Cost-Effective Enforcement Of Environmental Standards

The body of information presented in this paper is directed to those individuals concerned with cost-effective enforcement of environmental standards. Its aim is twofold. One is to determine some of the differing impacts upon firm behavior of legal enforcement, of economic incentive enforcement, and of mixed legal-economic enforcement. A second objective is to initiate identification of enforcement systems which are most likely to minimize resource costs to firms and enforcement agencies of meeting environmental standards. A computerized model is used to simulate enforcement of the new source particu-late matter discharge standard for coal-fired power plants. Under current legal enforcement it is found that most plants will violate the standard, that small plants will control to higher removal levels than large plants and that firms will install relatively costly pollution control technology. Three enforcement alternatives are considered for overcoming these shortcomings: more stringent legal enforcement, economic incentive enforcement using effluent taxes, and a mixed system which uses device certification tests and effluent taxes. It is found that each of the alternatives can lead to the standard being met and tc more-or-less equal sharing in control burden across plant size. But it is only the two systems which use effluent taxes that give incentive for choosing least costly control technology. It is concluded that the two enforcement systems which use effluent taxes probably would encourage adoption of least cost control technology. This is likely to be a desirable outcome since it may lead to minimum resource costs to power plants and pollution control agencies of meeting fty ash standards. The general applicability of this conclusion to other enforcement situations is discussed.     

Elemental carbon in urban soils and road dusts in Xi'an,China and its implication for air pollution

Increasing evidence confirms that elemental carbon (EC) is not only a light-absorbing constituent that warms the atmosphere but also a significant environmental pollutant. Investigations were conducted to identify carbonaceous pollution signatures in road dusts and urban soils and to evaluate potential sources in Xi'an. Average concentrations of EC, char-EC, and soot-EC in soils were 0.90, 0.51, and 0.39 mg g^?1, respectively, a little higher than or comparable to prior studies on the Loess Plateau. Vertical profiles in soils revealed soot-EC concentrations from pre-industrialized samples close to ～0.20 mg g^?1, while EC and char-EC varied widely, with no distinct pattern. Enrichment factor analysis indicated that EC, char-EC, and soot-EC in road dusts were all elevated by an order of magnitude. The spatial distribution of total EC, char-EC, and soot-EC in road dusts revealed close correspondence with human activities such as coal combustion and vehicle emissions. The average char-EC/soot-EC ratio was 1.66 for road dusts, suggesting that the main sources of carbonaceous particles are local coal combustion and vehicle emissions. The study demonstrated that EC, char-EC, and soot-EC levels in road dusts are effective indicators of anthropogenic pollution.     

Effect of varying the phosphorus content of dairy cow diets on losses of phosphorus in overland flow following surface applications of manure

The increasing use of concentrate feedstuffs within Northern Ireland dairy systems has resulted in significant farm gate phosphorus (P) surpluses, and these have contributed to increased soil P levels and risk of P loss to overland flow. However, the P content of feed concentrates can be lowered without compromising animal performance. This study focuses on P losses from grassland and evaluates how adjusting the P content of manure impacts on the P composition and concentration in overland flow. Dairy cows were offered diets containing 5.3 to 3.0 g P kg(-1) dry matter (DM) and produced manures with a range of P contents. Manure was applied at a rate of 50 m3 ha(-1) to 0.5-m2 grassland plots, and simulated rainfall (40 mm h(-1)) was applied repeatedly 2, 9, 28, and 49 d after during the summer, winter, and spring. Decreasing the P content in the diet, from the highest to the lowest P treatment (43%), produced a proportionately greater reduction in manure TP content (63%), but reductions were not exclusively in the water-soluble fraction. Following surface applications of manure, P concentrations in overland flow increased in all seasons (P < or = 0.001), while the greatest impact of varying the manure P content was most evident during the first simulated overland flow event. When diet P content was reduced from 5.4 to 3.0 g P kg(-1) DM, a statistically significant reduction in runoff P concentration was observed in all seasons. Elevated P concentrations in overland flow were observed for 28 d in spring and 9 d in summer and winter. The large drop in P concentrations between simulated rainfall events on Day 2 and Day 9 suggests that increasing the time interval between manure application and the generation of overland flow has a greater impact on P losses than does varying the dietary P content.     

