APHA Method Research Articles

Phytoplankton Community of Elechi Creek, Niger Delta, Nigeria-A Nutrient-Polluted Tropical Creek

Problem statement: Elechi Creek of the Upper Bonny Estuary in the Niger Delta contributes to the Rivers State Fish resources. It is a sink receiving organic anthropogenic wastes from Diobu, Eagle Island and waterfront dwellers of Diobu areas. Fishing, car washing, bathing, swimming and other human activities are constantly going on within and around this creek. Based on these activities, there is urgent need to study the phytoplankton community that supports its fisheries. Approach: The study investigated the phytoplankton composition, diversity, abundance and distribution as well as surface water physico-chemical parameters. Phytoplankton and surface water samples were collected bi-monthly from October 2007-March 2008 at high tide from five stations according to APHA methods. These were analyzed for temperature, transparency, dissolved oxygen, salinity, alkalinity, chloride and nutrients. Phytoplankton was identified microscopically. Species diversity was calculated using standard indices. Results: A total of 169 species of phytoplankton, based on cell counts, was dominated by diatoms, 33255 counts mL-1 (36%) and blue-green algae, 32909 counts mL-1 (35.7%) were identified. The abundance of phytoplankton decreased downstream of this creek (1>2>3>4) except in station 5 with the highest phytoplankton abundance (23938 counts mL-1). There was slight fluctuation in the measured physico-chemical parameters. The results of this study indicated the characteristic species and distribution of phytoplankton in Elechi Creek during the dry months. Conclusion/Recommendation: The high level of phosphate above the permissive limit showed that this creek is hypereutrophic and organic polluted. The high nutrients status favors the high abundance of phytoplankton. The municipal effluents (especially raw human and animal faces) discharges must be discontinued. Detergents with low concentration of phosphate are recommended for manufacturing and use. Municipal wastes must be treated and/or recycled before discharge into this natural aquatic body. Therefore, a continuous environmental surveillance of this creek is advocated to keep its biological integrity.

Toxicity Assessment of some Crude Oil Contaminated Soils in the Niger Delta

This paper considered the toxicity assessment of some crude oil contaminated soils in Niger Delta areas. The soil samples were collected from different horizontal distances, vertical depths and contaminated soil of different ages. The heavy metals in the contaminated soils were digested and extracted using di-acid digested and DTPA extraction methods respectively. The physiochemical parameters (moisture content, pH, N, P and heavy metals (Ni, Pb and Cd) were analysed with APHA method. The heavy metals concentration was determined using atomic absorption spectrophotometer (AAS). The results show that the metals concentration decreased with the age of the contaminated soil and with increased vertical depths. However, the metals concentrations were almost constant at different horizontal distances. Similar trend was observed for the moisture content, pH, N, P and K.

Lead dustfall from demolition of scattered site family housing: Developing a sampling methodology

Background Over 3000 older homes containing lead-based paint are demolished in Chicago each year. While previous studies investigating large multifamily housing demolitions have shown high levels of lead in dustfall, dispersed single-family housing demolition have yet to be assessed. Presently, no standards exist to regulate the extent of lead dustfall from housing demolition. Objectives We studied ten residences in Chicago undergoing demolition and debris removal and compared dustfall rates to five standing homes from March to October 2006. Methods Dustfall was measured using a modification of APHA Method 502; samplers consisted of plastic buckets filled with 1 l of deionized water, elevated to breathing zone height and placed around the demolition site perimeter. Laboratory analysis consisted of filtration, acid digestion and analysis by ICP/MS. Results During demolition, the geometric mean lead dustfall ( n=43 at 10 locations) was 64.1 μg Pb/m 2/h (range: 1.3–3902.5), while the geometric mean lead dustfall for areas with no demolition ( n=18 at 6 locations) was 12.9 μg Pb/m 2/h (range: 1.8–54.5). This difference was highly statistically significant ( p=0.0004). When dust suppression measures were used, dustfall lead levels were lower, although the difference was not statistically significant. The geometric mean lead dustfall with dust suppression ( n=25 at five locations) and without ( n=22 at six locations) was 48 Pb μg/m 2/h and 74.6 μg Pb/m 2/h, respectively. Conclusion Demolition dustfall lead levels are much higher than background levels of lead during demolition of single-family housing and may constitute a yet uncharacterized but important source of lead exposure to nearby residents. Simple dust suppression methods are likely to reduce the contamination considerably.

