Mercury in Florida Bay fish: spatial distribution of elevated concentrations and possible linkages to Everglades restoration

Health advisories are now posted in northern Florida Bay, adjacent to the Everglades, warning of high mercury concentrations in some species of gamefish. Highest concentrations of mercury in both forage fish and gamefish have been measured in the northeastern corner of Florida Bay, adjacent to the dominant freshwater inflows from the Everglades. Thirty percent of spotted seatrout (Cynoscion nebulosus Cuvier, 1830) analyzed exceeded Florida’s no consumption level of 1.5 μg g−1 mercury in this area. We hypothesized that freshwater draining the Everglades served as the major source of methylmercury entering the food web supporting gamefish. A lack of correlation between mercury concentrations and salinity did not support this hypothesis, although enhanced bioavailability of methylmercury is possible as freshwater is diluted with estuarine water. Stable isotopes of carbon, nitrogen, and sulfur were measured in fish to elucidate the shared pathways of methylmercury and nutrient elements through the food web. These data support a benthic source of both methylmercury and nutrient elements to gamefish within the eastern bay, as opposed to a dominant watershed source. Ecological characteristics of the eastern bay, including active redox cycling in near-surface sediments without excessive sulfide production are hypothesized to promote methylmercury formation and bioaccumulation in the benthos. Methylmercury may then accumulate in gamefish through a food web supported by benthic microalgae, detritus, pink shrimp (Farfantepenaeus duorarum Burkenroad, 1939), and other epibenthic feeders. Uncertainty remains as to the relative importance of watershed imports of methylmercury from the Everglades and in situ production in the bay, an uncertainty that needs resolution if the effects of Everglades restoration on mercury levels in fish are to be modeled and managed.

Trace element concentrations in muscle tissue of the benthopelagic grenadier (Coryphaenoides armatus) from the Iberian deep-sea

11 specimens of Coryphaenoides armatus were collected at former dumping sites for radioactive material in the Iberian deep sea at a depth of 4700 m and their muscle tissue was analysed for four trace elements (copper, zinc, cadmium and lead) by differential pulse anodic stripping voltammetry (DPSAV). Concentrations of zinc were typical for fish muscle in general; copper content was somewhat higher than generally found in fish. The cadmium and lead contents were at a level found in fish from the open sea but the lead content of 2 specimens taken in area East-B was found to be higher.

Study on the biomass yield of Duckweed (Lemna minor) (L.) in hydroponic cultures containing different concentrations of aquaeous extract of chicken manure

The biomass yields of duck week (Lemna minor(L) was monitored in hydroponic media prepared by variously extracting 0.50, 1.00 and 2.00g of dried chicken manure per liter of city water (tap water) supply. The culture media consisting of aqueous extract of the various manure treatments were made up to 12 liters in all cases with tap water as control. Plastic baths of 25 liters capacity with 0.71 super(m2) surface area were used as culture facility. Each bath was stocked at a density of 30g super(m-2) with fresh weed samples (i.e 21.30g/bath). Maximum yields were obtained at all treatment levels and control on day 3 and based on the highest yield of 0.37gm super(-2)d super(-1) (dry matter) obtained at 1.00gL manure treatment which was however not significantly higher (P>0.05) than the 0.36gm super(-2)d super(-1) (dry matter) at 0.05gl super(-1) media manure content, an average manure level of 0.75l super(-1) was selected and used to determine the operational plant density. Thus fresh weights of 30 to 300gm super(-2) was grown in triplicate at 30g intervals for a period of 3 days. A regression equation of Y=2.6720+0.0021x with a corresponding maximum density or operational plant density of 266gm super(-2) and yield of 0.98gm super(-2), d super(-1) (dry matter) were obtained. Further growth trials were carried out at the operational density and manure levels of 0.50, 0.75, 1.00, 1.25, 1.50, 1.75 and 2.00gl super(-1) media manure concentration giving a significantly higher yield (P<0.05) of 17gm super(-2), d super(-1) (dry matter). This yield was however doubled to between 2.21 and 2.24gm super(-2) d super(-1) (equivalent to 7.96 to 8.06mt.ha-1, Yr-1 dry matter on extrapolation) if 25% and 75% respectively of the total weed cover were harvested daily within the experimental period. The role of some dissolved plant nutrients (DPN) were also discussed

Seasonal variation of some trace metal concentrations in some fish species on stretch of River Kubanni, Zaria

