Persistent organic pollutants in a multimedia environment, and associated human health risks: case studies in the region of Campania, Italy, and south-central China

Persistent organic pollutants (POPs) are notoriously toxic chemicals that pose significant threats to human health and ecosystem security. As a result of their volatility and persistence, POPs can be subject to long-range atmospheric transport (LRAT) and, as a result, may be redistributed globally. The harm of POPs to the eco-system is regarded as a global environmental problem, threatening people and animals, which has caused heavy losses economically, ecologically and socially. The environmental problems caused by POPs have finally lead the international community to address the global presence of POPs and reduce their emissions to the environment. Many treaties and laws have been enacted to eliminate or restrict the production and use of some POPs, of which the Stockholm Convention of 2004 on POPs is one of the most famous. Soils are important POPs reservoirs due to their tremendous retention capabilities for these compounds. The huge quantities of POPs accumulated in soils have been an important reemission sources to the atmosphere even after the phasing out of these compounds decades ago. Atmospheric processes are largely responsible for the transport and deposition of polycyclic aromatic hydrocarbons (PAHs), and these compounds may adhere to both atmospheric aerosols and dustfall. Organochlorine pesticides (OCPs) can be easily adsorbed on to suspended particulate matter (SPM) as sediments. SPM can then precipitate in sediments and eventually lower the OCP concentrations in water. Under favorable conditions, sediments can be resuspended, release previously adsorbed OCPs back into the water phase, and initiate another cycle of environmental contamination. So far, the Stockholm Convention has not been ratified by Italy, however, several other regulatory schemes, such as a European Directive in 2000, the UNECE POPs Protocol, and the Rotterdam Convention, are actively followed. The region of Campania falls within the subtropical zone and enjoys a Mediterranean climate. High temperatures in tropical/subtropical regions can facilitate the volatilization and escape of POPs from soils, sediments, and water. The lack of sufficient data on POPs residues, limits the understanding of their health effects, environmental dynamics, and the ultimate fate of these chemicals. China is one of the largest agricultural industries in the world, and was once the largest global producer and consumer of OCPs, especially in the arable southeast region. This Ph.D. thesis presents the results of a series of investigations using a systematic sampling method and geostatistics to illustrate spatial and temporal variations in the concentrations of POPs in different environments, and associated human health risks in Campania, Italy, and south-central China

Status, sources and contamination levels of organochlorine pesticide residues in urban and agricultural areas: a preliminary review in central–southern Italian soils

Organochlorine pesticides (OCPs) are synthetic chemicals commonly used in agricultural activities to kill pests and are persistent organic pollutants (POPs). They can be detected in different environmental media, but soil is considered an important reservoir due to its retention capacity. Many different types of OCPs exist, which can have different origins and pathways in the environment. It is therefore important to study their distribution and behaviour in the environment, starting to build a picture of the potential human health risk in different contexts. This study aimed at investigating the regional distribution, possible sources and contamination levels of 24 OCP compounds in urban and rural soils from central and southern Italy. One hundred and forty-eight topsoil samples (0–20 cm top layer) from 78 urban and 70 rural areas in 11 administrative regions were collected and analysed by gas chromatography–electron capture detector (GC–ECD). Total OCP residues in soils ranged from nd (no detected) to 1043 ng/g with a mean of 29.91 ng/g and from nd to 1914 ng/g with a mean of 60.16 ng/g in urban and rural area, respectively. Endosulfan was the prevailing OCP in urban areas, followed by DDTs, Drins, Methoxychlor, HCHs, Chlordane-related compounds and HCB. In rural areas, the order of concentrations was Drins > DDTs > Methoxychlor > Endosulfans > HCHs > Chlordanes > HCB. Diagnostic ratios and robust multivariate analyses revealed that DDT in soils could be related to historical application, whilst (illegal) use of technical DDT or dicofol may still occur in some urban areas. HCH residues could be related to both historical use and recent application, whilst there was evidence that modest (yet significant) application of commercial technical HCH may still be happening in urban areas. Drins and Chlordane compounds appeared to be mostly related to historical application, whilst Endosulfan presented a complex mix of results, indicating mainly historical origin in rural areas as well as potential recent applications on urban areas. Contamination levels were quantified by Soil Quality Index (SoQI), identifying high levels in rural areas of Campania and Apulia, possibly due to the intensive nature of some agricultural practices in those regions (e.g., vineyards and olive plantations). The results from this study (which is in progress in the remaining regions of Italy) will provide an invaluable baseline for OCP distribution in Italy and a powerful argument for follow-up studies in contaminated areas. It is also hoped that similar studies will eventually constitute enough evidence to push towards an institutional response for more adequate regulation as well as a full ratification of the Stockholm Convention

