Karla Pozo

Spatial and temporal pattern of pesticides in the global atmosphere

As part of the Global Atmospheric Passive Sampling (GAPS) study, XAD-resin based passive samplers are being deployed for consecutive one-year periods at numerous sites on all seven continents to determine annually averaged concentrations of persistent organic pollutants. Concentrations of banned organochlorine pesticides as well as a number of current-use pesticides in samples from the first four years, roughly coinciding with 2005, 2006, 2007 and 2008, show distinct spatial and temporal patterns. Whereas organochlorine pesticides such as alpha- and gamma-hexachlorocyclohexane, endosulfans, DDT and its metabolites, and chlordane-related compounds tend to be more prevalent in developing countries, especially in Asia, concentrations of current use pesticides such as trifluralin and chlorothalonil are often higher in Europe and North America. Based on 15 stations with four years of data, levels of hexachlorobenzene, hexachlorocyclohexanes and chlordanes decline in most world regions, which may reflect decreased usage in response to global restrictions. Levels of organochlorine pesticides in India, however, remain exceptionally high. Concentrations of alpha-endosulfan, chlorothalonil and trifluralin decrease in the European atmosphere during the sampling periods, indicating reduced usage. Consistently high alpha/gamma-HCH ratios in air samples from high Northern latitudes confirm that re-volatilization from the Arctic Ocean is a significant source of alpha-HCH. The highest levels of alpha-HCH, however, occur in conjunction with high gamma-HCH levels, suggesting that lindane use is now the major source of alpha-HCH to the global atmosphere. Although a wide variety of sampling site types aids in characterizing the entire global concentration variability of a pesticide, it also increases greatly the number of sites required for a robust regional differentiation.

Current Challenges in Air Sampling of Semivolatile Organic Contaminants: Sampling Artifacts and Their Influence on Data Comparability

With current science and policy needs, more attention is being given to expanding and improving air sampling of semivolatile organic contaminants (SVOCs). However, a wide range of techniques and configurations are currently used (active and passive samplers, different deployment times, different sorbents, etc.) and as the SVOC community looks to assess air measurements on a global scale, questions of comparability arise. We review current air sampling techniques, with a focus on sampling artifacts that can lead to uncertainties or biases in reported concentrations, in particular breakthrough, degradation, meteorological influences, and assumptions regarding passive sampling. From this assessment, we estimate the bias introduced for SVOC concentrations from all factors. Due to the effects of breakthrough, degradation, particle fractions and sampler uptake periods, some current passive and active sampler configurations may underestimate certain SVOCs by 30-95%. We then recommend future study design, appropriateness of sampler types for different study goals, and finally, how the SVOC community should move forward in both research and monitoring to best achieve comparability and consistency in air measurements.

Levels and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments from Lenga Estuary, central Chile

The Lenga Estuary is a small brackish wetland located southwest of San Vicente Bay, Region VIII, Chile. Surface sediment from nine sites in the estuary were analysed for PAHs and compared to Sediment Quality Guidelines (SQG). Sediment samples were freeze dried and soxhlet extracted for 16 h using DCM. Identification and quantification was carried out by HPLC. Organic carbon was also determined. Results showed total PAH concentrations ranged from 290 to 6118 (2025 ± 1975)ng g(-1) d.w. (2025 ± 1975). Results for organic carbon percentages ranged from 1% to 7%. Statistical analysis showed a significant positive correlation (Pearson test) between organic carbon percentage PAHs. Comparison of contaminant levels and international Sediment Quality Guidelines (SQG) (ERL and ER) suggested that sediment of the Lenga estuary did not show any ecotoxicological risk for benthic organisms where high levels of PAHs were detected. Monitoring of this and other contaminants is recommended in Chile.

Levels and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in superficial sediment from 15 Italian marine protected areas (MPA)

Surface sediment from 15 Italian marine protected areas (MPA) were analysed for polycyclic aromatic hydrocarbons (PAHs). The organic carbon percentage was also determined. Total PAH concentrations (ng g⁻¹ d.w.) ranged from 0.71 (Penisola del Sinis) to 1550 (Miramare). Individual PAH analysis showed that three and four rings PAHs were the most frequently detected isomers and accounted for 60-70% of the PAH total concentrations. PAH ratio analysis showed a prevalence of pyrolytic PAH origin at most of the MPAs with exception of Porto Cesareo and Ustica where a petrogenic origin was detected. Results for organic carbon percentages ranged from 0.3% (Capo Rizzuto) to 2% (Punta Campanella). These results are comparable to other Mediterranean marine environments. However, our results shows that some MPAs, such as Miramare, Porto Cesareo, Isola Capo Rizzuto and Punta Campanella, are subject to strong pressure from urban and industrial activities where high PAH levels were detected.

