Multivariate analysis of accumulation and critical risk analysis of potentially hazardous elements in forage crops

Environmental Monitoring and Assessment - Few estuaries remain unaffected by water management and altered freshwater deliveries. The Caloosahatchee River Estuary is a perfect case study for...     

Environmental management in an international consumer goods company

Many management processes and tools can provide companies with information to support their environmental decision making. Risk assessment, environmental auditing, life cycle assessment and environmental reporting are but a few examples. Each of these has typically evolved independently as the need for it has arisen. Today, however, this abundance of tools can lead to confusion: What is the exact objective of each tool? How do they differ? Are some ‘better’ than others? Should they be used in parallel, sequentially or in place of each other? More importantly, how do they fit together into a coherent environmental management framework that will ensure sound environmental and economic decision making in a company? This paper seeks to answer these questions. It describes the overall environmental framework that has been developed internally within Procter & Gamble and which allows the company to make coherent economically and environmentally sound decisions, in both the short- and long-term.     

Experimental design of the Svalbard shoreline field trials

Experimental oil spills on three mixed-sediment beaches in Svalbard, Norway, were designed to evaluate the effectiveness of in situ shoreline cleaning treatments to accelerate natural recovery. These were: sediment relocation (surf washing), mixing (tilling), bioremediation (fertilizer application), and bioremediation combined with mixing. Additionally, natural attenuation was studied as a treatment option. An intermediate fuel oil was applied to the sediment surface in the upper intertidal zone at three experimental sites, each of which had different sediment characteristics and wave-energy exposure. Over a 400-day period, the experiments quantified oil removal, documented changes in the physical character of the beach as well as oil fate and behaviour, assessed toxicity effects associated with treatment, and validated oil-mineral aggregate formation as a result of the selected treatment techniques. The three sites were chosen based on significant differences, and each treatment was quantitatively compared only with other treatments at that site.This paper describes the physical location and the experimental design of the field trials. Some of the key issues that were addressed in the design included: the methodology for application of oil, the application of treatment techniques, the realistic simulation of real-world conditions, and the sampling protocols to overcome sediment and oiling heterogeneity typical of mixed-sediment beaches in order to allow quantitative comparisons of the treatments.     

In-situ Treatment of Oiled Sediment Shorelines

Experimental oil spill studies were conducted to quantify the effectiveness of selected in-situ shoreline treatment options to accelerate natural oil removal processes on mixed-sediment (sand and pebble) shorelines. At each of three distinct shoreline sites, treatment test plots and control plots were established within a 40-, 80- and 143-m continuous stretch of oiled shoreline. A total of 5500 l of oil was deposited along a 3-m wide swath in the upper intertidal zone at each site. Approximately one week after oiling, a different treatment technique was applied to each plot. The treatment techniques were: sediment relocation (surf washing), mixing (tilling), bioremediation (fertilizer application), and bioremediation combined with mixing. One plot at each site was monitored for natural attenuation. The quantity of oil removed from the plots was measured six times up to 60 days post-treatment and then again one year later. Changes in the physical character of the beach, oil penetration, movement of oil to the subtidal environment, toxicity, and biodegradation were monitored over the 400-day period.The results verified quantitatively that relocation of oiled sediments significantly accelerated the rate of oil removal from the shoreline by more than one year. Microscopic observations and image analyses confirmed that the oil-mineral aggregate formation process was active and was increased by sediment relocation. Oil biodegradation occurred in this arctic environment, both in the oiled sediments and on the fine mineral particles removed from the sediment by natural physical processes. The biodegradation of oil in sediment was significantly stimulated by simple bioremediation protocols. Mixing (by tilling) did not clearly stimulate oil loss and natural recovery in the context of this experimental design. None of the treatment techniques elevated toxicity in the nearshore environment to unacceptable levels, nor did they result in consequential alongshore or nearshore oiling.     

