Sewage Sludge Disposal Site Research Articles

Methodology of the geoecological functional zoning of territories subjected to anthropogenic disturbance due to waste disposal

In the present contribution, the geochemical relationships of territorial units (landscapes), namely sewage sludge disposal sites and historical municipal solid waste landfills, that can be considered as chemical elements migration models and as dynamic components of ecological-geological systems (landfill site adjacent area recreation area)., is described. Since the study of pollutants migration in multicomponent systems is extremely time-consuming, the development of theoretical methods, able to simulate these processes, is of particular relevance. Therefore, in the present study, a geochemical model for substance migration in anthropogenically modified geoecological bodies and their surrounding was conceived, making use of complex mathematical processes and data analysis methodologies (parallel use of factor, cluster, canonical and discriminant analysis tools), and considering both geochemical specialization/composition of parent rocks and land use (functional geoecological zoning).

Seafloor ecological functioning over two decades of organic enrichment

Climate change and anthropogenic nutrient enrichment are driving rapid increases in ocean deoxygenation. These changes cause biodiversity loss and have severe consequences for marine ecosystem functioning and in turn the delivery of ecosystem services upon which humanity depends (e.g. fisheries). We seek to understand how such changes will impact seafloor functioning using biological traits analysis. Results from a sewage-sludge disposal site in the Firth of Clyde, UK spanning 26 years of monitoring showed that substantial changes in macrobenthic nutrient cycling and the provision of food for predators occurred, with elevated functioning on the margins 1–2 km from the centre of the disposal grounds. Thus, changes in food-web dynamics are expected, that weaken benthic pelagic coupling and lower secondary production (such as fisheries). Generally, functioning was conserved, but declined below a ~6% total organic carbon threshold. Similar to other severely deoxygenated systems, the recovery was slow and hysteresis was apparent.

GROWTH PERFORMANCE, BIOMASS AND PHYTOEXTRACTION EFFICIENCY OF <i>ACACIA MANGIUM</i> AND <i>MELALEUCA CAJUPUTI</i> IN REMEDIATING HEAVY METAL CONTAMINATED SOIL

Heavy metals are very toxic and soil contaminated with sewage sludge urgently need remediation in order to avoid related health hazards. Phytoremediation is a low cost and reliable technique to remediate heavy metal contamination. However phytoremediation using timber species was rarely reported and its efficiency was questionable. A field study was conducted to examine the efficiency of two timber species namely Acacia mangium and Melaleuca cajuputi in phytoextraction of Zn, Cu and Cd from contaminated soil. Two hundred of A. mangium and M. cajuputi were planted on sewage sludge disposal site and the growth was recorded for 12 months before at the end total biomass of each species was determined. Results show in 12 months, about 72 and 4 t ha-1 of aboveground biomass can be produced by A. mangium and M. cajuputi, respectively. Both species show potential for phytoremediation, however A. mangium is more efficient compared to M. cajuputi where efficiency of A. mangium to remove Zn was 24.4, 6.2 for Cu and 9.5% for Cd. As for M. cajuputi the efficiency was 1.3, 0.3 and 0.14% for Zn, Cu and Cd, respectively. It is projected that A. mangium require 5, 17 and 20 years to remove 79.82 kg ha-1 of Zn, 46.94 kg ha-1 of Cu and 2.33 kg ha-1 of Cd, respectively.

Mercury Speciation and Total Organic Carbon in Marine Sediments Along the Mediterranean Coast of Israel

