Toxicity to Plants

Spill Disposal In treatment of spills or wastes the suppression of vapors is the first concern and the aquatic toxicity to plants, fish, and microorganisms is the second. Normal procedures for flammable Hquids should also be carried out. 

Environmental Impact of Ambient Ozone. Ozone can be toxic to plants, animals, and fish. The lethal dose, LD q, for albino mice is 3.8 ppmv for a 4-h exposure (156) the 96-h LC q for striped bass, channel catfish, and rainbow trout is 80, 30, and 9.3 ppb, respectively. Small, natural, and anthropogenic atmospheric ozone concentrations can increase the weathering and aging of materials such as plastics, paint, textiles, and mbber. For example, mbber is degraded by reaction of ozone with carbon—carbon double bonds of the mbber polymer, requiring the addition of aromatic amines as ozone scavengers (see Antioxidants Antiozonants). An ozone decomposing polymer (noXon) has been developed that destroys ozone in air or water (157). 

Although the antibacterial and antifungal activities of bialaphos and phosphinothricin were not found to be usehil, the two agents were later used as biodegradeable, relatively nonselective, postemergent herbicides. Glutamine synthetase inhibition is toxic to plants because the enzyme is key to ammonia assimilation. There is some selectivity for individual plant species as shown by the LD for bialaphos ranging from 0.125 to 8.5 kg/ha (301—303). 

Calcium is a macronutrient essential for all organisms. Chlorine is a micronutrient essential for higher (ie, seed) plants but not considered essential for mammals. Above certain levels chloride is toxic to plants and animals, thus when considering calcium chloride, potentially large concentrations of calcium ion can be tolerated, but at these concentrations the chloride ion becomes toxic. 

Plant and Animal Nutrient. Copper is one of seven micronutrients that has been identified as essential to the proper growth of plants (87). Cereal crops are by far the most affected by copper deficiency (see Wheat and other cereal grains). Greenhouse studies have shown yield increases from 38% to over 500% for wheat, barley, and oats (88) using copper supplementation. A tenfold increase in the yield of oats was reported in France (89). Symptoms of copper deficiency vary depending on species, but often it is accompanied by withering or chlorosis in the leaves that is not ammenable to iron supplementation. In high concentrations, particularly in low pH sods, copper can be toxic to plants. 

Phenazine-l-carboxamide (137) is known as oxychlororaphine and has been isolated from cultures of Pseudomonas chlororaphisit has some limited inhibitory properties, but the inhibitory action of phenazines is generally disappointing. Some phenazine derivatives have insecticidal properties thus, phenazine itself has been found to be toxic to the clothes moth, the Hawaiian beet webworm, the rice weevil and larva of the codling moth, but under trial conditions its toxicity to plant material, as evidenced by severe burning of foliage, was found to be too high to make it of practical value. 

Terrestrial toxicity (to plants, earthworms, bees, birds)... 

Fatty Acids and Lipids Although several fatty acids, esters and alcohols are known to be toxic to plant growth, their role in allelopathy is not fully investigated (3). Dihydroxystearic acid (3, 49) is the classic example known to exhibit allelopathic activity. 

Thus it is significant that for such si/m-triazine herbicides as simazine, atrazine, etc., the health and hygiene MPC (toxicity to warm-blooded animals, including humans) and phytotoxic MPC (toxicity to plants) differ by more than an order of magnitude 0.2-0.5 mg/kg for warm-blooded animals, and 0.01 mg/ kg for plants [89]. Warm-blooded animals and arthropods have a difference in sensitivity to many pyretroids that can reach tens of thousands of times [90]. 

These acidic waters are toxic to plant and animal life, including fish and aquatic insects. Streams affected by acid drainage may be rendered nearly lifeless, their stream beds coated with unsightly yellow and red precipitates of oxy-hydroxide minerals. In some cases, the heavy metals in acid drainage threaten water supplies and irrigation projects. 

Heavy metals in the environment, especially their accumulation in soils, is a serious environmental problem which the whole world faces (Du et al. 2005). The farmland soils are an important media of the ecological cycle of Cadmium, and its harm to human health can t be neglected (Wu et al. 2004). Heavy metal migration, transformation and toxicity to plants in soil are directly influenced by the quantity proportions of various forms (Zhu et al. 2002). The toxicity of water-extractable and adsorbed and exchangeable metals are the greatest, and residual metals is the lowest (Liu etal. 2002). Different forms have different bioavailability thus their influences on the environment and human health are different. It is critical to have a good understanding of Cadmium forms in soil. This paper describes the Cadmium forms in the acid soils of eastern China. 

High concentrations of KNO3 are relatively toxic to plant growth because the ratio of K+ to Na+ is too high, and so the soil is not fertile. 

Boron and arsenic are natural components of soil and are both present as oxyanions. Boron is present as boric acid or borate polymers, and arsenic is present as arsenate. While boron is weakly held by soil, arsenic is similar to phosphate in its interactions with soil constituents. Boron is an essential nutrient for plants however, it is also toxic to plants at relatively low levels. Arsenic is toxic. The laboratory chemistry of both of these elements is well understood, but their environmental chemistry, speciation and movement, is less well understood [23-27],... 

Of particular concern in this analysis is sodium because it destroys soil structure, is associated with increased soil pH, and can be toxic to plants. Sodium can easily be determined by atomic absorption spectroscopy (AAS), flame ionization spectroscopy (FIS), and inductively coupled plasma (ICP) methods. Soil structure is discussed in Chapter 2 and the various spectroscopic methods discussed in Chapter 14. 

Further adsorption/desorption study 14-day earthworm toxicity Study of the effects on soil microorganisms Short-term toxicity to plants... 

PAN, CH3C002N02, is an important constituent of photochemical smog, acting as an irritant to the eyes and respiratory system and being highly toxic to plants. 

The dust and fumes from the powder form of most manganese compounds, especially the oxides, are very toxic to plants, animals, and humans. Even inhaling small amounts is toxic. The powder form of manganese metal is flammable, and manganese fires cannot be extinguished with water. They must be smothered by sand or dry chemicals. 

Many types of soaps have been used to kill, dislodge or repel certain garden pests. They vary greatly in effectiveness and in toxicity to plants. They are frequently effective against thrips and other small, soft-bodied insects such as aphids, mealybugs and whiteflies. Their disadvantages are that they are expensive and they need to be reapplied frequently, possibly every three or four days. 

Carbosulfan, CGA-73,102, and ONCOL are derivatives of carbofuran (2,3-dihydr0-2,2-dimethylbenzofuran-7-yl methylcarbamate) which have broad spectrum activity similar to that of carbofuran but are substantially less toxic to mammals. CGA-73,102 is particularly effective as a soil insecticide by both contact and systemic action (9). Thiodicarb (10) and U-56,299 (11) are highly effective lepidopterous larvicides but are less toxic to plants and mammals than me thorny 1. U-56,299, with a rat acute... 

Manganese Mining, industrial wastes Toxic to plants in high concentrations None established... 

The presence of iron in vegetable ash has been known since the beginning of the eighteenth century. Although iron is not a constituent of the chlorophyll molecule, a plant grown in a culture medium entirely free from it produces no chlorophyll. According to Roscoe W. Thatcher, plants take iron from the soil in the smallest proportion of any of the essential elements. Since ferrous compounds are toxic to plants, only the soluble ferric compounds can be utilized (195). 

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