Is an adjusted rhizosphere-based method valid for field assessment of metal phytoavailability? Application to non-contaminated soils

Previously recommended rhizosphere-based method (RHIZO) applied to moist rhizosphere soils was integrated with moist bulk soils, and termed adjusted-RHIZO method (A-RHIZO). The A-RHIZO and RHIZO methods were systematically compared with EDTA, DTPA, CaCl2 and the first step of the Community Bureau of Reference (BCR1) methods for assessing metal phytoavailability under field conditions. Results suggested that moist bulk soils are equally suited or even better than rhizosphere soils to estimate metal phytoavailability. The A-RHIZO method was preferred to other methods for predicting the phytoavailability of Ni, Cu, Zn, Cd, Pb and Mn to wheat roots with correlation coefficients of 0.730 (P<0.001), 0.854 (P<0.001), 0.887 (P<0.001), 0.739 (P<0.001), 0.725 (P<0.001) and 0.469 (P<0.05), respectively. When including soil properties, other extraction methods were also able to predict phytoavailability reasonably well for some metals. Soil pH, organic matter and Fe-Mn oxide contents, and cation-exchange capacity mostly influenced the extraction and phytoavailability of metals.     

Comparative losses of glyphosate and selected residual herbicides in surface runoff from conservation-tilled watersheds planted with corn or soybean

Residual herbicides regularly used in conjunction with conservation tillage to produce corn ( L.) and soybean [ (L.) Merr] are often detected in surface water at concentrations that exceed their U.S. maximum contaminant levels (MCL) and ecological standards. These risks might be reduced by planting glyphosate-tolerant varieties of these crops and totally or partially replacing the residual herbicides alachlor, atrazine, linuron, and metribuzin with glyphosate, a contact herbicide that has a short half-life and is strongly sorbed to soil. Therefore, we applied both herbicide types at typical rates and times to two chisel-plowed and two no-till watersheds in a 2-yr corn/soybean rotation and at half rates to three disked watersheds in a 3-yr corn/soybean/wheat-red clover ( L.- L.) rotation and monitored herbicide losses in surface runoff for three crop years. Average dissolved glyphosate loss for all tillage practices, as a percentage of the amount applied, was significantly less ( ≤ 0.05) than the losses of atrazine (21.4x), alachlor (3.5x), and linuron (8.7x) in corn-crop years. Annual, flow-weighted, concentration of atrazine was as high as 41.3 μg L, much greater than its 3 μg L MCL. Likewise, annual, flow-weighted alachlor concentration (MCL = 2 μg L) was as high as 11.2 and 4.9 μg L in corn- and soybean-crop years, respectively. In only one runoff event during the 18 watershed-years it was applied did glyphosate concentration exceed its 700 μg L MCL and the highest, annual, flow-weighted concentration was 3.9 μg L. Planting glyphosate-tolerant corn and soybean and using glyphosate in lieu of some residual herbicides should reduce the impact of the production of these crops on surface water quality.     

The Reduction of Stranded Oil by In Situ Shoreline Treatment Options

The Svalbard Shoreline Field Trials quantified the effectiveness of sediment relocation, mixing, bioremediation, bioremediation combined with mixing, and natural attenuation as options for the in situ treatment of oiled mixed-sediment (sand and pebble) shorelines. These treatments were applied to oiled plots located in the upper beach at three experimental sites, each with different sediment character and wave-energy exposure. Systematic monitoring was carried out over a 400-day period to quantify oil removal and to document changes in the physical character of the beach, oil penetration, oil loading, movements of oil to the subtidal environment, biodegradation, toxicity, and to validate oil-mineral aggregate formation.The results of the monitoring confirmed that sediment relocation significantly accelerated the rate of oil removal and reduced oil persistence where oil was stranded on the beach face above the level of normal wave activity. Where the stranded oil was in the zone of wave action, sediment relocation accelerated the short-term (weeks) rate of oil loss from the intertidal sediments.Oil removal rates on a beach treated by mechanical mixing or tilling were not significantly higher than those associated with natural recovery. However there is evidence that mixing/tilling may have enhanced microbial activity for a limited period by increasing the permeability of the sediment.Changes in the chemical composition of the oil demonstrated that biodegradation was significant in this arctic environment and a bioremediation treatment protocol based on nutrient enrichment effectively doubled the rate of biodegradation. However, on an operational scale, the success of this treatment strategy was limited as physical processes were more important in causing oil loss from the beaches than biodegradation, even where this oil loss was stimulated by the bioremediation protocols.     

