Immunity in children with exposure to environmental lead: II. Effects on humoral immunity

Lead has been found to depress the immune system in animal studies at levels far below those responsible for overt toxicity. Literature studies in animal systems most clearly showed an effect of lead on response to a specific immunogenic stimulus. Data are sparse concerning the effects of lead on the immune system in the human population at greatest risk for exposure-children up to six years of age. This portion of the Phase I study reports concentrations of IgG, IgM, IgA, and IgE, as well as antibody titers to the specific antigenic stimuli provided by the vaccines against diphtheria, tetanus, and Rubella. The study population consisted of a group of 193 children, ages 9 months to 6 years, who participate in the WIC (Women, Infants and Children) and Lead Poisoning Prevention Programs in the urban area of Springfield-Greene County Missouri. Blood lead levels ranged from 1 to 50 g dL^–1. Total Ig levels were determined and the data were analysed. No consistent significant differences were observed among the risk categories in the five age groups examined. A single Ig class in each of three age groups showed apparent significant differences among the various risk categories, but these differences were not correlated with blood lead. An analysis of specific antibody titers to diphtheria, tetanus, and Rubella was performed. Regression analyses of current data in Phase I of this study suggest a detrimental effect of lead on the antibody titres to diphtheria and Rubella.     

Declines in organochlorines in eggs of red-breasted mergansers from Lake Michigan, 1977–1978 versus 1990

From 1977–1978 to 1990, concentrations of polychlorinated biphenyls (PCBs) and most organochlorine pesticides declined in eggs of red-breasted mergansers (Mergus serrator) nesting on islands in northwestern Lake Michigan. Total PCBs decreased 60% (from 21 ppm in 1977–1978 to 8.5 ppm in 1990) and p,p-DDE decreased 66% (from 6.5 to 2.2 ppm). Dieldrin decreased only 16% (from 0.82 to 0.69 ppm). In 1990, 79.1% of incubated eggs hatched, which was not significantly different from the 83.5% that hatched in 1977–1978.The U.S. Government right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged.     

Book reviews

Cost Benefit Analysis of Environmental Change

Per‐Olov Johansson

Cambridge, Cambridge University Press, 1993, 232 pp., £13.95

Computerised Environmental Modelling: A Practical Introduction using Excel

J. Hardisty, D. M. Taylor & S. E. Metcalfe

Chichester, Wiley, 1993, 204 pp., £14.95

Keeping Pace with Science and Engineering: Case Studies in Environmental Regulation

Washington DC, US National Academy of Engineering, 1993

World Without End: Economics, Environment and Sustainable Development

D. W. Pearce & J. J. Warford

Oxford University Press, New York, 1993, 440 pp., £35.95     

Growth and development of cellular slime mould Dictyostelium discoideum treated with DDT

The effects of dichlorodiphenyl trichloroethane (DDT) on the growth, phagocytic activity, ultrastructure and developmental stages of a well known species of the cellular slime mould, Dictyostelium discoideum were studied. DDT, at doses of 60 ppm and above, inhibited growth of the vegetative cells and this was also evident from the colony blots which were smaller in size. A dose-dependent inhibition occurred in the phagocytic activity and macromolecular syntheses of DDT-treated cells. The cytomorphology of growing Dictyostelium cells, as revealed under light and electron microscopes, was profoundly affected by DDT treatment. Further, a considerable delay occurred in the various morphogenetic events in the slime mould cells exposed to DDT.     

