Trace Metal Content in Mussels, Perna viridis L., Obtained from Selected Seafood Markets in a Metropolitan City

Mussels, Perna viridis L., obtained from three selected seafood markets in Metro Manila, were tested for metal content including cadmium, copper, lead, and zinc through atomic absorption spectrophotometry. Water samples from Bacoor Bay, Cavite, which supplies mussels to the market, were likewise subjected to similar metal analyses. Of the metals analyzed in the soft tissues of mussels, only copper and lead with highest obtained values of 10.4 mg/kg and 2.3 mg/kg, respectively exceeded the PEMSEA guideline for safe human consumption. Water samples collected from the harvest sites in Bacoor Bay showed high concentrations of cadmium (0.023 mg/L) and lead (0.25 mg/L) that exceeded the standards of DENR, ASEAN, and US EPA. Zinc, though detected in relatively high concentrations in both water (0.03 mg/L) and soft tissues (12.16–14.43 mg/kg) of mussels remained below the criteria set by the above-mentioned agencies. Overall, the present study indicates that mussels being sold in selected Metro Manila seafood markets were contaminated with metals, notably Cu and Pb, at concentrations that are unsafe for human consumption and thus, represents a health risk.     

Norfluoxetine Induces Spawning and Parturition in Estuarine and Freshwater Bivalves

Fluoxetine, a commonly prescribed antidepressant (Prozac), has been detected in sewage effluent. Its active metabolite norfluoxetine is more potent and has been detected in sewage influent and in fish tissues. We tested the effects of norfluoxetine on spawning and parturition in bivalves. Norfluoxetine induced significant spawning in zebra mussels and dark false mussels at concentrations as low as 5 μM. Norfluoxetine induced significant parturition in fingernail clams at 10 μM. Fluoxetine also induced spawning in dark false mussels at concentrations as low as 100 nM. Implications for environmental impacts of norfluoxetine and fluoxetine on native and exotic bivalves are discussed.     

Multielemental Analysis of Migori (Southwest,Kenya) Artisanal Gold Mine Ores and Sediments by EDX-ray Fluorescence Technique: Implications of Occupational Exposure and Environmental Impact

The results of heavy element profiling of the gold ores and sediments associated with the artisanal gold mining activities of the Migori gold belt of Southwestern Nyanza, Kenya, were reported in this paper. The analysis was made to assess the occupational exposure of the miners as well as to investigate the environmental impact of toxic heavy metals. Gold ores and sediments from the artisanal gold processing were sampled in four artisanal gold mining areas: Osiri A, Osiri B, Mikei and Macalder (Makalda) and analyzed for heavy elemental content using ¹⁰⁹Cd radioisotope excited EDXRF spectrometry technique. Analysis consisted of direct irradiating of sample pellets. The concentrations of major elements detected were: titanium (711.41–10,766.67 mg/kg); cobalt (82.65–1,010.00 mg/kg); zinc (29.90–63,210 mg/kg); arsenic (29.30–8,246.59 mg/kg); gold (14.07–73.48 mg/kg); lead (16.31–14,999.40 mg/kg) and mercury (16.10–149.93 mg/kg). The average concentration of the heavy toxic metals i.e. arsenic, lead, titanium and zinc were found to be above 50 mg/Kg as recommended by World Health Organization.     

Interspecific Variation of Metal Concentrations in Three Bivalve Mollusks from Galicia