A hydrochemical profile for assessing the groundwater quality of Jaipur City

A study was conducted to evaluate the water quality of Jaipur City. Groundwater samples from hand pumps and tube wells of eleven sampling stations were analyzed during monsoon session with the help of standard methods of APHA. The analytical results shows higher concentration of total dissolved solids, electrical conductivity, total hardness and nitrate, which indicate signs of deterioration but values of pH, calcium, magnesium, sulphate and fluoride are within permissible limit as per WHO standards. From the Hill-Piper trilinear diagram, it is observed that the majority of ground water from sampling stations are calcium-magnesium-chloride-sulphate type water. The values of sodium absorption ratio and electrical conductivity of the ground water were plotted in the US salinity laboratory diagram for irrigation water. Most of the samples fall in C3S1 quality with high salinity hazard and low sodium hazard. Chemical analysis of groundwater shows that mean concentration of cation (in meq/l) is in order magnesium > sodium > calcium > potassium while for the anion (in meq/l) it is chloride > bicarbonate > sulphate > nitrate > carbonate > fluoride.

Antibacterial behavior of silver-modified clinoptilolite–heulandite rich tuff on coliform microorganisms from wastewater in a column system

The water disinfecting behavior of silver-modified clinoptilolite–heulandite rich tuff (ZSAg) as an antibacterial agent against coliform microorganisms from water in a continuous mode was investigated. Silver recovery from the disinfected effluents by the sodium-modified clinoptilolite–heulandite rich tuff (ZSNa) was also considered. Escherichia coli (ATCC 8739) and total coliform microorganisms, as indicators of microbiological contamination of water, were chosen to achieve the disinfection of synthetic wastewater or municipal wastewater. Ammonium (NH 4 +) and chloride (Cl −) ions were added to the synthetic wastewater as an interfering chemical species on the disinfection processes. The antibacterial activity of the ZSAg as a bactericide was measured by the coliform concentration as evaluated by the APHA method. The amount of silver in the disinfected effluents was determined using atomic absorption spectroscopy. The inactivation of the ZSAg was calculated from the breakthrough curves based on the model reported by Gupta et al. It was found that when the silver concentration in the effluent is less than 0.6 μg/mL, the bacterial survival percentage increased and the volume of disinfected water diminished. The total silver amounts found in the effluent at the end of the disinfection processes varied depending on the water treated (synthetic or municipal wastewater). The presence of NH 4 + ions in synthetic wastewater influent notably improved the disinfected water volume (zero NVC/100 mL), in comparison to the disinfection of the same influent without NH 4 + ions. A contrary water disinfection behavior was observed in the presence of Cl − ions. The silver recovery does not depend on the mass of the sodium zeolitic bed according with the wastewater to be treated (synthetic or municipal wastewater) and the presence of NH 4 + or Cl − ions in the influent also influenced the silver recovery from wastewater. The ZSNa did not have antibacterial activity. Therefore the amount of bactericide agent (silver-modified natural zeolite), coliform microorganisms from water ( E. coli or consort of coliform microorganisms) as well as the water quality (synthetic wastewater or municipal wastewater) influenced both the disinfection process and the silver recovery in a column system.

Uncertainty of Analytical Determinations

Two examples of uncertainty calculation are described for determination of nitrates in solution (APHA method 4500B) and total suspended solids in water (APHA method 2540D).

