Airborne PCB patterns and urban scale in the Southern Río de la Plata Basin, Argentina

Understanding urbanization development process and the associated PCBs concentration in urban soils - A genetic algorithm-based urbanization index approach

How to quantify urbanization process and the associated environmental consequence is still a hot issue worldwide. This study established an in situ-controlled experimental system to quantify polychlorinated biphenyls (PCBs) accumulation along an urban-rural gradient in Shanghai, a rapidly urbanizing region. By incorporating landscape-scale urbanized metrics, through correlation analysis and stepwise linear regression analysis a Genetic Algorithm-Based Urbanization Index (GA-based UI) was developed to systematically quantify the relationship between urbanization and PCB accumulation in soils. Key variables contributing to the GA-based UI included road density (0.675), population change index (0.287), industrial land use (0.126), and vegetation indices (0.296). Through random forest and piecewise regression analysis, the study identified critical urbanization thresholds. Piecewise regression revealed that PCB concentrations significantly increased within an optimal UI threshold range of 2.148-3.203, corresponding to a distance of 22.36-26.74 km from the urban center. This finding highlights a critical inflection point in urbanization where PCB accumulation intensifies. This research provides novel insights to understand urbanization development process and the associated spatial distribution of PCB contamination, offering a quantitative basis for urban planning and environmental management.

Current levels, sources, and risks of human exposure to PAHs, PBDEs and PCBs in South American outdoor air: A critical review

This study provides a comprehensive overview of the current levels, sources and human exposure risks to hazardous polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs) in South American outdoor air. Research documents were obtainable for only 6 countries within the target period (2014-2024). For all contaminants, urban concentrations exceeded that of rural/remote locations. PAHs were extensively reported with concentration reaching 1100 ∑16PAHs/m3 in Southwest of Buenos Aires province, Argentina. The health risk data also exceeded the threshold level in several locations. The profiles and seasonal fluctuations across all studies were widely influenced by the prevalent local/domestic sources. Biomass combustion (particularly of sugar cane/agricultural wastes and wood/coal for residential heating), vehicular emission, and industrial emission were accounted for most PAH sources. Regulations targeting biomass combustion for improved air quality seem not to currently have significant impacts on current PAH levels. PBDEs were widely reported within 0.3-55 pg ∑4-14BDE/m3, albeit high concentrations were documented in Concepción Bay, Chile (maximum = 1100 pg ∑4BDE/m3) and Córdoba, Argentina (maximum = 120 pg ∑4BDE/m3). Most notable source of PBDEs is solid municipal wastes. Similar to other global studies, BDE-47, 99 and 209 dominated the congeners reported. PCBs were reported with the highest concentrations measured in Córdoba, Argentina (maximum = 1700 pg ∑30PCBs/m3), but data remain limited in other important locations such as São Paulo, Brazil. Sources of PCBs were broadly associated with solid wastes, electric transformers, and re-volatilization from polluted environment. PAHs, PCBs and PBDEs were all within average to top global concentrations. This study underscores potential rise in atmospheric level of the target contaminants without sustainable regulatory structure and the need for continuous monitoring of these contaminants as a measure of policy impacts. We provide sustainable recommendations.

Occurrence of polychlorinated biphenyls (PCBs) in the sea anemone Bunodosoma zamponii, sediments and seawater from the southwestern Atlantic

Polychlorinated biphenyls (PCBs) are persistent and bioaccumulable organic compounds. The occurrence of PCBs was assessed in two populations of the intertidal sea anemone Bunodosoma zamponii living under different anthropogenic strains. One location was in vicinity to a wastewater plant (Las Delicias, LD), and the other was a preserved location chosen as a reference site (Punta Cantera, PC). Anemone populations were sampled 4 times (spring, summer, autumn and winter) throughout a year, in addition to seawater and sediment from those areas. PCB loadings ranged from 2.89 to 79.41 ng L^-1 in seawater samples and from 0.07 to 6.61 ng g^-1 dry weight in sediment samples. Total PCB levels ranged from 0.22 to 14.94 and 2.79 to 24.69 ng g^-1 wet weight in anemones from PC and LD, respectively. PCBs concentrations in anemones from LD were significantly greater than PC during spring, summer and winter. The congeners 18 and 44 prevailed in seawater samples, 44 and 52 in sediment and 18 and 132+153 in anemones. Redundancy analysis integrated PCB levels from all matrixes and bolstered contrast between sampling sites. Seasonality was also a relevant factor since during winter PCB loading was greater in sediment and anemone samples, coincident with the rainiest season. Disparity between sites could be due to LD's proximity to the wastewater plant, effect of littoral drift direction and/or asymmetries in anemones physiological condition.

