Sixty-three lakes were sampled semi-annually for acid precipitation – related variables in Canada's Atlantic Provinces,Nova Scotia and Newfoundland from 1983 to 1997. A further 31 sites were sampled beginning in 1989 in Nova Scotia. We analyzedthe water chemistry data for trends in pH, acid neutralization capacity, sulfate and base cations using the whole data set for the original 63 sites and the most recent eight years' data for all sites. We also analyzed acid deposition at two CAPMoN precipitation chemistry sites located at the two extremes of thesampling region for trends. We found that hydrogen deposition decreased by 20% in Newfoundland and 30% in Nova Scotia, and sulfate decreased by 36 and 34%, respectively. Sulfate and basecations in lake waters showed decreases as expected, though lakeacidity and acid neutralization capacity did not show improvements. The conflicting trends in chemical variables suggest that though anthropogenically-induced weathering is diminishing in this region, conditions have not returned to `natural' background conditions.

Changes in freshwater acidification trends in Canada's Atlantic Provinces: 1983-1997

Biological damage to sensitive aquatic ecosystems is among the most recognisable, deleterious effects of acidic deposition. We compiled a large spatial database of over 2000 waterbodies across southeastern Canada from various federal, provincial and academic sources. Data for zooplankton, fish, macroinvertebrate (benthos) and loon species richness and occurrence were used to construct statistical models for lakes with varying pH, dissolved organic carbon content and lake size. pH changes, as described and predicted using the Integrated Assessment Model (Lam et al., 1998; Jeffries et al., 2000), were based on the range of emission reductions set forth in the Canada/US Air Quality Agreement (AQA). The scenarios tested include 1983, 1990, 1994 and 2010 sulphate deposition levels. Biotic models were developed for five regions in southeastern Canada (Algoma, Muskoka, and Sudbury, Ontario, southcentral Quebec, and Kejimkujik, Nova Scotia) using regression tree, multiple linear regression and logistic regression analyses to make predictions about recovery after emission reductions. The analyses produced different indicator species in different regions, although some species showed consistent trends across regions. Generally, the greatest predicted recovery occurred during the final phase of emission reductions between 1994 and 2010 across all taxonomic groups and regions. The Ontario regions, on average, were predicted to recover to a greater extent than either southcentral Quebec or the Kejimkujik area of Nova Scotia. Our results reconfirm that pH 5.5-6.0 is an important threshold below which damage to aquatic biota will remain a major local and regional environmental problem. This damage to biodiversity across trophic levels will persist well into the future if no further reductions in sulphate deposition are implemented.

Assessing potential for recovery of biotic richness and indicator species due to changes in acidic deposition and lake pH in five areas of southeastern Canada.

The Quebec Lake Survey (QLS) was conducted as part of the Quebec Spatial Lake Acidity monitoring network (RESSALQ). A total of 1253 lakes were visited at winter-time between 1986 and 1990, to quantify and to extrapolate the water quality status of a statistically representative set of lakes to the target lake population of five subregions. Water quality is strongly influenced by terrain characteristics. The airborne anthropogenic pollution also influences greatly the water chemistry of lakes in areas receiving high SO4 depositions. Within the QLS study area, the Cote-Nord subregion is the most sensitive and the most affected by acidity. Yet, these acidic conditions can be mostly explained by the combination of an important organic acid contribution and the extreme sensitivity of the area. The Outaouais and Abitibi areas also present great proportions of acidic lakes. The acidity of these lakes originates mostly from anthropogenic sources.

Québec Lake Survey: I. Statistical assessment of surface water quality

This paper focuses on the utilization of factor analysis as a tool for water quality management. Factor analysis has the ability to reduce a large number of variables and identify a set of dimensions, which can not be easily observed in a large set of variables. Bimonthly water samples were collected along Tigris river within Mosul city from Sept 1999 to Aug 2000. Samples were tested for (16) chemical, physical and biochemical parameters. Factor analysis extracted five factors, which explain more than 83% of the variation in water quality. The results of the rotated factor loadings showed that rock dissolution has the maximum contribution in water quality variation. The other sources, which were noticed from the results of the analysis, were runoff, seasonal variations, industrial and domestic discharges. They contributed -at variable degreesto such variation. The study also concluded that factor analysis technique is an efficient tool for water quality management agencies. ــــــــــــــــــــ ــــــــــــــــــــــــــــــــــ لصوملا ةنيدم يف ةلجد رهن هايم ةيعون ةرادلا ةاداك يلماعلا ليلحتلا مادختسا

/pdf/application-of-factor-analysis-as-a-tool-for-water-quality-113dc5niug.pdf

Application of Factor Analysis as a Tool for Water Quality Management of Tigris River within Mosul City

The sensitivity of surface waters to acidic deposition is governed by the interaction of catchment geology, soils, topography, land use, climate and atmospheric deposition. Accordingly at the landscape scale, catchment attributes may be used to predict lake chemistry (for example, acid neutralising capacity (ANC), pH, calcium (Ca2+) and dissolved organic carbon (DOC)). Empirical (multiple linear regression) models based on average measured chemistry (2000–2006) for 204 lakes in Nova Scotia (NS) Canada, and their catchment attributes, were used to predict chemistry for all lakes in NS (n = 6104). Damage to aquatic biota, such as loss of species and/or reduced biodiversity has been widely evaluated using critical chemical thresholds commonly based on pH, ANC and Ca2+. The proportion of sensitive lakes in NS (that is, the stock at risk) was estimated as lakes with ANC less than 20 μeq l−1, pH below 6, and Ca2+ less than 75 μeq l−1 (13, 73 and 74%, respectively). Many lakes in NS are characterized by high DOC (>7 mg l−1); in these lakes organic acids contribute to total acidity, making anthropogenic influences difficult to discern. To account for the potential contribution of organic acidity, all lakes with pH below 6 (and DOC < 7 mg l−1) and lakes below a threshold for ANC adjusted for organic acids were quantified; 63% of the lakes fell below either of these thresholds. Despite substantial reductions in sulphur emissions in North America since the 1980s, many lakes in NS remain at risk to acidic deposition.

Acid Sensitivity of Lakes in Nova Scotia, Canada: Assessment of Lakes at Risk

Many lakes in eastern Canada are sensitive to long range transport of atmospheric pollutants because of their low buffering capacity. Thus, it is important to assess long term changes in water quality. Due to the large number of lakes, a method was needed for choosing a subset of lakes to monitor regularly. Preliminary surveys were conducted in Nova Scotia and Newfoundland in which water quality parameters connected with acidification were measured in a set of lakes in each region. This paper describes the division of each set of lakes into several groups, with lakes in a group having similar water quality parameter values, by means of cluster analysis and principal component ordination. The characteristics of the groups are shown by graphical procedures and summary statistics, and this characterization is used to both determine the number of groups and describe the final choice. The membership of the groups was subsequently assessed in terms of the influences of terrestrial weathering, marine aerosols, anthropogenically derived mineral acids and natural organic acids.

Spatial characterization of acidification related parameters in sensitive regions of Atlantic Canada

In planning a monitoring strategy to quantify the present chemical status of a population of lakes in regions susceptible to the effects of acidic deposition, a decision must be made regarding the number and locations of the lakes to be monitored. Statistical methods provide the bases for making a satisfactory decision by utilizing historical information available about the characteristics of the population of lakes. We present the statistical issues involved in making the decision and present examples using LRTAP data from Quebec.

The use of historical information for selecting a sample from a population of lakes

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Spatial characterization of acidification related parameters in sensitive regions of Atlantic Canada

The use of historical information for selecting a sample from a population of lakes