Low Pollution Load Research Articles

Magnetic properties of the surface sediments in the Yellow River Estuary and Laizhou Bay, Bohai Sea, China: Implications for monitoring heavy metals

The Yellow River Estuary (YRE) and adjacent Laizhou Bay (LB) encounter eco-environmental risks caused by heavy metals (HMs) pollution. Here magnetic measurements were performed on 239 surface sediment samples from the YRE and LB to establish a rapid and effective method for detecting HMs. Magnetite, maghemite, and hematite coexist in the sediments. The distributions of magnetic minerals are dominated by sediment sources (Yellow River in northern and western LB, and rivers in southern and eastern coastal LB), and the anticlockwise water current. Compared to the background values, Cd content is enriched for all samples, while Co, Cr, Ni, Cu, Zn, and Pb contents are lower for most samples. The low pollution load indexes (PLI) of HMs (< 1–1.56) indicate the unpolluted to moderately polluted status, while the muddy area is the most polluted. The principal component analysis indicates that Co, Cr, Ni, Cu, and Zn are mainly from natural weathering substances, while Cd and Pb are anthropogenic. Contents of fine-grained sediments and magnetic particles are positively correlated to Co, Ni, Cu, Zn, and PLI. The high-risk Co, Ni, Cu, and Zn regions can be quickly delineated with the frequency-dependent susceptibility.

A simple and sustainable beamhouse by the recycling of waste-water from KCl-dispase synergistic unhairing in leather making

The conventional beamhouse of leather making invariably results in serious pollution of sulfide, solid suspension and ammonia nitrogen because of the use of Na2S and Ca(OH)2 in unhairing (liming) and reliming. It is an urgent issue to develop alternatives of the Na2S and Ca(OH)2 system. In this work, the K+ and Cl− of Hofmeister series are chosen to improve the binding ability of dispase to water molecules and substrate, which can further enhance the unhairing/fiber opening effect of dispase, with only one step for unhairing, opening collagen fiber-bundles and bating. The cycle unhairing effect of K+/Cl−/dispase solution system and its unhairing waste-water recycling in fiber opening are studied. The effect of K+ and Cl− on the penetration of dispase in bovine hides, the hydrolysis for proteoglycans and elastic fibers, and the opening effect for collagen fiber-bundles are analyzed systematically. The results indicated that, the K+ and Cl− increase the stability of dispase activity to 12 times of recycling for unhairing. Due to the electrostatic attraction of K+ and Cl− to the charged amino acid residues, both the penetration of dispase in bovine hides and the hydrolysis of proteoglycans and elastic fibers are accelerated, and an easy step for unhairing/fiber opening is realized. Only 30 h is needed for unhairing/fiber opening, and the waste-water can be recycled for unhairing too. Because of the reuse of unhairing waste-water, low pollutant loads, high collagen fibril dispersity are reached. The resultant leathers are good in physical properties, and their thermal stability are comparable to that by the conventional process. The leather making system of KCl/dispase is suggested to be a cleaner and greener technology than the conventional ones.

Cleaner approach for medium consistency eucalyptus slab pulp production using ozone bleaching under turbulent mixing

Eucalyptus slab (ES), a cellulosic waste from wood processing is abundant and can be utilized for the pulping in many wood scarce countries. However, during chlorine dioxide (ClO2) bleaching, which is the current applied bleaching technique for medium consistency eucalyptus slab pulp (MC-ESP), toxic absorbable organic halides (AOX) is still generated, causing pollution to the water environment. Applying ozone gas (O3) to replace ClO2 for MC-ESP bleaching is a promising alternative way since O3 is a clean and powerful oxidizing agent but not producing AOX pollutant. In this work, the influences of the three most important O3-bleaching factors, i.e., O3-concentration, O3-dosage and mixing intensity to the bleaching properties of MC-ESP was systematically evaluated. It was found that increasing of O3-concentration and O3-dosage greatly improved the properties of MC-ESP. Turbulent mixing intensity had a effective effect on improving O3-bleaching of MC-ESP. The high O3-concentration (170 mg/L), 1.0% O3-dosage and 1200 rpm rotational speed were found to be optimum conditions for O3-bleaching of MC-ESP. Under this condition, the brightness, kappa number and viscosity of the pulp obtained were similar or even better than those of the ESP after bleaching with similar or higher ClO2-dosage, however, without generating toxic AOX and with lower pollution load of effluent. This research provided important supports for the development of MC-ESP cleaner production by reducing the pollutant from ClO2 bleaching. Such approach of using wood processing waste as raw material, O3 gas as AOX-free bleaching agent could provide the excellent options for eco-friendly pulp production.