There has been growing concern about the inflow of metals to the coastal areas because they can be toxic to aquatic and human life. Some studies have demonstrated the existence of species-specific differences in the metal concentrations of mollusks. We compared metal concentrations between Mytilus galloprovincialis, used as a water quality indicator, and two other bivalve species collected for human consumption (Venerupis pullastra and Cerastoderma edule) in different locations on the Galician coast (northwest Spain). M. galloprovincialis was found to be the best zinc and lead accumulator, whereas silver and arsenic were preferentially accumulated by V. pullastra and chromium and nickel by C. edule. Bivalve concentrations of mercury, cadmium, chromium, arsenic, silver, and zinc appeared to be linearly related to environmental concentrations, but this was not the case with copper, nickel, and lead in some species, which indicated that there is a nonlinear accumulation of these metals or an influence of the environmental conditions on species accumulation. The relationship between metal concentration in mussels and in the two other species varied with the metal and the species. In some cases the correlation was high, making it possible to use mussels as bioindicators for the other species. In other cases the correlation was moderate or low, therefore rendering mussels of little or no use in predicting the metal concentrations in the two other species. {texp}Commercial fisheries of bivalves are an important source of income to many coastal populations. Nevertheless, achieving compatibility between harvesting these resources and industrial development is a difficult task. Some industrial activities can produce significant heavy-metal contamination of mollusks as was evidenced by the mercury accidents in Japan, Sweden, Iraq, etc. (Mance 1987; Fergusson 1990). Consequently, the implementation of heavy-metal monitoring programs for shellfish is required to ensure the quality of the edible species. The European Union has dealt with this requirement through Council Directive 91/492/EC. Most national monitoring programs do not analyze the metal concentration in each harvested species and instead use the one or a few species that are assumed to be bioindicator species. Following this approach, metal concentrations in a bivalve species (usually mussels) are used to assess water quality, and it is assumed that all bivalves in good-quality water are safe for human consumption. This method does not hold when the metal accumulation characteristics of the target species are not similar to those of the bioindicator species, making the estimation of the risk incorrect. In Galicia, and in many other European areas, cockles (Cerastoderma edule) and clams (Venerupis pullastra) are species commercially important because of their high production and price. To prevent heavy-metal intoxication in these and other species, mussels (Mytilus galloprovincialis Lmk.) from the area were analyzed for heavy-metal content and used as bioindicators of metal contamination. However, the usefulness of M. galloprovincialis as an indicator of metal contamination in C. edule and V. pullastra has not been checked and—taking into account that several studies have demonstrated different bivalve species to differ substantially in their capability to accumulate various metals (Reinfelder et al. 1997; Wang and Fisher 1999; Chong and Wang 2000; Wang 2001)—it should be checked. Therefore, there is a need to evaluate both the usefulness of mussels as bioindicators and the actual concentrations of metals in these two species to guarantee their safety for consumption. In this study, we attempted to determine the how the metal concentrations of two poorly known species (V. pullastra and C. edule) compare with those of M. galloprovincialis in an area (the Galician coast) with diverse sources of metal pollution. We thus obtained an idea of the risk that these species represent as well as the usefulness of the concentrations found in mussels as an indicator for the other two species.     

Bioaccumulation of polychlorinated biphenyls and metals from contaminated sediment by freshwater prawns,Macrobrachium rosenbergii and clams,Corbicula fluminea

Freshwater prawns,Macrobrachium rosenbergii, and clams,Corbicula fluminea, were exposed for 48 or 50 days to three concentrations of a river sediment that contained environmental contaminants such as polychlorinated biphenyls (PCBs) and metals. Sediment was obtained twice during 1980 from the same location. Prawns were exposed to the first batch, sediment 5–80, which contained higher concentrations of some metals and PCBs compared to sediment 11–80, used with the clams. The highest concentration of sediment 5–80 was toxic to the prawns; sediment 11–80 was not toxic to the clams. Tissue analyses of prawns for PCBs, as Aroclors® 1242 and 1254, demonstrated bioaccumulation. Maximum concentration of 1242 in prawns was achieved by day 7 while 1254 continued to accumulate in prawn tissues during the initial 40 days of the exposure period. The PCB sediment bioaccumulation factors (BAF) for prawns ranged from 0.11 to 0.90 for 1242 and 0.20 to 2.40 for 1254, and were highest for animals exposed to 10% sediment. Exposed clams also accumulated PCBs (1242 + 1254) from the sediment. Sediment BAFs for clams were 0.54 to 12.52 and were highest for animals exposed to 10% sediment. Analyses of clams for metals showed lead (Pb) in exposed animals at higher concentrations compared with controls. Bioaccumulation of Pb differed from PCB in that the Pb concentrations did not increase over time and concentrations were higher among animals exposed to 10% sediment compared to animals exposed to 100% sediment. Sediment 11–80 contained 99 mg/kg of Pb while exposed animals, at 48 days, contained approximately 2.2 mg/kg Pb. Analysis of clams for cadmium (Cd) showed exposed animals contained less Cd than controls.     