Along the Israeli Mediterranean Coast, three areas are considered "hot spots" of mercury (Hg) pollution: (1) Northern Haifa Bay (NHB), (2) the lower Qishon River at the southern part of Haifa Bay, and (3) a marine outfall of activated sewage sludge at the southern coast off Palmachim (sewage-sludge disposal site [SDS]). Even though the total Hg (HgT) concentrations in the sediments at the three areas are of the same order of magnitude (250-500 μg kg(-1)), Hg was shown to bioaccumulate in fish and benthic fauna from Haifa Bay but not in benthic fauna or in commercial fish caught along the southern Mediterranean Coast of Israel near the SDS outfall. The primary goal of this study was to measure the concentrations of Hg species (HgT, methyl-Hg [MeHg], and Hg in different biogeochemical fractions)-in conjunction with organic carbon-in sediments of NHB and the lower Qishon River to assess its impact on Hg transitions among the species as characterized by different bioavailability and bioaccessibility. HgT concentrations in NHB and the Qishon River ranged from 249 to 347 and 165 to 667 μg kg(-1), respectively. MeHg was significantly higher in the Qishon River (6.3-34.0 μg kg(-1)) than in NHB (0.22-0.70 μg kg(-1)) as were total organic carbon (TOC) concentrations (average 2.5 vs. 0.13 %). The relative Hg distribution in the biogeochemical fractions in NHB was 2.3 % in the most bioaccessible fractions (F1 + F2), 55 % in the organo-chelated species fraction (F3), 42 % in the strong-complexed species fraction (F4), and 0.7 % in the mercuric-sulfide fraction (F5). In the Qishon River, the bioavailable F1 + F2 and F3 fractions were lower than in NHB (<0.01 and 23 %, respectively) and the more refractory F4 and F5 fractions higher (73 and 3.3 %, respectively). The fractionation of Hg in Qishon River sediments was similar to the distribution found in polluted stations at the SDS. TOC and MeHg were positively and negatively correlated, respectively, in Qishon River and NHB sediments. Methylation depended on TOC availability when its concentration was in the range of 2-4 wt%. It is possible that TOC in the sediment controlled Hg speciation: Hg in F3 decreased and in F4 increased with increasing TOC concentrations. In contrast, MeHg/HgT was significantly positively correlated with TOC and Hg in the stable F4 fraction and negatively correlated with Hg in the F3 fraction. It was therefore assumed that higher TOC concentrations enhanced microbial activity and decomposition of organic matter. Hg was released from the F3 fraction and was either transferred to the F4 fraction or made available for methylation processes.

Butyltin occurrence and risk assessment in the sediments of the Iberian Peninsula

The occurrence of butyltin (BT) compounds in more than 50 recent sediment samples of the Iberian Peninsula, collected in the harbours of the western Mediterranean Sea (Spain) and the North Atlantic Ocean (Portugal), including domestic and industrial sewage disposal sites, has been assessed. The highest levels of tributyltin (TBT) (7673 μg kg −1 dry wt.) were detected in commercial harbours associated with inputs from large vessels. However, relatively high TBT values (about 2150 μg kg −1 dry wt.) were also detected in fishing and recreational boating areas. Spanish marinas and harbours are more polluted in terms of TBT (5–7673 μg kg −1 dry wt.) compared to those in Portugal (4–12 μg kg −1 dry wt.). Generally, the Mediterranean sediments show a BT distribution characterized by the predominance of TBT over the degradation products dibutyl (DBT) and monobutyltin (MBT), indicating the presence of recent inputs, in contrast to the Portuguese coastal distribution. Calculation of butyltin degradation indexes (BDI) confirmed a different trend, depending on the area. Furthermore, a comparative study of the occurrence of BT in different sewage sludge disposal sites shows that domestic primary sewage sludge effluents can contribute to coastal BT pollution, but to a lesser extent when compared with harbours. Historical trends (1995–2003) for Barcelona harbour reveal that BT regulations on the use of TBT-based antifouling paints have not been fully effective. Finally, a comparison against the existing sediment quality guidelines (SQGs) indicated that acute toxic effects could only be expected for TBT in some Mediterranean harbours; conversely, in every North Atlantic Ocean station, a lesser environmental threat for the harbour benthic community is expected.

&lt;i&gt;Short communication&lt;/i&gt; Increase in metal extractability after liming of sacrificial sewage sludge disposal soils

A sandy and a sandy clay-loam soil from two dedicated (sacrificial) sewage sludge disposal sites were incubated with a total lime equivalent of 45 Mg·ha-1. Both these soils were acidified (pH 4.0 to 4.2) and had a significant accumulation of organic material (organic C of 2.9 to 3.7 %) compared to non-polluted soils (organic C of 0.6 to 1.0 %). The limed soils did not attain the desired pH of 6.5 after 6 months\' incubation due to a high buffer capacity. After incubation, soil samples were taken from the incubated pots and the levels of Al, Fe, Mn, Cu, Zn, Pb and Cd were determined by atomic absorption spectrophotometry (AAS) after extraction with NH4-EDTA and BaCl2. Most of the metals extracted with BaCl2 (except Mn in the sandy soil and Cd in both soils) decreased after liming. The EDTA-extractable Mn, Fe, and Cd in both soils and Cu and Pb in the sandy clayloam soil increased after liming, whereas Al and Zn, decreased in extractability (Statistically significant differences could not be determined for the trial due to the trial not having been designed for the results that were obtained). Similar results were reported in the literature for EDTA metal extraction but the phenomenon was not elaborated upon, except for Cr. The increased extractability of some of the metals after liming could negatively influence the use of EDTA as an extracting agent in proposed heavy-metal guidelines for similar sacrificial soils. Should liming be considered as a strategy to decrease metal mobility in sacrificial soils, the observed increase in extractability becomes a cause for concern and should receive attention in further research. Water SA Vol. 31 (2) 2005: pp.271-274

