Perfluorinated Compounds Distribution and Source Identification in Sediments of Lake Victoria Gulf Basin

Perfluorooctanoic acid and perfluorooctane sulfonate were determined in the sediments from Winam Gulf, which is in the Kenyan side of Lake Victoria and in its source rivers. The sources of perfluorinated compounds within the Gulf of Lake Victoria have been identified and their levels determined for the first time, in this study, using SPE and HPLC-MS-MS analytical methodology. Variability in the concentrations of perfluorooctanoic acid and perfluorooctane sulfonate ranged from 1.4–99.1 and <1–57.5 ng/g in river sediments, respectively, which was higher than concentrations obtained from lake sediments (range perfluorooctanoic acid <1–24.1 ng/g and perfluorooctane sulfonate <1–4.0 ng/g). The results obtained suggested generalized point sources such as domestic and industrial waste indicated by significant correlation and regression of r² = 0.857. Sampling sites within and near sewage and water treatment facilities gave the highest concentrations of both analytes, and were observed to be the main source of perfluorinated compounds pollution. The lowest limit of quantification was 1 ng/g for both analytes and limits of detection were 0.1 and 0.2 ng/g for perfluorooctanoic acid and perfluorooctane sulfonate, respectively. Typical values for recovery obtained were higher than 78% from spiked amounts ranging from 1 to 150 ng. Quantifying perfluoro alkylated compounds in sediments have provided insights into their source, distribution, and mobility in the Lake Victoria Basin.     

A 25,000-year history for Lake Victoria, East Africa, and some comments on its significance for the evolution of cichlid fishes

SUMMARY. 1. Microfossil and X-ray analyses of sediment cores from Lake Victoria. East Africa, reveal a history of dramatically shifting environmental conditions over the last 25,000 years.
2. The diatom record of a 10 m core collected from beneath 66 m of water at an offshore station extends the known history of the lake 10,000 years beyond the published records from Pilkington Bay and Damba Channel, and shows that maximal late Pleistocene aridity occurred between 15,000 and 13,000 bp . Lack of precipitated carbonates in the offshore sediments suggests that the lake remained relatively dilute throughout the period of record.
3. There is no evidence that the lake level fell low enough to confine fishes to refugia in small isolated ponds or around river mouths.     

Surficial sediment phosphorus fractions along a biogeochemical gradient in Nyanza (Winam) Gulf, northeastern Lake Victoria and their possible role in phosphorus recycling and internal loading

Different phosphorus fractions and metal element composition of surficial sediments were measured on three occasions in 2005 and 2006 along a transect between Nyanza Gulf and offshore Lake Victoria, in order to assess the potential for sediments to contribute to the water column P concentrations in Lake Victoria. Total phosphorus (TP), apatite phosphorus (AP), inorganic phosphorus (IP) and organic phosphorus (OP) increased in sediments along the gulf towards the main lake while the non-apatite inorganic phosphorus (NAIP) increases were less defined. The longitudinal gradient of sediment TP and its fractions in Nyanza Gulf is a result of high rates of terrigenous input and resuspension and transport of the light, phosphorus rich inorganic and organic matter towards the main lake. TP in the sediment ranged from 812.7 to 1,738 mg/kg dry weight (DW) and was highest in the Rusinga Channel, the exchange zone between the gulf and the main lake. AP was the most important TP fraction, contributing between 35 and 57.3% of TP. Ca content in the sediment was strongly associated with TP and AP in the sediment (r² = 0.92 and 0.98, respectively) in the gulf and the channel, indicating the importance of apatite in controlling P availability in these zones. In the gulf and the Rusinga Channel, the less bioavailable apatite phosphorus dominated, whereas in the deeper main lake OP was the major fraction illustrating the importance of anaerobic release of P from sediments and acceleration of internal P loading in the main lake.     