Assessment of Metallothioneins in Tissues of the Clam Megapitaria squalida as Biomarkers for Environmental Cadmium Pollution From Areas Enriched in Phosphorite

The aim of this study was to evaluate the use of metallothionein (MT) concentrations in tissues of the clam Megapitaria squalida as biomarkers of environmental cadmium (Cd) pollution from phosphorite enrichments in the marine environment, which resulted from mining activities in La Paz Bay, Baja California Sur, Mexico. Cd and MT were quantified in gills, digestive gland, and kidney of clams exposed to 0.2 or 0.5 mg Cd l⁻¹ for 10, 20, or 30 days. In addition, clams from four strategically selected natural sites of La Paz Bay were collected for analysis. In tissues of bioassayed and untreated clams, the gradient of Cd concentrations was digestive gland >> gills > kidney, whereas that of MT was digestive gland > gills > kidney. Digestive gland of the clams exposed to 0.5 mg Cd l⁻¹ for 30 days showed the highest concentrations of Cd (16.3 ± 3.9 μg Cd g⁻¹). The highest statistically significant MT concentrations were found in digestive gland at 10 days of exposure to Cd. In the untreated clams, one of the highest Cd concentrations, but not MT levels, was found in digestive glands of the organisms collected from the area close to phosphorite mining activities. For environmental monitoring, MT levels in digestive gland can be used as a first approximation of the presence of high levels of divalent metals in the environment. However, in this study, MT levels did not correlate with high Cd levels in clams that had been collected from areas associated with phosphorite enrichment.     

Environmental and toenail metals concentrations in copper mining and non mining communities in Zambia

Copper mining contributes to increased concentrations of metals in the environment, thereby increasing the risk of metals exposure to populations living in and around mining areas. This study investigated environmental and toenail metals concentrations of non-occupational human exposure to metals in 39 copper-mining town residents and 47 non-mining town residents in Zambia. Elevated environmental concentrations were found in samples collected from the mining town residents. Toenail concentrations of cobalt (GM 1.39 mg/kg), copper (GM 132 mg/kg), lead (21.41 mg/kg) selenium (GM 0.38 mg/kg) and zinc (GM 113 mg/kg) were significantly higher in the mining area and these metals have previously been associated with copper mining. Residence in the mining area, drinking water, dust and soil metals concentrations were the most important contributors to toenail metals concentrations. Further work is required to establish the specific pathways of exposure and the health risks of elevated metals concentrations in the copper mining area.     

Evaluation of clams as a food source of iron: Total iron,heme iron,aluminum, and in vitro iron bioavailability in live and processed clams

Clams are listed on prominent healthcare websites as an excellent source of iron (Fe). However, the amount, type and bioavailability of iron in clam products are poorly understood, as is their content of environmental metals such as aluminum (Al). In this study, live Manila and processed clams were assayed for Fe, Al, and heme-iron content. Results were compared to beef. Relative iron bioavailability was assessed by an in vitro digestion/Caco-2 cell method using FeSO₄ as a reference iron source. Inhibitory effects of Al and tea flavonoids on iron bioavailability were also evaluated. Mean iron content expressed as mg/reference amount (RA, 56 g edible portion) ranged from 0.57 in minced clams to 17.2 mg/RA in whole baby clams; Al ranged from 0.29 to 26.4 mg/RA, probably reflecting grit content. Beef contained 3.0 mg Fe and 0.07 mg Al per RA of 85 g. Heme iron was very low in clams (<0.4 mg/RA) relative to beef (2.3 ± 0.2 mg/RA). One serving (56 g) of live or minced clams provided less than one-third as much bioavailable iron as 9.8 mg FeSO₄; whereas one serving of whole baby clams provided the same amount of bioavailable iron as 9.8 mg of FeSO₄. Flavonoids reduced iron solubility and bioavailability; Al reduced only iron bioavailability. We conclude that live and minced clams should not be considered good sources of bioavailable iron, and the high Al content of whole baby clams raises concerns about recommending these clams as an iron source.     