Arsenic levels in rice grain and assessment of daily dietary intake of arsenic from rice in arsenic-contaminated regions of Bangladesh—implications to groundwater irrigation

Chronic exposure to arsenic (As) causes significant human health effects, including various cancers and skin disorders. Naturally elevated concentrations of As have been detected in the groundwater of Bangladesh. Dietary intake and drinking water are the major routes of As exposure for humans. The objectives of this study were to measure As concentrations in rice grain collected from households in As-affected villages of Bangladesh where groundwater is used for agricultural irrigation and to estimate the daily intake of As consumed by the villagers from rice. The median and mean total As contents in 214 rice grain samples were 131 and 143 μg/kg, respectively, with a range of 2–557 μg/kg (dry weight, dw). Arsenic concentrations in control rice samples imported from Pakistan and India and on sale in Australian supermarkets were significantly lower (p < 0.001) than in rice from contaminated areas. Daily dietary intake of As from rice was 56.4 μg for adults (males and females) while the total daily intake of As from rice and from drinking water was 888.4 and 706.4 μg for adult males and adult females, respectively. From our study, it appears that the villagers are consuming a significant amount of As from rice and drinking water. The results suggest that the communities in the villages studied are potentially at risk of suffering from arsenic-related diseases.     

Decline in extractable antibiotics in manure-based composts during composting

A wide variety of antibiotics have been detected in natural water samples and this is of potential concern because of the adverse environmental effects of such antibiotic residues. One of the main sources of antibiotics effluence to the surrounding environment is livestock manures which often contain elevated concentrations of veterinary antibiotics (VAs) which survive digestion in the animal stomach following application in animal husbandry practices. In Korea, livestock manures are normally used for compost production indicating that there is potential for antibiotic release to the environment through compost application to agricultural lands. Therefore, reduction of the amount of VAs in composts is crucial. The purpose of this study was to understand the influence of the composting process and the components of the compost on the levels of three common classes of antibiotics (tetracyclines, sulfonamides, and macrolides). Composted materials at different stages of composting were collected from compost manufacturing plants and the variation in antibiotic concentrations was determined. Three different antibiotics, chlortetracycline (CTC), sulfamethazine (SMZ), and tylosin (TYL) at three different concentrations (2, 10, and 20 mg kg⁻¹) were also applied to a mixture of pig manure and sawdust and the mixtures incubated using a laboratory scale composting apparatus to monitor the changes in antibiotic concentrations during composting together with the physicochemical properties of the composts. During composting, in both field and lab-scale investigations, the concentrations of all three different antibiotics declined below the relevant Korean guideline values (0.8 mg kg⁻¹ for tetracyclines, 0.2 mg kg⁻¹ for sulfonamides and 1.0 mg kg⁻¹ for macrolides). The decline of tetracycline and sulfonamide concentrations was highly dependent on the presence of sawdust while there was no influence of sawdust on TYL decline.     

Tillage system, application rate, and extreme event effects on herbicide losses in surface runoff

Conservation tillage can reduce soil loss; however, the residual herbicides normally used to control weeds are often detected in surface runoff at high levels, particularly if runoff-producing storms occur shortly after application. Therefore, we measured losses of alachlor, atrazine, linuron, and metribuzin from seven small (0.45-0.79-ha) watersheds for 9 yr (1993-2001) to investigate whether a reduced-input system for corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production with light disking, cultivation, and half-rate herbicide applications could reduce losses compared with chisel and no-till. As a percentage of application, annual losses were highest for all herbicides for no-till and similar for chisel and reduced-input. Atrazine was the most frequently detected herbicide and yearly flow-weighted concentrations exceeded the drinking water standard of 3 microg L(-1) in 20 out of 27 watershed years that it was applied. Averaged for 9 corn yr, yearly flow-weighted atrazine concentrations were 26.3, 9.6, and 8.3 microg L(-1) for no-till, chisel, and reduced-input, respectively. Similarly, flow-weighted concentrations of alachlor exceeded the drinking water standard of 2 microg L(-1) in 23 out of 54 application years and in all treatments. Thus, while banding and half-rate applications as part of a reduced-input management practice reduced herbicide loss, concentrations of some herbicides may still be a concern. For all watersheds, 60 to 99% of herbicide loss was due to the five largest transport events during the 9-yr period. Thus, regardless of tillage practice, a small number of runoff events, usually shortly after herbicide application, dominated herbicide transport.