Phytoplankton community structure and environment in the Kenyan waters of Lake Victoria

• 1 Phytoplankton species composition, numerical abundance, spatial distribution and total biomass measured as chlorophyll a concentration were studied in relation to environmental factors in September 1994 (dry season) and March 1995 (rainy season), respectively, in the Kenyan waters of Lake Victoria; 103 species were recorded.
• 2 Blue‐green algae (Cyanophyceae) were most diverse, followed by diatoms (Bacillariophyceae), green algae (Chlorophyceae) and dinoflagellates (Dinophyceae).
• 3 Twinspan separated the phytoplankton communities in the Nyanza Gulf and those in the open lake during both seasons. During the dry season, the Nyanza Gulf was strongly dominated by blue‐greens, while diatoms dominated in the open lake. During the rainy season, blue‐greens remained dominant in the Nyanza Gulf although the number of species found was lower than during the dry season; in the open lake, blue‐greens replaced diatoms as the dominant group and there were more species than in the dry season.
• 4 Canonical correspondence analysis indicated that the phytoplankton species distribution was significantly correlated with turbidity during the dry season and with SiO₂ during the rainy season. Chlorophyll a concentrations ranging from 2.0 to 71.5 mg m^‐3 in the dry season and 2.0–17.2 mg m^‐3 in the rainy season confirm earlier reports of increasing phytoplankton biomass in Lake Victoria since the 1960s.

     

Spatial distribution and historical deposition behaviors of perfluoroalkyl substances (PFASs) in sediments of Lake Chaohu,a shallow eutrophic lake in Eastern China

Sediment samples were collected from the Chaohu Lake basin to investigate the spatial distribution and historical deposition behaviors of 17 perfluoroalkyl substances (PFASs). Concentrations of the total PFASs (∑PFASs) in limnetic sediments ranged from 0.719 to 2.429 ng/g dry weight (dw), with an average of 1.449 ng/g dw. A clear gradient in the spatial distribution was observed from west to east in surface sediments of Lake Chaohu. Perfluorooctane sulfonic acid and perfluorooctanoic acid were predominant in limnetic sediments, with an average of 0.383 and 0.275 ng/g dw, respectively. The ∑PFASs concentrations in riverine sediments were the highest in the Shiwuli River, followed by the Nanfei River. PFASs in riverine sediments indicated that industrial discharge and urban runoff played key roles in PFAS distribution and pollution levels. In vertical profiles, concentrations of the ∑PFASs and PFAS congeners in three sediment cores generally increased with decreasing depths, indicating that the input history of the ∑PFASs could be attributed to the development of industrialization and urbanization in the Chaohu Lake basin. The correlations between PFASs and sedimentary characteristics, organic carbon, nutrients and inorganic salts suggested that both hydrophobic and electrostatic effects played important roles in PFAS distribution and pollution levels in sediments of Lake Chaohu.     

Organochlorine Pesticides in Sediments around Chaohu Lake: Concentration Levels and Vertical Distribution

Eighteen organochlorine pesticides (OCPs) were investigated in surface sediments from the Nanfei River and in four sediment cores from the primary estuaries of Chaohu Lake, Eastern China. The results indicate that the OCP concentrations in the surface and core sediments around Chaohu Lake were 3.48–121.08 (with a mean of 34.93) ng/g and 0.60–39.28 (7.07) ng/g, respectively. Significantly higher concentrations of ΣOCPs were observed in sediment samples from the Nanfei River and its estuary. The three important OCP contributors around Chaohu Lake were dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), and hexachlorobenzene (HCB), which originated primarily from the historical use of technical DDTs and HCHs. A principal component analysis (PCA) suggests that HCB and lindane may originate from the same sources, and DDTs were greatly influenced by organic carbon from the soil environment and the impact of urbanization processes.     

Effect of urban sewage treatment on total and methyl mercury concentrations in effluents

The purpose of this study was to investigate the effect of sewage treatment on total mercury (THg) and methylmercury (MeHg) concentrations in domestic effluents and the contribution of urban sewage treatment facilities to THg and MeHg in rivers. We determined the concentrations of THg and MeHg in unfiltered samples of untreated and treated domestic sewage from the three treatment facilities and receiving river water within the City of Winnipeg. The concentrations of THg in the Red and Assiniboine rivers ranged from 3–31 ng/L. THg was related positively to suspended sediment concentrations in the rivers. The concentrations of MeHg in these rivers were usually 0.2–0.3 ng/L. THg concentrations in raw sewage varied widely, from 2–150 ng/L. Treatment removed an average of 88% of this mercury. MeHg concentrations in raw sewage were 0.5–4.3 ng/L, however, after treatment at two treatment facilities, MeHg was greatly reduced, usually to 0.1–0.4 ng/L. Most treated sewage, therefore, had MeHg concentrations that were similar to levels in the receiving rivers and the effect of discharged effluent was usually a change of about 2% or less on concentrations in the rivers. However, one of the facilities (the West End plant) was discharging higher concentrations of MeHg, up to 2 ng/L, causing calculated increases of up to 11% in the concentration of MeHg in the Assiniboine River.     