First Evidence of Altered Immune Responses and Resistance to Air Exposure in the Clam <Emphasis Type="Italic">Chamelea gallina</Emphasis> Exposed to Benzo(<Emphasis Type="Italic">a</Emphasis>)pyrene

Effects of benzo(a)pyrene [B(a)P] (at a nominal concentration of 0.5 mg/L) on immune responses of the clam Chamelea gallina were investigated after 1, 7, and 12 days exposure. Total hemocyte count (THC), hemocyte volume, phagocytic activity, lysozyme-like activity in both hemocyte lysate (HL) and cell-free hemolymph (CFH) were measured. As unexpected alterations in hemocyte adhesion capability were observed in short-term hemocyte cultures for phagocytosis assays after a 1-day exposure, an adhesion test (not included in the original experimental setup) was performed after 7 and 12 days of exposure only. The survival-in-air test was carried out to evaluate general stress conditions in B(a)P-exposed clams. No alterations in THC was observed, whereas exposure for 7 and 12 days to B(a)P significantly decreased phagocytic activity and adhesion capability when compared with controls. Significant decreases in lysozyme activity were observed in CFH and HL, with respect to controls. B(a)P was also shown to alter the resistance to air exposure of clams. The LT₅₀ values fell from 9 days in control clams to 7 days in 1-day-exposed animals, and from 6 days in control clams to 5 days in 7-day-exposed bivalves. No significant variations in LT₅₀ values were recorded after 12 days of exposure. Results highlight a relationship between B(a)P exposure and alterations in hemocyte functionality and suggest that the contaminant induced irreversible immunosuppression in C. gallina, by altering phagocytic activity, adhesion capability, and enzymatic activity. Conversely, reduction in resistance to air exposure was reversible, suggesting that impairment of important physiological functions of clams occurred in the first phases of exposure only.     

Acute Toxicity of Nitrate and Nitrite to Sensitive Freshwater Insects,Mollusks, and a Crustacean

Both point- and nonpoint-sources of pollution have contributed to increased inorganic nitrogen concentrations in freshwater ecosystems. Although numerous studies have investigated the toxic effects of ammonia on freshwater species, relatively little work has been performed to characterize the acute toxicity of the other two common inorganic nitrogen species: nitrate and nitrite. In particular, to our knowledge, no published data exist on the toxicity of nitrate and nitrite to North American freshwater bivalves (Mollusca) or stoneflies (Insecta, Plecoptera). We conducted acute (96-h) nitrate and nitrite toxicity tests with two stonefly species (Allocapnia vivipara and Amphinemura delosa), an amphipod (Hyalella azteca), two freshwater unionid mussels (Lampsilis siliquoidea and Megalonaias nervosa), a fingernail clam (Sphaerium simile), and a pond snail (Lymnaea stagnalis). Overall, we did not observe a particularly wide degree of variation in sensitivity to nitrate, with median lethal concentrations ranging from 357 to 937 mg NO₃-N/l; furthermore, no particular taxonomic group appeared to be more sensitive to nitrate than any other. In our nitrite tests, the two stoneflies tested were by far the most sensitive, and the three mollusks tested were the least sensitive. In contrast to what was observed in the nitrate tests, variation among species in sensitivity to nitrite spanned two orders of magnitude. Examination of the updated nitrite database, including previously published data, clearly showed that insects tended to be more sensitive than crustaceans, which were in turn more sensitive than mollusks. Although the toxic mechanism of nitrite is generally thought to be the conversion of oxygen-carrying pigments into forms that cannot carry oxygen, our observed trend in sensitivity of broad taxonomic groups, along with information on respiratory pigments in those groups, suggests that some other yet unknown mechanism may be even more important.     

Assessment of Polycyclic Aromatic Hydrocarbons in <Emphasis Type="Italic">Lates niloticus,Oreochromis niloticus</Emphasis> and <Emphasis Type="Italic">Rastrineobola argentea</Emphasis> as Sources of Human Exposure in Kisumu Bay,Winam Gulf of Lake Victoria

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in Lates niloticus, Oreochromis niloticus and Rastrineobola argentea from three beaches were assessed to establish whether they are sources of human exposure in Kisumu Bay, Winam Gulf, Lake Victoria, Kenya. O. niloticus had 12 PAHs detected (TPAH 3.93 μg/kg); L. niloticus had 11 (TPAH 3.17 μg/kg). In both cases, the highest and lowest concentrations were Pyrene and Indeno(1,2,3-cd)pyrene, respectively, and the TPAHs were greater than the 2 μg/kg limit allowed by the European Commission although individually they were lower. R. argentea had 2 PAHs (TPAH 0.035 μg/kg). PAH pollution in the Winam Gulf, a potential source of exposure to human through contaminated fish, should be mitigated and safe management practices that reduce PAH levels should be adopted.     

