Age dependence accumulation of organochlorine pesticides and PAHs in needles with different forest types, southeast Tibetan Plateau

Effects of legacy mining on mercury concentrations in conifer needles and mushrooms in northern Palatinate, Germany

Due to integrated pollution prevention and control measures and the reduced burning of coal, air concentrations of mercury (Hg0) are currently levelling off. In the future, however, evasion from land surfaces will probably reverse this trend. Reasons are the rising temperatures and the loss of forest cover caused by calamities, droughts, storms and wildfires. Plant leaves constitute an important matrix for the accumulation of gaseous mercury and uptake and re-volatilisation by plants depends on the species, the vitality and the age and morphology of leaf organs. It has been shown that older conifer needles show higher concentrations than young needles and Hg accumulation is increasing throughout the season. In present study, we collected branches from Norway Spruce (Picea abies) in a former cinnabar mining region in Northern Palatinate, where artisanal and small-scale mining left innumerable waste dumps. While mining, smelting and processing of the ores were terminated during WWII, high total mercury concentrations remained in the top soils locally, with presumably only small fractions being plant available. In the lab, up to seven needle age classes were analysed. 1000 needle weights increased with age and as expected, also the Hg concentrations were elevated in the older needles. Needle concentrations were higher than those reported from other national biomonitoring programs confirming the regional imprint from legacy mercury. To complement our biomonitoring study, we collected edible mushrooms in former mining areas. Hg concentrations in most samples exceeded the EU maximum residue levels (MRL), while only a few broke the existing cadmium and lead limits. Tolerable weekly intake (TWI) for inorganic mercury would be surpassed with the consumption of a small portion of mushrooms. Further studies should be performed on the outgassing of Hg from mine wastes and the incorporation of Hg in the local food web, including its methylation and biomagnification.

Spatiotemporal patterns and deposition of organophosphate esters (OPEs) in air, foliage and litter in a subtropical forest of South China

Recent studies revealed the un-negligible impact of airborne organophosphate esters (OPEs) on phosphorus (P)-limited ecosystems. Subtropical forests, the global prevalence P-limited ecosystems, contain canopy structures that can effectively sequester OPEs from the atmosphere. However, little is known about the behavior and fate of OPEs in subtropical forest ecosystem, and the impact on the P cycling in this ecosystem. OPE concentrations in the understory air (at two heights), foliage, and litterfall were investigated in a subtropical forest in southern China. The median ∑OPE concentrations were 3149 and 2489 pg/m3 in the upper and bottom air, respectively. Foliage exhibited higher ∑OPE concentrations (median = 386 ng/g dry weight (dw)) compared to litter (median = 267 ng/g dw). The air OPE concentrations were ordered by broadleaved forest > mixed forest > coniferous forest, which corresponds to the results of canopy coverage or leaf area index. The spatial variation of OPEs in foliage and litter was likely caused by the leaf surface functional traits. Higher OPE concentrations were found in the wet season for understory air while in the dry season for foliage and litter, which were attributed to the changes in emission sources and meteorological conditions, respectively. The inverse temporal variation suggests the un-equilibrium partitioning of OPEs between leaf and air. The OPE concentrations during the litter-incubation presented similar temporal trends with those in foliage and litter, indicating the strong interaction of OPEs between the litter layer and the near-soil air, and the efficient buffer of litter layer played in the OPEs partitioning between soil and air. The median OPEs-associated P deposition fluxes through litterfall were 270, 186, and 249 μg P/m2·yr in the broadleaved, mixed, and coniferous forests, respectively. Although the fluxes accounted for approximately 0.2% of the total atmospheric P deposition, their significance to this P-limited ecosystem may not be negligible.

Review of scientific literature on available methods of assessing organochlorine pesticides in the environment

Organochlorine pesticides (OCPs) are persistent organic pollutants (POPs) widely used in agriculture and industry, causing serious health and ecological consequences upon exposure. This review offers a thorough overview of OCPs analysis emphasizing the necessity of ongoing work to enhance the identification and monitoring of these POPs in environmental and human samples. The benefits and drawbacks of the various OCPs analysis techniques including gas chromatography-mass spectrometry (GC-MS), gas chromatography-electron capture detector (GC-ECD), and liquid chromatography-mass spectrometry (LC-MS) are discussed. Challenges associated with validation and optimization criteria, including accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ), must be met for a method to be regarded as accurate and reliable. Suitable quality control measures, such as method blanks and procedural blanks, are emphasized. The LOD and LOQ are critical quality control measure for efficient quantification of these compounds, and researchers have explored various techniques for their calculation. Matrix interference, solubility, volatility, and partition coefficient influence OCPs occurrences and are discussed in this review. Validation experiments, as stated by European Commission in document SANTE/11813/2017, showed that the acceptance criteria for method validation of OCP analytes include ≤20 % for high precision, and 70-120 % for recovery. This may ultimately be vital for determining the human health risk effects of exposure to OCP and for formulating sensible environmental and public health regulations.