The occurrence of OCPs, PCBs, and PAHs in the soil, air, and bulk deposition of the Naples metropolitan area, southern Italy: Implications for sources and environmental processes

I am often reminded of the famous saying of Goethe: "Vedi Napoli e poi muori! - See Naples and die!". Sadly, Naples is now confronted with a number of serious, ongoing problems with a need to alleviate pressure on the worsening environment. One serious problem facing the environment is the presence of the potentially hazardous persistent organic pollutants (POPs), although few systematic studies at regional scale have been conducted. In this study, samples of soil, air, and bulk deposition were collected in Naples metropolitan area (NMA) to characterize the status of POPs, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). The results obtained showed that most of these compounds are pervasive in all the studied environmental matrices, especially in some hotspot areas, such as the Bagnoli Brownfield Site and the infamous "Triangle of the Death", where unwanted ecological risk conditions for PAHs and Endosulfan were determined, respectively. The interactional complexity between urban and the surrounding rural areas was also confirmed, as is the role that urban areas play in the migration and transformation process of POPs. High urban-rural gradients for atmospheric PAHs and PCBs were observed in the NMA, and the urban areas were identified as the emission source of these contaminants. Similarly, the OCP residues, historically originated from the nearby agricultural regions, experience long-term soil re-emission and continuously influence the connected urban environment via atmospheric transport processes. Keywords: Persistent organic pollutants, Emission sources, Geochemical baseline, Atmospheric transport, Naple

The occurrence of dichlorodiphenyltrichloroethanes (DDT) and its metabolites in Chinese forest soils: Implications for sources and environmental processes

&amp;lt;p&amp;gt;Dichlorodiphenyltrichloroethane (DDT) and its metabolites are highly toxic and pose chronic effects to the biosphere. As a natural storage pool, forests have great potential to capture them from the atmosphere and migrate them to the forest soil, which, in turn, influences the safety of the forest ecological environment. In this study, a systematical survey of DDT and its metabolites has been carried out to measure their spatial variations in Chinese forest soils. The main objectives of this study were to (1) investigate the levels, distribution and sources of DDT and its metabolites, and further estimate their mass inventories in Chinese forest soils, (2) explore the impact of soil properties on their distribution, and (III) assess the ecological and health risks of DDT and its metabolites. The research results were as follows. The average concentration of &amp;amp;#931;DDTs reached up to 9.75 ng/g, and &amp;lt;em&amp;gt;p,p&amp;amp;#8217;&amp;lt;/em&amp;gt;-DDT is the main component. Significant difference in the concentration of &amp;amp;#931;DDTs was observed between the southeast and northwest regions (&amp;lt;em&amp;gt;p&amp;lt;/em&amp;gt;&amp;lt;0.01), which may be related to multiple factors such as pesticide use, rainfall and altitude. The forest soil quality inventory is about 0.58&amp;amp;#215;103 tons, which is lighter than that of domestic farmland soil. 56.1% of soil samples were less than the low value of risk assessment (ERL). The concentration of &amp;amp;#931;DDTs in the East and middle is higher than that in the West, and the high value is mainly distributed in the coastal areas. DDTs were mainly from the input of the mixed source composed of industrial DDT and dicofol, of which at least 97% came from industrial DDT and up to 4% from dicofol. &amp;amp;#931;DDTs was only positively correlated with precipitation and population density (&amp;lt;em&amp;gt;p&amp;lt;/em&amp;gt;&amp;lt;0.05). The degradation of DDT in soil occured from primary stage to high stage. The possible degradation pathways involved in DDTs entering forest soil were preliminarily deduced. Firstly, the surrounding pollution sources volatilize DDTs from soils to the atmosphere through secondary emission. In this process, DDT was continuously transformed into DDE through photodecomposition. The atmosphere rich in DDTs were transported to the forest area and then into the forest surface soil through atmospheric dry and wet deposition. Then, DDT transported continuously accumulated and degraded in forest soil. In the alternation of anaerobic and aerobic process, the main degradation pathways are DDT&amp;amp;#8594;DDD&amp;amp;#8594;DDMU, DDT&amp;amp;#8594;dicofol+DBP, DDT&amp;amp;#8594;DDE&amp;amp;#8594;DDMU, DDMU&amp;amp;#8594;DDNU.&amp;lt;/p&amp;gt;</jats:p