Effects of Copper and Cadmium Exposure on Functional Responses of Hemocytes in the Clam, Tapes philippinarum

The effects of Cu and Cd on functional responses of hemocytes in Tapes philippinarum, a Veneridae clam widespread in the lagoon of Venice, were evaluated. Bivalves were exposed for 7 days to various concentrations of CuCl₂· 2H₂O (0, 10, 60, and 110 μg/L) and CdCl₂· H₂O (0, 150, 300, and 450 μg/L). Hemocytes were collected from exposed clams, and the effects of Cu and Cd on phagocytosis, Neutral Red retention capacity, superoxide dismutase, and cytochrome oxidase activities were investigated. Hemocytes from animals exposed to Cu showed a significant decrease in phagocytic activity, whereas no inhibition was observed in cells from Cd-exposed animals. Diffusion of Neutral Red into the cytosol, an index of lysosomal membrane alteration, was enhanced by high concentrations of both metals. Different results in biochemical parameters were observed. Exposure to 60 and 110 μg Cu/L caused a significant reduction in hemocyte superoxide dismutase activity, whereas no changes resulted after Cd exposure. Increased cytochrome oxidase activity was observed in hemocytes from mollusks exposed to 60 μg Cu/L and 300 μg Cd/L; no significant differences were found in cells from bivalves exposed to 110 μg Cu/L and 450 μg Cd/L. These results suggest a relationship between heavy metal exposure and alterations in functional responses of hemocytes in T. philippinarum and indicate that the type of observed effects vary with the nature and concentration of heavy metals. Moreover, the data obtained in the analyzed clam support the possibility of using it as sentinel organism in biomonitoring studies, even if used biomarkers will be further evaluated in field conditions. Received: 6 November 2000/Accepted: 6 March 2001     

Bioaccumulation of selenium (Se) in the Cienega de Santa Clara wetland, Sonora, Mexico

The Cienega de Santa Clara, on the east side of the Colorado River delta, is a brackish wetland supported by agricultural drainage water from the United States that provides habitat for endangered fish and bird species. Bioaccumulation of selenium has created toxicity problems for wildlife in similar wetlands in the United States. This is the first selenium survey in the Cienega de Santa Clara. Ten sites were selected to collect water (dissolved), sediments (total), plants, invertebrates, and fish. Samples were collected from October 1996 to March 1997. Selenium was detected in all samples. Concentrations in water ranged from 5 to 19 microg/L and increased along a salinity gradient. Although water levels of selenium exceeded EPA criterion for protection of wildlife, levels in sediments (0.8-1.8 mg/kg), aquatic plants (0.03-0.17 mg/kg), and fish (2.5-5.1 mg/kg whole body, dry wt) did not exceed USFWS recommended levels. It is concluded from this study that the levels of selenium in water did not affect the overall health of the fish sampled. Therefore, it is important to maintain or improve the water quality entering this wetland to continue to have normal levels of Se in the food chain components.     

Seawater and Shellfish (Geukensia demissa) Quality Along the Western Coast of Assateague Island National Seashore, Maryland: An Area Impacted by Feral Horses and Agricultural Runoff

We evaluated the quality of seawater and ribbed mussels (Gukensia demissa) at six sites along the West Coast of Assateague Island National Seashore (ASIS), a barrier island popular with tourists and fishermen. Parameters evaluated were summertime temperature, pH, salinity, dissolved oxygen, total phosphorus, total ammonia nitrogen, and nitrite levels for seawater and total heterotrophic plate counts and total Vibrionaceae levels for the ribbed mussels. Approximately 150 feral horses (Equus caballus) are located on ASIS and, combined with agricultural runoff from animals and croplands, local wildlife, and anthropogenic inputs, contribute to nutrient loads affecting water and shellfish quality. The average monthly dissolved oxygen for June was 2.65 mg L⁻¹, below the minimum acceptable threshold of 3.0 mg L⁻¹. Along Chincoteague Bay, total phosphorus generally exceeded the maximum level of 0.037 mg L⁻¹, as set by the Maryland Coastal Bays Program management objective for seagrasses, with a high of 1.92 mg L⁻¹ in June, some 50-fold higher than the recommended threshold. Total ammonia nitrogen approached levels harmful to fish, with a maximum recorded value of 0.093 mg L⁻¹. Levels of total heterotrophic bacteria spiked to 9.5 × 10⁶ cells g⁻¹ of mussel tissue in August in Sinepuxent Bay, leading to mussels which exceeded acceptable standards for edible bivalves by 19-fold. An average of 76% of the bacterial isolates were in the Vibrionaceae family. Together, these data suggest poor stewardship of our coastal environment and the need for new intervention strategies to reduce chemical and biological contamination of our marine resources. This study was performed in partial fulfillment of the requirements for a Master’s Degree in Natural Resources in the Agriculture and Natural Resources Graduate Program at Delaware State University. The mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Tissue Concentrations of Pesticides,PCBs and Metals Among Ospreys, <Emphasis Type="Italic">Pandion haliaetus</Emphasis>, Collected in France