In a semi-urbanized stretch of river Kubanni, Zaria, seasonal variations of some tree metals (copper, zinc and lead) in fish species (Clarias sp., Tilapia sp and Alestes sp) were investigated over a period of eight months. Water and fish were sampled monthly, pooled separately and seasonal analysis of each trace determined using atomic absorption method. The concentration of each of the elements in water higher in the dry season than during the rainy season. The dry and rainy season concentrations of copper, zinc and lead were 6.85~c10.66 mu gg super(-1)&1.45~c1.10 mu gg super(-1); 2.13~c1.68 mu gg super(-1)&0.1 5~c0.05 mu gg super(-1); and 0.52~c0.50 mu gg super(-1) & 0.31~c0.14 mu gg super(-1) respectively. Similarly, all the three accumulated more zinc and lead in the dry season than during the rainy season. Tilapia species and to some extent, Alestes species being pelagic had a higher concentration of trace metals than Clarias species which is a bottom dwelling fish Tilapia species may therefore be a better indicator species than Clarias species for monitoring trace metals in water bodies. Reasons for the observed variations in the trace metals were discussed

Concentrations of major ions in the stream water of the River Duddon, England, 1970-1974 [Dataset]

This dataset provides raw data of chemical analyses made during studies on seasonal variations of some major ions in the stream water of the River Duddon in Cumbria. Measurements of sodium, calcium, potassium, magnesium and chloride ions and pH were taken at 5 stations in the River Duddon between January 1970 and August 1974.

Concentrations of major ions in the stream water of the upper basin of the River Duddon, England, 1972-1974 [Dataset]

This dataset provides raw data of chemical analyses made during studies on seasonal variations of some major ions in the stream water of the upper basin of the River Duddon in Cumbria. Measurements of sodium, calcium, potassium, magnesium and chloride ions and pH were taken at 26 stations in the River Duddon basin between 1972 and 1974.

Concentrations of major ions in 182 tarns in the English Lake District (1953-1978) [Dataset]

This dataset provides raw data of chemical analyses made during studies on seasonal variations of 182 tarns in the English Lake District, Cumbria. Measurements of sodium, calcium, potassium, magnesium, pH, chloride ions, alkalinity, sulphite, strong acids and nitrate were taken between 1953 and 1978.

Concentrations en mercure dans les muscles de thons albacores (Thunnus albacares) du golfe de Guinee (1987-1988)

Samples of albacore tunny-fish (Thunnus albacares) caught from East Tropical Atlantic areas have been analysed in white and red muscles in order to determine the concentration of mercury. The results show that there are no significant differences between the mercury concentrations in the white and in the red muscles, and that a significant correlation exists between the mercury concentrations in the two types of muscles.

Concentrations en métaux toxiques chez Crassostrea gasar (huître de mangrove) en zone urbaine lagunaire d'Abidjan (Côte d'Ivoire)

This paper presents results related to a study of toxic heavy metals concentrations (Cd, Cu, Hg and Zn) in Crassostrea gasar (mangrove oyster). A comparative study is made between samples collected in urban region (Abidjan) and those from rural areas (Assinie-Mafia and Assouindé). Toxic metals concentrations in oyster samples collected in urban zone are higher than those in rural samples, as a result of chemical pollution due to urban and industrial wastes. Correlations between pollutants-weight of organisms and pollutants are good.

Aspects of mineral composition of male and female Heterobranchus bidorsalis adults exposed to different concentrations of Bonny-light crude oil

Studies were carried out to assess some macro and trace elements of mineral composition of the male and female Heterobranchus bidorsalis adults exposed to graded concentrations (1.00-8.00m/L-1) of Bonny-light crude oil (BLCO). The experiment was monitored for 4 days (toxicity) and 42days (recovery) periods. Significant decreases (P < 0.05)in the sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), phosphorus (P), zinc (Zn), iron (Fe), vanadium (Va), lead (Pb) and manganese (Mn) contents of the male H. bidorsalis corresponded with the increasing concentrations of BLCO. In contrast, the female fishes recorded significant increases (P < 0.05) in the values of the above elements in their tissues as the concentrations of BLCO increased. Furthermore, the values of Na, K, Mg, Ca, P, Zn, Fe, Va, Pb and Mn recorded in the male fishes where generally lower than those of their female counterparts and the control fish. Increased values of these elements were also recorded during the recovery periods (days 14, 28 and 42) of this study in the magnitudes of 15% at day 14, 20% at day 28 and 20% at day 42. This implied that the removal of crude oil stress during this period improved the quantity of these minerals deposited in the fish tissues. The highest percent proportion of Zn and the lowest proportion of Pb recorded in both male and female H. bidorsalis adults agreed with the report of other workers for other fish species. KEYWORDS: Heterobranchus bidorsalis, Mineral composition, Bonny-light crude oil, Toxicity, Recovery.