Remediation of Polluted River Water by Biological, Chemical, Ecological and Engineering Processes

Selection of appropriate river water treatment methods is important for the restoration of river ecosystems. An in-depth review of different river water treatment technologies has been carried out in this study. Among the physical-engineering processes, aeration is an effective, sustainable and popular technique which increases microbial activity and degrades organic pollutants. Other engineering techniques (water diversion, mechanical algae removal, hydraulic structures and dredging) are effective as well, but they are cost intensive and detrimental to river ecosystems. Riverbank filtration is a natural, slow and self-sustainable process which does not pose any adverse effects. Chemical treatments are criticised for their short-term solution, high cost and potential for secondary pollution. Ecological engineering-based techniques are preferable due to their high economic, environmental and ecological benefits, their ease of maintenance and the fact that they are free from secondary pollution. Constructed wetlands, microbial dosing, ecological floating beds and biofilms technologies are the most widely applicable ecological techniques, although some variabilities are observed in their performances. Constructed wetlands perform well under low hydraulic and pollutant loads. Sequential constructed wetland floating bed systems can overcome this limitation. Ecological floating beds are highly recommended for their low cost, high effectiveness and optimum plant growth facilities.

Simultaneous Ammonia Nitrogen and Phosphorus Removal from Micro-Polluted Water by Biological Aerated Filters with Different Media

In this study, volcanic rock, ceramsite, and zeolite as media in biological aerated filters (BAFs) were evaluated on simultaneous ammonia nitrogen and phosphorus (SNP) removal performance in micro-polluted water. The highest NH4+-N removal efficiencies were 92.3% for zeolite BAF, and the highest PO43−-P removal efficiencies were 67.4% for volcanic rock BAF. Zeolite BAF and volcanic rock BAF were more suitable for ammonia nitrogen and phosphorus removal than ceramsite BAF under various conditions. Ammonia nitrogen and phosphate removal in BAFs were promoted effectively with air/water = 1:1, hydraulic retention time = 3 h, low pollution loads, and a temperature of 10 °C. Also, the bacterial community results revealed that the long-time operation stage samples had the highest bacterial diversity in the volcanic rock BAF. The main bacterial species at a family level, including Nocardiaceae, Moraxellaceae, Burkholderiales, and Nitrospia, have a close association with SNP removal. These results demonstrated that volcanic rock BAF is more suitable to treat the micro-polluted water with the low content of ammonia nitrogen and phosphorus.

Spatial-seasonal variations and ecological risk of heavy metals in Persian gulf coastal region: case study of Iran.

This study aimed to perform a systematic review to analyse the seasonal concentration and ecological risk assessment of heavy metals (HMs) in seawater and sediment samples collected from the coastline of Jam city in Bushehr, Iran. A total of 96 sediment and seawater samples were collected from 16 sampling stations during the spring, summer, autumn, and winter of 2017. Then, the concentrations of Pb, Ni, Cd, Cr, Cu, Zn, and Fe were determined. Finally, the pollution load index (PLI), ecological risk (Er), and environmental risk (RI) were calculated to assess the HM ecological risk. The results showed that the mean concentrations of HMs were lower than the maximum acceptable concentration by SQG and NOAA. In addition, the PLI assessed a low pollution load level in the region. The ER and RI results also showed that the region was at low risk, and the metal risk was classified as Cd > Cu > Pb > Ni > Zn > Cr. In some samples, the mean concentrations of HM were found to be higher with a statistically significant difference (P˂0.05). The results also showed that sediments were engaging in a moderate Er by Cd. Generally, the rapid growth of urbanization, as well as industrial and human activities, along this coastline and area has increased the pollutants dumped into the seawater and sediments. Thus, it is necessary to take regular monitoring programs and develop better management strategies to minimize the amount of HMs entering into this coastal area.

