The aim of the present study was the influence of various methods of long-term soil utilisation on the content of polycyclic aromatic hydrocarbons (PAH) in selected silty soils. Four soils were selected for the present studies, i.e.: Eutric Fluvisol originating from silty formations, Haplic Phaeozem developed from loess, Haplic Luvisol (non-uniform) developed from silt, Haplic Luvisol developed from loess. Five study sites were chosen, i.e.: apple orchards, hop gardens, fields, grasslands and natural woodland ecosystems. Samples were collected from the depth of 0-10 cm. In the samples the content of 16 PAHs was determined by means of the HPLC-UV method. The total PAHs content was at a low level. Depending on the soil and object type, the total PAHs content ranged from 72.5 to 764.0 μg·kg-¹. The pollutant level determined together with composition of individual PAHs suggested a limited anthropogenic influence relating mainly to pyrolytic processes. The total PAH content as well as the content of individual PAHs depended on agricultural land use and management. It has been shown that PAH level was influenced by environmental conditions specific for a given type of land use. In the soils in which organic carbon content differed only slightly among locations, a higher influence of the soil utilisation method on the content of individual PAHs was observed.

Constructed wetlands have been recognized as offering a removal treatment option for high concentrations removal of chemical and biological contaminants in domestic wastewater. The enteric protozoan parasite Cryptosporidium is considered one of the highly resistant to treatment and highly infectious organisms to humans and animals. Moreover, some species of Cryptosporidium are known to have a zoonotic nature. In this investigation a pilot scale for domestic wastewater treatment system was used, consisting of the following steps in series: (1) up-flow anaerobic sludge blanket (UASB) reactor, (2) free water surface (FWS) wetland unit, and (3) sub-surface flow (SSF) wetland unit. This treatment system was fed with domestic wastewater to assess its efficiency in removing Cryptosporidium oocysts. The obtained Cryptosporidium oocysts were detected and enumerated by two different staining techniques 'acid fast trichrome (AFT) and modified Ziehl Neelsen (MZN) stains'. Polymerase chain reaction (PCR) technique was also used to detect Cryptosporidium DNA in wastewater samples. Results revealed that anaerobic treatment (using UASB reactor) could remove about 53.1% of Cryptosporidium oocysts present in raw wastewater. The in-series connection between the two wetland units allowed complete elimination of Cryptosporidium oocysts as the first (FWS) wetland unit removed 95.9% of the oocysts present in anaerobically treated wastewater and the remaining portion of oocysts was completely removed by the second (SSF) wetland unit. Cryptosporidium oocysts were detected in 95.8% of raw wastewater samples with a mean count of 43.8 oocysts/l when AFT stain was used while they were detected in only 87.5% of raw wastewater samples with a mean count of 35.6 oocysts/l when MZN stain was used. Polymerase chain reaction (PCR) technique was able to detect Cryptosporidium DNA in only 45.8% of raw wastewater samples. Positive PCR results were only achieved in wastewater samples containing 52 oocysts or more per liter.

Two Elsholtzia haichowensis S. populations, copper-tolerant (TLS) and non-tolerant (HA) ones were studied in hydroponic experiment for the nitrogen assimilation and plant growth under excess Cu conditions. The results demonstrated that there were surely the differences in nitrogen assimilation and plant growth between the two populations. Excess Cu caused evident decreases in the shoot and root biomass and root/shoot biomass ratio in HA population while no significant changes happened in TLS population. In addition, in HA population, excess Cu also induced apparent declines in activities of nitrate reductase (NR, EC 1.6.6.1) and glutamine synthetase (GS, EC 6.3.1.2) in the leaves and roots as well as the contents of nitrate, ammonium and amino acids in the roots. In TLS population, excess Cu did not significantly affect the NR activities in the leaves and roots and the nitrate content in the roots, and apparently elevated the root ammonium and amino acids contents, although it also clearly reduced the GS activities in the leaves and roots. Besides, with the addition of Cu in the culture solution, the Cu contents in the leaves and roots of the two populations markedly increased. But this increase was significantly lower in TLS population than that in HA population; the fact might be partly responsible for the relative stabilization of nitrogen assimilation in TLS population compared to that in HA population.