A survey of estuarine oxygen concentrations in relation to the passage of migratory salmonids

This report presents the first attempt at a national assessment of an Environmental Quality Standard (EQS) for dissolved oxygen (DO) in estuaries with the objective of allowing the passage of migratory salmonids. Under the Control of Pollution Act, Water Authorities and River Purification Boards have powers to control discharges to estuaries and need to define an EQS for the calculation of consent conditions. The object of any such standards is to permit the existence of good quality salmonid fisheries with only very occasional restrictions to the passage of fish. The report gives brief summaries of the DO regime in estuaries, the oxygen requirements of salmonids, and of tentative standards proposed by various authorities. These standards are then compared with DO and fishery data from UK estuaries, provided by the appropriate regulatory authorities. It concludes that a minimum annual lower 95-percentile of 5.0 mg/1 will meet the objective in most estuaries, and that a lower value of 3.0 mg/1 will permit the establishment of a more restricted fishery. However, more stringent standards may be needed in estuaries containing high concentrations of toxic pollutants. containing high concentrations of toxic pollutants.

Concentrations of Polychlorinated Biphenyls (PCB’s), Chlorinated Pesticides, and Heavy Metals and Other Elements in Tissues of Belugas, Delphinapterus leucas, from Cook Inlet

Tissues from Cook Inlet beluga whales, Delphinapterus leucas, that were collected as part of the Alaska Marine Mammal Tissue Archival Project were analyzed for polychlorinated biphenyls (PCB’s), chlorinated pesticides, and heavy metals and other elements. Concentrations of total PCB’s (ΣPCB’s), total DDT (ΣDDT), chlordane compounds, hexachlorobenzene (HCB), dieldrin, mirex, toxaphene, and hexachlorocyclohexane (HCH) measured in Cook Inlet beluga blubber were compared with those reported for belugas from two Arctic Alaska locations (Point Hope and Point Lay), Greenland, Arctic Canada, and the highly contaminated stock from the St. Lawrence estuary in eastern Canada. The Arctic and Cook Inlet belugas had much lower concentrations (ΣPCB’s and ΣDDT were an order of magnitude lower) than those found in animals from the St. Lawrence estuary. The Cook Inlet belugas had the lowest concentrations of all (ΣPCB’s aver-aged 1.49 ± 0.70 and 0.79 ± 0.56 mg/kg wet mass, and ΣDDT averaged 1.35 ± 0.73 and 0.59 ± 0.45 mg/kg in males and females, respectively). Concentrations in the blubber of the Cook Inlet males were significantly lower than those found in the males of the Arctic Alaska belugas (ΣPCB’s and ΣDDT were about half). The lower levels in the Cook Inlet animals might be due to differences in contaminant sources, food web differences, or different age distributions among the animals sampled. Cook Inlet males had higher mean and median concentrations than did females, a result attributable to the transfer of these compounds from mother to calf during pregnancy and during lactation. Liver concentrations of cadmium and mercury were lower in the Cook Inlet belugas (most cadmium values were <1 mg/kg and mercury values were 0.704–11.42 mg/kg wet mass), but copper levels were significantly higher in the Cook Inlet animals (3.97–123.8 mg/kg wet mass) than in Arctic Alaska animals and similar to those reported for belugas from Hudson Bay. Although total mercury levels were the lowest in the Cook Inlet population, methylmercury concentrations were similar among all three groups of the Alaska animals examined (0.34–2.11 mg/kg wet mass). As has been reported for the Point Hope and Point Lay belugas, hepatic concentrations of silver were re

Investigation of rising nitrate concentrations in groundwater in the Eden Valley, Cumbria: Phase 1 project scoping study

This is the Investigation of rising nitrate concentrations in groundwater in the Eden Valley, Cumbria report produced by the Environment Agency in 2003. This report focuses on groundwater nitrate concentrations in the Eden Valley. Most boreholes in the Eden Valley had nitrate concentrations less than 20 mg/l but a significant number had higher concentrations, some exceeding the EC maximum admissible concentration for drinking water of 50 mg/l. The main objectives of this report were to investigate the causes of rising nitrate concentrations in groundwater in the Permo-Triassic sandstone aquifers of the Eden Valley area and provide sufficient understanding of the groundwater and surface water flow system, including the sources of the nitrate contamination and the processes controlling nitrate movement, so that possible management options for reversing this trend can be considered.