In this study, osprey (Pandion haliaetus) tissues collected in France were used for contaminants analyses by a non-invasive approach. 53 pesticides (organochlorine, organophosphate, carbamate, pyrethroids, herbicides, anticoagulant rodenticides), 13 PCBs, and 5 metals (mercury, lead, cadmium, copper and arsenic) were quantified in liver of 14 individual samples. PCBs and mercury were frequent (mean 0.5 mg/kg, range < d.l.−2.6 mg/kg and mean 3.4 mg/kg, range < d.l.−16.3 mg/kg wet weight, respectively). Inter-individual variations in contaminant diversity and amounts were noticed. Immediate conservation of the species in the country does not seem to be threatened by global contamination.     

Analysis of Several Heavy Metals in Wild Edible Mushrooms from Regions of China

The metal (Cu, Ni, Cd, Hg, As, Pb) contents in wild edible mushrooms collected from three different sites in China were determined by atomic absorption spectrometry and atomic fluorescence spectrometry. All element concentrations were determined on a dry weight basis. A total of 11 species was studied, five being from the urban area and six from rural areas in China. The As content ranged from 0.44 to 1.48 mg/kg. The highest As content was seen in Macrolepiota crustosa from the urban area, and the lowest in Russula virescens from rural areas. A high Ni concentration (1.35 mg/kg) was found in Calvatia craniiformis from the urban area. The lowest Ni level was 0.11 mg/kg, for the species R. virescens and Cantharellus cibarius. The Cu content ranged from 39.0 to 181.5 mg/kg. The highest Cu content was seen in Agaricus silvaticus and the lowest in C. cibarius. The Pb content ranged from 1.9 to 10.8 mg/kg. The highest Pb value was found in C. craniiformis. The Cd content ranged from 0.4 to 91.8 mg/kg. The highest Cd value was found in M. crustosa. The Hg content ranged from 0.28 to 3.92 mg/kg. The highest Hg level was found in Agaricus species. The levels of the heavy metals Cd, Pb, and Hg in the studied mushroom species from urban area can be considered high. The metal-to-metal correlation analysis supported they were the same source of contamination. High automobile traffic was identified as the most likely source of the contamination. Based upon the present safety standards, consumption of those mushrooms that grow in the polluted urban area should be avoided.     

Anthropogenic and Authigenic Uranium in Marine Sediments of the Central Gulf of California Adjacent to the Santa Rosalía Mining Region

To investigate the causes of uranium (U) enrichment in marine sediments in the eastern sector of the Gulf of California, surface sediments and sediment cores were collected adjacent to the Santa Rosalía copper mining region in the Baja California peninsula. Three coastal sediment cores were found to display high concentrations of U (from 54.2?±?7.3?mg?kg(-1) to 110?±?13?mg?kg(-1)) exceeding those found in the deeper cores (1.36?±?0.26?mg?kg(-1) in the Guaymas Basin to 9.31?±?3.03?mg?kg(-1) in the SR63 core from the suboxic zone). The contribution of non-lithogenic U (estimated using scandium to normalize) to the total U content in sediments of three coastal cores varied from 97.2?±?0.4?% to 98.82?% versus 49.8?±?3?% (Guaymas Basin) to 84.2?±?8.2?% (SR62 core) in the deeper cores. The U content record in a lead-210 ((210)Pb)-dated core had two peaks (in 1923 and 1967) corresponding to the history of ancient mining and smelting activities in Santa Rosalía.     

A five-year study of needlestick injuries: significant reduction associated with communication, education, and convenient placement of sharps containers.