Pollution and Sustainability Indices for Small and Medium Wastewater Treatment Plants in the Southwest of Spain

Two indices have been defined in this work to measure the pollution load that a Wastewater Treatment Plant (WWTP) receives and the efficiency of the process it carries out from the overall perspective of pollution removal and energy efficiency. The aim is to provide two performance parameters which could be used to characterize both the working conditions of a WWTP and how well it treats the pollution it receives. In this way, they may be used to compare the behavior of different plants in a certain geographical area. Forty-five WWTPs in the Southwest of Spain were studied to find out the most significant information that is to be used to identify and define both indices. Seven of the variables recorded were used to define each one. Their values were calculated for the whole set of plants studied. The results showed that most of the plants received a low pollution load. Only six of them suffered from a high pollution load, probably because of farms and food industries located in their surroundings. Only three plants showed a poor efficiency, while 23 of them presented a very good one.

Assessing model parameters sensitivity and uncertainty of streamflow, sediment, and nutrient transport using SWAT

The objectives of this study were to (1) simulate streamflow, total sediment (TS), total phosphorus (TP), and total nitrogen (TN) loads; and (2) use the sequential uncertainty fitting (SUFI-2) algorithm to quantify the model parameter sensitivity and uncertainty in simulating streamflow, TS, TP, and TN loads using Soil and Water Assessment (SWAT) model in Big Sunflower River watershed (BSRW). The model was calibrated from 1996 to 2003 and validated from 2004 to 2010 for daily streamflow, TS load, TP load, and TN load. The model performed well simulating daily streamflow (R2 = 0.58–0.75, NSE = 0.47–0.75), TS load (R2 = 0.50–0.72, NSE = 0.47–0.66), and TP load (R2 = 0.79–0.82, NSE = 0.73–0.77), and the model performance was slightly low for TN load (R2 = 0.13–0.31, NSE = −0.09 to 0.07). This study determined that parameter uncertainty was greatest for simulating TN load (p-factor = 0.48, r-factor = 1.25) and that parameter uncertainty was lowest for simulating streamflow (p-factor = 0.70–0.78, r-factor = 1.18–1.19). Output uncertainty was much greater during peak streamflow and peak pollutant loads compared to periods of low streamflow and low pollutant loads. The sensitivity analyses found that streamflow was most sensitive to Manning’s roughness coefficient for the main channel (CH_N2), TS load was most sensitive the peak rate adjustment factor for sediment routing in the tributary channels (ADJ_PKR), TP load was most sensitive to the Phosphorus enrichment ratio for loading with sediments (ERORGP), and TN load was most sensitive to the denitrification exponential rate coefficient (CDN). Uncertainty was found to be much greater during peak streamflow and peak pollutant loads compared to periods of low streamflow and low pollutant loads.

Effect of eco-friendly production technologies on wastewater characterization and treatment plant performance

Operating a wastewater treatment plant (WWTP) efficiently is a knowledge required key issue than the entity of treatment plant. In this study, efficiency of WWTP of a metal finishing industry was evaluated and optimized after the process renovation by means of a modern eco-friendly process application. Three processes intensively consuming water and producing wastewater are metal surface pre-treatment, painting, and enamel coating. Based on the characterization studies, it is observed that the process renovation resulted in an improvement in the quality of the raw wastewater leading low pollutant load. Chemical treatment experiment was performed to assess optimum dosages for the WWTP. Also respirometric analyses were conducted in order to evaluate biological treatability of wastewater. Similar results were obtained for all the coagulants tested, but sludge quality after flocculation as well as settleability was better for both commercial and pure FeCl3 solutions. As a result of the observed low pollution load in the raw wastewaters and based on the respirometric analyses, biological treatment step of industrial wastewater was eliminated which was an important constituent of the overall energy requirement of the existing WWTP.