Benthic algal mats of some lakes of Inexpressible Island (northern Victoria Land,Antarctica)

 Benthic algal mats from four lakes located on Inexpressible Island (northern Victoria Land, Antarctica) were studied, analysing their structure and floristic composition. Thirty taxa of algae were identified: 11 Cyanophyta, 15 Bacillariophyta and 4 Chlorophyta. The lake mats contained from 15 (lake C) to 26 species (lake D). The number of diatom frustules in the mats varied from 771×10³ (lake C) to 9428×10³ frustules g^-1 (lake B). In terms of floristic composition and macromorphology, these mats were observed to be very similar to moat mats described from Lake Gondwana (northern Victoria Land) and the Dry Valleys lakes of southern Victoria Land. Received: 9 July 1995/Accepted: 12 February 1996     

Food web structure and mercury transfer in two contrasting Ugandan highland crater lakes (East Africa)

Volcanic crater lakes scattered throughout western Uganda are important local sources of water and fish. Two representative but contrasting crater lakes near the Kibale National Park were sampled in 2000; the hyper‐eutrophic Lake Saka, which is highly affected by agricultural practices, and the mesotrophic Lake Nkuruba that is still surrounded by intact forest. The food web structures in these two lakes were assessed using stable nitrogen (δ¹⁵N) and carbon (δ¹³C) isotope analyses, and the mercury (THg) transfer patterns were quantified. The δ¹⁵N results indicate that food webs in both lakes are abbreviated, with only one to two trophic levels from primary consumers. The Lake Saka biota had distinctively enriched δ¹³C values compared with those in Lake Nkuruba, which may be due to ¹²C‐limited phytoplankton blooms in this lake. In Lake Nkuruba, two introduced tilapiine species and the introduced guppy Poecilia reticulata fed predominantly upon invertebrates and decomposed terrestrial plant material. In Lake Saka, the introduced Nile perch Lates niloticus appeared to occupy the top trophic position, but stable isotope values of the endemic haplochromine cichlids exclude those as Nile perch prey items. THg was found to biomagnify through the food web, reaching highest concentrations in P. reticulata in Nkuruba, which tended to be higher than for L. niloticus in Saka, suggesting increased bioavailability of THg in Nkuruba. Maximum THg concentrations in fish never approached WHO recommended guidelines (200 ng g^?1) designed to protect at‐risk groups.     

可鲁克湖流域生态环境质量诊断

为查清可鲁克湖流域生态环境质量及其演化特征,依据环境生态学相关理论,运用综合调查、遥感解译与反演、统计分析等技术手段,选取自然地理、气象、土地利用/覆盖和社会经济4个方面的15个因子,采用因子分析和熵值法计算指标权重,建立流域土壤质量模型和生态环境质量诊断模型,分析2000、2005、2010和2015年可鲁克湖流域土壤与生态环境质量的变化特征。结果表明: 2000、2005、2010和2015年,可鲁克湖流域生态环境质量均值依次为21、47、54和72,呈稳定上升趋势,生态环境质量等级由较差转为良好,土壤质量整体处于中等水平;空间上,北部山区和流域下游湿地及河流周边区域的生态环境质量明显转好。流域生态环境质量变化是人类活动与自然因素共同作用的结果,土壤质量与湖泊面积是指示流域生态环境的关键因子,可鲁克湖最小生态需水量是维持流域生态环境良性发展的基本保障。     

The Dry Holocene Megathermal in Inner Mongolia

The paleoclimate since 14 kyr BP (¹⁴C age) was reconstructed based on a 16.22-m-long sediment core collected from Lake Yanhaizi, a saline lake located near the northern limit of the East Asian summer monsoon in Inner Mongolia. Coarse sediments were deposited there during a shrinkage phase of the lake when sand dunes reactivated. These sediments have low organic carbon contents but high maturity indices, indicating that they were deposited in an arid environment. By contrast, based on high organic contents and low maturity indices, fine sediments were deposited during periods of high lake stand in a humid environment. It was in general dry between 8.0 and 4.3 kyr BP. The above dry and wet phases are consistent with those recovered from the arid-semiarid transition zone elsewhere, but are unlike the widely perceived humid Holocene Megathermal reported in east China and the newly reconstructed record in the alpine Retreat Lake in Taiwan. The discrepancy may be due to a relative insensitivity to humidity changes in these two areas since they have both been under the total influence of the summer monsoon. On the other hand, much enhanced evaporation over higher monsoon precipitation at Lake Yanhaizi reduces the effective humidity in the warm climate near the northern boundary of the summer monsoon. This also accounts for the fact the high-temperature Holocene Megathermal, as revealed in the Okinawa Trough and the northern South China Sea, is correlated to the dry phases at Lake Yanhaizi. Conversely, the 4-2-kyr BP coldest period in the Holocene corresponds to a wet phase at Lake Yanhaizi.     