Increasing environmental concentrations of platinum group metals (PGMs), in particular platinum (Pt), rhodium (Rh) and palladium (Pd), from catalytic converters has been reported worldwide. The impact of these three metals on the uptake and use of essential mineral nutrients was examined using two plant models: the submerged aquatic plant, Elodea canadensis, and the terrestrial emergent plant, Peltandra virginica. Plants were grown for 2 weeks in nutrient solutions with either Pt⁴⁺ at concentrations between 0.05 and 5 mg/L, or a 0.1 mg/L Pt⁴⁺, Rh³⁺, Pd²⁺ mixture. Some treatments received additional Ca²⁺, Zn²⁺, or humic acid (with varying pH) to study how these conditions affected PGM uptake. Metal concentration analyses were conducted using a graphite furnace atomic absorption spectrometer (GFAAS) or an inductively coupled plasma emission spectrometer (ICP). Growth response was assessed through total chlorophyll content. There was significant Pt accumulation in plant tissues, from 55 to 326 times the concentration in nutrient solution. At pH 8, the addition of humic acid doubled Pt accumulation in comparison to the control. Additional exogenous minerals did not significantly affect PGM uptake, nor did the uptake of PGMs interfere with the uptake of Ca, Fe or Cu. Synthesis of chlorophyll in new shoots was not affected by Pt accumulation; however, visible chlorosis was observed in older shoots at 5 ppm Pt. Roadside Daucus carota samples from four heavy traffic locations in Dutchess County (New York) were also assessed for PGM content. Pt, Pd and Rh concentrations averaged 14.6, 10.2, and 0.7 μg/g, respectively.

A study was conducted to determine the efficiency and effectiveness of two commercial microbial based bioremediation products compared to indigenous tropical microorganisms in a small-scale trial. The oil and grease content of the samples was monitored as an indication of the levels of petroleum hydrocarbon during the experiment. The indigenous enriched culture generally biodegraded the petroleum hydrocarbon to a greater extent than the commercial products and media controls early in the bioremediation process (0–5 days). However, as time progressed the extents of biodegradation were not significantly different between treatments until late in the bioremediation process (after 18 days). Of the two commercial products, one was more effective, reducing the level of oil and grease by 52.5% over the 3 week study. However, neither commercial product was able to meet the manufacturer’s stated level of 95% removal within three weeks. Commercial microbial-based bioremediation products may be used with some success in tropical environments, however location-specific trials may be required to ensure that the best commercial product is selected. As an alternative, the selective enrichment of indigenous microorganisms may result in similar performance at a reduced cost.

Phosphorus (P) release from bottom sediments can be a significant source to the overlying water column, potentially maintaining and enhancing algal growth and eutrophic conditions in lakes and reservoirs. Thus, the objectives of this study were to: (1) measure P flux under aerobic and anaerobic conditions from intact sediment cores collected at Beaver Reservoir, northwest Arkansas, (2) evaluate the spatial variability in measured sediment P flux under aerobic and anaerobic conditions along the reservoir, and (3) compare external and internal P loads to Beaver Reservoir. Six intact sediment cores were collected at three sites representing the lacustrine, transitional, and riverine zones during June 2003, September 2003 and February 2004 and incubated for 21 days in the dark at ~22°C. Three cores from each site were incubated under aerobic conditions and anaerobic conditions. Water samples were collected from the overlying water column in each core daily for the first five days and every other day thereafter and analyzed for soluble reactive phosphorus (SRP). Water removed from the core was replaced with filtered lake water, maintaining a constant overlying water volume of 1 l. Sediment P flux under anaerobic conditions (<0.01-1.77 mg m-² day-¹) was generally greater than that measured under aerobic conditions (<0.01-0.89 mg m-² day-¹). Some spatial variability existed in sediment P flux where P flux was generally greatest at the sites in the riverine and transitional zones. Maximum sediment P flux was observed under anaerobic conditions in cores collected from the transitional zone during September 2003. Average sediment P flux under aerobic conditions (0.09 mg m-² day-¹) and anaerobic conditions (0.31 mg m-² day-¹) was greater than the external P flux (0.05 mg m-² day-¹) estimated from the Beaver Reservoir tributaries. Results showed that the annual internal P load (7 Mg year-¹) from bottom sediments in Beaver Reservoir was less than 10% of the annual external P load (~81 Mg P year-¹). The internal P load was significant, but it would not currently be cost effective to manage this P source given the large surface area of Beaver Reservoir.

In a step-by-step exercise - beginning at full greenhouse gas accounting (FGA) and ending with the temporal detection of emission changes - we specify the relevant physical scientific constraints on carrying out temporal signal detection under the Kyoto Protocol and identify a number of scientific uncertainties that economic experts must consider before dealing with the economic aspects of emissions and their uncertainties under the Protocol. In addition, we answer one of the crucial questions that economic experts might pose: how credible in scientific terms are tradable emissions permits? Our exercise is meant to provide a preliminary basis for economic experts to carry out useful emissions trading assessments and specify the validity of their assessments from the scientific point of view, that is, in the general context of a FGA-uncertainty-verification framework. Such a basis is currently missing.