EKTRAKSI ZAT WARNA ALAM DARI KAYU ULIN (Eusideroxylon zwageri), KAYU SECANG (Caesalpinia sp) DAN KAYU MENGKUDU (Morinda citrifolia) UNTUK BAHAN WARNA KAIN SASIRANGAN

Natural Dyes Extraction from Ulin Wood (Eusideroxylon zwageri), Secang Wood (Caesalpinia sp ) and Noni Wood (Morinda citrifolia ) for SasiranganNatural dyes have a beautiful and distinctive color that hard to imitate with synthetic colors. Natural dyes have been recommended as a dyes that safe for the environment and human health. It contains natural components that relatively low pollution load, easily biodegradable and non-toxic. The aim of this research is to identify the adsorption of natural dyes from ulin wood (Eusideroxylon zwageri), secang wood (Caesalpinia sappan) and mengkudu wood (Morinda citrifolia) to cotton and satin material by extrac and soaking processes. The results of organoleptic test showed that people prefers dyed satin than dyed cotton because the dyed colour in satin is brighter than in. The adsorption of dye in satin ranges from 1.81% to 5.68%, while in cotton ranges from 1.35% to 1.93%. The results showed that fabric with smaller size of fiber/yarn will have a higher colour adsorbtion rate because the dyes are easier to adsorb.Keywords: extraction, natural dyes, fabric, sasirangan

Effect of long-term operation of a subsurface wastewater infiltration system (SWIS) based on the limiting value of environmental carrying capacity

To evaluate the environmental carrying capacity of a subsurface wastewater infiltration system (SWIS) and the removal effect of nitrogen, the simulated soil column experiments were performed. After the SWIS was operated for three years with a hydraulic loading of 5mmd−1, the results indicated that the total nitrogen (TN) removal rate and the ammonia nitrogen (NH4±-N) removal rate were 74.22%, 99.69%, respectively, for the high pollution load treatment system and 80.45%, 99.72%, respectively, for the low pollution load treatment system (TN concentrations of 80mgL−1 and 40mgL−1for the two treatment systems, respectively). The ratios of the nitrate nitrogen (NO3−-N) concentration in the effluent, which satisfied grade III of the Chinese groundwater standard and the maximum international contaminant level of drinking water were 13.33%, 0.00% and 87.87%, 37.43%, respectively. Adopting the 20mgL−1 of the NO3−-N concentration in the soil leachate as the evaluation criterion, the environmental carrying capacity of nitrogen in the SWIS was in a range of 600kgNha−1y−1 to 1200kgNha−1y−1.

Production practice of total chlorine free clean bleaching bagasse pulp

The experimental research, process design and production practice of total chlorine free OpQPo bleaching bagasse pulp were introduced in this paper. The results showed that Kappa number decreased from 14.0-15.0 to 7.0-7.3 with a 50%-51% removal of residual lignin, and pulp brightness increased from 42%-45%(ISO) to 58%-60%(ISO) after a strengthened oxygen delignification. The production practice showed a better performance than that in lab. After subsequent pretreatment and pressurized hydrogen peroxide bleaching, the final pulp brightness was beyond 80% and the viscosity was over 800 mL/g. The pulp quality was much better than traditional Chlorine-Alkali Extraction-Hypochlorite(CEH) bleached pulp. Moreover, adsorbable organic halides (AOX) was not generated any more in the bleaching process. The wastewater was only discharged in chelating pretreatment (Q) stage and easily treated to meet the critical discharge standard due to its lower chromaticity and lower pollution load. In contrast to the traditional bleaching, no additional investment was needed in this new technology. Besides, the production procedure was flexible and the operation was stable. The investment of main equipments was about ¥13.55 million yuan.

