Low Pollution Load Research Articles

Modelling nutrient loads to Sydney estuary (Australia)

Sydney estuary (Australia) catchment is substantially urbanised (80%) and small (480 km2) with a large population (2.5 million) and is therefore highly sensitive to anthropogenic influence. The Model for Urban Stormwater Improvement Conceptualisation used to model nutrient export to the estuary determined an average annual load of 475 t total nitrogen, 63.5 t total phosphorus and 343,000 t total suspended solids. Model verification included intense, short-term water sampling and analysis undertaken in the current project and use of published data spanning 10 years. Under high-rainfall conditions (>50 mm day(-1)), the estuary becomes stratified and nutrients are either removed from the estuary directly in a plume or indirectly by advective/dispersive remobilisation. The majority of the nutrient load is delivered during moderate rainfall (5-50 mm day(-1)) conditions and accumulates close to discharge points and remains in the estuary. To significantly reduce nutrient load, management strategies should aim to minimise low and moderate rainfall pollutant loads.

Determination of inorganic and organic priority pollutants in biosolids from meat processing industry

The biosolids (BS) generated in the wastewater treatment process of a meat processing plant were monitored and the priority pollutant content was characterized. The trace metal and organic pollutant content--polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF)--were determined quantitatively and compared to guideline limits established by the US EPA and EU. PCBs were not detected in the solid samples, while trace metals, PAHs and PCDD/PCDF were detected in concentrations below the limits established by international standards. Toxic equivalent factors were evaluated for the biosolids, and the results proved that these wastes can be safely deposited on land or used in combustion/incineration plants. Since no previous data were found for meat processing waste, comparisons were made using municipal sewage sludge data reported in the literature. Since, this report monitored part of the priority pollutants established by the US EPA for meat and poultry processing wastewater and sludge, the results verified that low pollution loads are generated by the meat processing plant located in the southern part of Brazil. However, the BS generated in the treatment processes are in accordance with the limits established for waste disposal and even for soil fertilizer.

전북지역 농업용 하천유역의 수질과 부하량 특성

This study was conducted to evaluate water quality and pollutant loads on small agricultural watershed in Jeonbuk province. The EC level of investigated watershed ranged from 0.07 to 0.52 dS/m, BOD level ranged from 0.1 to 5.0 mg/L, and level ranged from 0.6 to 17.7 mg/L. As above, contents of water quality indicators covered wide range, but each indicator was alike in mean content every other year. The contents of EC, were decreased in rainy season, but the contents of BOD, , T-N and T-P were not greatly different as compared to dry season. And high content of SS showed substantial sediments near the surface flow out and influence on water system in rainy season. The pollutant loads measured in terminal of watershed were kg/day for BOD, kg/day for T-N and kg/day for T-P. The pollutant loads of BOD, T-N and T-P in rainy season increased several times as compared to dry season. In rainy season, watershed with more than 30% in the proportion of paddy field to land showed relatively low discharge and pollutant loads in comparison to watershed with less than 30%. The discharge of watershed in rainy season increased 5.7times compared with the dry season in watershed with less than 30% in the proportion of paddy field to land, whereas was only 2.3times in watershed with more than 30%. The correlation coefficient() of regression between discharge and pollutant loads of T-N were higher than those of BOD and T-P.

Effects of Ambient NOx on Chlorophyll a Fluorescence in Transplanted Flavoparmelia caperata (Lichen)

Transplants of Flavoparmelia caperata (L.) Hale were used to test possible relationships between chlorophyll a fluorescence (CaF) and ambient atmospheric conditions (temperature, precipitation, SO2 and NOx levels). Portions of the same thalli collected in a pristine site (A) of the Trieste Karst were exposed at that site, as the control, and in four other sites (B-E) in NE Italy, near to pollution monitoring stations. These sites had been selected in order to provide similar two by two climatic conditions (sites B,C: more humid; D,E: drier) and air pollution load (sites B,D: low; C,E: high). Before exposure and after 43 and 90 days of exposure, CaF measurements were carried out in the laboratory under controlled conditions. A classification of meteorological and pollution parameters recorded during exposure substantially confirmed the differences between site couplets. After 90 days, samples from sites A (control) and B (with very low pollution load) showed only slightly reduced NPQ, qN, Fo, and Fm values. Samples from site D, with medium air pollution load, and sites C,E, with high air pollution loads, showed proportionally greater variation for most of the CaF parameters. A highly significant correlation was found between NPQ, qN, Fm, and NOx pollution but not with SO2 or O3. Effects of NOx on lichens and possible action mechanisms are discussed. The results strongly suggest that CaF measurements of lichen transplants can be a valid tool in biomonitoring studies.

Water Quality changes in the Elbe River Basin

In the course of the 90s, the Czech part of the Elbe river basin underwent a significant change in the quality of surface water. After a long period of intensified pollution hitting the peak at the end of the 80s, reduced amount of emissions from main industrial and municipal sources led to a lower pollution load of the Elbe and its principal tributaries. The scope and speed of such water quality changes is unprecedented in the Czech as well as in the European perspective. Decrease in the pollution level is however spatially limited to the Elbe river and its main tributaries. Further reduction of emission load will not result in corresponding decline of water pollution. This is due to different evolution of rivers of different sizes, but mainly to insufficient decrease of pollution load in the he ad stream areas of the river basin. It is this area of small watercourses that has to be in the centre of attention because without its radical changes it isn't possible to ensure permanent improvement of water quality in the Elbe and its tributaries.