PFOS and PFC releases and associated pollution from a PFC production plant in Minnesota (USA)

Perfluorooctane sulfonate (PFOS) and PFOS-related substances have been listed as persistent organic pollutants in the Stockholm Convention. From August 2012, Parties to the Convention needed to address the use, storage, and disposal of PFOS—including production sites and sites where PFOS wastes have been deposited—in their national implementation plans. The paper describes the pollution in Minnesota (USA) caused by the 3M Company at one of the largest per/polyfluorinated chemical (PFC) production facilities. From early 1950s until the end of 2002, when 3M terminated PFOS and perfluorooctanoic acid (PFOA) production, PFOS, PFOA, and other PFC production wastes were disposed around the plant and in local disposal sites. Discharges from the site and releases from deposits caused widespread contamination of ground and surface waters including local drinking water wells. Fish in the river downstream were contaminated with PFOS to levels that led to fish consumption advisories. Human exposures resulted from ingesting contaminated drinking water, requiring installation of water treatment facilities and alternate water supplies. The critical evaluation of the assessments done revealed a range of gaps in particular of human exposure where relevant exposure pathways including the entire exposure via food have not been taken into consideration. Currently, the exposure assessment of vulnerable groups such as children or Hmong minorities is inadequate and needs to be improved/validated by epidemiological studies. The assessment methodology described for this site may serve—with highlighted improvements—as a model for assessment of other PFOS/PFC production sites in the Stockholm Convention implementation.     

Increase in phosphorus losses from grassland in response to Olsen-P accumulation

The Olsen-P status of grazed grassland (Lolium perenne L.) swards in Northern Ireland was increased over a 5-yr period (March 2000 to February 2005) by applying different rates of P fertilizer (0, 10, 20, 40, or 80 kg P ha(-1) yr(-1)) to assess the relationship between soil P status and P losses in land drainage water and overland flow. Plots (0.2 ha) were hydrologically isolated and artificially drained to v-notch weirs, with flow proportional monitoring of drainage water and overland flow. Annually, the collectors for overland flow intercepted between 11 and 35% of the surplus rainfall. Single flow events accounted for up to 52% of the annual dissolved reactive phosphorus (DRP) load. The Olsen-P status of the soil influenced DRP and total phosphorus (TP) concentrations in land drainage water and overland flow. Annual TP loss was highly variable and ranged from 0.19 to 1.55 kg P ha(-1) yr(-1) for the plot receiving no P fertilizer and from 0.35 to 2.94 kg P ha(-1) yr(-1) for the plot receiving 80 kg P ha(-1) yr(-1). Despite the Olsen-P status in the soils ranging from 22 to 99 mg P kg(-1), after 5 yr of fertilizer P applications it was difficult to identify a clear Olsen-P concentration at which P losses increased. Any relationship was confounded by annual variability of hydrologic events and flows and by hydrologic differences between plots. Withholding P fertilizer for over 5 yr was not long enough to lower P losses or to have an adverse effect on herbage P concentrations.     

Integrated Resource Management: Institutional Arrangements Regarding Nitrate Pollution in England

The emergence of problems such as nitrate pollution has drawn attention to the need for integrated management of land and water resources. Integrated management approaches require appropriate institutional arrangements. Unfortunately, in many countries, land and water resources are managed on a sectoral basis and institutions were not designed to deal with complex environmental problems. Institutional arrangements for management of nitrate pollution are evaluated on the basis of seven criteria. Results indicate that some progress was made after 1985 regarding inter-agency co-ordination, public participation, the mix of strategies and adaptive capacity. Nevertheless, key substantive issues involving equity, efficiency and effectiveness were not adequately resolved. Policy referral, catchment management planning, bargaining and negotiation are recommended as key processes and mechanisms for improved management of the nitrate problem.     

On the evaluation of biological hazards and competing risks

After some general remarks, and a brief explanation of Clifford's non-identifiability results for illness-death models, an attempt is made to view the competing-risk problem more biologically. The cause and time of death vary from individual to individual because they have different genetically determined susceptibilities and different life histories. Although one could define potential lifetimes associated with causes of death, averaging over different genetic susceptibilities means that from population data one cannot estimate the distribution of cause specific life spans in individuals with the same genetic susceptibility. In particular, the hazard curves for different genetic states cannot be resolved from population data.