Levels and spatial distribution of polychlorinated biphenyls (PCBs) in superficial sediment from 15 Italian Marine Protected Areas (MPA)

Human activities such as industry, sewage, coastal sprawl, intensive agriculture and oil spills have a high impact on the Mediterranean marine environment. In Italy, growing awareness of how man is threatening marine ecosystems has prompted conservation measures, including the designation of Marine Protected Areas (MPAs). MPAs are essential for conservation, providing protection for critical areas and refuges for overexploited species. They can also act as buffers against management miscelation (Allison et al., 1998). Italy has instituted a number of MPAs that are proving effective in protecting wildlife. Most of them contain one or more no-entry zones which coincide with the areas of greatest natural value (Boero et al., 1999). However, MPAs cannot protect populations or assemblages from transboundary movements of chemicals (I.U.C.N, 1981), a phenomenon observed mostly in MPAs located near human activities such as harbours. MPAs can be useful for monitoring release of contaminants. For instance, Terlizzi et al. (2004) reported the effects of organotin compounds such as tributyltin (TBT) and its transboundary movements in species of marine snails living in Italian MPAs. Persistent organic pollutants (POPs) are semivolatile organic compounds of special concern because of their toxicity, persistence, long-range transport and bioaccumulation potential (UNEP, 2001). POPs such as polychlorinated biphenyls (PCBs) have been widely used in industry and are characterized by low vapour pressure, low water solubility and environmental persistence (Mackay et al., 1992). Since they are hydrophobic they bind readily to particulate in water and are transported/deposited with sediment into rivers, lakes and oceans (Bergamaschi et al., 2001). The Stockholm Convention on POPs, coordinated through the United Nations Environment Programme (UNEP), aims to reduce or eliminate the use, discharge and emission of these compounds to the benefit of the environment, reducing risks to humans and wildlife (UNEP, 2001). Initially, 12 chemicals were identified as priority POPs: nine organochlorine pesticides (OCPs), one industrial chemical class, polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-pdioxins/dibenzofurans (PCDD/Fs) associated with various industrial/combustion emissions (UNEP, 2001). Several countries in Europe are parties to the Convention; Italy signed the Stockholm Convention in May 2001, but has not yet ratified it. PCBs were widely used as insulating fluids in electrical equipment, such as transformers and capacitors, and for many other uses. Italian production of PCBs began in 1958. PCB mixtures were

A review of analytical techniques for quantifying microplastics in sediments

In this review the analytical techniques for measuring microplastics in sediment have been evaluated. Four primary areas of the analytical process have been identified that include (1) sampling, (2) extraction, (3) quantitation and (4) quality assurance/quality control (QAQC). Each of those sections have their own subject specific challenges and require further method development and harmonisation. The most common approach to extracting microplastics from sediments is density separation. Following extraction, visual counting with an optical microscope is the most common technique for quantifying microplastics; a technique that is labour intensive and prone to human error. Spectroscopy (FTIR; Raman) are the most commonly applied techniques for identifying polymers collected through visual sorting. Improvements and harmonisation on size fractions, sampling approaches, extraction protocols and units for reporting plastic abundance would aid comparison of data generated by different research teams. Further, we advocate the development of strong QAQC procedures to be adopted like other fields of analytical chemistry. Finally, inter-laboratory proficiency testing is recommended to give an indication of the variation and reliability in measurements reported in the scientific literature that may be under- or overestimations of environmental burdens.