Photodissociation/gas-diffusion separation and fluorimetric detection for the analysis of total and labile cyanide in a flow system

Total cyanide species are determined in a flow injection system which includes UV-photodissociation, gas-diffusion separation and spectrofluorimetric detection. Without the irradiation step, only cyanide easily released in acid medium, i.e. labile cyanide, is determined. Cyanide diffuses through a microporous PTFE membrane from an acid donor stream to a sodium hydroxide acceptor stream. Then, the transferred cyanide reacts with ¶o-phthalaldehyde and glycine to form a highly fluorescent isoindole derivative. Complete cyanide recoveries were obtained for the most important metal cyanide complexes found in environmental samples, excepting cobaltocyanide. The sampling frequency for total cyanide was 4 samples h–1 and the detection limit was 0.4 μg L–1. Recoveries of total cyanide from river water obtained with this method are about 90% of those obtained with APHA Method 4500-CN C for total cyanide.

BOD sensors using multi-species living or thermally killed cells of a BODSEED microbial culture

A biochemical oxygen demand (BOD) biosensor installed with a biofilm containing immobilized thermally killed cells of a BODSEED (Cole-Palmer E-05466-00) microbial culture gave BOD sensing sensitivity comparable with that of a biosensor using the same population of the immobilized living cells of the same culture. The thermally killed cell sensor showed better response and storage stability but slightly longer response and recovery times than the living cell sensor. Both the living and thermally killed cell sensors generally underestimated the BOD 5 of wastewater differing by about −21–28.4% from the values obtained by the conventional APHA method of 5-day BOD measurement using the same BODSEED for seeding. The poor response of both the BOD biosensors to dairy wastewater and industrial organic waste and zero response to lactose compared with the conventional APHA method of 5-day BOD measurement could be attributed to the mass transfer resistance of the membranes in the sensor but more significantly to the slow assimilation and bio-oxidation rates of these components by the BODSEED microbial system. Unlike the living cell BOD sensor which requires periodic additions of nutrients and minerals to keep the microorganisms alive and viable, the thermally killed cell BOD sensor can be stored in phosphate buffer at room temperature over long idling period without such periodic additions. More significantly with respect to commercialization of these biosensors, the thermally killed cells can be prepared in bulk and stored in dry sealed container over long period.

Influence de la reminéralisation sur l'évolution de la biodégradabilité de la matière organique naturelle au cours de l'ozonation