Modelling of Cd, Cu, Ni, Pb and Zn uptake, by winter wheat and forage maize, from a sewage disposal farm

Abstract. A predictive model of metal concentrations in crops was developed to optimize soil liming and sludge application strategies at a dedicated sewage sludge disposal site. Predictions of metal concentrations in plant tissue were derived from measured values of soil metal concentration, humus content and soil pH. The plant and soil data used to parameterize the model were collected on site using quadrat sampling of mature crop and underlying topsoil. The uptake model was used to map predicted metal concentrations in wheat grain and forage maize based upon a database of soil characteristics (metal content, % humus and pH) measured as part of a routine geochemical survey of the site. The effect of a management strategy to modify uptake of Cd by wheat by changing soil pH was investigated. The effect of soil dust adhering to maize plants at harvest was also simulated to investigate the importance of this pathway for Cd transfer to animal feed such as silage.The model gave satisfactory predictions for uptake of Cd and Zn but less useful simulations for Pb, Cu and Ni. The results for Cd uptake showed a greater dependence on soil pH in the case of wheat in comparison to maize. It is suggested that, for the study site, liming to pH 7.0 will reduce Cd concentrations in wheat grain to within EC legal standards. However the Cd content of maize may still exceed these guidelines, with a relatively minor contribution from contamination with soil dust.

Organotin contamination in sediments from the Western Mediterranean enclosures following 10 years of TBT regulation

Organotin (OT) compounds, namely butyl and phenyl, were measured in 38 recent sediments collected in harbours of the Western Mediterranean Sea (Northern: 4 and Southern: 9) and domestic and industrial sewage disposal sites (Northern: 9 and Southern: 1). Butyltins were the predominant tin species identified as being tributyltin (TBT) widespread in the whole area which suggests recent inputs of OTs. The highest levels of TBT were detected in commercial harbours associated with inputs from large vessels (average value: 5.0 μg TBT g −1). Moreover, relatively high TBT values were also detected in fishing and recreational boating areas (average level ca. 1.0 μg TBT g −1). Phenyltin derivatives occurred at lower levels than butyltins being the monophenyltin the predominant compound (average values 45–945 ng g −1). The large predominance of the phenyltin degradation products (i.e. mono and diphenyltin) over the parent compound (i.e. triphenyltin) suggests that there are almost no recent inputs of these compounds. Furthermore, a comparative study of the OT occurrence in the sewage sludge disposal sites offshore Barcelona and Almerı́a (domestic) and into the Tarragona harbour (industrial) shows that domestic primary sewage sludge effluents can contribute to coastal OT pollution (244 ng TBT g −1). Nevertheless, sewage sludge is a secondary source of OT contamination in the coastal environment in comparison to commercial harbours. In a comparative study with previous data collected in the late 1980s, the present study reveals that OT regulations established in the Mediterranean region in 1991 on the use of TBT-based antifouling paints have been effective in marinas, but reveals a significant TBT contamination in commercial and fishing harbours.

Evaluation of dioxin contamination in sewage sludge discharges on coastal sediments from catalonia, spain

The fate of polychlorinated dibenzo- p-dioxins (PCDDs) and dibenzofurans (PCDFs) in sewage sludges after discharge into the sea was investigated. Sediment samples were analysed at a sewage sludge disposal site as well as in the surrounding areas. Moreover, eight sediment samples from two rivers in Catalonia and three sediment samples from Catalonian Coast were analysed to determine the background levels of contamination. Total international toxicity equivalent (I-TEQ) values for these sediments ranged from 0.42 to 8.01 pg/g, with a mean value of 4.15 pg/g and a median value of 3.69 pg/g. However, the I-TEQ values of sludge-treated areas were higher: 57.04 pg/g at the dumping site, and within a range of 13.42–47.76 pg/g near this site. Thus, European sediment quality objectives were exceeded. The higher concentrations coincided with changes in the ratio between PCDD and PCDF levels, suggesting the influence of the sewage sludge on coastal sediments.