마산만 재해방지시설을 이용한 해수교환 방안에 관한 연구

마산만은 반폐쇄성 해역으로, 느린 유속과 육상오염물질의 하천부하 등으로 인해 심각한 수질문제를 가지고 있으며, 동시에 폭풍해일에 취약한 입지적 특성을 나타내고 있다. 이 중 폭풍해일 저감대책으로 제시된 재해방지시설을 운용함과 동시에 이를 마산만 내측 수질개선에 활용하는 방안을 모색하였다. 즉, 재해방지시설을 가동하여 마산만 내측과 외측의 수위조건이 다를 때 발생하는 수두차를 이용하여 만 내 외의 해수를 교환하였다. 재해방지시설의 위치를 기존 만 입구부, 마창대교 인근, 그리고 돝섬 인근으로 가정하였으며, 선박운항 횟수와 연간조위를 분석하여 통항빈도가 가장 낮은 새벽시간(01~05) 및 수두차가 가장 큰 대조기에 운용된다고 가정하였다. 또한, 재해방지시설과 함께 약 10km 길이의 유출 입 관로를 통한 내 외해수의 해수교환 촉진을 위한 추가 실험안을 구성하였다. 수치모의 결과, 현재상태의 경우 마산만 전체 해수교환율은 38.62%을 나타냈으며, 모든 실험안에서 마산만 내 모든 구역에서 꾸준한 증가 추세를 보이고 있다. 이에 반해, 마산만 입구부와 비교한 마산만 내측의 해수교환율은 매우 낮게 나타나 반폐쇄성 내만해역의 특성을 잘 재현하는 것으로 판단된다. 재해방지시설과 관로를 이용한 실험안을 분석한 결과, 현재상태와 비교하여 재해방지시설을 운용한 경우 해수교환율이 높고, 그 운용빈도가 많아질수록 더 많은 순환이 이루어지는 것으로 나타났다. 또한, 재해방지시설에 의해 발생된 수두차를 이용하여 관로를 통해 해수를 유입 혹은 유출한 경우 마산만 가장 내측의 수질이 개선되는 것으로 나타났다. 재해방지시설의 위치는 마창대교 남측과 비교하여 마산만 입구와 돝섬에 위치한 경우 해수교환 효과가 더 좋게 나타났다. 한편 마산만 전체영역에 대한 해수교환율은 만 입구에 재해방지시설이 위치한 경우가 돝섬에 위치한 경우보다 높지만, 마산만 내측을 포함한 해수교환율은 반대로 돝섬에 위치한 경우가 더 높게 나타났다. Masan bay with a semi-enclosed waters has serious water quality problems due to the low flow and river pollution load from land, and shows the vulnerable locational characteristics to storm surge. We are seeking the way of both operating disaster prevention facilities and water quality improvement measures in the bay. That is, the water was exchanged using the head difference occurred by operating disaster prevention facilities. The location of disaster prevention facilities was assumed to be in the inlet of the bay, in the vicinity of Machang bridge, and in the vicinity of Dot island and the operation time was assumed to be early morning hours(01~05) considering the number of shipping passage and annual tide, and spring tide of the largest head difference. In addition, the experiment case of water exchange including the in-outflow feeder pipe was tested. According to the simulation results, water exchange rate in all experiments has shown a steady increase. Water exchange rate of the whole of Masan bay in the case of present is 38.62%. The water exchange rate of the inside of Masan bay compared with the inlet of bay, appeared to be very low. Thus, we judged that the characteristics of semi-enclosed waters were well reproduced. On the results of the experiment of disaster prevention facilities and in-outflow feeder pipe, the case of the operation of disaster prevention facilities, water exchage rate is high compared with the case of present. And, the higer the operating frequency, the more water exchange is appeared. The cases of water exchange prevention facilities through the in-outflow feeder pipe caused by the head difference, also showed the higest improvement of the water quality. Compared with the south of Machang bridge, the effect of water exchange was better in the inlet of Masan bay and Dot island. On the other hand, the inlet of Masan bay is higer than Dot island as for water exchange of the whole of Masan bay, but opposite, water change rate including Masan inside was higher in the case of Dot island.

Study on Chemical Enhanced Primary Treatment of Sewage

Chemically enhanced primary treatment (CEPT) process have advantages of low pollution load and low costs, it can greatly improve the removal efficiency of organic matter by primary treatment , so the process has been studied widely and intensively. In this thesis, the mechanism, coagulant type, dosage and precipitation time were studied.

Lichen community change over a 15-year time period: effects of climate and pollution

AbstractOver the last decades, levels of sulphur deposition from air pollution have been substantially reduced in Norway, whereas levels of nitrogen deposition have been stable or somewhat increased. In parallel, a clear trend of increasing annual temperatures, as well as precipitation, is evident. Human impact on natural ecosystems is predicted to reduce biodiversity at regional scales through facilitating a few generalist species at the expense of species with narrow habitat requirements. In this study, we investigate changes in community composition and the abundance of dominant lichen species on birch in subalpine forests over a 15-year period. The study is based on repeated measurements in five monitoring sites in Norway, representing regional gradients in temperature and precipitation as well as in deposition of nitrogen and sulphur compounds. Two dominant species are studied in particular; the generalist Hypogymnia physodes and the subalpine birch specialist Melanelia olivacea. The largest change in species composition was found in the site with the biggest reduction in sulphur deposition during the 15-year period, whereas the site with low precipitation and low pollution loads had small changes in species composition. The abundance of the generalist H. physodes increased in all sites and the specialist M. olivacea decreased in abundance, especially in sites with both high precipitation and heavy nitrogen deposition. Our study thus suggests that a warmer, humid climate is beneficial for the generalist H. physodes.

