Monitoring of Nutrients, Pesticides, and Metals in Waters, Sediments, and Fish of a Wetland

Wetland areas are of extraordinary importance for the conservation of wildlife. The Aiguamolls de l’Empordà Natural Park, located in Girona (northeast Spain), is one of the few areas in Europe acting as a way station for migratory birds. The natural park is made up of a brackish water reserve and a fresh water reserve. Agriculture and tourism, which are concentrated especially around coastal population centers, are the main activities in this area and result in the release into the environment of nutrients, pesticides, and heavy metals. This article aims to investigate the presence of nutrients, selected pesticides (organochlorine compounds, permethrin and triazines) and metals (Cr, Cu, Cd, Ni and Pb) in water, sediments, and fish samples. In the case of water, seasonal variations in levels of contamination were also monitored. Comparison was made of the fresh and brackish water reserves and concentration factors for metals and pesticides in sediment were determined. We conclude that the most significant sources of contamination in the natural park are from the entry of pesticides and nutrients into surface waters and sediments as a result of the intensive farming activity of the surrounding areas. The pesticides with the greatest presence were found to be lindane, heptachlor epoxide, permethrin, and atrazine. Among the metals analyzed, Cu and Cr presented the highest concentrations in surface waters and sediments.     

Heavy metal burdens in patches of asphyxiated swamp areas within the Qua Iboe estuary mangrove ecosystem

This study examined the burden of Zn, Cu, Ni, Pb, Cr and V in patches of asphyxiated mangrove swamp areas within Qua Iboe Estuary mangrove ecosystem by sediments and surface water analysis; in order to establish natural background levels of these metals and to assess anthropogenic influences on them. The analysis shows that the mean concentrations (mg/kg, dw) of Zn, Cu, Ni, Pb, Cr and V in sediments from asphyxiated and healthy mangrove ecosystems of Qua Iboe vary from 36.3-179.4, 29.2-43.2, 3.6-37.4, 39.6-93.8, 0.15-0.53 and 2.9-9.3, with the former exhibiting higher metal accumulating potential. Although heavy metal concentrations in surface water of the asphyxiated swamp were low, their accumulative effect is significant. The concentrations of Cu and Pb in surface water of this ecosystem exceeded the water quality criteria while Ni and Cr were under the maximum concentration for drinking water quality and protection of aquatic life. The values of pollution load index (PLI), which are generally greater than unity, show that the sediments and the surface water from the asphyxiated mangrove ecosystem were polluted with heavy metals, thus suggesting anthropogenic activities as a possible source of these metals. The mean concentrations of Zn, Ni and Pb exceeded the effects range-low (ERL), indicating that there may be some ecotoxicological risk to organisms living in asphyxiated mangrove sediments.     

Heavy metal toxicity to microbe-mediated ecologic processes: a review and potential application to regulatory policies

Microorganisms are sensitive to heavy metal pollution as are other components of the biota. However, most studies on the interactions between microbes and heavy metals have been conducted in synthetic media or in altered (e.g., sterilized) environmental samples and usually have used only single species. Few studies have evaluated the effects of heavy metals on the activities of natural heterogeneous microbial populations, both autotrophic and heterotrophic, in terrestrial and aquatic environments. These latter studies have shown that heavy metals inhibit primary productivity, nitrogen fixation, the mineralization of carbon, nitrogen, sulfur, and phosphorus, litter decomposition, and enzyme synthesis and activity in soils, sediments, and surface waters. The potential adverse effects of heavy metals on such microbe-mediated ecologic processes need to be incorporated into the methodologies used by regulatory agencies, such as the U.S. Environmental Protection Agency, to prepare environmental risk assessments which, in turn, are used to formulate environmental criteria, such as the Water Quality Criteria, and to evaluate the safety to the environment of exposure to "new chemical substances," as mandated by the U.S. Toxic Substances Control Act of 1976. To provide appropriate data that can be assimilated into regulatory policy, it is essential that microbial ecotoxicity tests be standardized, are neither costly nor difficult to train personnel to conduct, and produce data that can be quantitated.     

Acid Volatile Sulfides and Simultaneously Extracted Metals in a Metal-Polluted Area of Taihu Lake,China

There were similar distribution characteristics for acid volatile sulfides (AVS) and simultaneously extracted metals (SEM) in surface sediments, and the concentrations of AVS and SEM decreased from the deposition area to the center of the bay (lake). The ratio of AVS to SEM was <1 in the surface sediments, indicating that heavy metals in surface sediments may be bioavailable. The concentration of AVS increased with sediment depth, followed by a decrease with large variation, while the concentration of SEM remained constant. By comparing the concentration of SEM with total metals, it was shown that extracted Cu and Ni decreased with sediment depth, indicating increasing association of Cu and Ni with sulfides in deeper sediment layers. The lower extracted ratios for Pb and Zn compared with sulfidic sediment illustrated that AVS should not have strong control on sediment Pb and Zn. The molar ratio of AVS and reactive iron showed that heavy metals were dynamic and active in sediments in this lake.     