Comparison of Nine Native Grasses Grown on Sludge Applied Soil

The use of grasses native to New Mexico are preferred for revegetating Albuquerque's sewage sludge disposal site. A greenhouse study was conducted to determine the most appropriate grass species that could be used in revegetation. Nine grasses grown in soil collected at Albuquerque's sludge disposal site were compared based on germination measurements, including plant height and density. Final shoot and root weights also were taken for comparison. Plant tissue was analyzed for the accumulation of metals and salts. With 200 ml of water applied weekly, plant height was greatest in spike dropseed (Sporobolus contractus A. S. Hitchc.) at 33.86 cm; plant density was greatest in alkali sacaton (Sporobolus airoides Torr.). Results indicate the grasses that have the best potential for use in revegetation are blue grama [Bouteloua gracilis (H.B.K.) Lag. ex Griffiths], sideoats grama [Bouteloua curtipendula (Michx.) Torr.], and alkali sacaton.

Accumulation and persistence of chlorobiphenyls, organochlorine pesticides and faecal sterols at the Garroch Head sewage sludge disposal site, Firth of Clyde

The sediment concentrations of organic carbon, faecal sterols, individual chlorobiphenyl congeners and organochlorine pesticides have been measured in seabed cores from the sewage sludge disposal area at Garroch Head in the Firth of Clyde. The measurements confirm the accumulative nature of the site with high levels of sedimentary faecal sterols (152 mg kg −1 coprostanol). Levels of chlorobiphenyls, DDT compounds and dieldrin in surface sediment were elevated by factors of 12, 40 and 120, respectively, over those observed at a site remote from the effects of dumping. Total chlorobiphenyl levels of 515 μg kg −1 Arochlor 1254 in surface sediment were comparable to levels found in other areas heavily contaminated with sewage sludge. The 20-cm depth of heavily sludge-contaminated sediment overlays a mixed sludge/basal sediment layer some 10 cm in depth. Levels of organochlorine contaminants were elevated to depths of 90 cm in the sediment, suggesting that the surface layer is a source of contaminants to the deeper sediment. Within the upper 15–20 cm sediment in the disposal area, chlorobiphenyls are conservative, the variation in their concentration with respect to depth being related to historical input. Lindane and possibly dieldrin, and hexachlorobenzene are not conservative. Faecal sterols are removed in sub-surface sediment, in contrast to conservative behaviour previously found at other sewage polluted sites.

Sampling strategy to detect a change in concentration of trace organic contaminants in marine sediment

The ability to detect changes in the environmental level of contaminants depends on the variances associated with the measurements. The sources of variance contributing to the determination of chlorobiphenyls and organochlorine pesticides in sediment from the Garroch Head sewage sludge disposal site have been examined. The total variance is considered to be the sum of a ‘field variance’ associated with this site, and long-term analytical variance. The mean short-term coefficient of variance (CV) for analysis of seven chlorobiphenyls (CBs) and five pesticides was 10.4% and 14.4%, respectively. Long-term analytical variance was higher at 21% and 42% for CBs and pesticides. The field variance at the Garroch Head site was estimated from this data and analytical data from five replicate sediment cores by ANOVA. Field variance was 32.7% for CBs and 28.4% for pesticides. Using these estimates for variance components contributing to the overall variance of the measurements, the effect of varying sampling and analytical procedures on measurement precision and cost factors has been examined. Field variance generally dominates the overall measurement variance, such that improvement of the long-term analytical variance below 20–30% is of little benefit. Single or duplicate analysis and sample pooling are generally the most cost effective strategy.

Near-Bottom Pelagic Bacteria at a Deep-Water Sewage Sludge Disposal Site

The epibenthic bacterial community at deep-ocean sewage sludge disposal site DWD-106, located approximately 106 miles (ca. 196 km) off the coast of New Jersey, was assessed for changes associated with the introduction of large amounts of sewage sludge. Mixed cultures and bacterial isolates obtained from water overlying sediment core samples collected at the deep-water (2,500 m) municipal sewage disposal site were tested for the ability to grow under in situ conditions of temperature and pressure. The responses of cultures collected at a DWD-106 station heavily impacted by sewage sludge were compared with those of samples collected from a station at the same depth which was not contaminated by sewage sludge. Significant differences were observed in the ability of mixed bacterial cultures and isolates from the two sites to grow under deep-sea pressure and temperature conditions. The levels of sludge contamination were established by enumerating Clostridium perfringens, a sewage indicator bacterium, in sediment samples from the two sites. The results of hybridization experiments in which DNAs extracted directly from the water overlying sediment core samples were used indicate that the reference site epibenthic community, the disposal site epibenthic community, and the community in a surface sludge plume share many members. Decreased culturability of reference site mixed cultures in the presence of sewage sludge was observed. Thus, the culturable portions of both the autochthonous and allochthonous bacterial communities at the disposal site may be inhibited in situ, the former by sewage sludge and the latter by high pressure and low temperature.