Polycyclic aromatic hydrocarbons (PAHs) in air, foliage, and litter in a subtropical forest: Spatioseasonal variations, partitioning, and litter-PAH degradation

Forest canopies play a vital role in scavenging airborne semi-volatile organic compounds. The present study measured polycyclic aromatic hydrocarbons (PAHs) in the understory air (at two heights), foliage, and litterfall in a subtropical rainforest (the Dinghushan mountain) in southern China. ∑₁₇PAH concentrations in the air ranged from 2.75 to 44.0 ng/m³ (mean = 8.91 ng/m³), showing a spatial variation depending on the forest canopy coverage. Vertical distributions of the understory air concentrations also indicated PAH inputs from the above-canopy air. The concentrations of PAHs in fresh litter (with a mean of 261 ± 163 ng/g dry weight (dw)) were slightly lower than those in the foliage (362 ± 291 ng/g dw). Unlike the stable air PAH concentrations for most of the time of the year, the temporal variations of foliage and litter concentrations were remarkable but generally similar. Higher or comparable leaf/litter-air partition coefficients (K_LA) in fresh litter compared with living K_LA in leaves suggest that the forest litter layer is an efficient storage media for PAHs. Degradation of three-ring PAHs in litter under the field conditions follows first-order kinetics (R² = 0.81), while the degradation is moderate for four-ring PAHs and insignificant for five- and six-ring PAHs. The yearly net cumulative deposition of PAHs through forest litterfall in the whole Dinghushan forest area over the sampling year was about 1.1 kg, 46% of the initial deposition (2.4 kg). This spatial variations study provides the results of in-field degradation of litter PAHs and makes a quantitative assessment of the litter deposition of PAHs, deducing their residence dynamics in the litter layer in a subtropical rainforest.

Biomonitoring of atmospheric PAHs using fir and spruce needles in forests in the vicinity of mountain villages

The aim of the study was to use chemical analyses of spruce and fir needles to determine environmental exposure to polycyclic aromatic hydrocarbons (PAHs) in forests surrounding small mountain towns, including popular tourist destinations. The Beskid Mountains in Poland were chosen as the study area because they are very popular with tourists. The 6- and 12 month old needles were collected in two consecutive years from permanent study plots. Two vintages of needles were used to determine the differences between seasons in the profile of deposited pollutants. Some of plots were located away from roads and buildings, while others were located near tourist destinations. The comparison plots were located in the centre of a tourist resort, near a highway, and in a forest localised in the industrial city characterised by a high degree of urbanization. The analyses of 15 PAHs content showed that the amount and type of compounds retained by the needles were influenced not only by the proximity and amount of the surface emitters, but also by the location of the research sites above sea level. The results obtained can be explained, among other things, by the phenomenon of smog, which is not uncommon in the study region in autumn and winter.

Quantitative analysis and contamination profiles of PCBs, OCPs, and PAHs in black-tailed gull eggs in the Republic of Korea

The simultaneous determination of 8 polychlorinated biphenyls (PCBs), 23 organic chlorine pesticides (OCPs), and 35 polycyclic aromatic hydrocarbons (PAHs) in black-tailed gull eggs was described using ultrasound-assisted extraction and gas chromatography-tandem mass spectrometry (GC-MS/MS). The ranges of the lower limits of detection for PCBs, OCPs, and PAHs were 0.006-0.029, 0.01-0.10, and 0.01-0.20 μg kg^-1, respectively. The intraday precision was in the range of 0.650-12.9% and the intraday accuracy was in the range of 86.6-113%. When the proposed method was used to analyze the target compounds in gull eggs collected from six sites in the Republic of Korea, the analytical results demonstrated concentration ranges of 113.32-394.07 µg kg^-1 for total PCBs, 422.92-1082.09 µg kg^-1 for total OCPs, and 134.50-231.27 µg kg^-1 for total PAHs in the samples. The PCA results for PAHs and OCPs were well differentiated by sampling site, whereas those for PCBs differed little by sampling site. There were more pyrogenic PAHs in the West Sea and the South Sea with many industrial areas than in the East Sea with few industrial areas. Differences in the OCP patterns of samples from the West Sea close to China were considered to be related to the use of DDT in China until recently. PCBs were accumulated in the samples regardless of region, so there was no significant difference in the PCB patterns between the samples obtained from the three Seas.

