Evolution of particulate regulation in China--prospects and challenges of exposure-based control

China's urban and rural populations face very serious health risks from combustion particles. Major sources of exposure to inhalable particulates include the burning solid fuels (biomass and coal) for household cooking and heating, coal-fired industrial and residential boilers, tobacco smoking, and diesel motor vehicles. China began to address particulate pollution problems over 25 years ago and has implemented a series of progressively more aggressive policies. This paper reviews the successes and limitations of past and existing policies for particulate controls, as well as the effects of China's economic reforms and energy policies on particulate exposure and pollution management. We examine the challenge of emissions reporting, required as part of both China's pollution levy system and emerging system for "total emissions control." Finally, we discuss practical steps toward exposure-based regulation of particulates, which would take advantage of the high cost-effectiveness for lifesaving of controlling particulate exposure from household and neighborhood sources relative to that of controlling exposure from industrial sources.     

Determination of dibenzo-p-dioxin (DBD) and dibenzofuran (DBF) in paper pulp mill defoamer additives and in paper pulp samples

An analytical procedure has been developed for quantitatively measuring dibenzo-p-dioxin (DBD) and dibenzofuran (DBF) present at part-per-billion levels in paper mill defoamers and paper pulp using gas chromatography coupled with either low resolution mass spectrometry (GC-LRMS) or high resolution mass spectrometry (GC-HRMS).     

Haloacetic acids in the aquatic environment. Part II: ecological risk assessment

Haloacetic acids (HAAs) are environmental contaminants found in aquatic ecosystems throughout the world as a result of both anthropogenic and natural production. The ecological risk posed by these compounds to organisms in freshwater environments, with a specific focus on aquatic macrophytes, was characterized. The plants evaluated were Lemna gibba, Myriophyllum spicatum and M. sibiricum and the HAAs screened were monochloroacetic acid (MCA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA). Laboratory toxicity data formed the basis of the risk assessment, but field studies were also utilized. The estimated risk was calculated using hazard quotients (HQ), as well as effect measure distributions (EMD) in a modified probabilistic ecological risk assessment. EMDs were used to estimate HAA thresholds of toxicity for use in HQ assessments. This threshold was found to be a more sensitive measure of low toxicity than the no observed effect concentrations (NOEC) or the effective concentration (EC10). Using both deterministic and probabilistic methods, it was found that HAAs do not pose a significant risk to freshwater macrophytes at current environmental concentrations in Canada, Europe or Africa for both single compound and mixture exposures. Still, HAAs are generally found as mixtures and their potential interactions are not fully understood, rendering this phase of the assessment uncertain and justifying further effects characterization. TCA in some environments poses a slight risk to phytoplankton and future concentrations of TFA and CDFA are likely to increase due to their recalcitrant nature, warranting continued environmental surveillance of HAAs.     

Effects of a mixture of tetracyclines to Lemna gibba and Myriophyllum sibiricum evaluated in aquatic microcosms

The impact of a mixture of oxytetracycline, chlortetracycline, tetracycline and doxycycline on Myriophyllum sibiricum and Lemna gibba was investigated using fifteen 12,000-L microcosms (k=5, n=3). Significant concentration-response relationships were only found for M. sibiricum, where dry mass was 69, 47, 30, and 7% of controls at respective treatment concentrations of 0.080, 0.218, 0.668, and 2.289 micromol/L. Somatic endpoints were strongly and negatively correlated with percent light transmission, except plant length, which was positively correlated. Treated microcosms experienced a reduction in the percent of surface irradiance penetrating the water column as high as 99.8% at a depth of 70 cm, relative to controls. Position relative to the water column was likely responsible for the differential effects observed between floating (L. gibba) and submerged (M. sibiricum) species of macrophytes. A hazard quotient assessment of the lowest EC10 value indicated significant risk, exceeding the critical HQ value, but not the lowest EC25 value.     