Concentrations and Distribution of Mercury and Other Heavy Metals in Surface Sediments of the Yatsushiro Sea including Minamata Bay, Japan

The concentrations and distribution of heavy metals, such as mercury, zinc, copper, lead, and iron in surface sediments from 234 stations of the Yatsushiro Sea including Minamata bay were investigated. High concentrations of mercury were found in sediments from Minamata bay and its vicinity, but the levels decreased gradually with distance from the bay. The concentrations of mercury in sediments decreased gradually from south to north of the Yatsushiro Sea. These imply the lack of movement of mercury from Minamata bay to the northern Yatsushiro Sea. The geographical profiles of zinc and copper were contrary to that found for mercury, indicating the presence of natural and anthropogenic sources of copper and zinc in the northern Yatsushiro Sea.     

Acid volatile sulfide and simultaneously extracted metals in the sediment cores of the Pearl River Estuary, South China

The acid-volatile sulfide (AVS), simultaneously extracted metals (SEM), total metals, and chemical partitioning in the sediment cores of the Pearl River Estuary (PRE) were studied. The concentrations of total metals, AVS, and SEM in the sediment cores were generally low in the river outlet area, increased along the seaward direction, and decreased again at the seaward boundary of the estuary. The amounts of AVS were generally greater in deeper sediments than in surface sediments. SEM/AVS was >1 in the surface sediments and in the river outlet cores. The ratio was <1 in the sediments down the profiles, suggesting that AVS might play a major role in binding heavy metals in the deep sediments of the PRE. The SEM may contain different chemical forms of trace metals in the sediments, depending on the metal reaction with 1M cold HCl in the AVS procedure compared with the results of the sequential chemical extraction. The SEM/AVS ratio prediction may overestimate trace metal availability even in the sediments with high AVS concentrations.     

Heavy metal concentrations in organisms from an actively dredged Texas Bay

Conclusions Organisms from San Antonio Bay have been shown to have low heavy metal concentrations. This is most likely the result of low natural metal levels in the area and minimal man-introduced contamination due to the bay's location far from any dense industrial or population centers. In addition, vigorous shell dredging activity in the bay for more than 50 years has not in any obvious way increased the concentrations of heavy metals in the organisms found there.Analyses have shown that metal concentrations in sediments from depths up to 2 meters (representing several centuries) are both low and uniform (Trefry, 1974). This indicates that the sediments do not represent any unusual metal reservoir for dredging to disturb, and shows that no recent increase in metal input to the bay has occurred.In general, organisms from San Antonio Bay were lower in almost every metal than organisms from other areas where dredging and pollution are thought to be minimal. Molluscs were observed to concentrate metals more than the other organisms studied, but the levels observed are very much lower than those thought to be lethal or toxic (Bowen, 1966). Except for a few large fish, metal concentrations did not correlate significantly with the size or growth stage of the individual. In the fish, certain organs, such as the liver, were found to concentrate metals, in agreement with previous reports.     

Hemoglobin concentration and acetylcholinesterase activity of oligochaetes in relation to lead concentration in spiked sediments from Ignacio Ramirez reservoir

This paper presents toxicity and uptake data of Limnodrilus hoffmeisteri generated by lead in systems using natural sediments from Ignacio Ramírez reservoir. Lead uptake, hemoglobin concentration, and acetylcholinesterase activity were studied in L. hoffmeisteri exposed to spiked sediments. All assays of lead uptake were conducted using whole sediments. Sediment texture was also considered. Acetylcholinesterase activity and hemoglobin concentration decreased after treatment with lead. Acetylcholinesterase activity and hemoglobin concentration tests indicated a response to the concentration of lead. These results suggest the usefulness of a diversity of bioassays to evaluate the toxicity of sediments polluted with heavy metals.     

