Heavy metal pollution and co-selection for antibiotic resistance: A microbial palaeontology approach

Frequent and persistent heavy metal pollution has profound effects on the composition and activity of microbial communities. Heavy metals select for metal resistance but can also co-select for resistance to antibiotics, which is a global health concern. We here document metal concentration, metal resistance and antibiotic resistance along a sediment archive from a pond in the North West of the United Kingdom covering over a century of anthropogenic pollution. We specifically focus on zinc, as it is a ubiquitous and toxic metal contaminant known to co-select for antibiotic resistance, to assess the impact of temporal variation in heavy metal pollution on microbial community diversity and to quantify the selection effects of differential heavy metal exposure on antibiotic resistance. Zinc concentration and bioavailability was found to vary over the core, likely reflecting increased industrialisation around the middle of the 20th century. Zinc concentration had a significant effect on bacterial community composition, as revealed by a positive correlation between the level of zinc tolerance in culturable bacteria and zinc concentration. The proportion of zinc resistant isolates was also positively correlated with resistance to three clinically relevant antibiotics (oxacillin, cefotaxime and trimethoprim). The abundance of the class 1 integron-integrase gene, intI1, marker for anthropogenic pollutants correlated with the prevalence of zinc- and cefotaxime resistance but not with oxacillin and trimethoprim resistance. Our microbial palaeontology approach reveals that metal-contaminated sediments from depths that pre-date the use of antibiotics were enriched in antibiotic resistant bacteria, demonstrating the pervasive effects of metal-antibiotic co-selection in the environment.

Debris Flow Occurrence and Sediment Persistence, Upper Colorado River Valley, CO

Debris flow magnitudes and frequencies are compared across the Upper Colorado River valley to assess influences on debris flow occurrence and to evaluate valley geometry effects on sediment persistence. Dendrochronology, field mapping, and aerial photographic analysis are used to evaluate whether a 19th century earthen, water-conveyance ditch has altered the regime of debris flow occurrence in the Colorado River headwaters. Identifying any shifts in disturbance processes or changes in magnitudes and frequencies of occurrence is fundamental to establishing the historical range of variability (HRV) at the site. We found no substantial difference in frequency of debris flows cataloged at eleven sites of deposition between the east (8) and west (11) sides of the Colorado River valley over the last century, but four of the five largest debris flows originated on the west side of the valley in association with the earthen ditch, while the fifth is on a steep hillslope of hydrothermally altered rock on the east side. These results suggest that the ditch has altered the regime of debris flow activity in the Colorado River headwaters as compared to HRV by increasing the frequency of debris flows large enough to reach the Colorado River valley. Valley confinement is a dominant control on response to debris flows, influencing volumes of aggradation and persistence of debris flow deposits. Large, frequent debris flows, exceeding HRV, create persistent effects due to valley geometry and geomorphic setting conducive to sediment storage that are easily delineated by valley confinement ratios which are useful to land managers.

Analysis of Surface Water Pollution Accidents in China: Characteristics and Lessons for Risk Management

Understanding historical accidents is important for accident prevention and risk mitigation; however, there are no public databases of pollution accidents in China, and no detailed information regarding such incidents is readily available. Thus, 653 representative cases of surface water pollution accidents in China were identified and described as a function of time, location, materials involved, origin, and causes. The severity and other features of the accidents, frequency and quantities of chemicals involved, frequency and number of people poisoned, frequency and number of people affected, frequency and time for which pollution lasted, and frequency and length of pollution zone were effectively used to value and estimate the accumulated probabilities. The probabilities of occurrences of various types based on origin and causes were also summarized based on these observations. The following conclusions can be drawn from these analyses: (1) There was a high proportion of accidents involving multi-district boundary regions and drinking water crises, indicating that more attention should be paid to environmental risk prevention and the mitigation of such incidents. (2) A high proportion of accidents originated from small-sized chemical plants, indicating that these types of enterprises should be considered during policy making. (3) The most common cause (49.8% of the total) was intentional acts (illegal discharge); accordingly, efforts to increase environmental consciousness in China should be enhanced.

