Short chain chlorinated paraffins (SCCPs) are complex mixtures of polychlorinated n-alkanes, shown to bioaccumulate but with unknown effects in wild birds. The present study examined development-related effects of SCCPs on captive American kestrels (Falco sparverius) treated in ovo on embryonic day (ED) 5 by injection with technical Chloroparaffin® (C_10-13, 55.5% Cl) at environmentally relevant nominal (measured) concentrations of 10 (10), 50 (29) or 100 (97) ng ΣSCCP/g egg ww, and artificially incubated until hatching (ED27–ED29). The SCCP concentrations measured in the yolk sacs of the hatchling kestrels bracketed concentrations reported in the eggs of wild birds. Uptake and deposition of these SCCPs differed between male and female hatchlings, with only males showing differences in SCCP concentrations, being highest in the high-dose males than each of the other male groups. Embryonic exposure to SCCPs suppressed glandular total thyroxine (TT4) (20–33%) and reduced circulating triiodothyronine (TT3) (37–40%) in male hatchlings only when compared to control males, but had no effect on glandular TT3 or circulating TT4 in male or female kestrels. Histological assessments of thyroid glands showed that both sexes experienced significant structural changes indicative of gland activation. These thyroid glandular changes and the variations in SCCP concentrations were related to circulating TT3 in female hatchlings. Hepatic deiodinase enzyme (D1, D2) activities were stable and no SCCP-related changes were observed in hatching success, hatchling size, or immune organ size. However, several of the thyroid function indicators were correlated with hatchling size and smaller bursas and spleens, possibly indirectly through SCCP-induced changes in thyroid function. Because changes in thyroid function were evident at concentrations measured in wild bird eggs, similar changes may occur in wild nestlings. The potential impact of these changes on thyroid-mediated growth and survival in wild birds requires further investigation.

短链氯化石蜡（SCCP ）是多氯正构烷烃的复杂混合物，显示出生物蓄积性，但对野生鸟类的影响未知。本研究检查了短链氯化石蜡对在胚胎天（ED）5卵内注射技术性Chloroparaffin®（C _10-13）进行卵处理的圈养美洲k（Falco sparverius）的发育相关影响。在环境相关的标称（测量）浓度为10（10），50（29）或100（97）ngΣSCCP/ g鸡蛋当量时，浓度为55.5％Cl），并人工孵育直至孵化（ED27-ED29）。在孵化的茶the的卵黄囊中测得的短链氯化石蜡浓度是在野生鸟类卵中报道的括号内浓度。雄性和雌性幼体对这些短链氯化石蜡的吸收和沉积情况有所不同，只有雄性显示出短链氯化石蜡的浓度差异，大剂量雄性中的雄性最高，高于其他雄性组。胚胎暴露于短链氯化石蜡时，与对照雄性相比，仅在雄性孵化中抑制了腺总甲状腺素（TT4）（20–33％）并降低了循环三碘甲状腺素（TT3）（37–40％），但对腺体TT3或循环TT4没有影响在男性或女性的茶est中。甲状腺的组织学评估表明，两性都经历了表明腺体活化的显着结构变化。这些甲状腺变化和SCCP浓度的变化与女性孵化中的循环TT3有关。肝脱碘酶（D1，D2）活性稳定，在孵化成功率，孵化大小或免疫器官大小方面未观察到与SCCP相关的变化。但是，一些甲状腺功能指标与孵化的大小以及较小的囊和脾脏相关，可能是通过SCCP诱导的甲状腺功能变化间接引起的。因为在野禽卵中检测到的浓度下，甲状腺功能的变化是明显的，所以在野雏中也会发生类似的变化。