Association between the mollusc bivalve Loripes lucinalis and a Chlamydia-like organism,with comments on its pathogenic impact,life cycle and possible mode of transmission

Loripes lucinalis is a littoral bivalve which has already been confirmed to harbour endo-cellular sulfur-oxidizing bacteria within its gills. Examination of the digestive gland of L. lucinalis collected from the Moulin Blanc Beach in the Bay of Brest (Brittany, France) revealed the existence of an additional association involving a Chlamydia-like organism. Three different forms of Chlamydia-like bacteria were observed: reticulate rod-shaped cells, electron-dense cells and enlarged cells. The reticulate rod-shaped cells and the electron-dense bodies are thought to represent the germinal initial body and infectious form of the bacteria, respectively. The enlarged cells were always associated with what are believed to be spherical or icosahedral phages. Initial infestation seems to occur by phagocytosis at the apical pole of the digestive cells of the tubule and duct epithelia. Within the host cell, the bacteria undergo binary fission and budding, forming an inclusion which gradually fills up the cell. Inclusions are generally between 15 and 30 m in size, and > 85% of all individuals examined possessed inclusion bodies. The level of infestation varied between individuals, some being heavily colonized, but did not seem to be related to season. Histological and ultrastructural observations suggest that, once developed, the colony has three possible fates: (1) the cells will degenerate due to phage infection; (2) colony overcrowding will occur, causing the development of electron-dense bodies that will be released into the lumen; (3) the entire membrane-bound inclusion will be released into the lumen and subsequently into the pallial cavity. Inclusions within the pallial cavity may be ingested by the host or may even be phagocytized by bacteriocyte cells of the gill. It is proposed that this association could be a form of symbiosis and that L. lucinalis may, therefore, be a rare example of an organism adapted to harbour two very different symbioses.     

Comparison of allozyme and mitochondrial DNA spatial differentiation in the limpet Patella vulgata

Allozyme and restriction enzyme analysis of mtDNA was used to study variation in samples from British populations of the marine limpet Patella vulgata in two regions. South Wales and Northeast England. Allozyme analysis revealed significant differences in allele frequencies among samples. However F _ST (population differentiation) values were no higher between than within regions, indicating that genetic heterogeneity was localised and not related to geographic separation. For mtDNA, samples from South Wales exhibited higher haplotype diversity values than samples from Northeast England. In addition there were substantial differences in the haplotype distribution between regions. The value of , the haploid analogoue of F _ST , was low within regions (=0.09) but high between regions (=0.44). The estimated difference in migration rate for allozymes and mtDNA exceed the neutral expectation, unless it is assumed that there are influential differences in the magnitude of female and male gametic dispersal.     

Induction of metamorphosis in larvae of the oyster Crassostrea gigas using neuroactive compounds

Chemical (neuroactive compounds at different concentrations and exposure times) and physical (water agitation, light) factors with potential effects on the metamorphosis of larvae of the oyster Crassostrea gigas (Thunberg) larvae have been studied. The neurotransmitters l-dihydroxyphenylalanine (DO), epinephrine (EP), norepinephrine (NE), and acetylcholine (AC) have been identified as very active inducers of metamorphosis, whilst serotonin (SE), dopamine (DA) and potassium (K) were less effective inducers. The -aminobutyric acid (GA) and ammonium (AM) were found ineffective at the concentrations tested. Exposure to 10^-4 M EP for 15 min was sufficient to promote >80% metamorphosis within 48 h, whereas NE required 2 h to exert comparable induction. Maximum induction by DO (>50%) was achieved after 2 h exposure to 10^-4 M. However, unlike EP and NE, DO was lethal at that concentration in the long term. Maximum induction by AC (30% metamorphosis) was achieved at a concentration of 10^-4 M. In contrast to other neurotransmitters, AC induced settlement behaviour, cementation and eventual metamorphosis, yielding postlarvae which were all attached to the substratum. EP and NE triggered the morphogenetic changes, by-passing settlement and leading to postlarvae not cemented to the substratum. DO induced mostly attached spat at low concentrations (10^-5 M) and unattached spat at high concentrations (10^-4 M), and a similar pattern was apparent for the weaker inducers SE and DA. Regarding physical factors, a highly reflectant surface significantly increased the percentage of attached spat obtained, compared to a dark bottom. No consistent effect of water current or light was detected on the production of unattached spat. The three different forms of induction are discussed in relation to different regulatory pathways of settlement and metamorphosis.     