Six-decade change in water chemistry of large freshwater Lake Taihu, China

Taihu lake has become a hot spot internationally due to its algae bloom. However, its natural water chemistry (major ions) received little attention though it is equally important for drinking water and aquatic ecology. Using historical data (1950s-2012) we explored the drastic change of Taihu water chemistry over the past six decades and the driving factors. Results show that major ions increased around 2-7-fold and TDS increased nearly 3-fold during the last 60 years. The dominant cation has shifted from Ca(2+) to Na(+), and the current Cl(-) is dominant over HCO3(-), the predominant anion before the 2000s. Analyses show that population increase and human activities were the major driving factors responsible for the drastic change. Whereas the mechanism of increase was different for ions, i.e., Na(+) and Cl(-) increase was directly related to the population increase and sewage discharge in the basin; SO4(2-) was related to atmospheric deposition derived from increasing coal consumption and SO2 emissions; hardness (Ca and Mg) increase was closely linked to the acidic precipitation. No increase trend of HCO3(-) was attributable to frequent outbreaks of algae bloom which consumed HCO3(-). Estimation indicated that sewage discharge in the basin contributed 23% to the lake in terms of Cl(-), exceeding the contribution from rock weathering. Current water chemistry of Taihu lake has become "anthropogenic dominance" from its original rock dominance.

[History of heavy metal pollution from tidal flat in Haizhou Bay]

Coastal zone could be considered as an important sink of regional source to sink and preserve historical records of environmental evolution. Four sediment cores, collected from tidal flat at Haizhou Bay near Lianyungang City, were examined for concentrations of heavy metals including Cd, Cr, Cu, Mn, Pb and Zn in core sediments to investigate the historical input of trace metals. In addition, sediment rates of cores LH3 and LH4 were determined based on radionuclide 210Pb. The results showed that grain size control effect was not the main factor that influenced the distribution of heavy metals. Heavy metals concentrations in the surface sediments were higher than these regional background values. Furthermore, Al element as a proxy of grain size was selected for normalization and calculation of metal enrichment factor (EF) and anthropogenic heavy metal fluxes. The results revealed that heavy metals in tidal flats were continuously enriched in the past decades, meanwhile, tidal flats have been significantly subjected to contaminations due to anthropogenic activities. Moreover, the depth profiles of heavy metals fluxes correspond to scenario of social-economy development of Lianyungang, which is an important urban area near Haizhou Bay. From 1950s to 2005, anthropogenic fluxes of metals increased with fluctuations, whereas, since 2005 anthropogenic fluxes declined, which may be correlated to the adjustment of industrial structure as well as the strengthened environmental regulation.

A 60-year sedimentary record of natural and anthropogenic impacts on Lake Chenghai, China

Recent sediments from Lake Chenghai, China, were investigated at high temporal resolution to trace both natural and anthropogenic effects on the lake using total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), organic phosphorus (Po), inorganic phosphorus (Pi) and organic carbon and nitrogen stable isotopes (delta13Corg and delta15N) in a 137Cs-dated sediment core. The results indicated that the sedimentary record covers the last 60 years, during which the lake had undergone apparent changes in nutrient sources and productivity in response to nutrient loading. Prior to the late 1980s, the nutrient contents in sediments mainly originated from algae and lake productivity was relatively stable. Since the late 1980s, increasing TOC, TN and TP concentrations together with the change of delta13Corg and delta15N suggested anthropogenic perturbations in nutrient loading and lake productivity. Endogenic nutrients derived from algae and anthropogenic inputs were two important sources of sedimentary nutrients. The anthropogenic nutrients mainly originated from the discharge of industrial wastewater and artificial cultivation of Spirulina after the middle 1980s, and domestic wastewater discharged from Yongsheng County since 1993.

Distribution of heavy metals in sediments of the Pearl River Estuary, southern China: implications for sources and historical changes

The distribution of heavy metals (Pb, Zn, Cd and As) in sediments of the Pearl River Estuary was investigated. The spatial distribution of heavy metals displayed a decreasing pattern from the turbidity maxima to both upstream and downstream of the estuary, which suggested that suspended sediments played an important role in the trace metal distribution in the Pearl River Estuary. In addition, metal concentrations were higher in the west part of the estuary which received most of the pollutants from the Pearl River. In the sediment cores, fluxes of heavy metals were consistent with a predominant anthropogenic input in the period 1970-1990. From the mid-1990s to the 2000s, there was a significant decline in heavy metal pollution. The observed decline has shown the result of pollution control in the Pearl River Delta. However, it is noteworthy that the metal concentrations in the most recent sediment still remained considerably high. Taken together, the enrichment of heavy metals in sediments was largely controlled by anthropogenic pollution.