Assessing Polycyclic Aromatic Hydrocarbons (PAHs) using passive air sampling in the atmosphere of one of the most wood-smoke-polluted cities in Chile: The case study of Temuco

This study addresses human health concerns in the city of Temuco that are attributed to wood smoke and related pollutants associated with wood burning activities that are prevalent in Temuco. Polycyclic Aromatic Hydrocarbons (PAHs) were measured in air across urban and rural sites over three seasons in Temuco using polyurethane foam (PUF) disk passive air samplers (PUF-PAS). Concentrations of ΣPAHs (15 congeners) in air ranged from BDL to ∼70 ng m(-3) and were highest during the winter season, which is attributed to emissions from residential heating by wood combustion. The results for all three seasons showed that the PAH plume was widespread across all sites including rural sites on the outskirts of Temuco. Some interesting variations were observed between seasons in the composition of PAHs, which were attributed to differences in seasonal point sources. A comparison of the PAH composition in the passive samples with active samples (gas+particle phase) from the same site revealed similar congener profiles. Overall, the study demonstrated that the PUF disk passive air sampler provides a simple approach for measuring PAHs in air and for tracking effectiveness of pollution control measures in urban areas in order to improve public health.

Assessing levels and seasonal variations of current-use pesticides (CUPs) in the Tuscan atmosphere, Italy, using polyurethane foam disks (PUF) passive air samplers.

Polyurethane foam disks (PUF) passive air samplers (PAS) were deployed over 4 sampling periods of 3-5-months (≥ 1 year) at ten urban and rural locations throughout the Tuscany Region. The purpose was to assess the occurrence and seasonal variations of ten current-use pesticides (CUPs). PUF disk extracts were analyzed using GC-MS. The organophosphates insecticides; chlorpyrifos (3-580 pg m(-3)) and chlorpyrifos-methyl (below detection limit - to 570 pg m(-3)) presented the highest levels in air, and showed seasonal fluctuation coinciding with the growing seasons. The relative proportion urban/(urban + rural) ranged from 0.4 to 0.7 showing no differences between urban and rural concentrations. Air back trajectories analysis showed air masses passing over agricultural fields and potentially enhancing the drift of pesticides into the urban sites. This study represents the first information regarding CUPs in the atmosphere of Tuscany region using PAS-PUF disk.

Accumulation of polycyclic aromatic hydrocarbons by lichen transplants: Comparison with gas-phase passive air samplers

This study compared the accumulation of 16 polycyclic aromatic hydrocarbons (PAHs) in samples of the lichen Evernia prunastri exposed for 3 months in and around an industrial area of S Italy with that in co-located passive gas-phase air samplers. The results showed a strong linear correlations (R=0.96, P<0.05) between total PAHs in lichens and in passive samplers, clearly indicating that lichen transplants may provide direct quantitative information on the atmospheric load by total PAHs, allowing translation of lichen values into atmospheric concentrations. To the best of our knowledge this is the first study reporting such a correlation with gas-phase passive air samplers.

Paleolimnological studies of Laguna Chica of San Pedro (VIII Region): Diatoms, hydrocarbons and fatty acid records

Se realizo la reconstruccion historica de los ultimos 150 anos de Laguna Chica de San Pedro (Concepcion, VIII Region, Chile), a traves de la utilizacion de los restos de diatomeas, hidrocarburos y acidos grasos contenidos en la columna de sedimento. El analisis estratigrafico de las diatomeas revelo la presencia de tres periodos diferentes. El primer periodo (1883-1940s), mostro un marcado aumento de las tasas de sedimentacion y un leve aumento en la acumulacion de materia organica; en este periodo se registra un incremento de las especies eutroficas (Aulacoseira granulata y Staurosira construens). Desde los anos cuarenta hasta la decada del setenta el cambio en la comunidad de diatomeas fue mas evidente y las tasas de sedimentacion variaron fuertemente. A partir de 1978 disminuyen las especies eutroficas y aumentan las indicadoras de condiciones oligotroficas (Cyclotella stelligera y Aulacoseira distans). El cambio en el estado trofico del lago, no se atribuye a una reduccion de los aportes de nutrientes desde la cuenca, sino que se hipotetiza que la invasion de la macrofita Egeria densa, altero la disponibilidad de nutrientes en las comunidades planctonicas. Esto concuerda con el analisis de hidrocarburos y acidos grasos, registrandose una mayor concentracion de compuestos de cadena larga (caracteristicos de plantas superiores) en los estratos superficiales, mientras que en los estratos mas profundos se detecto una mayor concentracion de hidrocarburos y acidos grasos de cadena corta (caracteristicos de microalgas)