Assessment of Metal Toxicity in Sediment Pore Water from Lake Macquarie,Australia

Recent investigations into the level of heavy metal enrichment in the sediments of Lake Macquarie have indicated that significant contamination has occurred over the past 100 years, with elevated levels of lead, zinc, cadmium, copper, and selenium being observed in most parts of the lake. Pore water extracted from sediments showing the greatest contamination by these metals exhibited toxicity to the larval development of the sea urchin Heliocidaris tuberculata. However, an analysis of pore water metal concentrations revealed that the concentrations of these metals were too low to cause toxicity. Rather, pore water toxicity was highly correlated with manganese for the majority of sites sampled; subsequent spiking experiments confirmed manganese as a cause of toxicity. Current levels of manganese in the sediments of Lake Macquarie have arisen from natural sources and are not the result of anthropogenic activities. These results reiterate the importance of identifying the causes of toxicity in assessments of sediment contamination, particularly when testing sediment pore waters using sensitive early life stages. Received: 31 January 2002/Accepted: 5 September 2002     

Heavy metals in mosquito larval habitats in urban Kisumu and Malindi, Kenya, and their impact

Concentrations and distribution of cadmium, chromium, copper, iron, lead, manganese and zinc in mosquito larval habitats in urban Kisumu and Malindi, Kenya and their effect on the presence of Anopheles gambiae, Aedes aegypti, Culex quinquefasciatus and Anopheles funestus larvae were investigated. Manganese and iron were the most prevalent heavy metals in water of larval habitats in urban Kisumu and Malindi, respectively. Iron was the most prevalent heavy metal in bottom sediments in larval habitats in both cities. The highest concentrations of all heavy metals, except cadmium and iron, were recorded in the poorly planned-well drained stratum in the two cities. All heavy metals were more concentrated in human-made than in natural larval habitats. Copper was positively associated with the presence of Ae. aegypti, and lead was associated with the presence of An. gambiae and Ae. aegypti in urban Kisumu. Absence of significant correlation between the other metals and mosquito species in both cities, despite relatively high concentrations, suggest that the local larval populations, including key malaria vectors have adapted to the detected levels of these metals.     

Toxicity of sediments and pore water from Brunswick Estuary,Georgia

A chlor-alkali plant in Brunswick, Georgia, USA, discharged >2 kg mercury/d into a tributary of the Turtle River-Brunswick Estuary from 1966 to 1971. Mercury concentrations in sediments collected in 1989 along the tributary near the chlor-alkali plant ranged from 1 to 27 μg/g (dry weight), with the highest concentrations found in surface (0–8 cm) sediments of subtidal zones in the vicinity of the discharge site. Toxicity screening in 1990 using Microtox^® bioassays on pore water extracted on site from sediments collected at six stations distributed along the tributary indicated that pore water was highly toxic near the plant discharge. Ten-day toxicity tests on pore water from subsequent sediment samples collected near the plant discharge confirmed high toxicity to Hyalella azteca, and feeding activity was significantly reduced in whole-sediment tests. In addition to mercury in the sediments, other metals (chromium, lead, and zinc) exceeded 50 μg/g, and polychlorobiphenyl (PCB) concentrations ranged from 67 to 95 μg/g. On a molar basis, acid-volatile sulfide concentrations (20–45 μmol/g) in the sediments exceeded the metal concentrations. Because acid-volatile sulfides bind with cationic metals and form metal sulfides, which are generally not bioavailable, toxicities shown by these sediments were attributed to the high concentrations of PCBs and possibly methylmercury.     

Recent influxes of metals into Lake Pepin,a natural lake on the Upper Mississippi River

The recent chronology of metal deposition was examined in Lake Pepin, a large natural lake on the Upper Mississippi River about 75 km downstream from the Minneapolis-St. Paul, Minnesota, metropolitan area. The lake, which has a high trapping efficiency for suspended sediments, serves as a sink for metals from industrial and domestic effluents discharged into the river. Sediment cores collected in 1981 from seven locations in the lake were analyzed for Cd, Cr, Cu, Ni, Pb, Zn, and Al (a reference element). Dating of a core with¹³⁷Cs indicated that inputs of these metals increased markedly in the late 1950s, peaked in the early 1970s, and decreased in the late 1970s to 1981. Sediment enrichment factors decreased in the order Pb>Cd>CuCr>Zn>Ni. The depth of the most highly contaminated strata in the core profiles decreased longitudinally from upstream to downstream—paralleling the upstreamto-downstream decrease in sedimentation rates. Changes in metal inputs to the lake would be most readily detected by analysis of sediments from the uppermost reaches, but the potential for release of sediment-associated metals to the water column is probably greatest in downstream reaches.     