Reconstructing historical trends of Berre lagoon contamination from surface sediment datasets: influences of industrial regulations and anthropogenic silt inputs

These last decades, the Berre lagoon (in southeastern France) has been deeply affected since the 1930s by strong inputs of contaminants associated with industrial development and since 1966 by huge inputs of freshwater and silts due to the installation of a hydroelectric power plant. Surveys of the surface sediment contamination have been sparsely performed since 1964 for management and research purposes. These surveys were performed by various laboratories that investigated different chemicals and sampling areas using different analysis protocols. Therefore, the available data are disconnected in time and space and differ in quality. In order to reconstruct coherent time series of sediment contamination from this heterogeneous datasets and to discuss the influences of industrial and hydroelectric discharges we used a statistical approach. This approach is based on Principal Component Analysis (PCA) and Fuzzy clustering analysis on data from one extensive survey realized on surface sediments in 1976. The PCA allowed identifying two geochemical indexes describing the main surface sediment geochemical characteristics. The fuzzy clustering analysis on these indexes allowed identifying sub-areas under the specific influence of industrial or hydroelectric discharges. This allowed us to reconstruct, for each sub-area, a coherent and interpretable long-term time series of sediment contamination from the available database. Reconstructed temporal trends allowed us to estimate: (i) the overall decrease of sediment contamination since the mid-1970 attributed to industrial discharge regulations enacted at this period and (ii) the dilution of the concentrations of sediment bound contaminants induced by the hydroelectric power plant and its associated particulate matter inputs.

[Pollution history and sources of organotin compounds in aquaculture water of Tong'an Bay, Xiamen]

Six organotin compounds (OTs) in core sediment collected from aquaculture water of Tong'an Bay, Xiamen were detected by GC-FPD. Based on 210Pb-dating data, the pollution history (from 1931 to 2007) of OTs in this area was reconstructed and their possible sources were also discussed. The results showed that the inputs of organotin compounds in this sea area began from 1950's (0-80 cm). The vertical concentrations of OTs ranged from 3.43-69.6 ng x g(-1) (dry weight), the mean value was 15.0 ng x g(-1). Butyltins concentrations ranged from 2.51-68. 8 ng x g(-1) and the average concentration was 14.6 ng x g(-1) which accounted for 97.4% of total OTs, while phenyltins just accounted for 2.58%. It is indicated that the aquaculture waters of Tong'an Bay were mainly contaminated by butyltin compounds, inferring that they may come from the early antifouling paint of ships. The distributions of OTs concentrations and compositions may be related to the complex influence of the hydrodynamic conditions, antifouling paint leakages from ships and marine structures, and aquaculture. Compared to the other harbors and bays, the magnitude of OTs pollution in the sediment from Tong'an Bay was at the low midpoint on a global scale. Moreover, the sedimentary history showed that, vertical OTs distributions were in good agreement with the usage history of organotin compounds as antifouling paints and the changes of the major function regionalization in the surrounding area.

Comparison of elemental carbon in lake sediments measured by three different methods and 150-year pollution history in Eastern China

Concentrations of elemental carbon (EC) were measured in a 150 yr sediment record collected from Lake Chaohu in Anhui Province, eastern China, using three different thermal analytical methods: IMPROVE_A thermal optical reflectance (TOR), STN_thermal optical transmittance (TOT), and chemothermal oxidation (CTO). Distribution patterns for EC concentrations are different among the three methods, most likely due to the operational definition of EC and different temperature treatments prescribed for each method. However, similar profiles were found for high-temperature EC fractions among different methods. Historical soot(TOR) (high-temperature EC fractions measured by the IMPROVE_A TOR method) from Lake Chaohu exhibited stable low concentrations prior to the late 1970s and a sharp increase thereafter, corresponding well with the rapid industrialization of China in the last three decades. This may suggest that high-temperature thermal protocols are suitable for differentiating between soot and other carbon fractions. A similar soot(TOR) record was also obtained from Lake Taihu (~200 km away), suggesting a regional source of soot. The ratio of char(TOR) (low-temperature EC fraction measured by the IMPROVE_A TOR method, after correction for pyrolysis) to soot(TOR) in Lake Chaohu shows an overall decreasing trend, consistent with gradual changes in fuel use from wood burning to increasing fossil fuel combustions. Average higher char(TOR)/soot(TOR) was observed in Lake Taihu than in Lake Chaohu in the past 150 years, consistent with the longer and more extensive industrialization around the Taihu region.

Abandoning nature: swimming pools and clean, healthy recreation in Hamilton, Ontario, c. 1930s-1950s

Municipal swimming pools arose as a technological fix for an urban public health and recreation crisis in Hamilton when its bay became a polluted sink for residential and industrial wastes. Until World War II, city leaders and medical authorities believed that they could identify, delineate, and construct safe natural swimming areas along the bay's shore, supplemented by a few public artificial swimming pools. After the war, the pollution situation worsened. For those who couldn't travel to cleaner lakeshores elsewhere, local authorities created swimming pools, thus abandoning the natural waters of the bay to the "constructive power of the profit motive".