Effects of increased deposition of atmospheric nitrogen on an upland moor: leaching of N species and soil solution chemistry

This study was designed to investigate the leaching response of an upland moorland to long-term (10 yr) ammonium nitrate additions of 40, 80 and 120 kg N ha(-1) yr(-1) and to relate this response to other indications of potential system damage, such as acidification and cation displacement. Results showed increases in nitrate leaching only in response to high rates of N input, in excess of 96 and 136 kg total N input ha(-1) yr(-1) for the organic Oh horizon and mineral Eag horizon, respectively. Individual N additions did not alter ammonium leaching from either horizon and ammonium was completely retained by the mineral horizon. Leaching of dissolved organic nitrogen (DON) from the Oh horizon was increased by the addition of 40 kg N ha(-1) yr(-1), but in spite of increases, retention of total dissolved nitrogen reached a maximum of 92% and 95% of 80 kg added N ha(-1) yr(-1) in the Oh and Eag horizons, respectively. Calcium concentrations and calcium/aluminium ratios were decreased in the Eag horizon solution with significant acidification mainly in the Oh horizon leachate. Nitrate leaching is currently regarded as an early indication of N saturation in forest systems. Litter C:N ratios were significantly lowered but values remained above a threshold predicted to increase leaching of N in forests.     

Understanding the effectiveness of precursor reductions in lowering 8-hr ozone concentrations

Analyses of ambient measured ozone data were used in conjunction with the application of photochemical modeling to determine the technical feasibility of attaining the federal 8-hr ozone standard in central California. Various combinations of volatile organic compound (VOC) and oxides of nitrogen (NOx) emission reductions were effective in lowering modeled peak 1-hr ozone concentrations. However, VOC emissions reductions were found to have only a modest impact on modeled peak 8-hr ozone concentrations. NOx emission reductions generally lowered 8-hr ozone concentrations, but their effectiveness was partially or, in some cases, wholly offset by the increase in the number of NO cycles and, hence, in the ozone produced per NO. As a result, substantial NOx emission reductions--70 to 90%--were required to reduce peak 8-hr ozone concentrations to the level of the standard throughout the modeling domain. These modeling results provide a possible physical explanation for recent analyses that have reported more prominent trends in peak 1-hr ozone levels than in peak 8-hr ozone concentrations or in occurrences of mid-level (60-90 parts per billion by volume) ozone concentrations. The findings also have serious implications for the feasibility of attaining the 8-hr ozone standard in central California. Further efforts are needed to clarify the applicability of the modeling results to the full set of days with ozone levels exceeding the 8-hr ozone standard, as well as their applicability to other geographical areas.     

Groundwater conditions under a reconstructed prairie chronosequence

Chronosequences are useful to evaluate long-term changes in ecosystem services but assessing groundwater quality changes using this approach has rarely been done. In this study, groundwater level and quality comparisons were made in a watershed-scale reconstructed prairie chronosequence that extended back in time approximately 13 years at the Neal Smith National Wildlife Refuge (NSNWR) near Prairie City, Iowa. Our objectives were to determine whether groundwater conditions varied significantly across the chronosequence and quantify the rate of nitrate concentration reduction when row crop fields are replaced by prairie. We installed 19 groundwater wells at upland locations selected to provide similar soil type, landscape position and slope. Water samples were collected on five occasions in 2006 and 2007 and analyzed for field parameters, anions and NO₃-N, NH₄-N and PO₄-P. Significant groundwater changes were primarily associated with groundwater levels, and groundwater nitrate and chloride concentrations. The groundwater was deeper under the older prairie plantings but fluctuated similarly among all well sites. Groundwater nitrate and chloride concentrations decreased 0.58 and 0.52 mg/l per year over the 13-year chronosequence, respectively. Results are seen to provide some guidance to land managers regarding possible nitrate concentration reductions achievable from converting cropland to perennial land cover in similar geomorphic settings.     