Modeling Sediment Ni and V Spatial Distribution to Identify Hotspots in the Shadegan Wildlife Refuge,at the Head of the Persian Gulf

The distribution and origins of Ni and V were assigned in the surficial sediments from 160 stations in Shadegan international wetlands with 537,700 ha. The findings showed that the mean total content of Ni and V in the surface sediments were 45.08 ± 12.09 and 25.25 ± 20.8 μg g⁻¹ dw, respectively. According to the analysis chemical speciation, the Ni and V residual fraction in the surface sediments were calculated for > 80% of the total level of metals, indicating that the metals may be an indicator for the input of natural resources. The analysis of the interpolation maps according to their chemical fractionation manifested that the Ni and V pollution hotspots have been happened in the northern, southern, and western points. Interpolation maps also highlighted that Ni and V are often controlled by natural factors like parent material; however, anthropogenic inputs have also caused the accumulation of these metals in the sediment.

     

Soil Heavy Metal Contamination and Risk Assessment Around the Fenhe Reservoir,China

Heavy metal contamination in the soil around a water source is a particularly serious issue, because these heavy metals can be transferred into the water source and can pose significant human health risks through the contamination of drinking water or farmland irrigation water. In this paper, we collected surface soil samples from the area surrounding the Fenhe Reservoir. The concentrations of As, Cd, Cr, Cu, Hg, Ni, and Zn were determined and the potential ecological risks posed by the heavy metals were quantitatively evaluated. The primary inputs for As, Ni, and Zn were natural sources, whereas the other elements were derived from mainly anthropogenic sources. Hg displays more serious environmental impacts than the other heavy metals. The upper reaches of the reservoir, located in the northwest, display a higher potential ecological risk.     

Polynuclear aromatic hydrocarbon and heavy metal concentrations in sediments at coastal South Carolina Marinas

Sediment samples were collected from a fifteen station grid around three coastal South Carolina recreational marinas for the determination of sixteen polynuclear aromatic hydrocarbons and seven heavy metals. Results showed that sediments composed of larger, coarse-grained particles, such as sand and shell from along the center channel of each creek, consistently exhibited lower concentrations for both pollutant categories than sediments composed of finer particles, such as silts and clays from along either bank of the creeks. There was no significant input of heavy metals to sediments from the marinas. However, the hydrocarbon levels were influenced by the presence of the marinas and their associated activities. These data indicated that the creek bank of the intertidal zone was the preferable area for collection of sediments for contaminant monitoring compared to the mid-channel area due to apparent fundamental differences in the physical composition of sediment particle sizes between the two locations. Furthermore, polynuclear aromatic hydrocarbons provided better chemical parametric detection of recreational marina activities in estuarine waters than did heavy metals.     

In situ and laboratory bioassays with Chironomus riparius larvae to assess toxicity of metal contamination in rivers: the relative toxic effect of sediment versus water contamination

We used bioassays employing head capsule width and body length increase of Chironomus riparius larvae as end points to evaluate metal contamination in streams. Bioassays were performed in situ near an abandoned Portuguese goldmine in the spring of 2003 and 2004. Bioassays also were performed under laboratory conditions with water and sediment collected from each stream to verify if laboratory bioassays could detect in situ toxicity and to evaluate the relative contribution of sediment and water to overall toxicity. We used field sediments with control water and control sediments with field water to discriminate between metal contamination in water and sediment. Field water with dry and sieved, organic matter-free, and nontreated sediments was used to determine the toxicity of heavy metals that enter the organism through ingested material. In both in situ and laboratory bioassays, body length increase was significantly inhibited by metal contamination, whereas head capsule width was not affected. Body length increase was more affected by contaminated sediment compared to contaminated water. The lowest-effect level of heavy metals was observed in the dry and sieved sediment that prevented ingestion of sediment particles by larvae. These results suggest that body length increase of C. riparius larvae can be used to indicate the impact of metal contamination in rivers. Chironomus riparius larvae are more affected by heavy metals that enter the organism through ingested sediment than by heavy metals dissolved in the water column. Nevertheless, several factors, such as the particle size and organic matter of sediment, must be taken into account.     

Toxic effect of nickel on hemoglobin concentration of Limnodrilus hoffmeisteri in spiked sediments of trout farms

Toxicity and uptake data for Limnodrilus hoffmeisteri generated by nickel in systems using three natural sediments (trout farms: El Oyamel, El Truchón, and El Potrero), are presented. Nickel uptake and hemoglobin concentration were studied in L. hoffmeisteri exposed to spiked sediments. Nickel concentration and its toxic effect on hemoglobin were used as indicators of exposure. Sediment texture was also considered. Hemoglobin concentration decreased after treatment with nickel. The hemoglobin concentration test indicated a response to the bioavailability of nickel. This investigation clearly documents that sediments of El Truchón, El Oyamel, and El Potrero exhibit a toxicity potential. These results suggest the usefulness of diversity of bioassays for evaluating the toxicity of sediments polluted with heavy metals.     