Spatial and temporal distribution of Persistent Organic Pollutants and current use pesticides in the atmosphere of Argentinean Patagonia

XAD-based passive air samplers (PAS) were used to evaluate organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and some current use pesticides (chlorotalonil, trifluralin and dichlofluanid) in the atmosphere of Argentinian Patagonia. The PAS were deployed for 12 months during three consecutive years along a longitudinal (Rio Negro watershed) and a latitudinal (Patagonian coast) transect. Endosulfan, trifluralin and DDT-related substances were the most prevalent pesticides in the Rio Negro watershed, an intensive agricultural basin, consistent with ongoing use of endosulfan at the time of sampling. Concentrations of industrial contaminants were low (mean 25 pg/m³ and 1.9 pg/m³ for Σ₃₈ PCBs, and Σ₅PBDEs, respectively) and similar among sites. However, along the Patagonian coast, air concentrations of total contaminants were highly variable (14-400 pg/m³) with highest values recorded at Bahia Blanca, an important industrial area that is also downwind of the most intensively agriculturally used area of Argentina. Contaminant levels decreased toward the south, with the exception of the southernmost sampling site (Rio Gallegos) where a slight increase of total pollutant levels was observed, mainly due to the lower chlorinated PCB congeners. Interannual variability was small, although the last year tended to have slightly higher levels for different contaminant groups at most sampling sites. This large-scale spatial atmospheric monitoring of POPs and some CUPs in the South of Argentina highlights the important and continuing role of rural and urban areas as emission sources of these chemicals.

Indoor persistent organic pollutants in agricultural areas from Argentina

Persistent Organic Pollutants (POPs) are anthropogenic chemicals extensively used in the past for industrial and agricultural purposes, characterized by their lipophilicity, ubiquity, volatility and environmental persistence. By other hand, chlorpyrifos is the most widely used current pesticide (CUPs) being the main insecticide used for crops in Argentina. The aim of this work was to assess levels of POPs and CUPs in different fractions of airborne particles collected indoor in agricultural areas from Argentina. Particles higher than 2.5 µm were trapped in polyurethane foams (PUF) while particles smaller than 1 µm and volatile compounds were adsorbed on activated charcoal. Compounds were analyzed by gas chromatograph with electron capture detector (GC-ECD). Endosulfans, chlordanes, PCBs, and HCHs were detected in all PUF samples, while endosulfans, chlorpyrifos, PCBs, and HCHs were the most abundant in smaller particles. Majority of pesticides showed higher concentrations during the summer season (1397.7 vs 832.5 pg/m³ ). Even adding up all measured organic compounds, no sample reaches the threshold limit value for indoor pesticides levels (0.1 pg/m³ ), neither in the large or small particle fraction. However, the fact that chronic exposure to POPs has been linked to several diseases raises concern for human health.