Environmental Evolution of the Caravelas Estuary (Northeastern Brazilian Coast, 17° S, 39° W) Based on Multiple Proxies in a Sedimentary Record of the Last Century

ABSTRACT Sousa, S.H.M.; Amaral, P.G.C.; Martins, V.; Figueira, R.C.L.; Siegle, E.; Ferreira, P.A.L.; Silva, I.S.; Shinagawa, E.; Salaroli, A.; Schettini, C.A.F.; Santa-Cruz, J., and Mahiques, M.M., 2014. Environmental evolution of the Caravelas Estuary (northeastern Brazilian coast, 17° S, 39° W) based on multiple proxies in a sedimentary record of the last century, A sediment core (∼100 cm long) taken from the upper Caravelas estuary was interpreted based on sedimentological, microfaunal, geochemical, and historical data for the last 70 years. Outcomes are a significant contribution to the understanding of the relationship between anthropogenic impact and natural ecosystem change. The results obtained for the period between the 1930s and the beginning of the 1970s do not reveal any evidence of natural and/or anthropogenic impacts in the estuary. This period is characterized by a higher percentage of sandy sediments, lower pollution load index (PLI) values, and a mixed source of organic matter (C3 land pl...

Characterization of Storm Water–Suspended Sediments and Phosphorus in an Urban Catchment in Florida

Characterizing the incoming pollution load from contributing watersheds is a basic requirement to assess the functioning of storm water treatment systems. These systems are often built with assumed design performances, but their pollution loads and functioning are seldom checked, making their efficacy questionable. This paper presents a case study of a storm water system built in a 40-ha residential catchment in Gainesville, Florida. Despite its promising performance and assumed low pollution load, a receiving wetland basin overfilled with sediments, and a polishing pond was overgrown with algae. It was hypothesized that the system was not functioning as designed as a response to high sediment loads and poor treatment performance; hence, an investigation was carried out to quantify the suspended sediments through the storm water system during runoff events. Ten events were collected and analyzed for suspended sediment concentration (SSC), sediment mass load, and first flush intensity. In addition, total phosphorus (TP) associated with different particle fractions was analyzed. Results from this study showed that SSC event mean concentration (EMC) was 23.7-194.6 mg=L in untreated runoff, 8.8-65.1 mg=L after a hydrodynamic separator (HDS), and 4.6-107.5 mg=L in the receiving water. A large first flush intensity was found in most events, with 43-86% of the total mass of particulate matter (PM) coming during the first 20% of the storm water volume. Total phosphorus concentration in runoff was typical of similar land uses in Florida, ranging from 0.162 to 0.834 mg=L. Event mean concentration and load of PM were not significantly greater than estimates for similar catchments, but the HDS removal efficiency (46-88%) was considerably lower than the design estimates. These findings support the need for proper monitoring and maintenance of storm water treatment units despite their pollution loading intensity. DOI: 10.1061/(ASCE)EE.1943-7870.0000583. © 2013 American Society of Civil Engineers.

Climatic isotope signals in tree rings masked by air pollution: A case study conducted along the Mont Blanc Tunnel access road (Western Alps, Italy)