Three cruises were carried out in Jiaozhou Bay (JZB) in the neap tide in October 2002 (fall) and in both neap and spring tides in May 2003 (spring) to understand the relative importance of external nutrient inputs versus physical transport and internal biogeochemical processes. Nutrients ([graphic removed] , [graphic removed] , [graphic removed] , [graphic removed] , silicic acid, total dissolved nitrogen (TDN) and phosphorus (TDP), dissolved organic nitrogen (DON) and phosphorus (DOP)) were measured. The concentrations of nutrients were higher in the northern part than in the southern part. High concentrations of [graphic removed] and DON in JZB demonstrated the anthropogenic input. Ambient nutrient ratios indicated that the potential limiting nutrients for phytoplankton growth were silicon, and then phosphorus. Nutrients showed an obvious tidal effect with low values at flood tide and high values at ebb tide. Nutrient elements were transported into JZB in the north and output in the south (i.e., into the Yellow Sea), which varied with season, tidal cycle and investigation sites. Water exchange between JZB and the Yellow Sea exports [graphic removed] , [graphic removed] and DON out of JZB, while it inputs [graphic removed] , silicic acid and DOP into JZB. Nutrient budgets demonstrate that riverine input and wastewater discharge are major sources of nutrients, while residual flow is of minor importance in JZB ecosystem. JZB is a sink for the nutrient elements we studied except for DON. Stoichiometric calculations demonstrate that JZB is a net autotrophic system.

The recovery from acidification has led to the demand for more precise criteria for classification of acidification. The Swedish Environmental Protection Agency has revised Sweden's Ecological Quality Criteria for acidification to improve the correlation between the chemical acidification criteria and biological effects. This paper summarises the most relevant findings from several of the studies commissioned for this revision. The studies included data on water chemistry in 74 reference lakes in southern Sweden with data on fish in 61 of the lakes, as well as data on littoral fauna in 48 lakes. We found that the acidity variable most strongly correlated to the biota was the median pH from the current year. Our results probably do not reflect the mechanisms behind the negative effects of acidity on the biota, but are fully relevant for evaluation of monitoring data. The biogeochemical models used for predicting acidification reference conditions generate a pre-industrial buffering capacity. In order to get an ecologically more relevant criteria for acidification based on pH, we transferred the estimated change in buffering capacity into a corresponding change in pH. A change of 0.4 units was defined as the threshold for acidification. With this criterion a considerably lower number of Swedish lakes were classified as acidified when compared with the present Ecological Quality Criteria.

Phytoextraction is a promising technology that uses hyperaccumulating plants to remove inorganic contaminants, primarily heavy metals, from soils and waters. A field experiment was conducted to evaluate impacts of a mixture of chelators (MC) upon the growth and phytoextraction of heavy metals by the hyperaccumulator Sedum alfredii Hance in a co-planting system in a paddy soil that was historically irrigated with Pb and Zn contaminated mining wastewaters. The co-planting system used in this study was comprised of a Zn- and Cd-hyperaccumulator (S. alfredii) and a low-accumulating crop (Zea mays). Results showed that yields of S. alfredii were significantly increased with the addition of the MC and by co-planting with Z. mays. Our study further revealed that concentrations of Zn, Pb, and Cd in the corn grains of Z. mays conform to the Chinese hygiene standards for animal feeds and in the other parts of Z. mays conform to the Chinese organic fertilizer standards. The uptake of Zn, Cd, and Pb by S. alfredii was significantly increased with the addition of MC. The uptake of Zn by S. alfredii was also significantly enhanced by co-planting with Z. mays, but the interaction between MC and co-planting was not significant, meaning the effects of the two types of treatments should be additive. When the MC was applied to the co-planting system in the soil contaminated with Zn, Cd, and Pb, the highest phytoextraction rates were observed. This study suggested that the use of the hyperaccumulator S. alfredii and the low-accumulating crop Z. mays in the co-planting system with the addition of the MC was a more promising approach than the use of a single hyperaccumulator with the assistance of EDTA (ethylenediaminetetraacetic acid). This approach not only enhances the phytoextraction rates of the heavy metals but also simultaneously allows agricultural practices with safe feed products in the metal-contaminated soils.