Human stewardship or ruining cultural landscapes of the ancient Tula wells, southern Ethiopia

This article uses the concepts of "human stewardship" and "ruined landscape" as a theoretical framework for analysing the community's perception of landscape change in the ancient tula well system of Borana in southern Ethiopia. The ancient tula well system, the main permanent water source, has been in operation for more than five centuries and it closely links human activity and the environment. The welfare of the tula well system and the performance of the Borana pastoral system are directly related. Borana management of the tula wells uses concepts such as laaf aadaa seeraa and laaf bade to differentiate between ‘land managed by customary laws’ (hereafter human stewardship) and ‘lost’ or ‘ruined’ land (laaf bade). The cultural landscapes of the ancient wells have undergone changes from ecosystems featuring ‘human stewardship’ (before the 1960s), that is, laaf aadaa seeraa to ‘ruined landscapes’ (after the 1960s), that is, laaf bade. Our interest is in understanding how the Borana perceive the impact of land use changes from these two conceptual perspectives. In group discussions, key informant interviews and household surveys across five of the nine well clusters, we found that the society described the changed tula cultural landscape in terms of drivers of well dynamics (i.e. use and disuse), break up of land use zonations, patterns of human settlement (traditional versus peri-urban), expansion of crop cultivation, and changes in environmental quality. Using the two concepts, we analysed linkages between changing patterns of land use that transformed the system from laaf aadaa seeraa, which ensured human stewardship, to laaf bade, which resulted in ruined landscapes. From these we analysed environmental narratives that showed how the society differentiated the past human stewardship that ensured sustainable landscape management from the present ruining of tula well cultural landscapes.

From source to sink: "official" and "improved" water in Delhi, 1868–1956

This article examines the making of a modern colonial city through the rhetoric of ‘improvement’ and ‘progress’ in relation to water. The reference is to the history of water in the city of Delhi and what may be called ‘the first science of environment’ in a colonial urban context, with a focus not so much on the ‘extent’ of water supply and drainage, and its (in)adequacy in the colonial city, as on concerns around the ‘(im)purity’ of water, narratives of pollution, technologies of purity and the transformations they effected in a colonial context. In doing so it hopes to build upon a rich tradition of writings on urban water, its modernisation as also its location within a colonial regime, being suggestive of a framework in which we may consider water both as infrastructure and as environment, as much a network of pipes and drains as matters of pollution and well-being, as much a story of the search for and protection of the source as of the fate of the sink into which it ultimately flows.

The Kishon affair: science, law, and the politics of causation

This article describes how science and law were called upon (and failed) to resolve a controversy that created a painful rift between the Israeli State and some of its elite soldiers. The controversy, which came to be known as "the Kishon affair," erupted in 2000, when veterans of an elite and secretive unit in the Israeli navy claimed that pollution in the Kishon River where they had trained and dived during their military service had been the cause of a rash of cancers. The veterans demanded that the Ministry of Defense take responsibility for their illnesses, finance their medical treatment, and support their families if they die. The military denied the causal connection between the polluted river and the veterans' cancers and rejected their demands. The dispute quickly escalated into a bitter public controversy, and a high-rank commission comprised of one of Israel's top jurists and two prominent scientists was called upon to study the disputed causal relation and reveal its true nature. However, after nearly three years of intense inquiry the jurist and the scientists reached opposing conclusions: the jurist found a causal connection while the scientists rejected it.

Graphical methods and Cold War scientific practice: the Stommel Diagram's intriguing journey from the physical to the biological environmental sciences

In the last quarter of the twentieth century, an innovative three-dimensional graphical technique was introduced into biological oceanography and ecology, where it spread rapidly. Used to improve scientists' understanding of the importance of scale within oceanic ecosystems, this influential diagram addressed biological scales from phytoplankton to fish, physical scales from diurnal tides to ocean currents, and temporal scales from hours to ice ages. Yet the Stommel Diagram (named for physical oceanographer Henry Stommel, who created it in 1963) had not been devised to aid ecological investigations. Rather, Stommel intended it to help plan large-scale research programs in physical oceanography, particularly as Cold War research funding enabled a dramatic expansion of physical oceanography in the 1960s. Marine ecologists utilized the Stommel Diagram to enhance research on biological production in ocean environments, a key concern by the 1970s amid growing alarm about overfishing and ocean pollution. Before the end of the twentieth century, the diagram had become a significant tool within the discipline of ecology. Tracing the path that Stommel's graphical techniques traveled from the physical to the biological environmental sciences reveals a great deal about practices in these distinct research communities and their relative professional and institutional standings in the Cold War era. Crucial to appreciating the course of that path is an understanding of the divergent intellectual and social contexts of the physical versus the biological environmental sciences.