Three sites at about 1400 m a.s.l., were chosen for this study along the Mt. Blanc Motorway in Italy. Chronologies of stable isotope ratios (δ13C, δ18O, δ15N), total N concentration and ring width of Larix decidua Mill. were analyzed to observe changes in growth and climatic signals in tree rings after significant changes in air pollution emissions occurred locally over time. The tunnel opened in 1968 and was closed for three years from March 1999 to March 2002. The obtained series from the three sites (Close = C, High = H and Far = F from the highway) for the analyzed periods, 1950–1970 (only sites H and F) and 1985–2008 (all sites), did not show any particular long-term change except site H that showed significant changes in δ18O (enrichment), δ15N (depletion) and total N (increase). δ13C values at site C were enriched in the first year of the tunnel closure (1999), showing an opposite trend in δ13C at site C, in comparison to the two control sites H and F, which cannot be explained by climatic factors. Since no great differences in δ18O were recorded in 1999, this enrichment in δ13C could be related to an enhancement in photosynthetic rate during periods of low air pollution loads. Opposite to δ15N, total N concentration shows a generally good correlation between sites, and site F was measured as the most N enriched. In a correlation analysis performed on the two study periods between the climatic parameters and ring width, we did not find any clear relationships, whereas for the series of stable isotopes and total N, we found the strongest and most significant relationships only between δ13C and summer (June to August) temperature (positive correlations) and precipitation (negative correlations) at sites H and F. These same relationships at site C were, instead, mostly insignificant, indicating an alteration of the climatic signal recorded in the δ13C chronology, caused by direct exposure to the high level of air pollution at this site. Given that site C is more affected by pollution with respect to the other two sites (whereas the same climatic conditions influence tree growth at all sites), the lack of a climatic signal in the δ13C chronology at this site can be ascribed to air pollution. Few other long-term changes were recorded by tree rings (e.g. at site H), indicating that trees probably record better the pollution events or the worsening of the environmental conditions rather than a lack of pollution for a relatively short time period in a polluted environment.

New Molecular Quantitative PCR Assay for Detection of Host-Specific Bifidobacteriaceae Suitable for Microbial Source Tracking

Bifidobacterium spp. belong to the commensal intestinal microbiota of warm-blooded animals. Some strains of Bifidobacterium show host specificity and have thus been proposed as host-specific targets to determine the origin of fecal pollution. Most strains have been used in microbial-source-tracking (MST) studies based on culture-dependent methods. Although some of these approaches have proved very useful, the low prevalence of culturable Bifidobacterium strains in the environment means that molecular culture-independent procedures could provide practical applications for MST. Reported here is a set of common primers and four Bifidobacterium sp. host-associated (human, cattle, pig, and poultry) probes for quantitative-PCR (qPCR) assessment of fecal source tracking. This set was tested using 25 water samples of diverse origin: urban sewage samples, wastewater from four abattoirs (porcine, bovine, and poultry), and water from a river with a low pollution load. The selected sequences showed a high degree of host specificity. There were no cross-reactions between the qPCR assays specific for each origin and samples from different fecal origins. On the basis of the findings, it was concluded that the host-specific qPCRs are sufficiently robust to be applied in environmental MST studies.

Changes in the canopies of Pinus sylvestris and Picea abies under alkaline dust impact in the industrial region of Northeast Estonia

Studies were carried out in 1999, 2005 and 2007 in the area of Kunda cement plant in Northeast Estonia on sample plots 3 km W and 2.5 and 5 km E of Kunda. As control stands, two plots for pine and spruce were established in Lahemaa National Park (34–38 km W of Kunda). The selected pine and spruce stands were 75–85-year-old Myrtillus site type, of 0.7–0.8 density and II quality class, with moderately dense or sparse understorey. The values concerning needle density and number of needle scars were higher for shoots formed in the period of higher pollution than for the shoots grown under a considerably lower pollution load. Although the cement dust pollution has notably decreased from year to year, the number of needle pairs per 1 cm of the shoot was 1.8–2.1 times greater in the shoots formed in 1998 than in those formed in 2003, whereas the changes were statistically reliable. Possibly the low temperatures at the time of shoot and needle formation affected the density of needles on all sample plots, and thus the number of needles on shoots formed in 2003 was many times smaller. After the significant fall in the pollution load since 1996 the length growth of needles intensified around Kunda cement plant, at the same time no changes occurred in the length growth of needles in the control area. As compared to the data from 1998, the length growth of pine needles had improved, especially 2.5 and 5 km E from the cement plant, needles being respectively 1.5 and 1.1 cm longer than 6 years ago. The stimulation of the growth of pine and spruce needles 2.5 and 5 km E of the cement plant may be a sign of a positive effect of reduced doses of cement dust in soil. The greater length of pine and spruce needles is the reason for the larger biomass of the needles.