Nutrient concentrations in Nyanza Gulf, Lake Victoria, Kenya: light limits algal demand and abundance

Nyanza Gulf is a large shallow embayment connected to Lake Victoria by the deep narrow Rusinga Channel. Between December 2000 and May 2002 the gradient of nutrients along the axis of Nyanza gulf into the main lake was determined. Nutrient concentrations in the gulf were found to be different from those in the main lake with phosphorus fractions, SRP and TP being significantly higher in the main lake than in the gulf. Well oxygenated conditions in the gulf keep the PO₄–P strongly bound to mineral particles whereas in the main lake, where deeper depths allows for development of anoxia, it is released into solution. The low TN:TP molar ratio in the gulf and in the main lake indicates many algae may be N-limited and heterocystous N-fixing cyanobacteria may be favored. However, the high mineral turbidity in the gulf reduces light availability and hence limits algal abundance resulting in easily measure concentrations of mineral nutrients and in particular high levels of dissolved reactive silica. The gulf is a net source of dissolved silica and total nitrogen to the main lake while the main lake is potentially a source of P to the gulf depending on interchange through Rusinga Channel.     

The atmospheric deposition of phosphorus in Lake Victoria (East Africa)

Wet and dry atmospheric fluxes of total phosphorus (TP) and soluble reactive phosphorus (SRP) measured at four sites over a 12-month period were used to estimate lake-wide atmospheric phosphorus (P) deposition to Lake Victoria, East Africa. Atmospheric samples were collected in plastic buckets with top diameter of 25.5 cm by 30 cm deep. The highest P loading rates of 2.7 (TP) and 0.8 (SRP) kg ha^–2 year^–1 were measured at Mwanza compared to less than 1.9 (TP) and 0.65 (SRP) kg ha^–2 year^–1 measured in other three sites. By applying these loading rates to the lake surface, it was estimated that 13.5 ktons (13.5 × 10³ kg) of TP were deposited annually into the lake from the atmosphere. Thirty-two percent of the total was found to be in the SRP form. Dryfall, a component ignored in previous studies exceeded wet deposition by contributing 75% of the total P input. However, materials deposited by dryfall made a lesser contribution to soluble form of phosphorus, as SRP concentrations in the wet samples were 2–3 times higher than SRP concentrations in dry samples. The annual fluxes of phosphorus measured on the south and western shores of Lake Victoria (1.8–2.7 kg ha^–2 year^–1) are near the upper range of similar fluxes measured in the tropics. In comparison with the existing estimates of municipal and runoff P inputs from other studies, it is estimated that atmospheric deposition represent 55% of the total phosphorus input to the Lake Victoria. The four sampling sites were fairly clustered and wet and dry P deposition data were collected from shore/land stations and applied to open lake areas to estimate lake-wide P deposition. In this regard, the estimates determined here should be viewed as a first order approximation of actual P load deposited into the lake.     

Influence of soil temperature and moisture on the dissolved carbon,nitrogen, and phosphorus in organic matter entering lake ecosystems

Concentrations of terrestrially derived dissolved organic matter (DOM) have been increasing in many north temperate and boreal lakes for over two decades. The concentration of DOM in lakes is influenced by a number of environmental factors, but there is still considerable debate about how the availability of terrestrial DOM, and associated dissolved nitrogen and phosphorus, may be affected by drivers of climatic change. Using experimental and observational methods, we considered how changes in soil temperature and moisture affected the composition of carbon, nitrogen, and phosphorus entering freshwater lakes. In our experiment, organic soil cores were collected from the wetland shoreline of a darkly-stained seepage lake in northern Wisconsin, USA and manipulated in laboratory with temperature and moisture treatments. During the 28-day study, soil leachate was sampled and analyzed for optical properties of DOM via UV/Vis absorbance, as well as concentrations of dissolved organic carbon (DOC), total dissolved nitrogen, and total dissolved phosphorus (TDP). DOM optical properties were particularly sensitive to moisture, with drier scenarios resulting in DOM of lower molecular weight and aromaticity. Warmer temperatures led to lower DOC and TDP concentrations. To consider long-term relationships between climate and lake chemical properties, we analyzed long-term water chemistry data from two additional Wisconsin lakes from the long term ecological research (LTER) project in a cross correlation analysis with Palmer drought severity index data. Analysis of the LTER data supported our experimental results that soil moisture has a significant effect on the quality of DOM entering lakes and that climate may significantly affect lake chemical properties. Although unexpected in terms of DOM loading for climate change scenarios, these results are consistent with patterns of decomposition in organic soils and may be attributed to an increase in soil DOM processing.     