Polycyclic Aromatic Hydrocarbons in the Water Bodies of Dong Lake and Tangxun Lake, China: Spatial Distribution, Potential Sources and Risk Assessment

Polycyclic aromatic hydrocarbons (PAHs) are a group of highly toxic organic pollutants. At present, there has only been limited research into PAH contamination in Tangxun Lake and Dong Lake, which are the first and second largest urban inland lakes in China, respectively. This study investigated the concentration, spatial distribution, sources, and ecological risks of PAHs in the water from Dong Lake and Tangxun Lake. The focus of this study is to use models to analyze the sources of PAHs, as well as their potential toxicity to humans, in the water bodies of Dong Lake and Tangxun Lake. This study performed liquid&ndash;liquid extraction to extract PAHs from lake water samples using dichloromethane and then used gas chromatography&ndash;mass spectrometry (GC-MS) to quantitatively analyze the PAHs in the samples. The total concentration of the &sum;16PAHs showed high variability among different sampling points, ranging from 12.92 to 989.09 ng/L, with an arithmetic mean of 121.97 ng/L. The composition of the &sum;16PAHs was mainly concentrated at a low molecular weight (&gt;70%). The molecular distributions of PAH studies, combined with positive matrix factorization (PMF), indicate that oil and coal combustion are the main sources of PAHs in Dong Lake and Tangxun Lake. The model of PMF succeeded in identifying and quantifying five sources with similar contributions: the combustion of petroleum products, heavy oil burning, coal combustion, traffic emissions, and natural gas and oil combustion mixed. According to toxicity equivalency (TEQ) and lifelong cancer risk (ILCR) research, PAHs from traffic sources in the environment may be more toxic, and the potential carcinogenic risk of PAH pollution to humans in Tangxun Lake and Dong Lake water bodies is relatively inferior

Arsenic in water, sediment, and fish of lakes from the Central Tibetan Plateau

As a potential source of arsenic (As) for the downstream region of the South and East Asia, the As contamination in the Qinghai-Tibet Plateau (QTP) still needs more investigation. In this study, As concentrations in the surface water, lake sediments, and fish of lakes and endorheic rivers in the central Tibet Plateau (CTP) were investigated for the better understanding of As fate in the CTP. Extremely high levels of As in saline lakes water were found with concentrations up to 10,775.40 mu g/L, while the lowest level of As was found in freshwater lakes with a concentration of only 1.80 mu g/L. Natural loading and evaporation concentration were the main reasons for As accumulation in saline lakes in the CTP. Rock weathering and terrestrial ecosystem could affect the As level in the lake. As contents in lake sediments significantly positive related to the As/EC ratios but showed no correlation with As concentrations in the water. Although As levels in the fish were higher in lakes with higher As concentrations, they were still lower than those of the fish from As-contaminated lakes in other studies. Results of this study indicate that hot spots of As in the CTP require more in-depth attention and studies in the future to better understand their influence on the fragile CTP aquatic ecosystem.</p