Synthesis and Safety Evaluation of a New Enteric Coating Material

2011 ◽  
Vol 266 ◽  
pp. 157-160
Author(s):  
Xiao Lin Lai ◽  
Hua Jiang Deng ◽  
Zong Hua Wang ◽  
Jian Hua Guo
Keyword(s):  
Acute Toxicity ◽  
Model Compound ◽  
Safety Evaluation ◽  
Coating Material ◽  
Toxicity Tests ◽  
Enteric Coating ◽  
Coating Materials ◽  
Catalyst Amount ◽  
Acute Toxicity Tests ◽  
Molar Percent

A series of styrene-maleic anhydride (SMA)-ethanol polymers with different degree of esterification (DE) were synthesized, they had different pH-sensitive values and could be used as enteric coating materials. SMA-ethanol (DE50%) was used as the model compound to evaluate the safety as an enteric coating material, the results of acute toxicity tests showed that there was no acute toxicity. The reaction condition such as catalysts, catalyst amount, reaction time and temperature were also evaluated, the results indicated that the triethylamine (TEA) was the optimal catalyst, when methyl ethyl ketone (MEK) was the solvent, the catalyst amount was 15-20%(molar percent), the reaction at 80 OC for 8h could gain the highest conversation.

Acute Toxicity Testing with Juvenile White Sturgeon (Acipenser transmontanus)

1998 ◽  
Vol 33 (1) ◽  
pp. 95-110 ◽  
Author(s):  
W.R. Bennett ◽  
A.P. Farrell
Keyword(s):  
Acute Toxicity ◽  
Swimming Performance ◽  
Juvenile Fish ◽  
Toxicity Testing ◽  
White Sturgeon ◽  
Acipenser Transmontanus ◽  
Toxicity Tests ◽  
Fraser River ◽  
Acute Toxicity Tests ◽  
Acute Toxicity Testing

Abstract The primary goal of this study was to investigate the possibility of using early life stages of white sturgeon (Acipenser transmontanus) (eggs, larvae and fry) as a species relevant to the Fraser River, B.C., for the acute and sublethal toxico-logical testing of forest industry effluents. Here we report the first successful acute toxicity tests for 8-day-old larvae and 42-day-old fry exposed to several chemicals known to be released into the Fraser River (i.e., 6 monochlorovanillin [6 MVAN], 4,5 dichloroguaiacol [4,5 DCG], 4,5 dichlorocatechol [4,5 DCAT], pentachlorophenol [PCP], and didecyldimethylammonium chloride [DDAC]). In most cases, white sturgeon fry were at the lower end of the range for acute toxicity values for chlorinated phenolic compounds, when compared with other juvenile fish species, and they were extremely sensitive to DDAC. The larval stage was usually more sensitive than the fry stage. Acute toxicity tests with fertilized eggs were unsuccessful. A postexposure growth study was inconclusive because neither control nor toxicant-exposed larvae and fry withstood the additional handling used for measuring body mass. At 62-days-old, fry were more tolerant of handling. This allowed measurement of their swimming performance. Although we have concerns about the reliability of using larvae for acute toxicity testing at this time, 60-day-old white sturgeon fry would appear to be both a sensitive and relevant species for assessing environmental impacts relevant to the Fraser River.

Post-treatment of sanitary landfill leachate by coagulation–flocculation using chitosan as primary coagulant

2016 ◽  
Vol 74 (1) ◽  
pp. 246-255 ◽  
Author(s):  
Inara Oliveira do Carmo Nascimento ◽  
Ana Rosa Pinto Guedes ◽  
Louisa Wessels Perelo ◽  
Luciano Matos Queiroz
Keyword(s):  
Acute Toxicity ◽  
Removal Efficiency ◽  
Landfill Leachate ◽  
Post Treatment ◽  
Toxicity Tests ◽  
Process Conditions ◽  
Sanitary Landfill ◽  
Average Growth ◽  
Acute Toxicity Tests ◽  
Sanitary Landfill Leachate

Chitosan was chosen as an alternative primary coagulant in a complementary coagulation–flocculation treatment of sanitary landfill leachate with the aim of removing recalcitrant organic matter. In order to optimize the process conditions, central composite design and response surface methodology were applied. To evaluate the performance of the process using chitosan, we also carried out tests with aluminium sulphate (Al2 (SO4)3.14 H2O) as coagulant. In addition, acute toxicity tests were carried using the duckweed Lemna minor and the guppy fish Poecilia reticulata as test organisms. The analytic hierarchy process was employed for selecting the most appropriate coagulant. Mean values of true colour removal efficiency of 80% and turbidity removal efficiency of 91.4% were reached at chitosan dosages of 960 mg L−1 at pH 8.5. The acute toxicity tests showed that organisms were sensitive to all samples, mainly after coagulation–flocculation using chitosan. CE50 for L. minor was not determined because there was no inhibition of the average growth rate and biomass production; LC50 for P. reticulata was 23% (v v−1). Multi-criteria analysis showed that alum was the most appropriate coagulant. Therefore, chitosan as primary coagulant was not considered to be a viable alternative in the post-treatment of landfill leachate.