Occurrence of persistent organic pollutants in air at different sites in the province of Córdoba, Argentina

The occurrence of persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of six sites with different emission sources in the province of Córdoba, Argentina, was analyzed. The sites included urban, industrial, agricultural, and mountain areas. Samples were collected using passive air samplers (PAS) consisting of polyurethane foam disks (PUF). Samples were analyzed for 12 PAHs, 31 polychlorinated biphenyls (PCBs), 12 organochlorine pesticides (OCPs), and 11 polybrominated diphenyl ethers (PBDEs). The concentrations of PAHs in the atmosphere were elevated at urban sites and were even higher at the industrial site. With respect to OCPs, it was observed that the concentrations of endosulfan were greater at the agricultural site (AGR) (416 ± 4 pg m^-3). For hexachlorocyclohexanes (HCHs), only the alpha isomer was detected and there were minimal differences between the different sampling sites (5.9-13.3 pg m^-3). In the case of dieldrin, the highest concentrations (33.6 pg m^-3) were found at the mountain site, which may have been due to its use for insect control. Although heptachlor epoxide was not detected, the concentration of heptachlor was significantly higher at the agricultural and downtown sites (∼ 3.6 pg m^-3). Regarding DDTs, the isomers p,p'-DDT and p,p'-DDE showed the highest concentrations at the mountain site (ΣDDT 120 ± 12 pg m^-3) and downtown site (ΣDDT 157 ± 62 pg m^-3). The relationship between the isomers suggested that at the downtown site, the contribution of this pesticide to the environment was recent, probably for the control of diseases vectors. The congener pattern of PBDEs was dominated by BDE-47, and BDE-99 at all sites, with the downtown site having the highest concentrations of compound esters (ΣPBDEs 118 ± 38 pg m^-3). Finally, high concentrations of PCBs were found at the industrial site (ΣPCBs 1677 ± 134 pg m^-3), and the predominating homologs were 5-Cl and 6-Cl, in contrast to the other sites where PCBs were dominated by 3-Cl and 4-Cl. This is the first study of POPs carried out in the province of Córdoba.

Urban geochemistry and potential human health risks in the Metropolitan Area of Buenos Aires: PAHs and PCBs in soil, street dust, and bulk deposition

Soil, street dust, and bulk deposition (dry and wet deposition) were collected in the Metropolitan Area of Buenos Aires (MABA), Argentina, to assess the polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) pollution and the potential risks to human health. Compared with other countries, the mean concentration of PAHs and PCBs in surface soils, street dust and bulk deposition of MABA were at a low or moderate level. Average PAHs and PCBs concentrations in bulk deposition (5.7 ± 5.1 and 0.41 ± 0.25 µg g^-1, respectively) were five and ten times higher than those of soil (1.08 ± 0.98 and 0.02 ± 0.01 µg g^-1) and street dust (1.2 ± 0.95 and 0.04 ± 0.03 µg g^-1), respectively. Different compositional profiles, observed in the three matrices for both groups of contaminants, could be attributed to dissimilar source contribution, partition processes between gas and particulate phases, and transformation. The most contaminated bulk deposition presented higher values for cancer and non-cancer risks relative to soil and street dust. In all matrices, non-carcinogenic risks were below the safety threshold (HI < 1). Regarding carcinogenic risks, exposure to both bulk deposition and soil indicated a moderated potential for cancerous development (Incremental lifetime cancer risk ~ 3.0 × 10^-6).

Long-Term (1970-2017) Temporal Trends of Polychlorinated Biphenyls in Fish, Settling Material, and Sediments from Populated and Remote Sites in Río de la Plata Estuary, Argentina

Temporal trends of polychlorinated biphenyls (PCBs) were studied for detritivorous fish (1996-2017) and settling material (2002-2017) from polluted Buenos Aires coast and for a dated sediment core (1970-2013) from the outer Río de la Plata estuary. In spite of contrasting concentrations [5.3 ± 6.3 μg·g^-1 dry weight (dw) for fish, 48 ± 26 ng·g^-1 dw for settling material, and 1.5 ± 0.7 ng·g^-1 dw for core], all three revealed exponentially decreasing trends over time (97%, 83%, and 83%, respectively). Time trends showed peak maxima coincident with Argentina's period of maximum PCB usage in 1973-1980 (80 cm depth in the core) and pulse discharges related to PCB banning in 2001-2002 (fish) with a lighter signature enriched in less persistent tri- and tetrachlorobiphenyls. The log-linear PCB time trends compare well with the predicted decrease for a high emission scenario from global emission data; the best fit was observed for the less impacted sediment core (-2%·year^-1 versus -3%·year^-1 for emission scenario). Steeper slopes are observed for the more polluted settling material (-5%·year^-1) and especially for fish, in which the background decline trend tripled after the 2001 PCB pulse (from -7%·year^-1 to -21%·year^-1). These PCB time trends in related environmental compartments from contrasted sites provide rare evidence for evaluating the effectiveness of control measures in southern South America.