Tests were carried out in order to show the effects of recarbonation on the evolution of the biodegradability of natural organic matter during ozonation. To achieve this objective, four series of tests were conducted on the effluents of one of the sand–anthracite filters at the Ste-Rose plant (City of Laval, Canada). Table 1 presents the chemical characteristics of these effluents. In performing these four series of tests, each sample was divided into four portions. The first portion was not modified: this was the filter effluent water with an alkalinity of 25 mg/l CaCO 3. The alkalinity of the other three portions were adjusted to 100, 175 and 250 mg/l CaCO 3, respectively, by adding increasing quantities of sodium bicarbonate. Then, each portion was ozonated at the same ozone dose using the apparatus shown in Fig. 1. After ozonation, the UV absorbance, the alkalinity and the ozone, oxalate and BDOC concentrations were measured. Standard methods as described in APHA et al. (1992) [APHA, AWWA and WEF (1992) Standard Methods for the Examination of Water and Wastewater. Washington, D.C.] were used for alkalinity and ozone measurements. BDOC measurements were based on a modified version of the Joret and Levi method [Joret, J. C. and Lévi, Y. (1986) Méthode rapide d'évaluation du carbone éliminable des eaux par voie biologique. Trib. Cebedeau 39, 3–9; Joret, J. C., Lévi, Y., Dupin, T. and Gilbert, M. (1988) Rapid method for estimating bioeliminable organic carbon in water. AWWA 1988 Annual Conference, pp. 1715–1725. Orlando, Florida.] and on the Servais Billen method [Servais, P., Anzil, A., Ventresque, C., (1989) Simple method for determination of biodegrable dissolved organic carbon in water. Appl. Environ. Microbiol. 55(10), 2732–2734.]. These tests were performed four times at one-month intervals using filter effluent from the same filter each time. An ozone dose of 0.2 mg O 3/mg DOC was used for the first series of tests. The ozone doses for the other series were 0.5, 0.8 and 1.0 mg O 3/mg DOC respectively. Table 2 indicates the average ozonation conditions. These tests gave the following principal results. In one series (fixed ozone dose and an alkalinity ranging between 25 and 250 mg/l CaCO 3), the reduction in UV absorbance increased with alkalinity. For the first series of tests, this reduction measured 40% in water whose alkalinity was 25 mg/l CaCO 3 and increased to 50% in water whose alkalinity was 250 mg/l CaCO 3. In addition, it was observed that the reduction increased from series to series (Fig. 3). This is to be expected, since the ozone dose also increased from series to series. Thus, for the last series of tests, when the ozone dose was 1.0 mg O 3/mg DOC, the reduction in UV absorbance varied between 60 and 70%. Recarbonation also affects the production of oxalate and of biodegradable dissolved organic carbon (BDOC) as shown in Figs. 4 and 5. Thus, in one series of tests, oxalate production and BDOC production increased as a function of alkalinity. When the results obtained for a sample whose alkalinity was unajusted (25 mg/l CaCO 3) are compared with those obtained for a water whose alkalinity was modified to 250 mg/l CaCO 3, increases of 56 and 46% for the oxalate and the BDOC, respectively (third series of tests) were observed. It is expected that results for these two parameters would parallel one another since oxalate is easily biodegradable. Analysis of all the results has shown (Fig. 7) that there is a linear relationship between oxalate production and BDOC production. Specific UV absorbance (SUVA), which was defined by Edzwald and van Benschoten (1990) [Edzwald, J. K. and van Benschoten, J. E. (1990) Chemical Water and Wastewater Treatment. Springer-Verlag, Berlin.] as UV absorbance/DOC is correlated with BDOC/DOC on figure 6. A similar relationship was observed by Gilbert (1987) and Gilbert (1988) [Gilbert, E. (1987) Biodegradability of ozonation products as a function of COD and DOC elimination by example of substituted aromatic substances. Wat. Res. 21, 1273–1278; Gilbert, E., (1988) Biodegradability of ozonation products as a function of COD and DOC elimination by the example of humic acids. Wat. Res. 22, 123–126.] while they were working with water containing more aromatic compounds and humic acids.

On-line gas-diffusion separation and fluorimetric detection for the determination of acid dissociable cyanide

A flow injection system with gas diffusion separation and spectrofluorimetric detection is described for the determination of acid dissociable cyanide in waters. Cyanide diffuses through a microporous PTFE membrane from an acidic donor stream into a sodium hydroxide acceptor stream. The cyanide transferred reacts with o-phthalaldehyde and glycine to form a highly fluorescent isoindole derivative. Complete recovery of cyanide was found for Zn(CN)42–, Cu(CN)32–, Cd(CN)42–, Hg(CN)42–, Hg(CN)2 and Ag(CN)2– complexes and low recovery from Ni(CN)42–. No recovery was obtained from the species that are considered as non-free cyanide producing, viz., Fe(CN)64–, Fe(CN)63– and Co(CN)63–. The sampling frequency was 10 h–1 and the detection limit was 0.5 µg l–1. The method tolerates a 40-fold excess of sulfide. The results of cyanide determination in water samples obtained with the proposed method are consistent with those obtained with APHA Method 4500 CN– I for weak acid dissociable cyanide.