Current and historic mercury deposition to New Haven Harbor (CT, USA): implications for industrial coastal environments

This study quantifies historic and current mercury contamination in New Haven Harbor (New Haven, Connecticut, USA) through the analysis of sediment cores. The mercury concentration measured in surface sediment ranged from 320 to 1640 microg kg(-1) with an average of 530 microg kg(-1). The harbor is relatively small in area (6.6 km(2)) but displays a large range in concentrations, illustrating the important methodological issue that a large number of samples may be necessary to capture the variability in even a small area. Depth profiles of mercury reflect sedimentation over a range of 20 to 200 years and indicate a complex history of contamination. Mercury depth profiles were compared with lead, copper, cadmium, and silver concentrations and the metals generally covary. This trend indicates that the sources of mercury and heavy metals are linked and that regionally specific sources dominate the historic input of metals rather than large-scale atmospheric deposition patterns. Results also show there are large differences in absolute concentrations of metals among sites in the harbor. Differences in the abundance of Fe-rich, fine-grained sediment likely control the level of metals in various parts of the harbor. Proximity to current sources and the long, diverse industrial history of the harbor also influence the distribution pattern. All of the cores can be modeled as mixing between pre-industrial sediments and either one or two pollution endmembers. This study demonstrates the importance of riverine sources in the mass balance of mercury delivered to coastal areas and of watershed management to preserve coastal ecosystems.

Widespread waterborne pollution in central Swedish lakes and the Baltic Sea from pre-industrial mining and metallurgy

Metal pollution is viewed as a modern problem that began in the 19th century and accelerated through the 20th century; however, in many parts of the globe this view is wrong. Here, we studied past waterborne metal pollution in lake sediments from the Bergslagen region in central Sweden, one of many historically important mining regions in Europe. With a focus on lead (including isotopes), we trace mining impacts from a local scale, through a 120-km-long river system draining into Mälaren--Sweden's third largest lake, and finally also the Baltic Sea. Comparison of sediment and peat records shows that pollution from Swedish mining was largely waterborne and that atmospheric deposition was dominated by long-range transport from other regions. Swedish ore lead is detectable from the 10th century, but the greatest impact occurred during the 16th-18th centuries with improvements occurring over recent centuries, i.e., historical pollution > modern industrial pollution.

Pollution problems in the northeast Atlantic: lessons learned for emerging pollutants such as the platinum group elements

This paper provides an overview of the evolution of pollution problems in the Northeast Atlantic and associated responses and considers the effectiveness of these measures on environmental contamination. It identifies shortcomings in past practices and shows how marine environmental pollution may be perpetuated if new products and processes release novel contaminants or "emerging substances" without adequate management on a precautionary basis. The study concludes that it is necessary to develop innovative techniques capable of making reasonable quantitative estimates of not only environmental pathways, loads, and concentrations but also the socioeconomic drivers and "upstream" control measures (control, reduction, or elimination of emissions) so that a clear understanding of the causes and effects of our actions can be obtained. The development of a European Observatory for Emerging Substances to coordinate concerns, observations, and practices is suggested as a proactive approach for anticipating emerging problems.

Water systems and urban sanitation: a historical comparison of Tokyo and Singapore

The importance of a water supply and sewage treatment for urban sanitation is recognized in the modern world. Their contributions to public health have not, however, been well demonstrated by historical data, especially in Asian cities. In this research, we focused on the Asian cities of Tokyo and Singapore, which both developed significantly in the 20th century. We analysed their development processes statistically to determine what the key elements for the protection of urban sanitation have been. Although both cities constructed modern water supply systems at almost same time (Tokyo in 1898 and Singapore in 1878), and similarly modern wastewater treatment systems (Tokyo in 1922 and Singapore in 1913), the prevalence of water-borne diseases in Tokyo was more serious than it was in Singapore, in spite of Singapore's high infant mortality rate. The main reason for this was the differences in the systems of night-soil transport. We found that the water supply system in itself was not enough to resolve all urban sanitation problems, and appropriate night-soil removal was also crucial. In addition, historical trends and water consumption vary by city, so the appropriate technology and system are also different according to the unique characteristics and needs of each.