Pigment stratigraphy and trophic status: An evaluation of radionuclide‐dated lacustrine sediment

Sediment cores from the profundal region of relatively young (ca. 45 years), warm‐monomictic Lake Vechten were dated with Cs and ²¹⁰Pb and analyzed for major carotenoids, chlorophyll, and pheophytin. Vertical sediment accretion rates determined from a clay/sand horizon and from the radionuclide datings varied between 0.60 and 0.74 cm/year. Sedimentation rates based on paniculate matter collected in sediment traps agreed with results of the ¹³⁷Cs method with average values of respectively 2.9 and 2.3 kg dry weight m^‐2 year^‐1. It was concluded that the profundal sediment is fairly undisturbed. Pigments showed a severalfold increase from the deepest to the superficial sediment layers. Their profiles were compared with limnological data obtained during previous studies of Lake Vechten. Evidence was provided that the distribution of pigments reflected grossly the trophic history of the lake, which became more eutrophic during the last two decades. Pigment analyses of sediment cores may be a useful tool to rapidly obtain rough basic information on the recent trophic development of stratified lakes liable to eutrophication.     

Characteristic deformities in tubificid oligochaetes inhabiting polluted bays of Lake Vänern,Southern Sweden

Tubificid worms of the species Pomatothrix hammoniensis with characteristic, but hitherto unknown, deformities are described from four bays and fjords of Lake Vänern, Southern Sweden. These worms are easily recognized, since their chaetae are grotesquely enlarged distally, others are strongly serrated or deeply split, etc. These deformities are clearly associated with pollutants, since the limited areas of the lake in which they occur have long been under severe stress from industrial and municipal wastes, especially from nearby pulp mild and chlor-alkaline industries from which mercury compounds are known to emanate. Lake Vänern belongs to the most mercury-polluted major lakes of the world (Håkansson, 1976) with sediment concentrations of up to 10 000 ng Hg g^?1 dry weight (natural back-ground value about 30 ng g^?1 dry weight). The Kendall Rank statistical test showed a highly significant correlation (τ = 0.87; S = 14) between the incidence of deformities and mercury deposits in the lake. Zinc and cadmium are also deposited in large concentrations in the lake and there are also a variety of chlorinated organic compounds in the waste water about which we know little at present. It is speculated that synergistic effects between contaminants may be responsible for the deformities. It is likely that the observed deformities are mainly of phenotypic origin, since aberrant young specimens are uncommon.     

Polycyclic Aromatic Hydrocarbons in Surface Soils of Kunming,China: Concentrations,Distribution, Sources,and Potential Risk

The concentrations, distribution, possible sources, and potential risk of polycyclic aromatic hydrocarbons (PAHs) in surface soils were studied in Kunming, which is situated in a lake basin of the Yunnan-Guizhou plateau. 15 PAHs were analyzed in 40 surface soil samples (0–5 cm layer) collected from six types of land uses in the Kunming urban area. Meanwhile, the potential sources of PAHs in surface soils of Kunming were investigated by PAH composition ratios, isomer ratios, and principal component analysis (PCA). The total concentrations of 15 PAHs ranged from 101.64 to 6,208.25 ng/g (dry weight basis). The concentrations in different land uses increased in an order as: green space (541.43 ng/g) < education area (756.49 ng/g) < business area (810.17 ng/g) < residential area (1,034.36 ng/g) < industrial area (1,166.79 ng/g) < roadside greens (2,146.76 ng/g). The results of sources identification suggested that PAHs in surface soils of the Kunming urban area were greatly affected by combustion activities which came mainly from coal combustion and vehicular traffic. In addition, the toxic equivalency factors (TEFs) were used to estimate benzo[a]pyrene-equivalent concentration in surface soils of Kunming, and the risk level of PAHs in Kunming's urban surface soils was low as a whole.     