Practicality of Supercritical Fluid Extraction/Ir for the Measurement of Petroleum Hydrocarbons in Aged Soil: A Comparative Study Between Two Commercial Extractors

Petroleum hydrocarbons (PHCs) were determined in two industrial soils, a refinery sandy soil and a wood preserving (clayey) soil, using supercritical CO2(SC-CO2) and IR detection (2932 cm−1). Two commercial extractors, a Dionex SEE -703 and an HP 7680A Module were used to extract the soils under various drying conditions (MgSO4/Na2SO4, 3:0, 3:1, 3:3, 1:3, 0:6) and soil water content (>2% 60 % v/w). In the case of the clayey soil, both SFE extractors produced bell-shaped recovery curves, relating extracted amounts of PHCs with MgSO4/Na2SO4 ratio, with optimal recoveries occurring when both drying agents (MgSO4/Na2SO4, 3:1) were used to dry the soil. The lowest concentrations were obtained when only Na2SO4 was used to dry the soil. For the sandy soil the variation in the extracted amounts of PHCs did not exceed 10 % with the HP extractor, however, in the case of Dionex the extracted PHCs dropped by < 65 % when using Na2SO4 and by > 35 % when using MgSO4 as drying agent. Similar bell-shaped recovery curves, relating soil water content with extracted amounts of PHCs, were also produced from the sandy soil using the Dionex extractor with optimal concentrations achieved at around 20 % H2O that reduced by as much as 50 % when the soil was either dry (< 2%) or saturated (<45 %) with water. Whereas in the case of HP extractor the variation in PHCs recovery did not exceed 10 % and extracted amounts of PHCs were similar to those obtained by standard Soxhlet techniques (EPA Methods 418.1/3450 and APHA Method # 8520).

Dead Bacillus subtilis cells for sensing biochemical oxygen demand of waters and wastewaters

Bacillus subtilis, thermally killed by exposing its vacuum-dried cells to 280 °C for 2.5 min, has been used for sensing biochemical oxygen demand (BOD) of waters and wastewaters. The BOD sensor is fabricated by covering a dissolved oxygen probe with a biofilm containing the dead cells. Good BOD sensing characteristics comparable to those shown by microbial BOD sensors are observed. The BOD 5 values of some industrial and synthetic wastewater samples measured by the present sensor compare well with the results obtained by the conventional APHA method. The dead-cell sensor can be stored at room conditions in phosphate buffer solution without BOD or nutrients even for extended periods of time when most microbial BOD sensors would require BOD and nutrient additions to sustain the living microorganisms. This study confirms that Bacillus subtilis killed by a short exposure to high temperature still retains sufficient enzymic viability and activity for biooxidation of organics and BOD sensing.

Underestimation of Fecal Coliform Counts in Shellfish-Growing Waters by the Spanish Official Method

We compared two tube fermentation methods for the enumeration of fecal coliforms in mussels: the APHA method and the Spanish official method (CP method). In the study area (Galicia, northwest Spain), the regional authorities have proposed that the CP method be adopted as standard. Results showed that the APHA method gave significantly higher counts (P < 0.01) than the CP method. The mean difference between APHA-method counts and CP-method counts was particularly high when only those samples containing less than 500 fecal coliforms per 100 g (as determined by either method) were considered. A significantly higher number of samples were classified as unacceptable (more than 300 fecal coliforms per 100 g) by the APHA method than by the CP method. These results suggest that the CP method is inappropriate for the enumeration of fecal coliforms in mussels.

Field Evaluation of Two Colorimetric Coliphage Detection Methods

Two new methods for coliphage detection, a colorimetric agar-based (CAB) method and a liquid colorimetric presence-absence (LCPA) method, were compared to the coliphage method proposed by the American Public Health Association (APHA; Standard Methods for the Examination of Water and Wastewater, 18th ed., American Public Health Association, Washington, D.C., 1992). Both new methods are based on the induction of beta-galactosidase in Escherichia coli and the release of the enzyme through a lytic cell infection. The released enzyme then cleaves a chromogenic substrate which produces a colored reaction product. Ninety split water samples from four different sources were tested. A total of 52 samples were positive by the CAB method, 52 were positive by the LCPA method, and 53 were positive by the APHA method. Results indicated that (i) the CAB and LCPA methods were as sensitive in coliphage detection as the APHA method, (ii) both the CAB and LCPA methods were easier to read and interpret than the APHA method, and (iii) the CAB method detected more coliphages in a positive sample than the APHA method in two of the four types of water sources. Importantly, the rapid and simple LCPA method was as reliable and sensitive as either of the two agar-based methods in coliphage detection.