Water quality and fisheries in the Mersey estuary, England: A historical perspective

The Mersey estuary, NW England, once had a prolific fishery but in the aftermath of the industrial revolution water quality and fisheries declined and the Mersey became infamous as one of the most polluted rivers in Europe. Until relatively recently, almost all industrial and domestic effluents were discharged without treatment resulting in abominable fouling of the shoreline, and long anoxic reaches in the upper estuary during the summer. In addition, there were unknown biological impacts resulting from a complex mixture of dangerous substances present in the river. Over 1000 million pound has been spent to remedy this situation and there is unequivocal evidence that this has had the desired effect. Dissolved oxygen is now generally >60% saturation, salmon are now found at the tidal-limit and the estuary is becoming ever more popular for sea angling. The river is no longer an embarrassing liability but is now perceived as an important asset in the economic regeneration of this region of the United Kingdom.

Sewer solids-20 years of investigation

Knowledge about sewer solids has advanced rapidly in the last few decades due to academic research triggered by an emerging renewed interest from sewer operators. It is now known that sewer solids are implicated in: loss of conveyance; potential for acute and chronic pollution of watercourses and effects inside sewers such as generation of malodorous gases and fabric corrosion. Despite this advance in knowledge, there is much that still needs to be understood, particularly the details of some of the mechanisms of flow-solids interactions, such as deposition, consolidation, erosion, biochemical interactions and processes. The history of knowledge development is outlined and areas where there is a need for further elucidation are highlighted.

Trace element pollution records in some UK lake sediments, their history, influence factors and regional differences

Sediment cores were taken from six sites across the UK. Apart from Banbury Reservoir in London, all the other sites are relatively remote lakes. Trace elements Pb, Zn, Cu, Cd, Cr, Ni, Sn, As and V, major elements such as Fe, Mn, Ti and Al were analysed, and organic content measured as loss-on-ignition was determined in all of these cores. The result shows that these relatively remote sites have experienced enhanced atmospheric deposition of anthropogenically derived trace elements for over 100 years, and the contamination might start before industrialisation. Trace metal contamination remains the highest level at Banbury Reservoir showing "pollution source" influence. Despite the considerable reduction in atmospheric deposition in recent years, although some of the element concentrations in the surface sediments have declined, they are still much higher than their natural background values. In these sites, trace element pollution records have been influenced by many different factors. Redox condition could affect As distribution in the sediments. Sediment matrix could also affect trace element pollution signal. Apart from direct atmospheric deposition, the distributions of trace elements in the sediments have been affected by forestry activities and catchment erosion, and more contaminated soil in-wash could increase sediment pollution whilst less contaminated soil could dilute sediment pollution. In some sites, data suggest that catchment in-wash is an important source of elements for the lakes.

Science, policy and the management of sewage materials. The New York City experience

Development of national policy on sewage sludge management is a classic example of incremental policy formulation [Fiorino, D.J. 1995. Making Environmental Policy. University of California Press. Berkeley, CA. p. 269]. Consequently, policy has developed piecemeal, and results are, in some ways, different than intended. Land application of sewage sludge has not been a panacea. Many of the same types of policy are now being raised about it. We demonstrate this by examining the management of sewage materials by New York City from near the turn of the 20th century, when ocean dumping was viewed as a means to alleviate some of the gross pollution in New York Harbor, to when ocean dumping was banned, and thence to the present when sludge is applied to land as "biosolids." Lessons learned during this long, sometimes contentious history can be applied to present situations--specifically not understanding the long-term consequences of land-based reuse and disposal technologies.

Historical alpha-HCH budget in the Arctic Ocean: the Arctic Mass Balance Box Model (AMBBM)

An Arctic Mass Balance Box Model (AMBBM) has been developed to calculate a sequential historical alpha-hexachlorocyclohexane (alpha-HCH) budget in the Arctic Ocean from its introduction in the 1940s up to the present. The AMBBM is created in the context of the Arctic as a receptor, and has three major components: the air concentration module, the loading from Arctic river module and the transport/transformation module. The results of the model provide a more complete depiction of the behavior of alpha-HCH within the Arctic Ocean. Model output includes annual concentrations in Arctic air and water, annual alpha-HCH loading to, removal from the Arctic Ocean and annual cumulative burden of alpha-HCH in the Arctic waters from 1945 to 2000. Our model results compare well with published data in the 1980s and 1990s and show that the alpha-HCH burden in the Arctic Ocean started to accumulate in the early 1940s and reached the highest value of 6670 t in 1982, 1 year before China banned the use of technical HCH. Since then the burden of alpha-HCH in Arctic waters has decreased quickly by an average annual rate of approximately 270 ty(-1) during the 1990s, decreasing from 4220 t in 1990 to 1550 t in 2000. The complete elimination of alpha-HCH from Arctic waters would require another two decades. The total loading between 1945 and 2000 was 27700 t accounting for approximately 0.6% of total global alpha-HCH emission from agricultural land to the atmosphere. Differences in loadings of alpha-HCH to the North American Arctic Ocean and Eurasian Arctic Ocean are also discussed.

