the addition of the surfactants brij 35 and triton N101 at a concentration of 1 critical micelle concentration (CMC), and by the addition of yeast extract. Degradation rates were inhibited by the addition of acetate, pyruvate, lactate, FeCl₃, MnO₂, NaCl, heavy metals, and nonylphenol. Our results indicate that methanogen, sulfate-reducing bacteria, and eubacteria are involved in the degradation of PAEs.     

Quantifying the sources of hazardous elements of suspended particulate matter aerosol collected in Yokohama,Japan

We analyzed metals (Mg, Al, Ca, V, Cr, Mn, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, Cs, Ba, Pb and Bi), water-soluble ions (Na⁺, NH₄⁺, K⁺, Ca²⁺, Cl^?, NO₃^? and SO₄^2?) and carbonaceous mass (EC and OC) in SPM aerosol samples using an ICP-MS, ion chromatograph and CHN corder, respectively. The SPM samples were collected from 1999 to 2005 at two locations (urban site A and industrial site B) of Yokohama, Japan with concentrations in mean and ranges of 34.2 and 19.7–50.3 μg m^?3 and 22.9 and 12.7–35.1 μg m^?3 for the respective location. Source apportionment of SPM aerosol was conducted appropriately for the first time to these locations employing PCA-APCS technique. Major sources of SPM at site A were a) crustal source, b) urban origin, c) undefined, and d) mineral rock. At site B, the sources were predicted as a) urban origin, b) undefined, c) crustal source, and d) secondarily formed aerosol. The tracers and nature of the source related to urban origin at both sites were similar but retaining different source strength. Secondarily formed aerosol was quite unique at site B. However, mineral rock was remarkable at site A.     

Effects of film mulching on the distribution of phthalate esters in wheat grains from dryland

The application of plastic film in field crop production elevated the phthalate esters (PAEs) accumulation in wheat grains, which poses potential risks to human health. However, the variation of grain PAEs contents in different dryland areas is not clear, and the distribution of PAEs in different tissues of grains has not been studied yet. In the present study, field experiments in five sites (three provinces) with two treatments (soil with and without film mulching) were carried out to study the concentration and distribution of PAEs in grains and the effects of environmental factors on them. Results showed that the total PAE concentration (∑PAEs) in wheat grains ranged from 445 to 764 μg/kg, mainly in the forms of di-(2-ethylhexyl)-phthalate (DEHP), dibutyl phthalate (DBP), and diisobutyl phthalate (DIBP). Compared with control, total PAE concentrations in soils and wheat grains were significantly higher in treatments with film mulching. The effects of film on the proportion of PAEs in the flour and bran varied with experiment sites. Grain PAEs in the control groups presented significantly negative correlation with annual temperature, while there was a positive correlation between soil PAEs and bran PAEs in the film treatment. Results in this study are of great significance to comprehensively evaluate the effect of film mulching on grain safety in dryland wheat production.

     

Phthalate esters (PAEs): emerging organic contaminants in agricultural soils in peri-urban areas around Guangzhou, China

This study reports the first data on the concentrations and distribution of phthalate esters (PAEs) in the agricultural soils from the peri-urban areas of Guangzhou city. Σ₁₆PAEs concentrations ranged from 0.195 to 33.6 μg g⁻¹-dry weight (dw). Elevated levels of PAEs were recorded in the vegetable fields located next to the urban districts, and a decreasing trend exists following the distance away from the urban center. Diisobutyl phthalate (DiBP), Di-n-butyl phthalate (DnBP), and Di(2-ethylhexyl) phthalate (DEHP) dominated the PAEs in the agricultural soils. Significant relationship (correlation coefficient R² = 0.85, p < 0.01, n = 40) was present between the accumulation of PAEs and total organic carbons in agricultural soils. In addition, both pH and texture of soils are found to be important factors affecting the level of PAEs. This study shows that the agricultural soils in the peri-urban area of Guangzhou city were moderately polluted by PAEs.     

Effect of winds on SO2 and SPM concentrations in Delhi

A study of concentrations of sulfur dioxide (SO₂) and suspended particulate matter (SPM) has been performed in Delhi. The monthly and seasonal variations of concentrations and winds are analyzed. The monthly mean SO₂ concentrations were in the range of 16.15–34.44 μg m⁻³ and showed regular seasonal variations with the highest concentrations in winter and lowest in monsoon season. On the other hand, the monthly mean SPM concentrations reached the highest (465.68 μg m⁻³) in November and the lowest (150.07 μg m⁻³) in August. It was observed that high SO₂ concentrations were generally associated with the wind blowing from WNW–NW directions, and the high SPM concentrations were usually related to the wind blowing from W–NW directions.