Distribution Patterns and Seasonal Occurrence of Rhabdostyla sp. (Peritricha: Epistylididae) on Dero nivea (Oligochaeta: Naididae)

Rhabdostyla sp. preferentially infested Dero (Dero) nivea in an alkaline bog stream from June 1982 to December 1983. Rhabdostyla occurred infrequently on two other species of naidid oligochaetes but were absent from nonliving substrates, algae, macrophytes and other invertebrates. Seasonal abundance peaks of Rhabdostyla occurred in October of 1982 and September-October of 1983 coincident with abundance peaks of D. nivea. Prevalence of host infestation ranged from 7.5-100% when infestations were present. Overall mean number of Rhabdostyla, 1 SE per D. nivea, was 4.8-i-0.2; means of individual sampling periods ranged from 2.0/worm to 13.1/ worm. Up to .36 Rhabdostyla were present on individual D. nivea. Frequency distributions were significantly (P<0.05) fitted to the negative binomial; k values ranged from 0.02 to 3.22. Rhabdostyla were preferentially distributed on the anterior 20% and the posterior 30 % of their hosts presumably because food and/or oxygen availability was greater on these regions. Niche breadth values ranged from 0.107 to 0.413. Prevalence was significantly correlated to host size (P <0.001; r2 = 0.61). INTRODUCTION Peritrich protozoa are common constituents of freshwater ecosystems and are often attached to external surfaces of invertebrate metazoa such as Porifera, Coelenterata, Turbellaria, Oligochaeta, Hirudinea, Bryozoa, Mollusca, Crustacea and Insecta (Corliss, 1979; Kudo, 1966; Lust, 1950; Matthes, 1950; Stephenson, 1930). Epizoic protozoa of zooplankton have received considerable attention recently (e.g., Evans et al., 1979, 1981; Henebry and Ridgeway, 1979), yet comparatively little quantitative data have been published on epizoic protozoa associated with benthic fauna. During a study of the population dynamics of naidid oligochaetes (Smith, 1984, 1986), I observed these worms infested with the peritrich Rhabdostyla sp. and undertook a study of the host-epibiont association. Specific objectives of the study were to determine seasonal abundance patterns of Rhabdostyla, host specificity, prevalence of host infestation and distribution patterns of Rhabdostyla on worm populations and on individual hosts. MATERIALS AND METHODS The study site was a sluggish, alkaline bog stream situated within Cedarburg Bog, Ozaukee Co., Wisconsin, at lat 43 ?22 'N and long 87?59 'E. Physical and chemical parameters of the stream were measured concurrently with biological samplings using APHA (1976) methods. Smith (1984, 1986) provides a detailed list of these parameters measured over the study period. Naidid oligochaetes were collected monthly from June 1982 to March 1983 and twice monthly from April 1983 to December 1983, using four multiple-plate samplers (Weber, 1973) suspended adjacent to the stream bottom. Colonization period for the samplers was 4 weeks. Naidids were scraped from the samplers, counted and sorted alive under a dissecting microscope at 80X in the laboratory within 4 hr of collection. Worms were preserved in 70% ethanol and mounted whole in CMC-9. Confirmation of naidid species, enumeration of Rhabdostyla and location of Rhabdostyla on individual worms were accomplished using light microscopy. Size of Dero nivea was determined by counting the number of segments present in individual worms.