Palynological investigations at the Late Bronze–Early Iron Age lakeshore settlement of Luokesa 1 (Moletai District,Lithuania): a contribution to the Middle-Late Holocene vegetation history of the south-eastern Baltic regions

Today, the settlement site of Luokesa 1 (L1) lies under water at the northern edge of Lake Luokesa in the Baltic Uplands, south-eastern Lithuania. Its 60 cm-thick Late Bronze–Early Iron Age cultural layer lies on top of lake marl. During excavations in 2008 and 2009, core samples at L1 were taken for the purpose of multidisciplinary investigations. From this material, five on-site pollen diagrams were created in parallel with geo-archaeological investigations and the examination of the botanical macro-remains. Two of these cores mainly comprised the cultural layer, another two consisted largely of the underlying lake marl and the fifth contained primarily the transition from the lake marl to the cultural layer. The chronological sequence was established through 11 AMS dates. The woodland history, starting from the Late Atlantic period, was recorded. The Quercetum mixtum values are quite low in the Subboreal, with the coniferous forest consisting mainly of Pinus and, though significantly less, Picea. At the transition to the cultural layer (Subatlantic) the pollen curves are highly variable, showing peaks in the curves for Betula and Alnus. Pollen from aquatic plants is also present. Changes in riparian vegetation and turbulent sedimentation conditions are to be expected and can be explained by a drop in the water level. As L1 was located on damp ground at that time, water influxes alternating with dry episodes were observed. In the area around L1 the sedge belt was less pronounced, and riparian woodland extended all the way to the shores of the lake. Pollen analyses of four sheep/goat dung samples provide information on the grazing season and pasture location of these domestic animals. The paper also discusses layer formation processes such as water level fluctuations and hiatuses.     

Energy Density of Lake Whitefish Coregonus clupeaformis in Lakes Huron and Michigan

We collected lake whitefish Coregonus clupeaformis off Alpena and Tawas City, Michigan, USA in Lake Huron and off Muskegon, Michigan USA in Lake Michigan during 2002–2004. We determined energy density and percent dry weight for lake whitefish from both lakes and lipid content for Lake Michigan fish. Energy density increased with increasing fish weight up to 800 g, and then remained relatively constant with further increases in fish weight. Energy density, adjusted for weight, was lower in Lake Huron than in Lake Michigan for both small (≤800 g) and large fish (>800 g). Energy density did not differ seasonally for small or large lake whitefish or between adult male and female fish. Energy density was strongly correlated with percent dry weight and percent lipid content. Based on data from commercially caught lake whitefish, body condition was lower in Lake Huron than Lake Michigan during 1981–2003, indicating that the dissimilarity in body condition between the lakes could be long standing. Energy density and lipid content in 2002–2004 in Lake Michigan were lower than data for comparable sized fish collected in 1969–1971. Differences in energy density between lakes were attributed to variation in diet and prey energy content as well as factors that affect feeding rates such as lake whitefish density and prey abundance.     

Chromium,Copper, and Arsenic Concentrations in Soil Underneath CCA-Treated Wood Structures

Soils below nine structures (decks and foot bridges) in Florida were examined to evaluate potential impacts from chromated copper arsenate (CCA), a common wood preservative. Eight of the nine structures were confirmed to have been treated with CCA. Soils collected were evaluated for arsenic, chromium, and copper concentrations as well as pH, volatile solids content and particle size distribution. Two types of soil samples were collected: a soil core and surface soil samples (upper 2.5 cm). One soil core was collected from below each deck and one control core was collected from an area removed from one of the structures. Eight or nine surface soil samples were collected in a grid-like fashion from beneath each structure. Equal numbers of surface control samples were collected from areas away from the structures. Metal concentrations were elevated in both the soil cores and surface samples collected from below the CCA-treated structures. Core samples showed elevated concentrations of metals at depths up to 20 cm. The arithmetic mean concentrations of arsenic, chromium, and copper in the 65 surface soil samples collected from below CCA-treated structures were 28.5 mg/kg, 31.1 mg/kg, and 37.2 mg/kg, respectively, whereas the mean concentrations of arsenic, chromium, and copper in the control samples were 1.34 mg/kg, 8.62 mg/kg, and 6.05 mg/kg, respectively. Arsenic concentrations exceeded Florida's risk-based soil cleanup target level (SCTL) for residential settings in all 65 surface soil samples. The industrial setting SCTL was exceeded in 62 of the 65 samples.