OBJECTIVE: To decrease the numbers of needlesticks among healthcare workers. DESIGN: All reported needlestick injuries at Santa Clara Valley Medical Center, San Jose, California, were reviewed, analyzed, and tabulated by the infection control department yearly from 1986 to 1990. SETTING: A 588-bed county teaching hospital in San Jose, California, affiliated with Stanford University. PARTICIPANTS: All employees of Santa Clara Valley Medical Center who reported needlestick injuries on injury report forms. INTERVENTIONS: From April to December 1987, more needle disposal containers were added to as many patient care areas and as close to the area of use as possible. Results of 1986, 1988, 1989, and 1990 analyses were communicated yearly to all personnel, extensive educational programs were conducted in 1987 and 1988, and educational efforts continued in 1989 and 1990. RESULTS: In 1986, there were 259 needlestick injuries at our institution, 22% (32) from recapping. After needle disposal containers were added to all patient care areas, needlestick injuries for 1988 totalled 143, a 45% decrease in the total needlestick injuries and a 53% decrease in recapping injuries. Communication of results to all areas of the hospital and educational activities were started in 1987 and continued through the next 3 years. In 1989, there were 135 needlestick injuries, a decrease of 6% from 1988; recapping injuries decreased 40% from 1988. In 1990, there were 104 needlestick injuries, a 23% decrease since 1989, and a 33% decrease in recapping injuries. The total number of needlestick injuries from 1986 to 1990 decreased by 60%, and those injuries from recapping decreased by 81% to 89%. CONCLUSIONS: We have continued to monitor needlestick injuries, communicate findings to all personnel, and include needlestick prevention in educational programs. We contend that more convenient placement of needle disposal containers, communication of findings, and education do decrease needlestick injuries in healthcare workers.     

Organ Distribution and Food Safety Aspects of Cadmium and Lead in Great Scallops, Pecten maximus L., and Horse Mussels, Modiolus modiolus L., from Norwegian Waters

The purpose of the study was to determine the levels and organ distribution of the potentially harmful inorganic elements cadmium and lead in great scallops and horse mussels from unpolluted Norwegian waters. The scallops far exceeded the EU-limit for cadmium in bivalves when all soft tissues were analysed. When only muscle and gonad were included, however, the level of cadmium was acceptable, because cadmium accumulated in the digestive gland with a mean of 52 mg/kg ww (wet weight). In horse mussel, lead was the most problematic element and the concentration varied from 1.4 to 6.6 mg/kg ww with a mean of 3.7 mg/kg ww, exceeding the EU limit of 1.5 mg Pb/kg. The highest concentration of lead was found in the kidney with an average of 120 mg/kg ww and with a maximum value of 240 mg/kg ww. The kidney tissue accounted for approximately 94% of the lead burden in the horse mussel. In order to consume these bivalves, only muscle and gonad of great scallops should be used for consumption and the kidney of horse mussel should be removed prior to consumption.     

Paralytic shellfish poisoning toxin profiles in green mussels from Trinidad and Venezuela

Paralytic shellfish poisoning (PSP) toxins were determined in green mussels (Perna viridis) from the Gulf of Paria between Trinidad and Venezuela, as well as from the northern coast of Venezuela. Aqueous extracts of samples were purified by passage through SPE C-18 and carboxylic columns, and oxidized by periodate and peroxide reagents, before analysis by LC with fluorescence detection. Spike and recovery of mixed toxins from uncontaminated mussel tissues, with % recoveries from 83 to 103, validated the method of analysis. Saxitoxin (STX), gonyautoxins (GTX), their analogs, and C toxins were identified in mussels from both countries. In the Gulf of Paria, PSP toxin profiles in mussels from the north were similar to each other, as were those from the south. However, the toxin profiles and concentrations varied widely among geographic areas, with GTX analogs and C1,2 toxins predominating. The highest total PSP concentrations (468 μg/100 g), as well as the largest number of individual toxins identified (7 of 8), were found at Playa Patilla on the northern coast of Venezuela, followed by Chaguaramas (244 μg/100 g; 6 of 8) and Güiria (154 μg/100 g; 5 of 8) in the northern Gulf of Paria in Trinidad. While the calculated STX equivalents in each sample were below the maximum permissible level (80 μg/100 g) permitted by Venezuela and other countries, its very detection prohibits their consumption in Trinidad under existing legislation.