Population and Reproductive Dynamics of Nais communis (Oligochaeta: Naididae) from a Wisconsin Limnocrene

Population and reproductive dynamics of Nais communis were studied from August 1982 to November 1983 in an Ozaukee Co., Wisconsin, limnocrene. Population density was significantly (P 0.05) correlation of percentage of worms undergoing paratomy to environmental physico-chemical parameters and worm density. Mean aSD doubling time for the field population of N. communis was 13.57 4 13.00 days. INTRODUCTION Naidid oligochaetes are primarily freshwater organisms, although a few species can be found in brackish waters (Brinkhurst and Jamieson, 1971). Large seasonal fluctuations in density have been observed for many naidid species from a variety of habitats (e.g., Dyga and Lubyanov, 1980; Frenzel, 1981, 1983; Learner et al., 1978; Loden, 1981; McElhone, 1978). Often, a complete absence of naidids is noted during certain months (e.g., Frenzel, 1981, 1983; Learner et al., 1978; Loden, 1981). Reproduction in the Naididae is generally asexual by paratomy or fragmentation. Asexual reproduction is observed throughout the majority of the life cycle in most species (Frenzel, 1983; Learner et al., 1978; Loden, 1981; McElhone, 1978; Pfannkuche, 1979, 1981). Sexual reproduction in naidids usually takes place during a particular time of the year and can be short-lived (Frenzel, 1983; Hiltunen, 1967; Poddubnaya, 1968). The purpose of this study was to examine the population and reproductive dynamics of Nais communis Piguet from a Wisconsin limnocrene, a spring discharging into a small basin which overflows into a stream channel. Furthermore, several abiotic and biotic parameters were correlated in an attempt to characterize and quantify the intrinsic and extrinsic factors regulating N. communis population and reproductive parameters. MATERIALS AND METHODS The study site was located between 43?20' and 42?25'N, 87057'30 and 88?30E in the township of Saukville, Ozaukee Co. (Ti iN, R2 1 E), Wisconsin. The limnocrene was roughly circular with a diam of approximately 5 m and a maximum depth of approximately 1.5 m. Physico-chemical parameters of the study site were measured immediately prior to collection of oligochaetes using APHA (1976) methods. Organic content of the substratum was estimated based on volatile matter. Four samples were collected from September 1982-September 1983 at 4-month intervals. Six replicates were measured in each collection by placing substratum in a crucible, drying at 100 C and weighing. These samples were then ashed in a muffle furnace at 600 C, cooled and weighed. The difference between dry weight and ashed weight was volatile matter (Lind, 1979). Naidid oligochaetes were sampled monthly from August 1982-April 1983 and twice monthly from May 1983-November 1983. Naidids were found only among the large floating mats of Spirogyra (Chlorophyta) which covered most of the limnocrene. Spirogyra was present during all months except February and March; hence, naidids were not

Quantitative Estimation of Fecal Coliforms in Fresh and Frozen Fishery Products by APHA and Modified A-1 Procedures

Fresh, frozen and breaded fish were analyzed for fecal coliforms by the modified A-1 (A-1 M) and APHA procedures. The A-1M method produced significantly lower numbers of fecal coliforms. The lower values derived by the A-1M procedure were attributed to the inhibiting effect of sample sediment on gas formation in fermentation tubes. By altering the A-1M technique, estimates comparable to those produced by the presently used APHA method were obtained. Changes consisted of an increase in incubation time at 44.5°C and/or elevating gas vials in the culture tubes.

On Turbidity and Transmittance Grade Tests for Water Analysis. III : Standardization of the Standard Kaolin Suspension and Alteration of the Transmittance Grade Meter.

In the examination of water, the standard of turbidity is the kaolin suspension of 1 g/L in Japan officially. In this method, the coefficient of variation is about 28% in intensity of turbidity of standard suspension prepared from various kaolin articles of commerce, and is about 8%, prepared from purified kaolin obtained through the sedimentation method (reference to report I). In the method that kaolin suspension is standardized by transmissible light path length in the standard turbidimeter based on"the standard methods for the examination of water and waste water of APHA" the coefficient of variation is about 3.9% in intensity of turbidity of standard suspension standardized. This standard turbidimeter is more convenient for routine works than the candle turbidimeter of"the standard methods of APHA" In stead of the standard turbidimeter, the transmittance grademeter with double cross mark is available as simple method, but in this case the coefficient of variation is about 8%. In the examination of transmittance grade of water by this transmittance grademeter with double cross mark, precision is higher than by the Japan water works association method with No. 5 type character mark.