The mediation of mutagenicity and clastogenicity of heavy metals by physicochemical factors

Heavy metals are an important class of environmental hazards, and as the use of heavy metals metals in industry continues to increase, larger segments of the biota, including human beings, will be exposed to increasing levels of these toxicants. As many heavy metals are mutagenic and clastogenic, they cause teratogenic and/or carcinogenic effects. Studies with microbes and representatives of the aquatic biota have shown that the toxicity of heavy metals is mediated by the physicochemical characteristics of natural environments. A few studies have also indicated that such abiotic factors (e.g. pH, chelating agents, inorganic anionic and cationic composition) mediate the mutagenicity and clastogenicity of heavy metals. These studies indicate that the physicochemical characteristics of natural environments may also potentiate or attenuate the mutagenicity and clastogenicity of heavy metals to the indigenous biota. Furthermore, studies with laboratory animals have shown that the acute and chronic toxicity, including the teratogenicity and carcinogenicity, of heavy metals is mediated by physicochemical factors. A similar dependence of the mutagenicity and clastogenicity of heavy metals by the physicochemical characteristics unique to specific body fluids and tissues may explain the association of specific heavy metal-induced tumors with specific tissues. There is an apparent need to develop genotoxicity tests that incorporate into their procedures the mediating influence of physicochemical factors (pH, for example), as the use of only standardized procedures may hinder the detection of heavy metal, as well as of organic, genotoxins whose mutagenicity or clastogenicity is altered by conditions other than those used in the standardized assay, thereby producing false negative results.     

Speciation of heavy metals in recent sediments of three coastal ecosystems in the Gulf of Cádiz, southwest Iberian Peninsula

A live-step sequential extraction technique was used to determine the partitioning of Cr, Mn, Fe, Cu, Zn, Cd, and Pb among the operative sedimentary phases (exchangeable ions, carbonates, manganese and iron oxides, sulfides and organic matter. and residual minerals) in coastal sediment from three locations in the southwest Iberian Peninsula. Two sites are located close to industrial areas, the salt marshes of the Odiel River and Bay of Cádiz, and one in a nonindustrial area, the Barbate River salt marshes. The Odiel River salt marshes also receive the drainage from mining activities in the Huelva region. In the sediments from the Bay of Cádiz and Barbate River salt marshes, Cr, Cu, Fe, and Zn were extracted from the residual fraction at percentages higher than 60%. In the sediments from the Odiel River salt marshes, concentrations of all the metals, except Cu. Zn, and Cd, exceeded 60% in the residual fraction as well. In the sediments from the Bay of Cádiz and Barbate River salt marshes, the main bioavailable metals were Mn and Cd; in those from the Odiel River salt marshes, the main bioavailable metals were Zn and Cd, respectively. The environmental risk was determined by employing the environmental risk factor (ERF), defined as ERF = (CSQV - Ci/CSQV), where Ci is the heavy metal concentration in the first four fractions and CSQV is concentration sediment quality value (the highest concentration with no associated biological effect). Our results showed that the sediments from the Cádiz Bay and Barbate River salt marshes do not constitute any environmental risk under the current natural conditions. In contrast, in the Odiel River salt marshes, Cu, Zn, and Pb yielded ERFs of less than zero at several sampling stations and, consequently, pose a potential threat for the organisms in the area. This is a consequence of the high levels of metals in the area derived from the mining activity (pyrite) and industrial activities and the association of these heavy metals with more labile fractions of the sediments.     

Heavy Metal Pollution Characteristics in the Modern Sedimentary Environment of Northern Jiaozhou Bay,China

The particle size distribution characteristics of sediments and the concentrations of heavy metals in Jiaozhou Bay were investigated in this study. The average concentrations of Cu, Pb, Zn, Cr, Cd, Hg and As were 36.88, 29.60, 82.08, 77.48, 0.083, 0.048 and 11.00 mg/kg, respectively. The heavy metal concentrations were highest in the eastern sediments, followed by those at the top of the bay, and the lowest concentrations were observed in the central region. Overall, a decreasing trend from the center of the bay to the periphery was observed. Additionally, the distribution of heavy metals in sediments was not completely controlled by sediment particle size. The degree of heavy metal contamination was evaluated using the geoaccumulation index and Hakanson’s method. The results revealed that the level of heavy metal pollution in the sediments was relatively low and that the main pollution elements were Cu and Hg. In addition, the sediments are associated with various levels of potential ecological risk due to the high pollution levels of Hg and Cd.