Runoff and dissolved organic carbon loss from a paired-watershed study of three adjacent agricultural Watersheds

Organic matter plays several important roles in the biogeochemistry of terrestrial and aquatic ecosystems including the mobilization and transport of nutrients and pollutants. Cropping, tillage practices and vegetative buffer strip installation affect losses of dissolved organic carbon (DOC). While many studies show reductions in pollutant export from agroecosystems where vegetative buffers have been implemented, buffer strips may be a source of DOC and contribute to surface water pollution. Using a paired-watershed approach, the objectives of this study were to determine the effect of grass and agroforestry buffers on runoff and DOC loss, compare runoff and DOC losses between the growing and fallow seasons, and investigate crop effects on runoff and DOC losses. The study design consisted of three small agricultural Watersheds in a no-till, maize-soybean rotation located in the claypan region of northeast Missouri, USA; one watershed was planted with grass buffer strips, one with agroforestry buffer strips, and one unaltered watershed served as the control. Runoff and DOC loss were measured during a six-year calibration period (1991–1997) prior to buffer installation and for a nine-year treatment period (1997–2006). The grass buffer strips significantly decreased runoff by 8.4% (p = 0.015) during the treatment period while the agroforestry buffer system exhibited no significant change in runoff (p = 0.207). Loss of DOC was not significantly affected by grass or agroforestry buffer installation (p = 0.535 and p = 0.246, respectively). Additionally, no significant difference in runoff or DOC loss was found between crops (maize and soybean) or between seasons (growing and fallow). Overall, this study indicates that grass buffer systems are effective at reducing runoff and that DOC contamination of surface waters is not exacerbated by either type of vegetative buffer strip.     

Managing the nitrogen cycle to reduce greenhouse gas emissions from crop production and biofuel expansion

Public policies are promoting biofuels as an alternative to fossil fuel consumption in order to mitigate greenhouse gas (GHG) emissions. However, the mitigation benefit can be at least partially compromised by emissions occurring during feedstock production. One of the key sources of GHG emissions from biofuel feedstock production, as well as conventional crops, is soil nitrous oxide (N₂O), which is largely driven by nitrogen (N) management. Our objective was to determine how much GHG emissions could be reduced by encouraging alternative N management practices through application of nitrification inhibitors and a cap on N fertilization. We used the US Renewable Fuel Standards (RFS2) as the basis for a case study to evaluate technical and economic drivers influencing the N management mitigation strategies. We estimated soil N₂O emissions using the DayCent ecosystem model and applied the US Forest and Agricultural Sector Optimization Model with Greenhouse Gases (FASOMGHG) to project GHG emissions for the agricultural sector, as influenced by biofuel scenarios and N management options. Relative to the current RSF2 policy with no N management interventions, results show decreases in N₂O emissions ranging from 3 to 4 % for the agricultural sector (5.5–6.5 million metric tonnes CO₂?eq.?year^?1; 1 million metric tonnes is equivalent to a Teragram) in response to a cap that reduces N fertilizer application and even larger reductions with application of nitrification inhibitors, ranging from 9 to 10 % (15.5–16.6 million tonnes CO₂?eq.?year^?1). The results demonstrate that climate and energy policies promoting biofuel production could consider options to manage the N cycle with alternative fertilization practices for the agricultural sector and likely enhance the mitigation of GHG emissions associated with biofuels.     

STATE WATER LAW REFORM: IDENTIFYING LEGAL AND MANAGERIAL ISSUES AND OPTIONS1

ABSTRACT: Statutory and case law at the state level provide critical legal frameworks for water management. As many state governments struggle to improve efficiency in water management and resolve conflicts over water usage, they must continually assess the efficacy of their state water law. Most states have water laws that are disconnected and overlapping. This article presents a methodology to assess state water law and take first steps toward a comprehensive state water resources act. The methodology is driven by issues and conflicts in water management. It synthesizes management and legal analyses into a process that incorporates the diverse perspectives of state water stakeholders. The results of the analysis are identification of management issues, profiles of state water law, and explorations of legal options that are available to the state government. Illinois is provided as a case study for this methodology.