CEPA—The Canadian. Environmental Protection Act

CEPA, the Canadian Environmental Protection Act, is a law of the Parliament of Canada that provides a framework for protecting Canadians from all forms of pollution caused by toxic substances. CEPA improves the federal government’s ability to manage chemical substances. The approach is comprehensive. It encompasses the entire life cycle of toxic substances— from their development and manufacture, through the stages of transport, distribution, use, and storage, to their ultimate disposal. CEPA not only guarantees a safer environment for all Canadians, it also provides for better enforcement and tougher punishment of polluters than ever before.     

Use of a Continuous Nephelometer to Measure Personal Exposure to Particles During the U.S. Environmental Protection Agency Baltimore and Fresno Panel Studies

ABSTRACT

In population exposure studies, personal exposure to PM is typically measured as a 12- to 24-hr integrated mass concentration. To better understand short-term variation in personal PM exposure, continuous (1-min averaging time) nephelometers were worn by 15 participants as part of two U.S. Environmental Protection Agency (EPA) longitudinal PM exposure studies conducted in Baltimore County, MD, and Fresno, CA. Participants also wore iner-tial impactor samplers (24-hr integrated filter samples) and recorded their daily activities in 15-min intervals. In Baltimore, the nephelometers correlated well (R² = 0.66) with the PM₂₅ impactors. Time-series plots of personal nephelometer data showed each participant's PM exposure to consist of a series of peaks of relatively short duration. Activities corresponding to a significant instrument response included cooking, outdoor activities, transportation, laundry, cleaning, shopping, gardening, moving between microenvironments, and removing/putting on the instrument. On average, 63-66% of the daily PM exposure occurred indoors at home (about 2/3 of which occurred during waking hours), primarily due to the large amount of time spent in that location (an average of 7277%). Although not a reference method for measuring mass concentration, the nephelometer did help identify PM sources and the relative contribution of those sources to an individual's personal exposure.     

Error propagation in pesticide residue measurements estimated by computational simulations and inter-laboratory sample analysis

An assessment of the error associated with conventional pesticide residue analysis has been conducted based on computer simulations and inter-laboratory residue analysis. Computational simulations were conducted based on (i) typical performance and regulatory acceptance criteria of analytical methods, and (ii) field residue distributions. In addition, field samples with incurred residues were sent to different private laboratories and the results compared. The relative difference in pesticide residues obtained when samples from the same field or produce lot are analyzed at separate laboratories was used to quantify the uncertainty associated with residue analyses performed using common analytical technology, and methods that are in compliance with current regulatory requirements. The study showed that differences of > 100% are common and should be expected when samples from the same crop are analyzed at different laboratories. The results also suggest that the error within residue measurements can be particularly detrimental when a result is reported near the maximum residue limit (MRL).     

Importance of sulfate reducing bacteria in mercury methylation and demethylation in periphyton from Bolivian Amazon region

Sulfate reducing bacteria (SRB) are important mercury methylators in sediments, but information on mercury methylators in other compartments is ambiguous. To investigate SRB involvement in methylation in Amazonian periphyton, the relationship between Hg methylation potential and SRB (Desulfobacteraceae, Desulfobulbaceae and Desulfovibrionaceae) abundance in Eichhornia crassipes and Polygonum densiflorum root associated periphyton was examined. Periphyton subsamples of each macrophyte were amended with electron donors (lactate, acetate and propionate) or inhibitors (molybdate) of sulfate reduction to create differences in SRB subgroup abundance, which was measured by quantitative real-time PCR with primers specific for the 16S rRNA gene. Mercury methylation and demethylation potentials were determined by a stable isotope tracer technique using ²⁰⁰HgCl and CH₃²⁰²HgCl, respectively. Relative abundance of Desulfobacteraceae (<0.01-12.5%) and Desulfovibrionaceae (0.01-6.8%) were both highly variable among samples and subsamples, but a significant linear relationship (p < 0.05) was found between Desulfobacteraceae abundance and net methylmercury formation among treatments of the same macrophyte periphyton and among all P. densiflorum samples, suggesting that Desulfobacteraceae bacteria are the most important mercury methylators among SRB families. Yet, molybdate only partially inhibited mercury methylation potentials, suggesting the involvement of other microorganisms as well. The response of net methylmercury production to the different electron donors and molybdate was highly variable (3-1104 pg g⁻¹ in 12 h) among samples, as was the net formation in control samples (17-164 pg g⁻¹ in 12 h). This demonstrates the importance of community variability and complexity of microbial interactions for the overall methylmercury production in periphyton and their response to external stimulus.     

Critical analysis of the waste management performance of two uranium production units in Brazil--part II: Caetite production center

This paper discusses the environmental waste management of the Heap-Leach Uranium Production Facility of Caetité located in a semi-arid region in Brazil. A comparison is made with the first uranium production site of the country located in Poços de Caldas. It is demonstrated that differences in the operational process along with different environmental conditions can lead to different impacts. In the present case groundwater is the potential most sensitive environmental medium despite the well-established consensus in the literature that radon and aerosol emissions may turn-out to be the most relevant environmental aspects of an installation located at this type of region. Most of the ²²⁶Ra content in the ore remains in the leached ore that is deposited with the waste rock. A lack in appropriate prediction of the hydrological balance has been causing unanticipated emissions of liquid effluents into the environment. Chemical treatment of this effluent may be needed. Contamination of groundwater in the short term by the waste ponds is not to be expected but it can be a relevant issue in the long term. As a consequence, careful closure schemes will need to be put in place. Finally, the overall costs with remediation in the Caetité production center are lower than those observed at the Poços de Caldas mining site.     

First flush in a combined sewer system

Pollutant first flush was examined in an urban catchment with area of 12.7 ha and drained by a combined sewer system located in northern Italy. A total of 23 rainfall-runoff events were monitored and 281 samples were analyzed. The selected quality parameters were biochemical oxygen demand, chemical oxygen demand, suspended solids, settleable solids, total phosphorus, total nitrogen, ammonium nitrogen, lead, and zinc, specific conductivity and hydrocarbons. A subset of representative storms was selected for first flush analysis. The catchment presented a strong first flush for almost all storms and most constituents. The analysis shows that treating the maximum amount of the early part of the runoff is a better strategy than treating a constant flow rate. Best management practices that can treat or store the first runoff are favored in this kind of system for these water quality parameters.     

Strategies for testing the "irritation-signaling" model for chronic lung effects of fine acid particles

The "irritation signaling" model proposed that a long term contribution to chronic bronchitis might result from the repeated delivery of "signals" resulting from temporary localized acidification of the bronchial epithelium by the action of individual particles. This led to a prediction that the effectiveness of particles in inducing changes in mucus secreting cell numbers/types should depend on the number of particles deposited that contained a particular amount of acid--implying that particles below a certain size cutoff (and therefore lacking a minimum amount of acid) should be ineffective; and that particle potency per unit weight should be greatest at the cutoff and decline strongly above the cutoff. Since the development of this hypothesis both epidemiological observations and some experimental studies have tended to reinforce the notion that acid particles can make a contribution to relatively long lasting bronchitic-like changes, and enhance the desirability of more direct testing of the model. In this paper we develop a general theoretical framework for the contributions of environmental agents to chronic obstructive lung disease, and a series of alternative hypotheses against which the predictions of the "irritant signaling" model can be compared. Based on this, we suggest a research program that could be used to further develop and test the model and reasonable alternatives.