Toxicity of sewage sludge toCrangon crangonandArtemia salina,with reference to other marine Crustacea

The toxicity of sewage sludge to adult and larval Sand shrimp, Crangon crangon, and larval brine shrimp Artemia salina, was studied. Temporal changes in toxicity, ammonia and pH of sewage sludge in seawater were determined. The feasibility of sediment choice bioassays using adult Crangon were examined. The 24 h LC50 of sewage sludge at 20 °C was 0.4% sludge for Crangon larvae, and 10.0% for Artemia larvae. Toxicity to Crangon larvae decreased with decreasing ammonia and increasing pH as sludge decayed over 7 days. In adult Crangon, a dose response with greater variation at < 3% sewage sludge (wet volume in seawater) was found. For adult Crangon at 10 °C, the LT50 at 1% sludge was 80-90 h and 96 h LC50 0.8-1.7% sludge. No clear differences were apparent between 96 h LC5O's in static and 24 h renewal tests. Adult Crangon avoided sediments mixed to concentrations of 6.25% and 10% sewage sludge, but buried at similar frequencies in uncontaminated and 1.57% sludge sediments. In addition to possible chemical effects from ammonia and other sewage sludge components (e.g. metals, organochlorines, hydrocarbons), sludge solids may have physical effects on Crustacea. Bioaccumulation is possible if persistent contaminants occur in the sludge. From estimated field concentrations of sewage sludge, and the results of this and other toxicity studies, lethal effects at sewage sludge disposal sites are believed unlikely. However, further sediment studies (longer-term, life-cycle, bioaccumulation, and mesocosm) are required to evaluate the role of sediment tests in understanding the effects of sewage sludge on benthic Crustacea.

Relationships amongst organic matter content, heavy metal concentrations, earthworm activity, and soil microfabric on a sewage sludge disposal site

From 1973 to 1980, sewage sludge precipitated by three chemical treatment processes (aluminum sulphate, ferric chloride and calcium hydroxide) was applied to replicated plots on a silt loam soil at four different rates. The sludge was contaminated by heavy metals associated with industrial activity in the metropolitan areas from where it was collected. The grass on the plots has been mown regularly from 1973 onwards. Soil and earthworm populations were subjected to analysis in 1989 and 1990. Soil pits were dug and sampled to a depth of 50 cm in four plots receiving the highest rates of the three different types of sewage treatment processes (and a control plot treated through the same period with ammonium nitrate) to determine heavy metal contents and soil organic matter distributions with depth. The earthworm fauna of the plots was almost entirely represented by populations of Lumbricus terrestris L. that were analyzed for abundance and biomass following collection using the formalin expulsion method. Earthworm biomass was higher in sludge treatments than in control plots. Cadmium concentrations in earthworm tissues were correlated with soil Cd concentrations Only worms from Al-sludge treatments had elevated tissue concentrations of Cd. Cadmium distributions in sludgetreated soils were correlated with organic matter distributions in the soil profile (for individual profiles). Intact blocks of soil were removed from soil pits for chemical analysis of the soil microfabric by PIXE (proton induced X-ray emission) and electron micro-probe (EMP). Concentrations of several trace metals on the inner walls of the earthworm channels correlated with those added to the soil via the sludge. Water flow through earthworm burrows lined with fecal material, which had higher metal concentrations than the adjacent soil matrix, could move soluble forms of the elements, thus accelerating leaching of metals into the aquifer from surface-applied sludge.