An Analysis of Possible Genotoxic Exposure in Adult and Juvenile Royal Terns in North Carolina, USA

-We studied possible genotoxic exposure in Royal Terns (Sterna maxima) by collecting blood from adults and juveniles at five breeding colonies in coastal North Carolina in 1999. These colonies are located in three estuarine systems (Core Sound, Pamlico Sound, and Cape Fear River), each subjected to different contaminant loads. DNA in red blood cells was analyzed using the comet assay to determine levels of DNA strand breaks, a technique previously not applied to birds. In addition, we weighed each bird and estimated its fat reserves as an indication of nutritional health. Gross health assessments showed no significant differences between study sites, both for adult and juvenile terns. The comet assay indicated that blood cells from the adult andjuvenile terns from two Core Sound colonies, Wainwright and Sand Bag Islands, had significantly higher levels of apparent DNA damage than the remaining study sites. Based on previously published studies of sediment contaminants, the Core Sound colonies have relatively low overall pollutant loads, a finding contrary to the expected result based on the DNA damage. Plausible explanations for these finding are that birds from the Core Sound are exposed to an undetected genotoxic contaminant(s) or that birds from the more polluted sites have had an adaptive response to the contaminant exposure. Received 30 October 2000, accepted 25 March 2001.

Methane oxidation in Polish forest soils of contrasting atmospheric pollution

Methane consumption was measured in forest soils of Poland in areas of high regional air pollution (SO 2 loads) and compared to the activity in areas of low air pollution loads. The areas include the regions with the highest input of SO 2 found in Europe and cover a range of average acid deposition up to a factor of 10. No distinct pattern of methane oxidation activities was identified that could be related to present or previous SO 2 loads. Methane consumption activity ranged between 16 and 110 μg CH 4 m −2 h −1 similar to the activity encountered in previous studies of forested areas.

Deposition and adsorption of the air pollutant HNO 3 vapor to soil surfaces

Deposition of nitric acid (HNO 3) vapor to soils has been evaluated in three experimental settings: (1) continuously stirred tank reactors with the pollutant added to clean air, (2) open-top chambers at high ambient levels of pollution with and without filtration reducing particulate nitrate levels, (3) two field sites with high or low pollution loads in the coastal sage plant community of southern California. The results from experiment (1) indicated that the amount of extractable NO 3 − from isolated sand, silt and clay fractions increased with atmospheric concentration and duration of exposure. After 32 days, the highest absorption of HNO 3 was determined for clay, followed by silt and sand. While the sand and silt fractions showed a tendency to saturate, the clay samples did not after 32 days of exposure under highly polluted conditions. Absorption of HNO 3 occurred mainly in the top 1 mm layer of the soil samples and the presence of water increased HNO 3 absorption by about 2-fold. Experiment (2) indicated that the presence of coarse particulate NO 3 − could effectively block absorption sites of soils for HNO 3 vapor. Experiment (3) showed that soil samples collected from open sites had about 2.5 more extractable NO 3 − as compared to samples collected from beneath shrub canopies. The difference in NO 3 − occurred only in the upper 1–2 cm as no significant differences in NO 3 − concentrations were found in the 2–5 cm soil layers. Extractable NO 3 − from surface soils collected from a low-pollution site ranged between 1 and 8 μg NO 3–N g −1, compared to a maximum of 42 μg NO 3–N g −1 for soils collected from a highly polluted site. Highly significant relationship between HNO 3 vapor doses and its accumulation in the upper layers of soils indicates that carefully prepared soil samples (especially clay fraction) may be useful as passive samplers for evaluation of ambient concentrations of HNO 3 vapor.

Water quality issues in the Nakdong River Basin in the Republic of Korea

A framework for evaluating alternative management strategies for the Nakdong River Basin in the Republic of Korea (South Korea) was developed and applied jointly by Argonne National Laboratory in Argonne, Illinois, USA, and the Research Institute of Industrial Science and Technology in Pohang, South Korea. Water from this basin, the second largest in South Korea, supports a total population of more than 13 million people. Rapid industrial expansion, urbanization, and population growth have dramatically increased the demand for water and have severely degraded water quality, particularly near large industrial complexes and in the lower portion of the basin. Management strategies for the entire basin through to the year {dy2011} were evaluated with a computer model for basin-wide predictions of water flow and quality (HSPF). This continuous-event model was developed and calibrated using site-specific data for the basin over a two-year period (1994-1995) that included periods of both high (monsoonal) and low (drought) flows. Water quality impacts for different wastewater treatment strategies were assessed in terms of biochemical oxygen demand (BOD), nitrogen (N) and phosphorous (P) levels. The results of the study indicate that BOD levels in the main stem of the Nakdong River below the Kumhogang (a major tributary with low flow and heavy pollution loads) cannot be significantly improved by reducing direct BOD loads from point sources along the river. To reduce main stem BOD levels, the nutrient loading to the river must be reduced. In order to reduce these loads, additional advanced treatment methods (i.e., tertiary treatment) must be incorporated in the treatment facilities to remove N and P. The discharge inventory data further suggest that a large portion of N and P loads are derived from non-point agricultural practices. Reduction of these loads is difficult to accomplish and may require extensive modifications in agricultural and land-use practices. The modeling frame-work developed provides a means to evaluate these and other basin management strategies.

Energy simulation of displacement ventilation in offices

Modelling and simulation of heating, ventilating, and air-conditioning systems in the context of building performance evaluation is rapidly gaining more and more interest. The objective of the case study described in this paper is to evaluate the performance of displacement systems in offices (i.e. an environment with a low air pollution load) in terms of thermal energy.The paper describes the modelling, how the model is verified, and summarises the simulation results. The main conclusion of this case study is that — from an thermal energy point of view — application of a displacement system in typical offices is only recommended when the casual gains are relatively low (i.e. up to 30 W m-2).