Polychlorinated biphenyl concentrations, accumulation rates in soil from atmospheric deposition and analysis of their affecting landscape variables along an urban-rural gradient in Shanghai, China

This study initiated an in-situ soil experimental system to quantify the annual dynamics of polychlorinated biphenyl (PCB) congener's concentrations and accumulation rates in soil from atmosphere deposition in a rural-urban fringe, and correlated them by landscape physical and demographic variables in the area. The results showed that the concentrations of all PCB congeners significantly increased with the sampling time (p < 0.05); nearly all the PCB congener concentrations decreased while moving outwards from the urban center. The moderate average concentrations along the gradient for PCB 8, 18, and 28 were 31.003, 18.825, and 19.505 ng g-1, respectively. Tetra-CBs including PCB 44, 52, 66, and 77 were 10.243, 31.214, 8.330 and 9.530 ng g-1, respectively. Penta-CBs including PCB 101, 105, 118, and 126 were 9.465, 7.896, 17.703, and 6.363 ng g-1, respectively. Hexa-CBs including PCB 128, 138, 153, 170, 180, and 187 were 6.798, 11.522, 4.969, 6.722, 6.317, and 8.243 ng g-1 respectively. PCB 195, 206, and 209 were 8.259, 9.506, and 14.169 ng g-1, respectively. Most of the PCB congeners had a higher accumulation rate approximately 28 km from the urban center. The computed variables were found to affect the soil PCB concentrations with a threshold effect (p < 0.05). Regression analysis showed that the thresholds were 10-20 km, 1 km/km², 30%, and 20% for distance, road density, population change index, and built-up area percentage, respectively. It was concluded that factors related to industrial development, traffic, and urban sprawling (i.e. built-up areas expanding) were the sources of PCBs.

Polyurethane foam (PUF) disk passive samplers derived polychlorinated biphenyls (PCBs) concentrations in the ambient air of Bursa-Turkey: Spatial and temporal variations and health risk assessment

Polyurethane foam (PUF) passive samplers were employed to assess air concentrations of polychlorinated biphenyls (PCBs) in background, agricultural, semi-urban, urban and industrial sites in Bursa, Turkey. Samplers were deployed for approximately 2-month periods from February to December 2014 in five sampling campaign. Results showed a clear rural-agricultural-semi-urban-urban-industrial PCBs concentration gradient. Considering all sampling periods, ambient air concentrations of Σ₄₃PCBs ranged from 9.6 to 1240 pg/m³ at all sites with an average of 24.1 ± 8.2, 43.8 ± 24.4, 140 ± 190, 42.8 ± 24.6, 160 ± 280, 84.1 ± 105, 170 ± 150 and 280 ± 540 pg/m³ for Mount Uludag, Uludag University Campus, Camlica, Bursa Technical University Osmangazi Campus, Hamitler, Agakoy, Kestel Organised Industrial District and Demirtas Organised Industrial District sampling sites, respectively. The ambient air PCB concentrations increased along a gradient from background to industrial areas by a factor of 1.7-11.4. 4-Cl PCBs (31.50-81.60%) was the most dominant homologue group at all sampling sites followed by 3-Cl, 7-Cl, 6-Cl and 5-Cl homologue groups. Sampling locations and potential sources grouped in principal component analysis. Results of PCA plots highlighted a large variability of the PCB mixture in air, hence possible related sources, in Bursa area. Calculated inhalation risk levels in this study indicated no serious adverse health effects. This study is one of few efforts to characterize PCB composition in ambient air seasonally and spatially for urban and industrial areas of Turkey by using passive samplers as an alternative sampling method for concurrent monitoring at multiple sites.