The endangered African Great Ape: Pesticide residues in soil and plants consumed by Mountain Gorillas (Gorilla beringei) in Bwindi Impenetrable National Park, East Africa

Bwindi Impenetrable National Park situated southwest of Uganda is a biodiversity hotspot that is home to about half of the world's endangered mountain gorilla (Gorilla beringei). Given its ecological significance and mounting pressures from agricultural activities such as tea growing, continuous monitoring of the levels of chemical toxins like pesticides in the park and surrounding areas is needed for effective conservation strategies. Furthermore, persistent organochlorine pesticides (OCPs) like DDT were used in agricultural gardens and indoor spraying in Kanungu district between the 1950s and 80s. The focus of this study was to explore the possible exposure of mountain gorillas to OCPs and cypermethrin used by the farmers in the areas near the park. Data from our interviews revealed that glyphosate is the most widely used pesticide by the farmers in areas surrounding the park, followed by cypermethrin, and mancozeb. Samples of leaves from plants consumed by mountain gorillas along the forest edges of the park and surficial soils (15-20 cm depths) were collected from three sites (Ruhija, Nkuringo and Buhoma) and analysed for the presence of cypermethrin and OCPs residues. Concentrations of total (∑) DDTs and ∑endosulfans were up to 0.34 and 9.89 mg/kg dry weight (d.w), respectively in soil samples. Concentrations of ∑DDTs and ∑endosulfans in samples of leaves ranged from 0.67 to 1.38 mg/kg d.w (mean = 1.07 mg/kg d.w) and 0.9 to 2.71 mg/kg d.w (mean = 1.68 mg/kg d.w), respectively. Mean concentration of ∑DDTs in leaves exceeded the European pharmacopeia and United States pharmacopeia recommended maximum residue limit values for DDTs in medicinal plants (1.0 mg/kg). In addition, calculated hazard indices for silverbacks (36.35), females (57.54) and juveniles (77.04) suggested potential health risks to the mountain gorillas. o,p'-DDT/p,p'-DDT ratios (0.5-0.63) in samples of leaves confirmed recent input of dicofol-DDT type in Bwindi rainforest.

Significance of the long-term biomonitoring studies for understanding the impact of pollutants on the environment based on a synthesis of 25-year biomonitoring in the Holy Cross Mountains, Poland

This review presents compiled results of complex biomonitoring studies that have been conducted in the Holy Cross Mountains, south-central part of Poland, since the 1990s. The significance of these studies results from several aspects: (i) a number and a variety of plant organisms used, e.g., mosses, lichens, coniferous and deciduous trees, and their tissues (wood, bark, needles, leaves, the aboveground parts of several vascular plants); (ii) applications of a broad scope of instrumental methods aiming at determining major and trace elements (including rare earth elements), organic compounds (PAHs, PCBs, phenols), and stable sulfur isotopes (δ³⁴S); and (iii) different methodological and environmental issues addressed. The comparison and interpretation of results derived from seventeen sampling campaigns carried out between 1994 and 2017 are a valuable source of information on the following: (i) bioaccumulative properties of organisms used in air quality monitoring, (ii) identification and variations of local and regional pollution sources and geochemical landscape patterns and processes over years, and (iii) establishing environmental factors that variously affected chemical composition of plants growing under physiological stress, including roadside vegetation and plants from acid mine drainage areas.

The use of Pinus nigra as a biomonitor of pesticides and polycyclic aromatic hydrocarbons in Lebanon

Among the various species of vegetation, conifers play an important role as a biomonitor of air pollution. The current study presents the determination of pesticides and polycyclic aromatic hydrocarbons in 15 conifer samples collected in August 2018 (summer season) from different regions in north Lebanon (Tripoli, Koura, Bcharre, and Akkar). Pollutants were extracted based on QuEChERS-SPME followed by liquid and gas chromatography-tandem mass spectrometry. Results showed that the samples collected from Bcharre region had the lowest concentration in both pesticides and polycyclic aromatic hydrocarbons with a total concentration of 50 and 66 ng g^-1, while the samples collected from the regions widely known by their agriculture (Akkar, Tripoli, and Koura areas) were the most polluted with concentrations of 231 and 422 ng g^-1, 192 and 370 ng g^-1, and 127 and 98 ng g^-1 for pesticides and polycyclic aromatic hydrocarbons respectively. This study revealed that conifers are suggested to be efficient biomonitors of contamination levels in the air.