'Iraq Water Treatment Vulnerabilities': a challenge to public health ethics

A formerly classified US document, 'Iraq Water Treatment Vulnerabilities,' provides evidence that ill health was knowingly induced in the population of Iraq through the ruination of that country's water purification system. We believe that the uncovering of this document should stimulate the public health community to clarify principles of public health ethics and to formulate statements giving voice to these principles. We propose here two statements, one dealing with the broad issue of public health ethics and international relations, and one dealing specifically with public health ethics and water purification.

The Mersey Basin: an historical assessment of water quality from an anecdotal perspective

The freshwaters of the Mersey Basin have been seriously polluted for over 200 years. Anecdotal evidence suggests that the water quality was relatively clean before the start of the Industrial Revolution. The development of the cotton and chemical industries increased the pollution load to rivers, and consequently a decline in biota supported by the water was observed. Industrial prosperity led to a rapid population increase and an increase in domestic effluent. Poor treatment of this waste meant that it was a significant pollutant. As industry intensified during the 19th century, the mix of pollutants grew more complex. Eventually, in the 1980s, the government acknowledged the problem and more effort was made to improve the water quality. Knowledge of social and economic history, as well as anecdotal evidence, has been used in this paper to extrapolate the changes in water quality that occurred.

Decadal change in vegetation and soil phosphorus pattern across the Everglades landscape

Wetlands respond to nutrient enrichment with characteristic increases in soil nutrients and shifts in plant community composition. These responses to eutrophication tend to be more rapid and longer lasting in oligotrophic systems. In this study, we documented changes associated with water quality from 1989 to 1999 in oligotrophic Everglades wetlands. We accomplished this by resampling soils and macrophytes along four transects in 1999 that were originally sampled in 1989. In addition to documenting soil phosphorus (P) levels and decadal changes in plant species composition at the same sites, we report macrophyte tissue nutrient and biomass data from 1999 for future temporal comparisons. Water quality improved throughout much of the Everglades in the 1990s. In spite of this improvement, though, we found that water quality impacts worsened during this time in areas of the northern Everglades (western Loxahatchee National Wildlife Refuge [NWR] and Water Conservation Area [WCA] 2A). Zones of high soil P (exceeding 700 mg P kg(-1) dry wt. soil) increased to more than 1 km from the western margin canal into the Loxahatchee NWR and more than 4 km from northern boundary canal into WCA-2A. This doubling of the high soil P zones since 1989 was paralleled with an expansion of cattail (Typha spp.)-dominated marsh in both regions. Macrophyte species richness declined in both areas from 1989 to 1999 (27% in the Loxahatchee NWR and 33% in WCA-2A). In contrast, areas well south of the Everglades Agricultural Area, induding WCA-3A and Everglades National Park (ENP), did not decline during this time. We found no significant decadal change in plant community patterns from 1989 and 1999 along transects in southern WCA-3A or Shark River Slough (ENP). Our 1999 sampling also included a new transect in Taylor Slough (ENP), which will allow change analysis here in the future. Regular sampling of these transects, to verify decadal-scale environmental impacts or improvements, will continue to be an important tool for long-term management and restoration of the Everglades.

Historical pollution trends in coastal environments of India

Seventeen sediment cores were collected from different coastal ecosystems of Tamil Nadu, India that include coastal lagoon (Pulicat), polluted rivers in Chennai (Adyar and Cooum), Coral reef (Gulf of Mannar) and a perennial river (Tamiraparani). Radiometric dating has been used to determine the modern sedimentation rates in these ecosystems. The Pulicat Lake and the polluted rivers (Adyar and Cooum) yield an average sediment accumulation rate of 12.34 and 7.85 mm yr(-1), respectively. In the Gulf of Mannar coral reef, the sedimentation rate averages 17.37 mm yr(-1), while the rate in Tamiraparani River is 11.00 mm yr(-1). In the Tamiraparani River basin, the deposition rates were an order of magnitude higher when compared to the erosion rates, which may be due to bank erosion and the intense human activity. In general high rates of sedimentation observed in the coastal ecosystems not only reflect the capacity of the coastal regions as sinks for trace metals but also denote increased input of pollutants into the coastal environments in the recent past. The deposition rates of heavy metals--Fe, Mn, Zn, Cu, Cr and Ni in the depth profiles have been computed using sedimentation rates and their distribution is discussed. It can be seen that the mean deposition rates of all the measured elements in the Tamil Nadu coastal ecosystems are high compared with rates determined for the sediments of the deltaic regions of India and the Bay of Bengal.