Effects of acid rain on growth and nutrient concentrations in Scots pine and Norway spruce seedlings grown in a nutrient-rich soil

The effects of artificially applied acid precipitation on growth and nutrient concentrations of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst.) seedlings were investigated in a long-term acid irrigation experiment in field conditions. Seedlings of northern and southern origin were planted in boxes containing peat and composted soil rich in nutrients, and sprinkler irrigated with water acidified with nitric and sulphuric acids to pH 3 or pH 4 for periods varying from two to three and a half growing seasons during 1986-1989. Water irrigated (pH 5.4-7.6) and non-irrigated groups of seedlings were also included in the experiment. At the end of the experiment needles, main and lateral shoots and roots were collected from the seedlings for the determination of height growth and biomass partitioning, and for the analysis of S, N, Mg, P, K, Ca, Mn and Fe concentrations. The treatment effects compared to the irrigated control were studied using multivariate analyses of variance and covariance. In the pine seedlings the total dry matter production increased by 25-70% compared with the irrigated controls when the total wet deposition to the seedlings exceeded 67 kg S ha(-1) and 36 kg N ha(-1) (e.g. after two growing seasons' exposure of the pH 3 treatment). The increase was mainly due to an increase in needle dry weight (54-72% greater at pH 3) and root weight (20-65% greater at pH 3), whereas the height growth or shoot weight growth were less affected. The northern provenance pine seedlings responded more clearly to the pH 3 irrigation than the southern ones. The treatments had no consistent effects on any of the growth variables studied in the spruce seedlings, however. The pines had higher root and foliage Ca concentrations as a result of the acid irrigation, whereas in spruce, acid rain decreased the Ca concentration in needles and shoots. Root Mn and Fe concentrations were higher in both species as a result of the pH 3 treatment. A higher soil conductivity and Ca concentration resulted from the prolonged pH 3 treatment. The results strongly support the hypothesis that the long-term growth and nutrient allocation response of conifers to acid precipitation is dependent both on the tree species and on the nutritional status of the soil.     

Interactions between copper and cadmium modify metal organ distribution in mature tilapia, Oreochromis mossambicus

Sexually mature female tilapia were exposed to sublethal concentrations of waterborne Cu and/or Cd over 6 days, and subsequent body concentrations of these metals were determined in several organs. The results show that the distribution of Cu and Cd was metal and organ specific. This is demonstrated, for example, by the observation that in tilapia, Cu exposure did not result in Cu accumulation in the liver, whereas in the intestinal wall, notably high concentrations of Cu and Cd were measured in metal exposed fish. In addition to single metal exposed fish, we also determined Cu and Cd body distribution in Cu?Cd co-exposed fish. The observed interactions in metal accumulation were most pronounced in the organs of fish exposed to low, environmentally realistic, metal concentrations.     

Estimation of volatile organic compounds in Kuwaiti houses after the Gulf war

Interest in indoor air quality is steadily increasing. Exposure to volatile organic compounds (VOCs) is associated with health effects as diverse as childhood respiratory disease, lung cancer and cardiovascular disease. In an effort to assess the environmental impact indoors from possible sources of VOCs, such as (i) open oil lakes, (ii) chemical and petrochemical industries and (iii) indoor pollution from household items, concentrations of aliphatic and aromatic VOCs, comprising n-hexane to n-hexadecane, benzene, toluene, xylene, ethyl benzene, methanol and o-dichlorobenzene, were measured in indoor air samples from seven different cities in Kuwait using a gas chromatograph. The data for the period March to May 1993 are presented. The VOCs, as measured, were surprisingly low and they are below the concentrations set by the American Hygienists Association. However, although the concentration of the estimated VOCs being low, were cumulative effects of them entering the human body and water sources cannot be ruled out.