scholarly journals Nano-sized zeolites as modulators of thiacloprid toxicity onChironomus riparius

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3525 ◽  
Author(s):  
Carla S. Lorenz ◽  
Anna-Jorina Wicht ◽  
Leyla Guluzada ◽  
Barbara Crone ◽  
Uwe Karst ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Imaging Techniques ◽  
Toxicity Tests ◽  
Biting Midge ◽  
Ms Imaging ◽  
Icp Ms ◽  
Small Primary ◽  
Acute Toxicity Tests ◽  
Investigation Period ◽  
Adsorption Rates

This study investigated whether zeolites of different size (Y30 (nano-sized) and H-Beta(OH)-III (forming large aggregates/agglomerates composed of 50 nm small primary particles)) exerted acute toxicity on larvae of the non-biting midge,Chironomus riparius, and whether such zeolites are able to modulate the toxicity of a common insecticide, thiacloprid, by means of adsorption of a dissolved toxicant. We conducted acute toxicity tests with fourth instar larvae ofC. riparius. In these tests, larvae were exposed to zeolites or thiacloprid solely, or to mixtures of both compounds. The mixtures comprised 1.0 µg/L thiacloprid in addition to low (5.2 mg/L), medium (18.2 mg/L), and high (391.7 mg/L) zeolite concentrations, resulting in different adsorption rates of thiacloprid. As biological endpoints, changes in mortality rates and in behavior were monitored every 24 h over a total investigation period of 96 h. Furthermore, we conducted chemical analyses of thiacloprid in the medium and the larvae and located the zeolite particles within the larvae by LA-ICP-MS imaging techniques. Our results demonstrate that both types of zeolites did not exert acute toxicity when applied as single-substances, but led to reduced acute toxicity of thiacloprid when applied together with thiacloprid. These results are in line with the sorption properties of zeolites indicating reduced bioavailability of thiacloprid, although our data indicate that thiacloprid can desorb from zeolites to some extent. While freely dissolved (i.e., non-sorbed) fraction of thiacloprid was a good parameter to roughly estimate toxic effects, it did not correlate with measured internal thiacloprid concentrations. Moreover, it was shown that both zeolite types were ingested by the larvae, but no indication for cellular uptake of them was found.

Acute Toxicity of Copper, Cadmium, and zinc to Larvae of the Crab Paragrapus quadridentatus (H. Milne Edwards), and Implications for Water Quality Criteria

1978 ◽  
Vol 29 (1) ◽  
pp. 1 ◽  
Author(s):  
M Ahsanullah ◽  
GH Arnott
Keyword(s):  
Water Quality ◽  
Heavy Metal ◽  
Acute Toxicity ◽  
Metal Toxicity ◽  
Quality Criteria ◽  
Toxicity Tests ◽  
Water Quality Criteria ◽  
Minimal Risk ◽  
Larval Stages ◽  
Acute Toxicity Tests

Acute toxicity tests were carried out on the larvae of P. quadridentatus and 96-h LC50 values of 0.17, 0.49, and 1.23 mg/l were determined for copper, cadmium, and zinc respectively. Potency ratios of the three metals were as follows: Cu/Cd 3.1, Cu/Zn 7.2, and Cd/Zn 2.4. Larvae were found to be nine times more sensitive to zinc and at least 29 times more sensitive to cadmium than were adults. The larval 96-h LC50 values multiplied by an application factor of 0.01 (as recommended in Victorian water quality criteria) results in derived 'safe' concentrations, which in the case of copper and zinc are below the stated 'minimal risk concentrations' of 10 and 20 �g/I respectively. In view of the known greater sensitivity of larvae of many taxa to heavy metal toxicity, the validity of using the same application factor for both adult and larval stages is questioned.

Acute toxicity tests on three species of the genus Lecane (Rotifera: Monogononta)

Rotifera IX ◽  
2001 ◽  
pp. 375-381
Author(s):  
Ignacio Alejandro Pérez-Legaspi ◽  
Roberto Rico-Martínez
Keyword(s):  
Acute Toxicity ◽  
Toxicity Tests ◽  
Acute Toxicity Tests

The laboratory estimation of the biological effects of organic pollutants

1975 ◽  
Vol 189 (1096) ◽  
pp. 459-477 ◽  
Keyword(s):  
Acute Toxicity ◽  
Organic Pollutants ◽  
Biological Effects ◽  
Well Being ◽  
Toxicity Tests ◽  
Test Organisms ◽  
Acute Toxicity Tests ◽  
Animal Community ◽  
Measured Response

The laboratory estimation of the toxic effects of organic pollutants relies on successive investigations of increasing sensitivity. Acute toxicity tests are useful in providing an index of relative toxicity between compounds but are of limited value for making ecological predictions. Many factors can influence the assessment of acute toxicity, with chemical stability of the test solutions and the species of test organisms employed being perhaps the most important of these. Many sub-lethal tests are also of limited value because the importance of the measured response for the well-being of the animal community as a whole is not established. The basic requirements of sub-lethal techniques are discussed, especially in relation to compounds which may exert their toxic action through accumulation in the tissues in the long term. The possibility of relating the toxicity of a compound to its chemical structure is considered.

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