Benthic Distribution of Sewage Sludge Indicated by Clostridium perfringens at a Deep-Ocean Dump Site

Clostridium perfringens in sediment samples collected at the Deep Water Municipal Sewage Sludge Disposal Site (also called the 106-Mile Site), off the coast of New Jersey, was enumerated. The counts of C. perfringens found in sediment samples collected within and to the southwest of the 106-Mile Site were significantly elevated (P < 0.01) compared with counts of samples from reference stations of similar depth (2,400 to 2,700 m), topography, and distance from the continental shelf, indicating that the benthic environment was contaminated by sewage dumping at this site. Low counts of C. perfringens in sediment samples collected at stations between the base of the continental shelf and the 106-Mile Site indicated that coastal runoff was not a significant source of contamination. Elevated counts were observed for samples up to 92 km to the southwest, whereas low counts were obtained for samples from stations to the east of the 106-Mile Site. This distribution is consistent with previous model predictions of sludge deposition. In areas heavily impacted by sludge dumping, C. perfringens counts were generally highest in the top 1 cm of sediment and exceeded 9,000 CFU g (dry weight) of sediment. The patterns of C. perfringens dispersal observed in this study have proved useful for selection of heavily impacted areas and control stations for further ecological evaluation by a multidisciplinary research team.

Retention of trace metal contaminants in the sediment at an accumulating sewage sludge disposal site

Since 1974 sewage sludge has been dumped in the Firth of Clyde at a position 6 km south of Garroch Head point on the Isle of Bute. The water currents in this area allow sludge solids to settle on the sea bed, resulting in the accumulation of trace metal contaminants in the sediments at the disposal site. The present study was carried out to investigate the degree to which the dumped metal contaminants are retained within the sediments. The quantity of trace metals in the sludge dumped at the site since 1974, calculated from historical records, was compared with the quantity of trace metal in the sediment which could be ascribed to the sludge disposal. This comparative study showed that 36–38% of the copper and mercury and 18–20% of the cadmium, lead and zinc from the sludge could be accounted for by elevations in trace metal concentrations in the sediments. The sensitivity of these estimates to uncertainties in the values of the various parameters of the calculations are discussed.

Estimates of the seafloor area impacted by sewage sludge dumped at the 106-mile site in the mid-atlantic bight

Approximately 8 × 10 6 wet tons of sewage sludge is dumped annually at the 106-Mile Deep Water Municipal Sewage Sludge Disposal Site, 185 km off the New Jersey coast (Sano, 1989). A simple particle-tracking model is used to estimate the areas of sludge deposition using current meter observations made as part of the Mid-Atlantic Slope and Rise (MASAR) Study (Brown et al., 1987) and Lavelle et al.'s (1988) settling velocity distribution for sewage sludge. Model results indicate that sewage particles settle primarily to the southwest of the dump site due to the mean southwesterly flow throughout the water column. Only the coarser fraction (particles with settling velocities greater than 0·04 cm s −1), about 23% of the sludge discharged, is predicted to settle on the seafloor within 350 km of the site. The model predicts a maximum flux in the southwestern quarter of the site of 60 mg m −2 day −1 which decreases to about 25 and 1 mg m −2 day −1 at distances of approximately 50 and 350 km to the southwest, respectively. Little material is predicted to reach the shelf and the finer particles are assumed to be widely dispersed in the water column. These estimated fluxes compare with a natural particle flux of 100–150 mg m −2 day −1 as measured by sediment traps to the north of the 106-mile site (Biscaye et al., 1988). Field studies to assess the effects of sludge dumping on benthic organisms should initially focus on the region 0–50 km southwestward of the site.

The Monitoring of UK Sewage Sludge Disposal Sites

Abstract In recent years there has been an increase in the intensity and frequency of environmental monitoring surveys at UK sewage sludge disposal sites. These have been carried out by the regulatory authorities and by the licensees. in order to ensure maximum efficiency, a coordinated and harmonised programme of monitoring has been developed. the programme concentrates on sediment chemical and biological quality but also includes assessments of water and fish quality In England and Wales the Ministry of Agriculture, Fisheries and Food is the regulatory authority and the Water Authorities are the licensees. the Ministry's first priority is the collection of samples for temporal trend analysis but in addition, infrequent surveys are made to check the status of the disposal site and surrounding areas. in the periods between status surveys, regular spatial surveys designed to define the area of impact are carried out by the Water Authorities.

Human pathogenic viruses at sewage sludge disposal sites in the Middle Atlantic region.

Human enteric viruses were detected in samples of water, crabs, and bottom sediments obtained from two sewage sludge disposal sites in the Atlantic Ocean. Viruses were isolated from sediments 17 months after the cessation of sludge dumping. These findings indicate that, under natural conditions, viruses can survive for a long period of time in the marine environment and that they may present potential public health problems to humans using these resources for food and recreation. The isolation of viruses in the absence of fecal indicator bacteria reinforces previous observations on the inadequacy of these bacteria for predicting the virological quality of water and shellfish.