Sedimentation rates and pollution history of a dried lake: Al-Oteibeh Lake

Sediment accumulation rates as well as the distribution of selected elements in a dried Syrian lake (Al-Oteibeh Lake), near Damascus City, are reported. Five core samples from different locations of the lake were collected, and four major elements (Fe, K, Mg and Na) and six trace metals (Co, Ni, Cr, Pb, Zn, U and Cu) were analyzed. Sedimentation rates were determined applying the 210Pb dating method and found to vary between 0.100 and 0.793 cm year(-1). The results showed that the constant flux constant sedimentation rate (CF:CS) simple dating model is applicable for dating recent dried sediment and recording the past historical pollution of the last 100 years. However, the method was found to be only applicable for dating trace and major elements, which cannot be leached to deeper layers by rainwater. In addition, the obtained records can be used to verify the date of water level declining.

Attributions in explanations of risk estimates

In the spring of 1993, nearly 40 percent of Milwaukee-area residents experienced a nationally publicized outbreak of cryptosporidium, a parasite that infested the metropolitan drinking water supply. Using open-ended survey data gathered from 610 adult residents in the wake of that outbreak, this study looks at factors related to the ways in which people make sense of their quantitative personal risk estimates. The concepts of informal reasoning and attribution aided this endeavor. Analysis of open-ended comments about the risk of getting ill from a waterborne parasite indicated that explanations of personal risk were consistent with predictions made by attribution theory. Good outcomes, which included having remained healthy during the outbreak, were associated with a greater likelihood that respondents would attribute causation to themselves, while one specific bad outcome, having experienced the illness, was associated with a greater likelihood that respondents would attribute causation externally. This study also examined predictors of whether respondents employed probabilistic language in those attributions. Analysis indicated that income was positively related to the use of probability-oriented language, while age and race were negatively related to the use of such language (i.e., persons of color and older individuals were less likely to use such language).

Marine organic pollution history in the Changjiang Estuary and Zhejiang coastal area--HCHs and DDTs stratigraphical records

The variations of concentrations of hexachloro-cyclohexane (HCHs), dichloro diphenyl trichloroethane (DDTs) in surface sediments from the Changjiang Estuary and Zhejiang coastal area suggests that although there is a substantial decrease of these persistent trace compounds since the last two decades, they still presented in recent surface sediments. Their concentration levels in suspended matter are still quite high. In dated sedimentary cores, the DDTs and HCHs concentration peaks appeared in 1960s to 1980s, which approximately corresponded to their production and usage history.

Sediment evidence of early eutrophication and heavy metal pollution of Lake Mälaren, central Sweden

Lake Mälaren is the water supply and recreation area for more than 1 million people in central Sweden and subject to considerable environmental concern. To establish background data for assessments of contemporary levels of trophy and heavy metal pollution, sediment cores from the lake were analyzed. Diatom-inferred lake-water phosphorus concentrations suggest that pre-20th century nutrient levels in Södra Björkfjärden, a basin in the eastern part of Mälaren, were higher (c. 10-20 micrograms TP L-1) than previously assumed (c. 6 micrograms TP L-1). Stable lead isotope and lead concentration analyses from 3 basins (S. Björkfjärden, Gisselfjärden and Asköfjärden) show that the lake was polluted in the 19th century and earlier from extensive metal production and processing in the catchment, particularly in the Bergslagen region. The lake has experienced a substantial improvement of the lead pollution situation in the 20th century following closure of the mining and metal industry. The lead pollution from the old mining industry was large compared to late-20th century pollution from car emissions, burning of fossil fuels and modern industries.

'A sort of destiny': the multi-jurisdictional response to sewage pollution in the Great Lakes, 1900-1930

At the turn of the twentieth century, water pollution was the primary vector spreading waterborne disease and a public health issue. In the Great Lakes basin, unprecedentedly high mortality from typhoid fever prompted a conference of federal and provincial public health officials in 1910. Three related initiatives resulted: the provincial government amended the Public Health Act in 1912; federal legislators attempted to develop national pollution control legislation between 1912 and 1915; the International Joint Commission investigated cross boundary pollution in 1912 and recommended a convention to control it. Of the three initiatives, only the provincial Public Health Act amendments were carried to fruition. By 1915, the almost universal adoption of chlorine treatment for municipal water supplies effectively controlled waterborne disease and there was no longer a perceived need for further action.